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Health effects of discontinuities in female employment and marital status
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Sot. Sci. Med. Vol. 36, No. 8, pp. 1099-1104, 1993 Printedin Great Britain.All rights reserved
Copyright 0 1993 Pergamon Press Ltd
HEALTH EFFECTS OF DISCONTINUITIES IN FEMALE EMPLOYMENT AND MARITAL STATUS JUDITH H. HIBBARD’
and
CLYDE R. POPE’
I19 Hendricks Hall, University of Oregon, ‘Department of Planning, Public Policy and Management, Eugene, OR 97403, U.S.A. and ‘Center for Health Research, Kaiser Permanente, Northwest Region, 1315 N. Kaiser Center Drive, Portland, OR 97227, U.S.A. Abstract-The discontinuities that characterize women’s work histories are also a factor in women’s marital histories. Family obligations and childbearing contribute to women’s unique employment histories, which include intermittent labor force participation and mobility between employers. While research has increasingly focussed on the effect of labor force participation on women’s health, little attention has been given to the effect of the consistency or the stability of labor force participation on health. The purpose of this paper is to examine 15 years of employment histories and marital status changes among a cohort of women and to determine the cumulative effect of these histories on subsequent morbidity and self-reported health. The cohort of 556 women examined in this study were interviewed via a mail-out as part of a household interview survey completed in 1970-71, and resurveyed questionnaire, in 1985586. Medical record data for the full 15 years of the study have been linked with the survey data. The findings suggest that work discontinuities and marital status discontinuities are unrelated to morbidity during the study period. However, two or more changes in marital status are related to poor self-reported health at follow-up. Key words-social employment history.
roles,
employment
characteristics,
of women’s employment, work history, and career activity have been strongly shaped by their roles as wives and mothers. Family obligations and childbearing contribute to women’s unique employment histories, which include intermittent labor force participation and mobility between employers. The discontinuities that characterize women’s work histories are also a prominent factor in marital histories. While research has increasingly focussed on the effect of role occupancy on women’s health, little attention has been given to the effect of the consistency or the stability of roles on health. The purpose of this paper is to examine 15 years of employment histories and marital status changes among a cohort of women and to determine the cumulative effects of these histories on subsequent morbidity and general health status. Intermittency in labor force participation among women has been explored primarily as a mechanism to explain the wage gap between men and women. It is understood, however, that the phenomenon is primarily a response to the demands put on women in their traditional roles as wives and mothers. In a study of work patterns among employed women, Gwartney-Gibbs [l] reported the effect of children on employment patterns among married women. Employed women without children had fewer spells of no employment and fewer months between spells of employment than did employed women with children at home. Women without children averaged two long spells of employment in their work lives with only 4.3 months spent on the average between spells. Employed women with children averaged three spells
The patterns
morbidity,
role
changes,
women’s
health,
of employment over their work lives, with 77 months out of the labor force. Marital status and health Most research shows that marriage is related to lower morbidity and mortality rates. While this is true for both genders, men tend to derive greater health benefits from marriage than do women [2]. Evidence also suggests that the quality of marriage is a significant predictor of health. Cohesion, companionship, and cooperation in marriage are related to better health for spouses [3]. Wingard [4] reports that divorced women are healthier than are unhappily married women. Thus, a change from married to unmarried could represent anything from a welcome relief to a devastating loss. Irrespective of the emotional valence of a marital status change, such a change often has significant implications for women’s economic status and security. Marital status changes may also involve geographic relocation that can cause disruptions in employment and social ties. Thus, marital status changes may have important implications for women’s health even when the changes are welcome. Employment
and health
The research findings on the health effects of women’s employment have not been unambiguous. However, the weight of the evidence suggests that employment has no ill effects and may provide some health advantage. Cross-sectional studies show that employed women report better overall health, fewer chronic and acute illnesses, make fewer physician
1100
JUDITH H. HIBBARO and CLYDE R. POPE
