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Flows of social support and health status among older persons in China
Soc. Sci. Med. Vol. 41, No. 8, pp. 1175-1184, 1995
Pergamon
0277-9536(94)00427-7
Copyright © 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0277-9536/95 $9.50 + 0.00
FLOWS OF SOCIAL SUPPORT AND HEALTH STATUS AMONG OLDER PERSONS IN CHINA XIAN LIU, l* JERSEY LIANG 1 and SHENGZU GU ~ qnstitute of Gerontology, The University of Michigan, 300 North Ingalls, Ann Arbor, MI 48109-2007 U.S.A. and 2Institute of Population Research, Wuhan University, People's Republic of China Abstract--As a consequence of the political, social, and economic developments in contemporary China, there have been considerable changes in the patterns of flows of social support between Chinese older people and their significant others. There is evidence that Chinese elders are now under strong pressure to provide more social support, instrumental support in particular, to their children and other relatives while they receive less. Such a change in the direction of flows of social support has been reported to worsen the elders' health. This paper describes the general pattern of social support both to and from the Chinese elders, using data of a probability sample survey conducted in Wuhan, China in 1991. The association between social support, both receiving and providing, and old-age health status is also analysed within a multivariate framework. The results of two probit models suggest that emotional support received plays a crucial role in affecting an elder's health status, while instrumental support received does not have explicit impacts. In addition, there is no empirical evidence that increased instrumental support from elders has worsened their health status as reported. Key words
social support, health status, China, older people
INTRODUCTION
A considerable body of research on old-age social support has been devoted to its linkages with health status [1, 2]. Early findings that stronger social support received by an elder was associated with decreased risks to both death and morbidity [3, 4] have prompted the development of a wide array of empirical models to test the validity of such hypothetical causality, both cross-sectionally and longitudinally [5-12]. Although they have consistently revealed the negative relationships, either directly or indirectly, between social support and the risks to death and health status, these empirical research studies have been limited to the developed world. Ascertaining the causal linkages between social support and health status among older persons in China poses special importance given that the vast majority of the Chinese elderly population do not have access to health insurance of any kind and the family still serves as the primary source to provide old-age support [13]. Traditionally, the essentiality of old-age support was deeply embedded in the Chinese culture, which fostered the establishment of an intrafamilial patriarchal and hierarchical system [14--16]. Specifically, parents had the obligation to raise their children in all important ways, including providing them with spouses and some inheritance; and when their physical ability deteriorated with age, the balance of support flowed increasingly from the younger to the older generations [17]. After the parents *Author for correspondence.
reached a certain age, the children, sons in particular, were obligated to show them respect and filial piety, and provide them with various necessities, with the seniors still controlling substantial assets and having the power of ruling the family [14, 18]. Such an inter-generational relationship continued to be seen as mutually beneficial and rewarding; and on the elders' part, they could benefit from receiving incessant flows of social support, even if they were disabled [19, 20]. Since the founding of the People's Republic in 1949, the pattern of the intra-familial support system in China has gradually altered. Although for the elders the extensive welfare dependence on their children is still common in China [19], the flows of old-age support are no longer dominantly onedirectional. There is evidence that the Chinese elders are now under strong pressure to provide more social support, instrumental support in particular, to their children and other younger relatives while they receive less [15, 16,20, 21]. While many argue that such changes may be rooted in the political economy socialism that has weakened the patriarchal power with the high degree of socialization exercised over the Chinese families [22], some suggest that social change per se may also contribute substantially to this phenomenon. Whyte and Parish [16], for example, indicate that without the help provided by the elders, the burden of household chores may weigh too heavily on a working couple. Whatever has caused the reversal of old-age social support in China, an important theoretical concern should be advanced promptly: do these changes
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worsen the elders' health? There are reports that reduction in old-age support received, and the increase in that provided, have both ushered in the worsening of health status among Chinese elders [15, 21]. To date, however, no one has yet tested a model examining whether such reports have mirrored a universal phenomenon, or they have just reflected some accidental cases. Explicating the relationship between social support and health status among Chinese elderly persons will provide intuitive implications in this regard. While previous research in developed societies has concentrated on the onedirectional flows, it is imperative to involve social support both to and from elderly persons within the context of contemporary China. The way of assessing social support is also of theoretical concern with specific regard to Chinese older folks. Social gerontologists have viewed social support as reflecting the quality of the functional contents of social relationships and, accordingly, have classified it into two primary dimensions-emotional social support and instrumental social support [6, 23]. In analyzing the relationship between social support and old-age health, emotional support has often been found to be crucial [6, 10, 12]. A closer probe into the circumstances in China, however, suggests caution in applying the same measurement to Chinese elders. First, whether a given type of social support has impact on health status depends highly on its need. According to Masiow's Need Hierarchy Theory [24], the dominance of a higher need would not take place before a specific need is satisfied. Considering that the vast majority of Chinese elderly persons lived long with a deficiency of physiological or security needs, would a lack of love or respect worsen their health? Second, Chinese elderly persons are survivors from numerous calamities in previous decades such as wars, famines, and formidable political struggles. Being so uniquely selected, are Chinese older folks still concerned more about the quality of emotional support than about that of instrumental, or material, support? Third, different from the U.S. and other developed countries that are highly individual centered, contemporary China is a collectivism-oriented society with greatly reduced privacy, emotional dependence on organizations and institutions, and a belief in the superiority of group over individual decisions [25]. Given these characteristics, would the importance of the intra-familial emotional support be warranted for Chinese elders? While negative associations between both emotional and instrumental supports and old-age health status have been observed [15,26], there have been no systematic attempts to gauge the reliability of such reports. It has also been reported that Chinese rural elders received less but provided more support than their urban counterparts, while the distribution of their health status was fairly close to that of the urban [21]. Does this imply that social support, both received
and given, has weaker impacts on health status among rural elders? Identifying such areal differentials will be of special importance to both planners and researchers since a vast majority of Chinese older people reside in the rural areas. This article estimates a model of social support and health status to test: (1) the relationships between social support both to and from Chinese elders and their health status; (2) whether emotional support plays a crucial role in shaping such relationships; and (3) whether there are strong differentials in these linkages between the urban and the rural areas. The data used are primarily based on a probability sample survey of Chinese older adults aged 60 and over conducted in Wuhan, China in November 1991. While it serves as an exploratory analysis with the limitation of using a single set of cross-sectional data, this research is considered essential to guide dynamic analyses in the future using longitudinal data. MODEL SPECIFICATION
A theoretical framework is specified to explicate the causal linkages between social support and health status according to existing literature in this regard and relevant observations in China. Figure 1 shows the diagram. Health status is viewed as a function of social support and a number of other factors that act as control variables in the present research. As specified by previous research, we view health status as consisting of three inter-related aspects: chronic disease, functional limitation, and self-rated health. Considering the substantial correlation among these three health indicators, it is intuitive to specify their interrelations to guide the data analysis. Given that it is the most commonly used measure of general health status assessment [12, 27, 28], self-rated health is regarded as the general indicator representing health status in the present research. Chronic disease and functional status are assumed to affect directly the level of self-rated health [12, 29]. Social support, both received and given, is assumed to have direct impacts on self-rated health [30, 31]. Both social support received and social support given are seen through emotional support and instrumental support. Specifically, social support received, either emotional or instrumental, is assumed to be positively linked to self-rated health. On the other hand, social support given is two-directional: while instrumental support given is posited to be negatively linked to self-rated health [15, 20, 21], we assume that emotional support given produces some positive influences on subjective health status because such support may be more likely to be self-motivated and hence may be of benefit to one's health. These aspects of social support are also hypothesized to affect chronic disease and functional status in the same orientation as to self-rated health [1, 12]. Therefore social support, both receiving and providing, is hypothesized to affect self-rated health through
Flows of social support and health status among older persons in China chronic diseases and functional status. Reciprocal linkages between social support and self-rated health are possible. However, given the sole availability of cross-sectional data at this time, they cannot be empirically evaluated at this stage. A number of factors other than social support are assumed to have direct effects on self-rated health. Social networks, sometimes referred to as "social embcddedness" [13], are posited to have positive impacts on self-rated health, and negative influences on chronic diseases and functional disability [6, 15]. Although social networks are assumed to be correlated with social support, as shown in Fig. 1, they may not necessarily be causally linked [1, 7, 32, 33]. Sociodcmographic characteristics, such as age, education, and place of residence, and health behavior are also hypothesized to affect self-rated health, chronic diseases, and functional disability [34-36]. In analyzing the effects of social support on self-rated health, these factors are considered control variables. It is also assumed that social support has a strong influence on health behavior [12], in turn producing an additional indirect impact on self-rated health through health behavior. There are also associations among these control variables, but they are not
elaborated in the present research given our concentration on social support. As shown by Fig. 1, social support received, social support given, social networks, sociodemographic characteristics are viewed as exogenous variables since their causes are not generated within the theoretical framework. Chronic diseases, functional status, and health behavior serve as mediating factors. Selfrated health is the dependent variable in the present research. METHODS
Sample and data Data used for the present research was primarily based on the 1991 Survey of Health and Living Conditions of the Aged Persons in the Wuhan area of China including the city proper of Wuhan and the surrounding suburban and rural areas. The survey, jointly conducted by Institute of Gerontology, the University of Michigan and the Wuhan Bureau of Statistics, involved a three-stage stratified probability sample of the elderly population in the Wuhan area. Eligibility was defined as individuals aged 60 or over who were residents in the Wuhan area on 1 July 1990. The selection was stratified by administrative areas,
Chronic disease
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J Health behavior
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Fig. I. Conceptual framework of relationships between social support and self-rated health: Chinese elderly.