visits, and restrict activities for illness less often than do nonemployed women [5-91. In addition, results from a cross-sectional study suggest almost a dose-response relationship between employment and health: full-time employed women have the best health, part-time employed women intermediate health, and nonemployed women the poorest health [IO]. It is not clear from cross-sectional studies, however, if poor health results from nonemployment or if poor health deters women from labor force participation. Longitudinal studies have been relatively few and findings are very recent. The results of these studies mostly indicate some health advantage to employment, or at least no health disadvantage [II-151. However, Ebi-Kryson et al. [ 151, in examining several health outcomes, did find slightly higher prevalence rates of respiratory conditions among employed women as compared to nonemployed women. The measurement approach to employment patterns has varied in these longitudinal studies. Some measure employment status only at baseline and use this measure to predict health outcomes over time [I 1, 12, 141. Kolter and Wingard [12] used a more developed baseline measure in that they coded women as employed only if they were currently working full-time and had done so for at least 50% of their adult lives since age 22. Ebi-Kryston et al. [I 51 used a four-category typology to characterize work patterns over a 20-year follow-up: employed at baseline/employed at follow-up; homemaker at baseline/employed at follow-up; employed at baseline/homemaker at follow-up; homemaker at baseline/homemaker at follow-up. McKinlay et al. [13] elaborated on this typology in their three-year study, adding a fifth category: changed employment more than once. In their population of 1944 women, 28.2% had at least one change in their employment status and 14.3% had more than one change in the three-year observation period. The McKinlay et al. study is the only one of these longitudinal investigations to examine the effect of intermittency in employment on health. They found no negative health effects from more than one change in employment over a three-year period. Some of these studies fail to control for baseline or initial health status or have only weak controls for baseline health [12, 151. This is important since it leaves open alternative interpretations of the findings. It could be that at the initial survey healthier women were more likely to be in the work force and/or more likely to remain in the work force. Building on these past studies, the present investigation controls for baseline health status and uses months of employment and the number of entrances into the labor force during the first 5 (and 10) years of the study to predict health outcomes over the last 10 (and 5) years of the study. In addition, months of employment and marital status stability over the entire 15 years of observation are examined as
predictors of self-rated health at the end of the study period. An initial step in the analysis is to describe the work patterns of a cohort of women over a IS-year period and examine these patterns in relationship to women’s marital and parental roles. The discontinuities associated with women’s employment patterns may be a source of stress and thus add to health risks. Alternatively, the discontinuities may be an avenue for the relief of other sources of stress associated with domestic and family obligations. An empirical examination of the long-term effects of the work patterns will help to illuminate this question. METHODS
The cohort of women examined in this study were interviewed as part of a household interview survey conducted in 197OG71 by the Center for Health Research, of the Northwest Region of Kaiser Permanente, and resurveyed via a mail-out questionnaire in 1985586. The initial household interview survey achieved a 92% response rate, yielding a beginning cohort of 1140 women. The cohort of women were between the ages of 18 and 65 in 1970-71. Over the 15 years of the study period about half of the cohort was lost to follow-up (there were 103 documented deaths), yielding a final cohort of 556. Four hundred and eighty women had discontinued membership in the health plan over the 15 years of the study. However, they were included in the follow-up survey and there was a 26% response rate among those women who had discontinued health plan membership. There was an 8 1% response rate among respondents still enrolled in the health plan. The cohort members who remained in the study have sociodemographic characteristics very similar to the entire cohort, with one exception. The cohort members who remained in the study were older than the average initial cohort member. medical records have been The respondents’ routinely abstracted for research purposes since enrollment. or since January 1967 if enrollment was prior to this date. The dependent variables in this analysis are self-reported health status at follow-up and serious morbidities occurring subsequent to the interview date. Three diagnoses are examined: ischemic heart disease (ICDA 9th edition 410414) stroke (ICDA 430438) and malignancy (ICDA 140-208, except 173). For each morbidity, the analysis excludes subjects whose morbidity predated the initial interview. The outcome variable of selfreported health status is a three-value variable. Respondents at follow-up indicated how they would rate their health: excellent, good, or fair/poor. Over the 15year period there were 46 diagnoses of ischemic heart disease, 47 diagnoses of malignancies, and 24 diagnoses of stroke in the study population. The morbidity rates are adjusted for health plan
Discontinuities in female employment and marital status eligibility. Seventy-eight percent of the study population were enrolled in the health plan for the full 15-year period. Only 3% had less than 10 years of health plan eligibility over the study period. Predictor and control variables The predictor variables are measures of the stability of employment and marital status over the 1j-year study period. Months of‘ employment. This variable is a simple count of the number of months of employment from 1971 through 1985. In the follow-up survey respondents reported each of their paid positions during this period, the length of time employed, and whether the position was full- or part-time. In this analysis, no differentiation is made between full- and parttime employment. Thus the number of months of employment in each five-year time period within the 15-year study period was ascertained. For some of the analysis the first 5 or 10 years of employment history is used to predict morbidity in the subsequent 10 or 5 years. In other parts of the analysis the stability of employment for the full 15 years is examined. In addition to these variations, different forms of the variable ‘months of employment’ are also used in the analysis. For example, the full variable of number of months of employment (O-180) is used in the univariate and bivariate portions of the analysis. However, for the multivariate portion of the analysis, dummy variables are constructed using the trichotomy of: no months of employment during the study period; full months of employment during the study period (e.g. 180 months within a 15-year period); and some employment with less than full months during observation period. Where dummy variables are used, the reference category is some employment with less than full months. Total entrances into employment. This variable is a simple count of the number of times that women reported entering paid employment for either the first time or after a minimum of a 2-month hiatus. This variable was constructed from the employment history reported in the follow-up survey. Women who were employed at baseline, then, could have zero entrances if they either never had a two-month hiatus in work or left the work force and did not reenter during the study period. This variable ranges from 0 to 5. Marital status stability. This variable is a summary of marital status changes over the study period. The full variable has the categories: married at baselineremained married through 15 year study period; unmarried at baseline-remained unmarried through study period; changed marital status once during study period; changed marital status two or more times during the study period. For the multivariate analysis, dummy variables are constructed using the category married and remained married as the reference category.
1101
Included in all the multivariate analyses are three control variables; age, education, and baseline selfreported health status. Self-reported health status is a three-value variable. Respondents rated their health as: excellent, good, or fair/poor. By controlling for baseline self-reported health, the effect of the stability of the role (employment or marital status) may be observed while removing the effect of initial health status. Also examined in relationship to months of employment are family and occupational variables. Number of children as well as parental status (whether or not there are any children in the home under the age of 19 at baseline), and baseline marital status are examined in relationship to months of employment over the study period. In addition, occupational status, an ordinal five value variable reflecting occupational prestige, is examined in relationship to stability of employment. Design and statistical
analysis
The study utilizes a longitudinal cohort design. Employment and marital status stability for the study are used to predict morbidity and health status outcomes over a 15-year period. Cox proportional hazards regression models are used to assess the relative risk of morbidity over the study period. An important feature of this statistical method is that it provides for varying lengths of observation. In this investigation, respondents free of morbidity at baseline are observed until a morbidity is diagnosed, disenrollment occurs, or the study period concludes. These nonparametric models allow the hazards of death and disease incidence to be arbitrary functions of follow-up time but require the proportional effects of predictors on hazards to be independent of followup time. That is, the effects of each predictor variable are assumed in the Cox model to be the same over the entire period of observation. The SAS SUGI procedure PHGLM was used [16]. This procedure handles censoring due to health plan disenrollment and includes a goodness-of-fit test of the proportional hazards assumption. The exponential function of the Cox regression coefficient is the relative hazard of the outcome for a unit of difference in the predictor variable [17]. The analysis begins with a univariate and “ivariate assessment of the research variables. The frequency distributions of the main predictor variables are presented along with the intercorrelations of sociodemographic factors and predictor variables. The multivariate analysis is carried out using several different permutations. One of these permutations is to examine the first 5 years of employment history as a predictor of morbidity in the last 10 years, and also to examine the first 10 years of employment history as a predictor of morbidity in the last five years. TO examine discontinuities in employment as predictors of morbidities in a concurrent time frame would leave the direction of causality in question. That is, it