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including seven urban districts, two suburban districts and four rural counties. The primary sampling unit (PSU) was street committee in the urban and Xiang, or town, in the rural, with neighborhood committee in the city and village committee in the countryside, which serve as the grass-roots administrative units in China, as the second stage unit (SSU). Ninety PSUs and 180 SSUs were selected according to the probability proportional to population size. Using 1990 Chinese census as the sampling frame, 3543 elders were selected from all eligible residents in the Wuhan area, among whom 2943 responded with a response rate of 83%. The questionnaire elicited information on an elder's current health status, sociodemographic characteristics, living conditions, health care utilization, etc. The sample used for the present research was viewed as an epitome of contemporary China because the Wuhan area typifies China in terms of socioeconomic and geographic conditions [131.
Table 1. Percentage distribution of Wuhan elderly persons by three health variables: effective sample, 1991
Measurement
emotional support received was measured by two five-point scales (the five points ranged from 0 to 4) assessing (1) the willingness of the most willing person to listen to the difficulties and inner feelings of the respondent; and (2) the amount of respect the respondent can expect from the most respectful person. Instrumental support received was scaled by two five-point items regarding the degree of sick care and financial assistance received by the respondent during the 12-month period prior to the interview. Similarly, emotional support given was obtained from two five-point scales indicating the extent to which the respondent listened to and encouraged people close to him or her. Instrumental support given was measured by a composite of the assistance provided by the respondent and his or her spouse to the significant others during the 12-month period, including household chores, finance, gifts, business and farming, or other work-related activities. Each of these four composite variables ranged from 0 to 8. Our preliminary data analysis showed that these four variables of social support were not highly correlated (e.g. the correlation between instrumental support received and instrumental support given was lower than 0.01 with P = 0.93), therefore statistically including all four composites in the model was not unreasonable. Social networks were measured by five indicators including employment status, living arrangement, marital status, social contacts, and social participation [5, 11, 13]. Employment status was coded as a dummy variable with 'working' taking the value 1. Living arrangement was measured by the number of people living in the household, which, in the context of China, may also be viewed as an indicator of family ties [13]. Marital status was coded as a dummy variable such that I = currently married. Social contacts were assessed by the average frequencies of contacting with children, relatives, and friends, while
Information on self-rated health, the dependent variable in the present research, was originally obtained by a five-point-scale response to a question on one's overall health: (1) not at all healthy, (2) not very healthy, ( 3 ) O k a y , (4)fairly healthy, and (5) very healthy. In data analysis, we condensed such classification into three scales: (1) poor (not at all healthy), (2) average (including 'not very healthy' and 'Okay'), and (3) good ('fairly healthy' and 'very healthy'). To conform to our previous research and future research agenda regarding health status, the proportional distribution of the older people in these three states of self-rated health was viewed as the dependent variable; and the effects of the explanatory variables were examined through their influences on such a distribution. Chronic disease was indicated by the number of chronic illnesses reported by the respondents, as was used by some of the previous research [12]. In terms of functional status, we used the Index of Independence in Activities of Daily Living [37] to indicate the degree of difficulty in bathing, dressing, going to the toilet, moving in and out of bed, urinating and defecating, and eating. An elder was defined as ' functionally disabled' in a given activity if he or she had any degree of difficulty in performing the activity without help. On the basis of such an operational definition, functional status was indexed as the number of functional disabilities, ranging from 0 to 6. Table 1 presents the distribution of the respondents by the three variables of health status considered in the present research. The measure of social support consisted of two aspects indicating, respectively, support received and support given, as indicated earlier. Each of the aspect included two composite variables representing, respectively, 'emotional support' and 'instrumental support.' With respect to social support received,
Health variable
Frequency
%
Self-rated health Poor Average Good
121 1254 1251
4.6 47.8 47.6
2626
100.0
434 693 719 494 286
16.5 26.4 27.4 18.8 10.9
2626
100.0
2218 278 51 27 52
84.5 10.6 1.9 1.0 2.0
2626
100.0
Total
Number of chronic diseases No disease 1 Disease 2 Diseases 3 Diseases 4 and over Total
Functional limitation No limitation 1 Limitation 2 Limitations 3 Limitations 4 and over Total
Flows of social support and health status among older persons in China social participation being operationalized by the frequencies o f attending the activities o f the organizations to which the r e s p o n d e n t was affiliated. As suggested by previous findings [5, 38, 39] a n d o u r own preliminary d a t a analysis, the effects of social contacts a n d social participation on mortality a n d health status were n o t linear. Therefore two more d u m m y variables were created with ' n o social contact,' and ' n o social participation at all' coded as O's, a n d all else as l's. These variables o f social networks were not highly correlated to each other with some smaller t h a n 0.01; a n d neither were they f o u n d to be highly correlated with the variables indicating social support. As indicated by our previous research [12, 39], we viewed the r e s p o n d e n t ' s feeling o f loneliness as a cognitive assessment of the adequacy of b o t h social s u p p o r t a n d social networks, a n i m p o r t a n t proxy variable to control for the variation in the quality of social s u p p o r t [40]. It was ascertained by a threepoint scale: (1) little, (2) some, a n d (3) strong. Health b e h a v i o r was operationalized by two variables: the a m o u n t of drinking alcohol within one m o n t h (unit of drinking was Chinese Liang) and the daily a m o u n t of s m o k i n g by five groups: (0) none, (2) 1-5 cigarettes, ( 3 ) 6 - 1 0 cigarettes, ( 4 ) ! 1 - 2 0 cigarettes, a n d (5) 21 or more. In the multivariate analysis, the variable 'drinking' for drinkers was t r a n s f o r m e d as the natural logarithm o f the m o n t h l y a m o u n t of drinking due to the skewed distribution in this regard. F o u r sociodemographic characteristics were also included as the control variables. G e n d e r was indexed as a d u m m y variable, with male as 0 and female as 1. Age was m e a s u r e d in terms o f the actual years of age at the time of the survey. Place of residence was indicated as a d u m m y variable such that rural residence coded as 0 and u r b a n residence as 1. A n d educational a t t a i n m e n t was measured by the total
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n u m b e r of years in school, as reported by the respondent. In order to analyse the areal differentials in the effects of social support, we created four interaction terms, with each o f the four variables regarding social support multiplied by the d u m m y variable 'residence.' Table 2 presents the means a n d s t a n d a r d deviations of the explanatory a n d control variables, together with their coding schemes, o n the basis of the effective sample. A l t h o u g h there were 317 missing cases, the distribution for the whole sample, n o t presented here, agreed closely with the pattern s h o w n in Table 2. Data analysis
In the present research, we sought to model the factors associated with a Chinese elder's self-rated health. First, we assumed that there existed a latent variable of self-rated health, y*, which was continuously and normally distributed. Since y * is unobservable, we specified further a n ordinal variable y (y = ! if self-rated health was poor, y = 2 if self-rated health is average, and y = 3 if self-rated health is good) as the discrete realization of the c o n t i n u o u s variable y*. As indicated earlier, we intended to model the probability distribution of the elders in the three states of self-rated health a n d therefore the d e p e n d e n t variable in the model contained three probabilities such t h a t P~ = p r o b ( y = 1); P 2 = p r o b ( y = 2 ) ; a n d P3 = prob(y = 3). Given t h a t the latent dependent variable y* was normally distributed a n d the y ' s were ordered, we used the ordered probit model with employing m a x i m u m likelihood a p p r o a c h [41]. The relationship between the dependent variable and the model parameters was specified as: P, = 1 - ~ ( ~ ' x ) , p~ = q,(~ - / ~ ' x )
- a,( - / ~ ' x ) ,
P3 = l - q~(p -- fl'X),
Table 2. Means, standard deviations, and coding schemes of the explanatory variables for Wuhan elderly persons: effective sample, 1991 (n = 2626) Explanatory variable Mean SD Coding scheme Demographic and socioeconomic
Age Female Urban residence Education
68.651 0.549 0.564 2.603
6.038 0.498 0.496 3.970
Actual number of years I = yes, 0 = no 1 = yes, 0 = no Actual years of attending school
Health behavior
Drinking alcohol Smoking
15.675 0.857
39.358 Monthly amount of drinking alcohol (unit: Liang) 1.291 Dailyamount of smoking cigarette
Social networks
Currently working Living arrangement Currently married Social contact Social participation
0.321 3.766 0.623 0.998 0.182
0.467 2.005 0.485 0.044 0.386
1 = yes, 0 = no Number of people living in the household I = yes, 0 = no 1 = yes, 0 = no I = yes, 0 = no
5.458 4.041 5.646 2.129 1.482
2.017 2.320 1.850 1.723 0.679
A eight-level score: 0 = no support, 8 = maximum support Same as above Same as above Same as above A three-item scale: I = never, 2 = sometimes, 3 = often
Social support
Emotional support received Instrumental support received Emotional support given Instrumental support given Loneliness
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where X denoted a vector of explanatory variables and fl was the vector of regression coefficients. represented the cumulative normal distribution function, and #'s were unknown parameters to be estimated with fl, serving to separate y = I, y = 2, and y = 3. A didactic introduction to the ordered probit models can be found in Greene [42]. As it is very difficult, if not impossible, to interpret directly the regression coefficients in a probit model, we calculated the marginal effects of the explanatory variables on the three probabilities to help present the results of the regression, as suggested by Greene [42]. Specifically, letting P~,0be the estimate of P~ (i = 1, 2, 3) when a specific explanatory variable was scaled as its sample mean (it was 0 if the variable was dummy) and Pi.x be the estimate when the value of the explanatory variable was one unit greater than its sample mean (it was 1 for a dummy variable), we defined the difference between Pi.x and P~.0 as the marginal effect of this explanatory variable. In deriving such effects, all other explanatory variables were regarded as control variables with the values fixed at sample means. Substantively, the marginal effect of a given variable thus defined reflects the degree of probability redistribution in self-rated health with a sample-mean-based unit change in the variable, other things remaining unchanged on their means. We developed two ordered probit regression models according to the theoretical framework. The first regression was the full model with all exogenous and mediating variables involved, indicating the direct effects of social support on self-rated health. The second regression estimated the reduced form omitting the mediating variables, reflecting the overall influences of the exogenous factors. Methodologically the difference between the total effect and direct effect of a given social support variable yields the indirect effect through the mediation of chronic disease, functional status, and health behavior [43]. However, with the possible presence of reciprocal causality, such a decomposition does not necessarily provide meaningful implications, hence this method has not been executed in the present research.
RESULTS
Description of patterns Most elderly persons received a substantial amount of emotional support: more than seven in ten of the Wuhan elders reportedly obtained at least 5 units of such support from their significant others. Only about 4% of the respondents did not receive any emotional social support. A majority of these elderly persons also received a considerable amount of instrumental support, though with a lower level than that of emotional support. In terms of social support given, a vast majority of the Wuhan elders provided a substantial quantity of emotional support to their
significant others, whereas most offered none or limited amount of instrumental support. It seems that the exchange of social support between Chinese elders and their significant others did exist, but the extent of such exchange did not appear to be as substantial as some researchers perceived [l 5, 20, 21]. The distribution of mean scores of health status suggests the bivariate relationship between health status and each of the four aspects of social support. The increase in emotional support received as accompanied with both the rise in the mean score of self-rated health and the decline in the mean number of chronic disease and of functional disability. Instrumental social support received was negatively related with self-rated health, and positively linked to the number of chronic disease and of the number of functional disability. Increased emotional support given was indicated by enhanced mean score of self-rated health, decreased number of chronic diseases, and reduced mean number of functional disability, as expected. On the other hand, instrumental support given was positively associated with mean score of self-rated health, and negatively related to the mean scores of the number of chronic diseases and of the number of functional limitations. As these patterns only reflected the bivariate associations between health status and social support, their causal linkages were further analyzed below controlling for the potential confounding effects of the control variables.
Results of probit regressions The marginal effect of each explanatory or control variable was calculated. Interpreting the marginal effects is much like interpreting unstandardized linear regression coefficients. For instance, the marginal effect of -0.0034 for emotional support received meant that a unit increase in emotional support received decreased the probability of being in 'poor' health by 0.0034, other things remaining constant on their means. These effects would remain fairly consistent over the changes in the baseline values of the explanatory variables. The interpretation of the four interaction terms depends on the comparison between the mean marginal effect of a given social support variable and the marginal effect of the relevant interaction term. Specifically, if the marginal effect of an interaction term took the opposite sign to that of the mean effect, we would observe an offsetting deduction from the mean effect, hence we may infer that the influence of this variable on self-rated health appears to be weaker in the urban area, other things equal. The coefficients of both regressions show that the effects of all four variables concerning social support were statistically significant, based on a two-tail test. In both models, increased emotional support received was shown to reduce the probability of being 'poor' or 'average' in health, and, accordingly, enhance the portion of being 'good'. The signs of the marginal
Flows of social support and health status among older persons in China
effects of the interaction term between emotional support received and urban residence turned out contrary to the mean effects, reflecting a weaker influence of this factor on self-rated health in the urban area. In line with the pattern shown by the bivariate analysis, instrumental support received had a negative association with self-rated health. That is, elders with more such support were more likely to be in 'poor' and 'average' health and less likely to he 'good,' which indicated implicitly the reciprocal causal linkage. In addition, given the different signs of the interaction term in this regard, such effects were stronger in the rural area. The absolute values of the mean and the interaction effects appeared greater in the second regression (the reduced form), but the patterns shown in both models appeared similar. Emotional social support given had positive impacts on self-rated health. Its mean marginal effect on the probability of being in 'good' health was 0.0211 in the full model, and 0.0257 in the reduced form. In contrast, the likelihood of being in the other two health states were lowered accordingly. The marginal effects of the interaction term in this regard had opposite signs, reflecting again that the effects of emotional support given were stronger in the rural area. We observed a positive association between instrumental support given and self-rated health, other things equal. And the absolute values of such effects in the model of reduced form appeared somewhat greater. The different signs of the interaction effects indicated the existence of the areal differentials in this regard, with the urban area having weaker positive effects. Compared with the magnitudes in conjunction with social support received, the areal differentials in the effects of support given appeared much smaller. In addition, among the four social support variables considered in the present research, only the interaction term for emotional support received was statistically significant. On the whole, emotional social support, both received and given, had impacts on self-rated in the direction as expected, whereas the influences of the two composites representing the two aspects of instrument support were not anticipated. Questions might be advanced toward the specification of our conceptual framework. While the reciprocal linkages between social support and self-rated health were likely to exist, a thorough and effective examination of the causality requires the availability of longitudinal data. These theoretical issues will be further discussed below. The variable 'loneliness,' serving as a control factor for the variation in the quality of social support, had strong negative impacts on an elder's health status. A unit increase in loneliness would lower substantially the probability of being in 'good' health. As the effects of social support and social networks were