1102
JUDITHH. HIBBARDand CLYDER. POPE Table
I. Months of employment the study period
0 months l-36 months 37-72 months 73-1 IO months II I-148 months 149-192 months 192 months
Table 3. Marital
over
N
%
256 28 30 31 26 I7 I68
46.0 50 5.4 5.6 4.7 3.1 14.5
status changes over the study period
Married at baseline no changes Unmarried at baseline no changes Married at baseline unmarried at follow-up Unmarried at baseline married at follow-up Two or more marital status changes
would not be clear whether morbidity came first and caused the discontinuities in employment or whether the discontinuities caused the morbidity. The other permutations of the multivariate analysis are elaborated on in the findings section. FINDINGS Table 1 shows a frequency distribution of the months of employment reported during the l5-year study period. Almost half of the population (46%) remained outside the work force during the entire period of observation. Only 14.5% of the population was employed for the full 192 months. About 40% of the population was employed for some period although not the entire time period. Table 2 shows the number of entrances into paid employment over the study period. For women employed at baseline, 78% had no new entrances. That is, they either stayed in employed positions the entire period of observation (76% of the 222 women) or left paid employment at some point in the study period and did not re-enter (24% of 222 women). Among women not employed at baseline, only about 4% entered the work force during the study period. Thus, while Table 1 suggests a fair amount of discontinuity in employment histories, the data in Table 2 suggests that women are not continually exiting and entering the work force. What is not reflected in either of these tables is job mobility. That is, changes in jobs without a hiatus in working are not included. Table 3 shows the stability of marital status in the study population over the 15-year period. The majority of the women were married at baseline and remained in the same marriage over the study period (65.9%). Almost 17% of the population had at least one marital status change and 5.3% had two or more marital status changes over the study period.
Employed al baseline 0 entrances= I entrance 2 entrances 3 entrances or more
78.0% 17.0% 3.0% 2.0%
(222) (49) (9) (5)
Nonemployed at baseline 96.0% 3.0% 0.4% 0.4%
“An entrance refers to either a new entrance entrance following at least a two-month employment.
at
(256) (8) (I) (I) or to an hiatus in
65.9% 12.0%
16
13.8%
I6 29
2.9% 5.3%
Table 4 shows the correlations between the number of months of employment and socio-demographic and health status factors. Age is positively related to the number of months employed during the study period. That is, older women had more months of employment. Education is also positively correlated with the number of months of employment. While education is significantly related to months of employment, occupational status is not. The three variables relating to family roles are significantly related to months of employment. Women who were unmarried at baseline had more months of employment, as did women with no or with fewer children at home. Baseline self-reported health status is not significantly related to the number of months of employment over the study period. The multivariate analysis examining morbidity outcome is carried out in a variety of ways. First, the relative hazards are examined both for the individual morbidities, and for the occurrence of any of the three morbidities. Second, the full variable of months of employment is used as well as the dummy variables (no employment, discontinuous employment, and continuous employment) to predict subsequent morbidity. Third, family role variables are added to the control variables in the equation. These family role variables include baseline marital status (married or unmarried) and parental status (whether there are children under the age of 19 in the household). Finally, the first 5 years of employment history is used to predict morbidities in the last 10 years of the study, as well as the first 10 years of employment history to predict morbidity in the last 5 years. Not all of these permutations in the analysis are shown. In Table 5 the relative hazards of morbidity are shown for women with discontinuity in their employment patterns in the first 10 years of the study as Table
4. Months
of employment and s&o-demographic characteristics of cohort Correlation coefficient
Table 2. Number of entrances’ into paid employment over the study period by employment status at baseline
362 66
Age Education Occupational status Number of children Marital status at baseline (married or unmarried) Parental status (no vs any children) Baseline health status (3-value self-report) ‘P co.05 **P
X2
0.07’ 0.07’ 0.04 -0.17” l
** *
“S.