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controlled, such a strong association suggests that the Chinese public should pay closer attention to an elder's sentiments. Among other variables, chronic disease and functional disability had strong negative impacts on selfrated health, as expected. However, 'drinking' and 'smoking' were not associated with self-rated health in the direction we posited. The factor 'urban residence' also had an explicit influence on self-rated health. And among the five variables indicating social networks, working status and social participation had statistically significant impacts on self-rated health. Namely, working and socially active elders had better self-rated health than their non-working and socially inactive counterparts, other things remaining constant. For the other three variables, the effects were either contrary to our expectation or statistically insignificant. DISCUSSION
The results presented above provided new evidence that enhanced social support to an elder was associated with improved health status; and of the two aspects of such support considered, emotional support received played a crucial role, consistent with the pattern observed in developed world. Noting Wuhan's representativeness in certain socioeconomic and geographic characteristics, it is fair to assume that such patterns are general throughout China. With the use of cross-sectional data in the present research, one may suggest that the observed association between instrumental support received and health status be due to the existence of the reversed causality: it is poorer health status that has caused more instrumental support received. However, this would not overturn our conclusion in this regard because, if increased instrumental support received had strong positive impacts on health status, one might not expect to see a significant negative association between the two factors. Similarly, such reversed causality may also exist in the mechanisms of providing emotional support, because showing respect and delivering material assistance were expected to occur in the same direction in Chinese society [15, 16, 20]. If so, the positive effects of emotional support received on health status, shown in the present research, would be still underestimated since the latent reversed causality would counteract a part of the total effects. Such inference can also be applied with respect to instrumental social support given. While the results of the present research in this regard contradicted our expectation, it is likely that the positive association between instrumental support given and health status reflected the reversed causal linkage, that is, healthier elders tended to provide more instrumental support to their significant others. This in turn would imply the absence of the causality that a heavier burden of providing instrumental support would worsen
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significantly an elder's health status, because otherwise such a strong positive association would be counteracted. In terms of the relationship between emotional support given and health status, there is no solid base for a confident judgement. Did the positive association occur because more emotional support given improved health status, or did it mask a reversed linkage between these two factors? Numerous studies of patterns on social support, including the present research, showed better health status among the elders with more emotional support received [5, 6, 39]. A similar phenomenon may be operating with regard to emotional support given. Since both aspects reflect the emotional exchanges with network members, it is not unreasonable to conjecture that more emotional support given may also improve health status. Although it is impossible to establish how reversed causalities operated at this stage, several important implications follow from the present research. First, consistent with the pattern often observed in developed societies, a lack of emotional support received is crucial for the worsening of an elder's health status, whereas the magnitude of instrumental support received does not contribute significantly in this regard. Such phenomena indicate that the Chinese elders still consider emotional support highly important in their lives, perhaps as a consequence of rapid socioeconomic development in the past decade, or simply because the need system may not necessarily be hierarchical [44]. This feature will in turn derive an instructive policy implication that expressing love and respect to Chinese elders may be more important than simply providing them with necessities or sick care. Second, we found no evidence that increased instrumental support from Chinese elders had caused the worsening of their health status. While not intending to deny the existence of such events in China, we believe that such phenomena did not occur universally and the negative outcomes of elders' providing more instrumental support to their significant others may have been exaggerated. It is likely that a high proportion of Chinese elderly persons have provided such support voluntarily as a response to the massive social change. As Whyte and Parish [16] pointed out that, without such help provided by the older folks, the youngsters would bear a very heavy burden of household chores. As a consequence, increased instrumental social support given by elders would not worsen their physical and mental health to a noticeable extent. Third, in contrast with our expectation, the relationship between social support perspectives and health status had stronger impacts in the rural areas of China. That is, the Chinese rural elders appeared more sensitive than their urban counterparts to the lack of social support from their relatives and friends. Such vulnerability may be closely related to the unavailability of a sound social security system in
rural China. Considering the huge size of Chinese rural elders and a lesser extent to which they can expect to receive emotional support, the significance of such areal differentials should be brought to the attention of Chinese policy-makers. Although it has derived important policy implications regarding a number of research issues, the present research remains an exploratory study. With the restriction of using cross-sectional data, the underlying causal linkages between old-age social support and health status cannot be tested effectively. Thus it is necessary to address the directions for further inquiries. With the availability of longitudinal data in this regard, the research can be extended to dynamic perspectives. Specifically, we may examine first the dynamic transitions over time in an elder's health status with the levels of social support fixed at the initial point of time as the explanatory variables; and the changing pattern in social support, in turn fixing the level of health status at the initial point of time, can be analyzed next. More explicit causal relationships between social support and health status can be generated. Another issue deserving attention in future research is the identification of specific sources of social support to elderly persons. While the data used for the present research do not allow such examination, in the future it may be useful to elicit information on the number and gender of children who are providing support of different sorts for analyzing intergenerational flows of social support. This will enable us to extend our research to the domain of demography on fertility, especially the costs and benefits of children, and address the implications of the one-child policy for the elderly persons. For example, sons have been found as the major providers of instrumental support, and daughters as the suppliers of emotional support, which might be the underlying reason for many Chinese couples to desire a daughter [22]. It must also be noted that the generality of the present research may be somewhat restricted because only data of the Wuhan area were used. Although Wuhan was viewed as epitomizing the whole country within this context, it is unrealistic to conclude that the patterns observed in the Wuhan area can be found everywhere in China given its huge size, diversity, and a lack of mobility both socially and geographically. We believe that extended surveys concerning social support and health status among Chinese elderly persons will help provide a wider array of unique patterns. While conducting a national probability sample survey is extremely difficult in China, both administratively and financially, a purposive selection of several survey sites, with each representing a specific region of China, will provide a solid ground for a deeper probe into the research issue and hence widen researchers' awareness of the causal linkages between social support and health status in China.
Flows of social support and health status among older persons in China
Acknowledgements--This is a revised version of a paper presented at the 46th Annual Scientific Meeting of the Gerontological Society of America in New Orleans, 22 November 1993. Support of this research was provided by the Department of Veterans Affairs grant HSR&D IIR # 90-089B and by grant R01 AG08094 provided by the U.S. National Institute on Aging. Susan Greenhalgh has made valuable remarks on an earlier version of this manuscript. The assistance provided by Joan Bennett and Cathy Fegan is gratefully acknowledged. REFERENCES I. Berkman L. F. Assessing the physical health effects of social networks and social support. Ann. Rev. pub. Hlth 5, 413, 1984. 2. House J. S., Landis K. R. and Umberson D. Social relationships and health. Science 241, 540, 1988. 3. Cassel J. The contribution of social environment to host resistance. Am. J. Epidemiol. 104, 107, 1976. 4. Cobb Sidney. Social support as a moderator of life stress. Psychosom. Med. 38, 300, 1976. 5. Berkman L. F. and Syme L. Social networks, host resistance and mortality: Nine-year follow-up study of Alameda County residents. Am. J. Epidemiol. 109, 186, 1979. 6. Berkman L. F. The relationship of social networks and social support to morbidity and mortality. In Social Support and Health (Edited by Cohen S. and Syme S. L.), pp. 241-262. Academic Press, New York, 1985. 7. Ell K. Social networks, social support, and health status: A review. Soc. Serv. Rev. 58, 133, 1984. 8. Hanson B. S., lsacsson S. O., Janzon L. and Lindell S. E. Social networks and social support influence mortality in elderly men--the prospective population study of "men born in 1914," Malmo, Sweden. Am. J. Epidemiol. 130, 100, 1989. 9. Hessler R. M., Pazaki S. H., Madsen R. W. and Blake R. L. Predicting mortality among independently living rural elderly: A 20-year longitudinal study. Sociol. Q. 31, 253, 1989. 10. House J. S. and Kahn R. L. Measures and concepts of social support. In Social Support and Health (Edited by Cohen S. and Syme S. L.), pp. 83-108. Academic Press, New York, 1985. I 1. Jylha M. and Aro S. Social ties and survival among the elderly in Tampere, Finland. Int. J. Epidemiol. 18, 158, 1989. 12. Sugisawa H., Liang J. and Liu X. Social networks, social support, and mortality among older people in Japan. J. Gerontol.: soc. Sci. 49, $3, 1994. 13. Liang J., Gu S. and Krause N. Social support among the aged in Wuhan, China. Asia-Pacific popn J. 7, 33, 1992. 14. Ikels C. Settling accounts: The intergenerational contract in an age of reform. In Chinese Families in the Post-Mao Era (Edited by Davis D. and Harrell S.), pp. 307 333. University of California Press, Berkeley, Calif., 1993. 15. Wang J. New features of family conflicts in urban China. Zhejiang Xuekan 6, 146, 1990. 16. Whyte M. K. and Parish W. L. Urban Life in Contemporary China. The University of Chicago Press, Chicago, Ill., 1984. 17. Parish W. L. and Whyte M. K. Village and Family in Contemporary China. The University of Chicago Press, Chicago, I11., 1978. 18. Greenhalgh S. Income units: The ethnographic alternative to standardization. In Income Distribution and the Family (Edited by Ben-Porath Y.), supplement to Vol. 8 of Population Review and Development, pp. 70-91, 1982. 19. Davis-Friedmann D. Long Lives: Chinese Elderly and
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FLOWS OF SOCIAL SUPPORT AND HEALTH STATUS AMONG OLDER PERSONS IN CHINA XIAN LIU, l* JERSEY LIANG 1 and SHENGZU GU ~ qnstitute of Gerontology, The University of Michigan, 300 North Ingalls, Ann Arbor, MI 48109-2007 U.S.A. and 2Institute of Population Research, Wuhan University, People's Republic of China Abstract--As a consequence of the political, social, and economic developments in contemporary China, there have been considerable changes in the patterns of flows of social support between Chinese older people and their significant others. There is evidence that Chinese elders are now under strong pressure to provide more social support, instrumental support in particular, to their children and other relatives while they receive less. Such a change in the direction of flows of social support has been reported to worsen the elders' health. This paper describes the general pattern of social support both to and from the Chinese elders, using data of a probability sample survey conducted in Wuhan, China in 1991. The association between social support, both receiving and providing, and old-age health status is also analysed within a multivariate framework. The results of two probit models suggest that emotional support received plays a crucial role in affecting an elder's health status, while instrumental support received does not have explicit impacts. In addition, there is no empirical evidence that increased instrumental support from elders has worsened their health status as reported. Key words
social support, health status, China, older people
INTRODUCTION
A considerable body of research on old-age social support has been devoted to its linkages with health status [1, 2]. Early findings that stronger social support received by an elder was associated with decreased risks to both death and morbidity [3, 4] have prompted the development of a wide array of empirical models to test the validity of such hypothetical causality, both cross-sectionally and longitudinally [5-12]. Although they have consistently revealed the negative relationships, either directly or indirectly, between social support and the risks to death and health status, these empirical research studies have been limited to the developed world. Ascertaining the causal linkages between social support and health status among older persons in China poses special importance given that the vast majority of the Chinese elderly population do not have access to health insurance of any kind and the family still serves as the primary source to provide old-age support [13]. Traditionally, the essentiality of old-age support was deeply embedded in the Chinese culture, which fostered the establishment of an intrafamilial patriarchal and hierarchical system [14--16]. Specifically, parents had the obligation to raise their children in all important ways, including providing them with spouses and some inheritance; and when their physical ability deteriorated with age, the balance of support flowed increasingly from the younger to the older generations [17]. After the parents *Author for correspondence.
reached a certain age, the children, sons in particular, were obligated to show them respect and filial piety, and provide them with various necessities, with the seniors still controlling substantial assets and having the power of ruling the family [14, 18]. Such an inter-generational relationship continued to be seen as mutually beneficial and rewarding; and on the elders' part, they could benefit from receiving incessant flows of social support, even if they were disabled [19, 20]. Since the founding of the People's Republic in 1949, the pattern of the intra-familial support system in China has gradually altered. Although for the elders the extensive welfare dependence on their children is still common in China [19], the flows of old-age support are no longer dominantly onedirectional. There is evidence that the Chinese elders are now under strong pressure to provide more social support, instrumental support in particular, to their children and other younger relatives while they receive less [15, 16,20, 21]. While many argue that such changes may be rooted in the political economy socialism that has weakened the patriarchal power with the high degree of socialization exercised over the Chinese families [22], some suggest that social change per se may also contribute substantially to this phenomenon. Whyte and Parish [16], for example, indicate that without the help provided by the elders, the burden of household chores may weigh too heavily on a working couple. Whatever has caused the reversal of old-age social support in China, an important theoretical concern should be advanced promptly: do these changes
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worsen the elders' health? There are reports that reduction in old-age support received, and the increase in that provided, have both ushered in the worsening of health status among Chinese elders [15, 21]. To date, however, no one has yet tested a model examining whether such reports have mirrored a universal phenomenon, or they have just reflected some accidental cases. Explicating the relationship between social support and health status among Chinese elderly persons will provide intuitive implications in this regard. While previous research in developed societies has concentrated on the onedirectional flows, it is imperative to involve social support both to and from elderly persons within the context of contemporary China. The way of assessing social support is also of theoretical concern with specific regard to Chinese older folks. Social gerontologists have viewed social support as reflecting the quality of the functional contents of social relationships and, accordingly, have classified it into two primary dimensions-emotional social support and instrumental social support [6, 23]. In analyzing the relationship between social support and old-age health, emotional support has often been found to be crucial [6, 10, 12]. A closer probe into the circumstances in China, however, suggests caution in applying the same measurement to Chinese elders. First, whether a given type of social support has impact on health status depends highly on its need. According to Masiow's Need Hierarchy Theory [24], the dominance of a higher need would not take place before a specific need is satisfied. Considering that the vast majority of Chinese elderly persons lived long with a deficiency of physiological or security needs, would a lack of love or respect worsen their health? Second, Chinese elderly persons are survivors from numerous calamities in previous decades such as wars, famines, and formidable political struggles. Being so uniquely selected, are Chinese older folks still concerned more about the quality of emotional support than about that of instrumental, or material, support? Third, different from the U.S. and other developed countries that are highly individual centered, contemporary China is a collectivism-oriented society with greatly reduced privacy, emotional dependence on organizations and institutions, and a belief in the superiority of group over individual decisions [25]. Given these characteristics, would the importance of the intra-familial emotional support be warranted for Chinese elders? While negative associations between both emotional and instrumental supports and old-age health status have been observed [15,26], there have been no systematic attempts to gauge the reliability of such reports. It has also been reported that Chinese rural elders received less but provided more support than their urban counterparts, while the distribution of their health status was fairly close to that of the urban [21]. Does this imply that social support, both received