Discontinuities Table 5. Number
of months
of enmlovment
in female employment and marital status
in first 10 years as predictors
of morbidity
amona
1103
wmen
in last 5 “ears of studv Deriod
Adjusted relative hazards” of malignancy, stroke or ischemic heart disease No employment as compared to some months of employment Full number of months of employment as compared to smne months ‘Adjusted
for age, education,
and baseline self-reported
of marital
(0.7-3.2) (0.5-3.0)
95%C.I. 95% Cl.
health.
compared to the hazards of morbidity for women with either no employment or full employment. What is shown in Table 5 is the hazard of the occurrence of any of the three morbidities (stroke, ischemic heart disease, or a malignancy). There is apparently no statistically significant increased hazard of morbidity associated with discontinuous employment patterns over continuously employed or continuously unemployed. All the other permutations to the analysis mentioned above also yielded similar nonsignificant findings. An analysis that examined the total number of entrances into employment was also carried out. This variable was not a significant predictor of morbidity, either independently or additively with the months of employment variables. Finally, the months of employment over the full 15 years is examined as a predictor of selfreported health at follow-up. In this analysis, as in the previous one, baseline self-reported health, age, and education are used as control variables. In this analysis also, months of employment (or the dummy variables) fail to predict follow-up self-reported health status. The last portion of the analysis examines marital status stability and health and morbidity outcomes. The relative hazards of morbidity associated with martial status stability are shown in Table 6. As in Table 5, the relative hazards are for any of the three morbidities examined. However, unlike the relative hazards shown in Table 5, these hazards are calculated for the entire 15-year study period. The reference category in this analysis is married and remained married over the study period. There is apparently no increased hazard of morbidity associated with remaining unmarried or having one or more marital status changes as compared to being continuously married. This finding is true when looking at marital status stability as a sole predictor as well as when months of employment is included in the equation. However, in the analysis examining self-reported health status reported at follow-up, it does appear that those women with two or more marital status changes are significantly more likely to report poorer Table 6. Number
R.H. 1.5 R.H. 1.3
of employment
status changes as uredictors
health than women who were continuously married (1 = 2.6, P < 0.01). The other categories of marital stability were also compared to women who were continuously married, and no other statistically significant differences were noted. CONCLUSIONS
The findings confirm that women’s work patterns are characterized by discontinuities, and that these discontinuities are related to women’s domestic and family obligations. The degree of discontinuity is somewhat less than reported in others studies [l, 151. The design of this study may be biased toward subjects with stable work patterns. Women who moved from the area because of job changes may have been lost to follow-up. Women are most likely to return to employment when their children reach school age. Thus, it was surprising that of those women not employed at baseline, only 4% entered the labor force during the study period. However, among those employed at baseline 40% (I 16) left the labor force at least once during the study period. The long-term trend is for women to pursue a more continuous pattern of labor force participation throughout adulthood [2]. As work patterns evolve, employment will likely become a more stable and permanent facet of women’s lives. The results suggest that employment discontinuities are not related to subsequent morbidities or to self-rated health. Thus, there is no evidence to suggest that employment discontinuities, in themselves, are a major stressor in women’s lives. These findings are consistent with those of McKinlay et al. [13] who found no health effects associated with intermittency in employment. Discontinuities in marital status (at least two changes) is related to poorer self-reported health. This is true whether or not they are accompanied by discontinuities in employment. However, marital discontinuities were not related to morbidity outcomes. The self-reported health effect may reflect a of morbiditv
anmne women in 15 Years of studv oeriod Adjusted relative hazards” of malignancy. stroke or ischemic heart disease
Unmarried at baseline married at baseline One change in marital married at baseline Two or more changes married at baseline “Adjusted
with no changes over study as compared with no changes Over study period status as compared to with no changes Over study period in marital status as compared to with no changes over study period
for age, education,
and baseline self-reported
health.
to R.H. 0.92
95% C.I.