and given, has weaker impacts on health status among rural elders? Identifying such areal differentials will be of special importance to both planners and researchers since a vast majority of Chinese older people reside in the rural areas. This article estimates a model of social support and health status to test: (1) the relationships between social support both to and from Chinese elders and their health status; (2) whether emotional support plays a crucial role in shaping such relationships; and (3) whether there are strong differentials in these linkages between the urban and the rural areas. The data used are primarily based on a probability sample survey of Chinese older adults aged 60 and over conducted in Wuhan, China in November 1991. While it serves as an exploratory analysis with the limitation of using a single set of cross-sectional data, this research is considered essential to guide dynamic analyses in the future using longitudinal data. MODEL SPECIFICATION
A theoretical framework is specified to explicate the causal linkages between social support and health status according to existing literature in this regard and relevant observations in China. Figure 1 shows the diagram. Health status is viewed as a function of social support and a number of other factors that act as control variables in the present research. As specified by previous research, we view health status as consisting of three inter-related aspects: chronic disease, functional limitation, and self-rated health. Considering the substantial correlation among these three health indicators, it is intuitive to specify their interrelations to guide the data analysis. Given that it is the most commonly used measure of general health status assessment [12, 27, 28], self-rated health is regarded as the general indicator representing health status in the present research. Chronic disease and functional status are assumed to affect directly the level of self-rated health [12, 29]. Social support, both received and given, is assumed to have direct impacts on self-rated health [30, 31]. Both social support received and social support given are seen through emotional support and instrumental support. Specifically, social support received, either emotional or instrumental, is assumed to be positively linked to self-rated health. On the other hand, social support given is two-directional: while instrumental support given is posited to be negatively linked to self-rated health [15, 20, 21], we assume that emotional support given produces some positive influences on subjective health status because such support may be more likely to be self-motivated and hence may be of benefit to one's health. These aspects of social support are also hypothesized to affect chronic disease and functional status in the same orientation as to self-rated health [1, 12]. Therefore social support, both receiving and providing, is hypothesized to affect self-rated health through
Flows of social support and health status among older persons in China chronic diseases and functional status. Reciprocal linkages between social support and self-rated health are possible. However, given the sole availability of cross-sectional data at this time, they cannot be empirically evaluated at this stage. A number of factors other than social support are assumed to have direct effects on self-rated health. Social networks, sometimes referred to as "social embcddedness" [13], are posited to have positive impacts on self-rated health, and negative influences on chronic diseases and functional disability [6, 15]. Although social networks are assumed to be correlated with social support, as shown in Fig. 1, they may not necessarily be causally linked [1, 7, 32, 33]. Sociodcmographic characteristics, such as age, education, and place of residence, and health behavior are also hypothesized to affect self-rated health, chronic diseases, and functional disability [34-36]. In analyzing the effects of social support on self-rated health, these factors are considered control variables. It is also assumed that social support has a strong influence on health behavior [12], in turn producing an additional indirect impact on self-rated health through health behavior. There are also associations among these control variables, but they are not
elaborated in the present research given our concentration on social support. As shown by Fig. 1, social support received, social support given, social networks, sociodemographic characteristics are viewed as exogenous variables since their causes are not generated within the theoretical framework. Chronic diseases, functional status, and health behavior serve as mediating factors. Selfrated health is the dependent variable in the present research. METHODS
Sample and data Data used for the present research was primarily based on the 1991 Survey of Health and Living Conditions of the Aged Persons in the Wuhan area of China including the city proper of Wuhan and the surrounding suburban and rural areas. The survey, jointly conducted by Institute of Gerontology, the University of Michigan and the Wuhan Bureau of Statistics, involved a three-stage stratified probability sample of the elderly population in the Wuhan area. Eligibility was defined as individuals aged 60 or over who were residents in the Wuhan area on 1 July 1990. The selection was stratified by administrative areas,
Chronic disease
// h
\
//
J Health behavior
J
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I
Fig. I. Conceptual framework of relationships between social support and self-rated health: Chinese elderly.
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including seven urban districts, two suburban districts and four rural counties. The primary sampling unit (PSU) was street committee in the urban and Xiang, or town, in the rural, with neighborhood committee in the city and village committee in the countryside, which serve as the grass-roots administrative units in China, as the second stage unit (SSU). Ninety PSUs and 180 SSUs were selected according to the probability proportional to population size. Using 1990 Chinese census as the sampling frame, 3543 elders were selected from all eligible residents in the Wuhan area, among whom 2943 responded with a response rate of 83%. The questionnaire elicited information on an elder's current health status, sociodemographic characteristics, living conditions, health care utilization, etc. The sample used for the present research was viewed as an epitome of contemporary China because the Wuhan area typifies China in terms of socioeconomic and geographic conditions [131.
Table 1. Percentage distribution of Wuhan elderly persons by three health variables: effective sample, 1991
Measurement
emotional support received was measured by two five-point scales (the five points ranged from 0 to 4) assessing (1) the willingness of the most willing person to listen to the difficulties and inner feelings of the respondent; and (2) the amount of respect the respondent can expect from the most respectful person. Instrumental support received was scaled by two five-point items regarding the degree of sick care and financial assistance received by the respondent during the 12-month period prior to the interview. Similarly, emotional support given was obtained from two five-point scales indicating the extent to which the respondent listened to and encouraged people close to him or her. Instrumental support given was measured by a composite of the assistance provided by the respondent and his or her spouse to the significant others during the 12-month period, including household chores, finance, gifts, business and farming, or other work-related activities. Each of these four composite variables ranged from 0 to 8. Our preliminary data analysis showed that these four variables of social support were not highly correlated (e.g. the correlation between instrumental support received and instrumental support given was lower than 0.01 with P = 0.93), therefore statistically including all four composites in the model was not unreasonable. Social networks were measured by five indicators including employment status, living arrangement, marital status, social contacts, and social participation [5, 11, 13]. Employment status was coded as a dummy variable with 'working' taking the value 1. Living arrangement was measured by the number of people living in the household, which, in the context of China, may also be viewed as an indicator of family ties [13]. Marital status was coded as a dummy variable such that I = currently married. Social contacts were assessed by the average frequencies of contacting with children, relatives, and friends, while
Information on self-rated health, the dependent variable in the present research, was originally obtained by a five-point-scale response to a question on one's overall health: (1) not at all healthy, (2) not very healthy, ( 3 ) O k a y , (4)fairly healthy, and (5) very healthy. In data analysis, we condensed such classification into three scales: (1) poor (not at all healthy), (2) average (including 'not very healthy' and 'Okay'), and (3) good ('fairly healthy' and 'very healthy'). To conform to our previous research and future research agenda regarding health status, the proportional distribution of the older people in these three states of self-rated health was viewed as the dependent variable; and the effects of the explanatory variables were examined through their influences on such a distribution. Chronic disease was indicated by the number of chronic illnesses reported by the respondents, as was used by some of the previous research [12]. In terms of functional status, we used the Index of Independence in Activities of Daily Living [37] to indicate the degree of difficulty in bathing, dressing, going to the toilet, moving in and out of bed, urinating and defecating, and eating. An elder was defined as ' functionally disabled' in a given activity if he or she had any degree of difficulty in performing the activity without help. On the basis of such an operational definition, functional status was indexed as the number of functional disabilities, ranging from 0 to 6. Table 1 presents the distribution of the respondents by the three variables of health status considered in the present research. The measure of social support consisted of two aspects indicating, respectively, support received and support given, as indicated earlier. Each of the aspect included two composite variables representing, respectively, 'emotional support' and 'instrumental support.' With respect to social support received,