(0.3-2.8)
R.H. 1.0
95% c. 1.
(0.k2.9)
R.H. 0.8
95% c. 1.
(0.1-6.3)
1104
JUDITH H. HIBBARD and CLYDE R. POPE
more general feeling about the quality of life as well as actual health deficits. Thus, further research which examines the health effects beyond self-reported measures would be desirable. Thus, of the discontinuities that characterize women’s lives examined in this investigation, marital instability is the only one that appears to be related to subsequent health. Instability in this more intimate aspect of life likely has more pervasive life consequences for women than changes in employment. In addition, there may be a greater element of choice in the discontinuities associated with employment than with the discontinuities associated with marital status. That is, if discontinuities in employment represent a strategy to reduce the stress associated with family obligations, then the changes are likely to be freely chosen. On the other hand, some marital discontinuities (widowhood and divorce) among middle-aged women are very likely to be unwelcome and unchosen life changes. Further research that examines the reasons for employment discontinuities and satisfaction with employment status changes is needed to understand the impact of this type of discontinuity in women’s lives. Similarly, are marital status changes which are freely chosen less likely to lead to poorer health than marital status changes that are unwelcome? While the evidence produced to date suggests employment discontinuities have no direct health effect, the question of how these changes may affect women’s health indirectly should also be investigated. That is, if intermittency affects women’s long-term occupational opportunities and earnings, is there an indirect effect on women’s health through reduced material circumstances and reduced life chances? Finally, as more women enter retirement the question of the degree to which women’s employment patterns affect adjustment to retirement and health in the post retirement years becomes important. Some of the questions surrounding work histories and postretirement adaptation and health will be examined, since the authors plan to follow the cohort studied in this investigation into their retirement years. Acknowledgement-This research is supported from the National Institute on Aging, AG03824,
by a grant USDHHS.
REFERENCES
1. Gwartney-Gibbs P. A. Women’s work experience and the rusty skills hypothesis. Women and Work; An Annual Review (Edited by Gutek B. A., Stromberg A. H. and Larwood L.), Vol. 3, pp. 1699189, 1988. 2 Sorenson G. and Verbrugge L. Women, work and health. Annual Ret&w, qf Public Health (Edited by Breslow L., Fielding J. and Lavc L.), Vol 8. pp. 2355252. 1987. 3 Schmolt R., Pope C. R. and Hibbard J. II. Marital interaction and spousal health and wellbeing. Women Hlth 15, 35-56, 1989. 4 Wingard D. L. The sex differential in mortality rates. Am. J. Epidemiol. 115, 205-216. 1982. 5 Nathanson C. A. Social roles and health status among women: The significance of employment. Sot. Sci. Med. 14, 4633471, 1980. Verbrugge L. M. Multiple roles and physical health of women and men. J. Hlrh sot. Behar. 24, 16-30, 1983. Verbrugge L. M. and Madans J. H. Women’s roles and health. Am. Demographics 7. 