Health variable
Frequency
%
Self-rated health Poor Average Good
121 1254 1251
4.6 47.8 47.6
2626
100.0
434 693 719 494 286
16.5 26.4 27.4 18.8 10.9
2626
100.0
2218 278 51 27 52
84.5 10.6 1.9 1.0 2.0
2626
100.0
Total
Number of chronic diseases No disease 1 Disease 2 Diseases 3 Diseases 4 and over Total
Functional limitation No limitation 1 Limitation 2 Limitations 3 Limitations 4 and over Total
Flows of social support and health status among older persons in China social participation being operationalized by the frequencies o f attending the activities o f the organizations to which the r e s p o n d e n t was affiliated. As suggested by previous findings [5, 38, 39] a n d o u r own preliminary d a t a analysis, the effects of social contacts a n d social participation on mortality a n d health status were n o t linear. Therefore two more d u m m y variables were created with ' n o social contact,' and ' n o social participation at all' coded as O's, a n d all else as l's. These variables o f social networks were not highly correlated to each other with some smaller t h a n 0.01; a n d neither were they f o u n d to be highly correlated with the variables indicating social support. As indicated by our previous research [12, 39], we viewed the r e s p o n d e n t ' s feeling o f loneliness as a cognitive assessment of the adequacy of b o t h social s u p p o r t a n d social networks, a n i m p o r t a n t proxy variable to control for the variation in the quality of social s u p p o r t [40]. It was ascertained by a threepoint scale: (1) little, (2) some, a n d (3) strong. Health b e h a v i o r was operationalized by two variables: the a m o u n t of drinking alcohol within one m o n t h (unit of drinking was Chinese Liang) and the daily a m o u n t of s m o k i n g by five groups: (0) none, (2) 1-5 cigarettes, ( 3 ) 6 - 1 0 cigarettes, ( 4 ) ! 1 - 2 0 cigarettes, a n d (5) 21 or more. In the multivariate analysis, the variable 'drinking' for drinkers was t r a n s f o r m e d as the natural logarithm o f the m o n t h l y a m o u n t of drinking due to the skewed distribution in this regard. F o u r sociodemographic characteristics were also included as the control variables. G e n d e r was indexed as a d u m m y variable, with male as 0 and female as 1. Age was m e a s u r e d in terms o f the actual years of age at the time of the survey. Place of residence was indicated as a d u m m y variable such that rural residence coded as 0 and u r b a n residence as 1. A n d educational a t t a i n m e n t was measured by the total
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n u m b e r of years in school, as reported by the respondent. In order to analyse the areal differentials in the effects of social support, we created four interaction terms, with each o f the four variables regarding social support multiplied by the d u m m y variable 'residence.' Table 2 presents the means a n d s t a n d a r d deviations of the explanatory a n d control variables, together with their coding schemes, o n the basis of the effective sample. A l t h o u g h there were 317 missing cases, the distribution for the whole sample, n o t presented here, agreed closely with the pattern s h o w n in Table 2. Data analysis
In the present research, we sought to model the factors associated with a Chinese elder's self-rated health. First, we assumed that there existed a latent variable of self-rated health, y*, which was continuously and normally distributed. Since y * is unobservable, we specified further a n ordinal variable y (y = ! if self-rated health was poor, y = 2 if self-rated health is average, and y = 3 if self-rated health is good) as the discrete realization of the c o n t i n u o u s variable y*. As indicated earlier, we intended to model the probability distribution of the elders in the three states of self-rated health a n d therefore the d e p e n d e n t variable in the model contained three probabilities such t h a t P~ = p r o b ( y = 1); P 2 = p r o b ( y = 2 ) ; a n d P3 = prob(y = 3). Given t h a t the latent dependent variable y* was normally distributed a n d the y ' s were ordered, we used the ordered probit model with employing m a x i m u m likelihood a p p r o a c h [41]. The relationship between the dependent variable and the model parameters was specified as: P, = 1 - ~ ( ~ ' x ) , p~ = q,(~ - / ~ ' x )
- a,( - / ~ ' x ) ,
P3 = l - q~(p -- fl'X),
Table 2. Means, standard deviations, and coding schemes of the explanatory variables for Wuhan elderly persons: effective sample, 1991 (n = 2626) Explanatory variable Mean SD Coding scheme Demographic and socioeconomic
Age Female Urban residence Education
68.651 0.549 0.564 2.603
6.038 0.498 0.496 3.970
Actual number of years I = yes, 0 = no 1 = yes, 0 = no Actual years of attending school
Health behavior
Drinking alcohol Smoking
15.675 0.857
39.358 Monthly amount of drinking alcohol (unit: Liang) 1.291 Dailyamount of smoking cigarette
Social networks
Currently working Living arrangement Currently married Social contact Social participation
0.321 3.766 0.623 0.998 0.182
0.467 2.005 0.485 0.044 0.386
1 = yes, 0 = no Number of people living in the household I = yes, 0 = no 1 = yes, 0 = no I = yes, 0 = no
5.458 4.041 5.646 2.129 1.482
2.017 2.320 1.850 1.723 0.679
A eight-level score: 0 = no support, 8 = maximum support Same as above Same as above Same as above A three-item scale: I = never, 2 = sometimes, 3 = often
Social support
Emotional support received Instrumental support received Emotional support given Instrumental support given Loneliness
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where X denoted a vector of explanatory variables and fl was the vector of regression coefficients. represented the cumulative normal distribution function, and #'s were unknown parameters to be estimated with fl, serving to separate y = I, y = 2, and y = 3. A didactic introduction to the ordered probit models can be found in Greene [42]. As it is very difficult, if not impossible, to interpret directly the regression coefficients in a probit model, we calculated the marginal effects of the explanatory variables on the three probabilities to help present the results of the regression, as suggested by Greene [42]. Specifically, letting P~,0be the estimate of P~ (i = 1, 2, 3) when a specific explanatory variable was scaled as its sample mean (it was 0 if the variable was dummy) and Pi.x be the estimate when the value of the explanatory variable was one unit greater than its sample mean (it was 1 for a dummy variable), we defined the difference between Pi.x and P~.0 as the marginal effect of this explanatory variable. In deriving such effects, all other explanatory variables were regarded as control variables with the values fixed at sample means. Substantively, the marginal effect of a given variable thus defined reflects the degree of probability redistribution in self-rated health with a sample-mean-based unit change in the variable, other things remaining unchanged on their means. We developed two ordered probit regression models according to the theoretical framework. The first regression was the full model with all exogenous and mediating variables involved, indicating the direct effects of social support on self-rated health. The second regression estimated the reduced form omitting the mediating variables, reflecting the overall influences of the exogenous factors. Methodologically the difference between the total effect and direct effect of a given social support variable yields the indirect effect through the mediation of chronic disease, functional status, and health behavior [43]. However, with the possible presence of reciprocal causality, such a decomposition does not necessarily provide meaningful implications, hence this method has not been executed in the present research.
RESULTS
Description of patterns Most elderly persons received a substantial amount of emotional support: more than seven in ten of the Wuhan elders reportedly obtained at least 5 units of such support from their significant others. Only about 4% of the respondents did not receive any emotional social support. A majority of these elderly persons also received a considerable amount of instrumental support, though with a lower level than that of emotional support. In terms of social support given, a vast majority of the Wuhan elders provided a substantial quantity of emotional support to their
significant others, whereas most offered none or limited amount of instrumental support. It seems that the exchange of social support between Chinese elders and their significant others did exist, but the extent of such exchange did not appear to be as substantial as some researchers perceived [l 5, 20, 21]. The distribution of mean scores of health status suggests the bivariate relationship between health status and each of the four aspects of social support. The increase in emotional support received as accompanied with both the rise in the mean score of self-rated health and the decline in the mean number of chronic disease and of functional disability. Instrumental social support received was negatively related with self-rated health, and positively linked to the number of chronic disease and of the number of functional disability. Increased emotional support given was indicated by enhanced mean score of self-rated health, decreased number of chronic diseases, and reduced mean number of functional disability, as expected. On the other hand, instrumental support given was positively associated with mean score of self-rated health, and negatively related to the mean scores of the number of chronic diseases and of the number of functional limitations. As these patterns only reflected the bivariate associations between health status and social support, their causal linkages were further analyzed below controlling for the potential confounding effects of the control variables.