36 39, 19X5. Hibbard J. H. and Pope C. R. Employment status. employment characteristics, and women’s health. Women Hlth 10, 59-77, 1985. 9 Adelmann P. K., Antonucci T., Crohan S. and Coleman L. A causal analysis of employment and health in midlife women. Women Hlth 16, 5-20. 1990. and 10. Herold J. and Waldron I. Part-time employment women’s health. J. occupat. Med. 27, 405 412, 1985. Il. Hibbard J. H. and Pope C. R. Effect of domestic and occupational roles on morbidity and mortality. Sot. Sci. Med. 32, 805-81 I, 1991. 12. Kolter P. and Wingard D. The effect of occupational, marital and parental roles on mortality: The Alameda study. Am. J. publ. Hlih 79, 607612, 1989. S. M.. Tirant R. S., McKinlay J. B., 13 McKinley Brambilla D. and Ferdock M. The relative contributions of work and three nurturing roles to the health of mid-aged women: The Experience of the Massachusetts Women’s Health Study. In Gender, Health and Longevily: Multidisciplinary Perspectiws (Edited by Ory M. G. and Women H. R.). Springer, New York, 1990. 14 Waldron I. and Jacobs J. A. Effects of multiple roles on women’s health-Evidence from a national longitudinal study. Women Hlth 15, 3319, 1989. K. L., Higgins M. W. and Keller J. B. 15 Ebi-Kryston Health and other characteristics of employed women and homemakers in Tecumseh. 1959 1978. Women Hlth 16, 23-39, 1990. 16 SAS Institute: SUCI Supplemental Librarla User’s Guide Version 5 Edition. SAS Institute Inc. Cary, NC, 1986. 17 Kelsey J. L., Thompson W. D. and Evans A. S. Methods in Observational Epidemiology,. Oxford University Press, New York, 1986.
Sot. Sci. Med. Vol. 36, No. 8, pp. 1099-1104, 1993 Printedin Great Britain.All rights reserved
Copyright 0 1993 Pergamon Press Ltd
HEALTH EFFECTS OF DISCONTINUITIES IN FEMALE EMPLOYMENT AND MARITAL STATUS JUDITH H. HIBBARD’
and
CLYDE R. POPE’
I19 Hendricks Hall, University of Oregon, ‘Department of Planning, Public Policy and Management, Eugene, OR 97403, U.S.A. and ‘Center for Health Research, Kaiser Permanente, Northwest Region, 1315 N. Kaiser Center Drive, Portland, OR 97227, U.S.A. Abstract-The discontinuities that characterize women’s work histories are also a factor in women’s marital histories. Family obligations and childbearing contribute to women’s unique employment histories, which include intermittent labor force participation and mobility between employers. While research has increasingly focussed on the effect of labor force participation on women’s health, little attention has been given to the effect of the consistency or the stability of labor force participation on health. The purpose of this paper is to examine 15 years of employment histories and marital status changes among a cohort of women and to determine the cumulative effect of these histories on subsequent morbidity and self-reported health. The cohort of 556 women examined in this study were interviewed via a mail-out as part of a household interview survey completed in 1970-71, and resurveyed questionnaire, in 1985586. Medical record data for the full 15 years of the study have been linked with the survey data. The findings suggest that work discontinuities and marital status discontinuities are unrelated to morbidity during the study period. However, two or more changes in marital status are related to poor self-reported health at follow-up. Key words-social employment history.