Results of probit regressions The marginal effect of each explanatory or control variable was calculated. Interpreting the marginal effects is much like interpreting unstandardized linear regression coefficients. For instance, the marginal effect of -0.0034 for emotional support received meant that a unit increase in emotional support received decreased the probability of being in 'poor' health by 0.0034, other things remaining constant on their means. These effects would remain fairly consistent over the changes in the baseline values of the explanatory variables. The interpretation of the four interaction terms depends on the comparison between the mean marginal effect of a given social support variable and the marginal effect of the relevant interaction term. Specifically, if the marginal effect of an interaction term took the opposite sign to that of the mean effect, we would observe an offsetting deduction from the mean effect, hence we may infer that the influence of this variable on self-rated health appears to be weaker in the urban area, other things equal. The coefficients of both regressions show that the effects of all four variables concerning social support were statistically significant, based on a two-tail test. In both models, increased emotional support received was shown to reduce the probability of being 'poor' or 'average' in health, and, accordingly, enhance the portion of being 'good'. The signs of the marginal
Flows of social support and health status among older persons in China
effects of the interaction term between emotional support received and urban residence turned out contrary to the mean effects, reflecting a weaker influence of this factor on self-rated health in the urban area. In line with the pattern shown by the bivariate analysis, instrumental support received had a negative association with self-rated health. That is, elders with more such support were more likely to be in 'poor' and 'average' health and less likely to he 'good,' which indicated implicitly the reciprocal causal linkage. In addition, given the different signs of the interaction term in this regard, such effects were stronger in the rural area. The absolute values of the mean and the interaction effects appeared greater in the second regression (the reduced form), but the patterns shown in both models appeared similar. Emotional social support given had positive impacts on self-rated health. Its mean marginal effect on the probability of being in 'good' health was 0.0211 in the full model, and 0.0257 in the reduced form. In contrast, the likelihood of being in the other two health states were lowered accordingly. The marginal effects of the interaction term in this regard had opposite signs, reflecting again that the effects of emotional support given were stronger in the rural area. We observed a positive association between instrumental support given and self-rated health, other things equal. And the absolute values of such effects in the model of reduced form appeared somewhat greater. The different signs of the interaction effects indicated the existence of the areal differentials in this regard, with the urban area having weaker positive effects. Compared with the magnitudes in conjunction with social support received, the areal differentials in the effects of support given appeared much smaller. In addition, among the four social support variables considered in the present research, only the interaction term for emotional support received was statistically significant. On the whole, emotional social support, both received and given, had impacts on self-rated in the direction as expected, whereas the influences of the two composites representing the two aspects of instrument support were not anticipated. Questions might be advanced toward the specification of our conceptual framework. While the reciprocal linkages between social support and self-rated health were likely to exist, a thorough and effective examination of the causality requires the availability of longitudinal data. These theoretical issues will be further discussed below. The variable 'loneliness,' serving as a control factor for the variation in the quality of social support, had strong negative impacts on an elder's health status. A unit increase in loneliness would lower substantially the probability of being in 'good' health. As the effects of social support and social networks were
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controlled, such a strong association suggests that the Chinese public should pay closer attention to an elder's sentiments. Among other variables, chronic disease and functional disability had strong negative impacts on selfrated health, as expected. However, 'drinking' and 'smoking' were not associated with self-rated health in the direction we posited. The factor 'urban residence' also had an explicit influence on self-rated health. And among the five variables indicating social networks, working status and social participation had statistically significant impacts on self-rated health. Namely, working and socially active elders had better self-rated health than their non-working and socially inactive counterparts, other things remaining constant. For the other three variables, the effects were either contrary to our expectation or statistically insignificant. DISCUSSION
The results presented above provided new evidence that enhanced social support to an elder was associated with improved health status; and of the two aspects of such support considered, emotional support received played a crucial role, consistent with the pattern observed in developed world. Noting Wuhan's representativeness in certain socioeconomic and geographic characteristics, it is fair to assume that such patterns are general throughout China. With the use of cross-sectional data in the present research, one may suggest that the observed association between instrumental support received and health status be due to the existence of the reversed causality: it is poorer health status that has caused more instrumental support received. However, this would not overturn our conclusion in this regard because, if increased instrumental support received had strong positive impacts on health status, one might not expect to see a significant negative association between the two factors. Similarly, such reversed causality may also exist in the mechanisms of providing emotional support, because showing respect and delivering material assistance were expected to occur in the same direction in Chinese society [15, 16, 20]. If so, the positive effects of emotional support received on health status, shown in the present research, would be still underestimated since the latent reversed causality would counteract a part of the total effects. Such inference can also be applied with respect to instrumental social support given. While the results of the present research in this regard contradicted our expectation, it is likely that the positive association between instrumental support given and health status reflected the reversed causal linkage, that is, healthier elders tended to provide more instrumental support to their significant others. This in turn would imply the absence of the causality that a heavier burden of providing instrumental support would worsen
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significantly an elder's health status, because otherwise such a strong positive association would be counteracted. In terms of the relationship between emotional support given and health status, there is no solid base for a confident judgement. Did the positive association occur because more emotional support given improved health status, or did it mask a reversed linkage between these two factors? Numerous studies of patterns on social support, including the present research, showed better health status among the elders with more emotional support received [5, 6, 39]. A similar phenomenon may be operating with regard to emotional support given. Since both aspects reflect the emotional exchanges with network members, it is not unreasonable to conjecture that more emotional support given may also improve health status. Although it is impossible to establish how reversed causalities operated at this stage, several important implications follow from the present research. First, consistent with the pattern often observed in developed societies, a lack of emotional support received is crucial for the worsening of an elder's health status, whereas the magnitude of instrumental support received does not contribute significantly in this regard. Such phenomena indicate that the Chinese elders still consider emotional support highly important in their lives, perhaps as a consequence of rapid socioeconomic development in the past decade, or simply because the need system may not necessarily be hierarchical [44]. This feature will in turn derive an instructive policy implication that expressing love and respect to Chinese elders may be more important than simply providing them with necessities or sick care. Second, we found no evidence that increased instrumental support from Chinese elders had caused the worsening of their health status. While not intending to deny the existence of such events in China, we believe that such phenomena did not occur universally and the negative outcomes of elders' providing more instrumental support to their significant others may have been exaggerated. It is likely that a high proportion of Chinese elderly persons have provided such support voluntarily as a response to the massive social change. As Whyte and Parish [16] pointed out that, without such help provided by the older folks, the youngsters would bear a very heavy burden of household chores. As a consequence, increased instrumental social support given by elders would not worsen their physical and mental health to a noticeable extent. Third, in contrast with our expectation, the relationship between social support perspectives and health status had stronger impacts in the rural areas of China. That is, the Chinese rural elders appeared more sensitive than their urban counterparts to the lack of social support from their relatives and friends. Such vulnerability may be closely related to the unavailability of a sound social security system in
rural China. Considering the huge size of Chinese rural elders and a lesser extent to which they can expect to receive emotional support, the significance of such areal differentials should be brought to the attention of Chinese policy-makers. Although it has derived important policy implications regarding a number of research issues, the present research remains an exploratory study. With the restriction of using cross-sectional data, the underlying causal linkages between old-age social support and health status cannot be tested effectively. Thus it is necessary to address the directions for further inquiries. With the availability of longitudinal data in this regard, the research can be extended to dynamic perspectives. Specifically, we may examine first the dynamic transitions over time in an elder's health status with the levels of social support fixed at the initial point of time as the explanatory variables; and the changing pattern in social support, in turn fixing the level of health status at the initial point of time, can be analyzed next. More explicit causal relationships between social support and health status can be generated. Another issue deserving attention in future research is the identification of specific sources of social support to elderly persons. While the data used for the present research do not allow such examination, in the future it may be useful to elicit information on the number and gender of children who are providing support of different sorts for analyzing intergenerational flows of social support. This will enable us to extend our research to the domain of demography on fertility, especially the costs and benefits of children, and address the implications of the one-child policy for the elderly persons. For example, sons have been found as the major providers of instrumental support, and daughters as the suppliers of emotional support, which might be the underlying reason for many Chinese couples to desire a daughter [22]. It must also be noted that the generality of the present research may be somewhat restricted because only data of the Wuhan area were used. Although Wuhan was viewed as epitomizing the whole country within this context, it is unrealistic to conclude that the patterns observed in the Wuhan area can be found everywhere in China given its huge size, diversity, and a lack of mobility both socially and geographically. We believe that extended surveys concerning social support and health status among Chinese elderly persons will help provide a wider array of unique patterns. While conducting a national probability sample survey is extremely difficult in China, both administratively and financially, a purposive selection of several survey sites, with each representing a specific region of China, will provide a solid ground for a deeper probe into the research issue and hence widen researchers' awareness of the causal linkages between social support and health status in China.
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