roles,
employment
characteristics,
of women’s employment, work history, and career activity have been strongly shaped by their roles as wives and mothers. Family obligations and childbearing contribute to women’s unique employment histories, which include intermittent labor force participation and mobility between employers. The discontinuities that characterize women’s work histories are also a prominent factor in marital histories. While research has increasingly focussed on the effect of role occupancy on women’s health, little attention has been given to the effect of the consistency or the stability of roles on health. The purpose of this paper is to examine 15 years of employment histories and marital status changes among a cohort of women and to determine the cumulative effects of these histories on subsequent morbidity and general health status. Intermittency in labor force participation among women has been explored primarily as a mechanism to explain the wage gap between men and women. It is understood, however, that the phenomenon is primarily a response to the demands put on women in their traditional roles as wives and mothers. In a study of work patterns among employed women, Gwartney-Gibbs [l] reported the effect of children on employment patterns among married women. Employed women without children had fewer spells of no employment and fewer months between spells of employment than did employed women with children at home. Women without children averaged two long spells of employment in their work lives with only 4.3 months spent on the average between spells. Employed women with children averaged three spells
The patterns
morbidity,
role
changes,
women’s
health,
of employment over their work lives, with 77 months out of the labor force. Marital status and health Most research shows that marriage is related to lower morbidity and mortality rates. While this is true for both genders, men tend to derive greater health benefits from marriage than do women [2]. Evidence also suggests that the quality of marriage is a significant predictor of health. Cohesion, companionship, and cooperation in marriage are related to better health for spouses [3]. Wingard [4] reports that divorced women are healthier than are unhappily married women. Thus, a change from married to unmarried could represent anything from a welcome relief to a devastating loss. Irrespective of the emotional valence of a marital status change, such a change often has significant implications for women’s economic status and security. Marital status changes may also involve geographic relocation that can cause disruptions in employment and social ties. Thus, marital status changes may have important implications for women’s health even when the changes are welcome. Employment
and health
The research findings on the health effects of women’s employment have not been unambiguous. However, the weight of the evidence suggests that employment has no ill effects and may provide some health advantage. Cross-sectional studies show that employed women report better overall health, fewer chronic and acute illnesses, make fewer physician
1100
JUDITH H. HIBBARO and CLYDE R. POPE
visits, and restrict activities for illness less often than do nonemployed women [5-91. In addition, results from a cross-sectional study suggest almost a dose-response relationship between employment and health: full-time employed women have the best health, part-time employed women intermediate health, and nonemployed women the poorest health [IO]. It is not clear from cross-sectional studies, however, if poor health results from nonemployment or if poor health deters women from labor force participation. Longitudinal studies have been relatively few and findings are very recent. The results of these studies mostly indicate some health advantage to employment, or at least no health disadvantage [II-151. However, Ebi-Kryson et al. [ 151, in examining several health outcomes, did find slightly higher prevalence rates of respiratory conditions among employed women as compared to nonemployed women. The measurement approach to employment patterns has varied in these longitudinal studies. Some measure employment status only at baseline and use this measure to predict health outcomes over time [I 1, 12, 141. Kolter and Wingard [12] used a more developed baseline measure in that they coded women as employed only if they were currently working full-time and had done so for at least 50% of their adult lives since age 22. Ebi-Kryston et al. [I 51 used a four-category typology to characterize work patterns over a 20-year follow-up: employed at baseline/employed at follow-up; homemaker at baseline/employed at follow-up; employed at baseline/homemaker at follow-up; homemaker at baseline/homemaker at follow-up. McKinlay et al. [13] elaborated on this typology in their three-year study, adding a fifth category: changed employment more than once. In their population of 1944 women, 28.2% had at least one change in their employment status and 14.3% had more than one change in the three-year observation period. The McKinlay et al. study is the only one of these longitudinal investigations to examine the effect of intermittency in employment on health. They found no negative health effects from more than one change in employment over a three-year period. Some of these studies fail to control for baseline or initial health status or have only weak controls for baseline health [12, 151. This is important since it leaves open alternative interpretations of the findings. It could be that at the initial survey healthier women were more likely to be in the work force and/or more likely to remain in the work force. Building on these past studies, the present investigation controls for baseline health status and uses months of employment and the number of entrances into the labor force during the first 5 (and 10) years of the study to predict health outcomes over the last 10 (and 5) years of the study. In addition, months of employment and marital status stability over the entire 15 years of observation are examined as
predictors of self-rated health at the end of the study period. An initial step in the analysis is to describe the work patterns of a cohort of women over a IS-year period and examine these patterns in relationship to women’s marital and parental roles. The discontinuities associated with women’s employment patterns may be a source of stress and thus add to health risks. Alternatively, the discontinuities may be an avenue for the relief of other sources of stress associated with domestic and family obligations. An empirical examination of the long-term effects of the work patterns will help to illuminate this question. METHODS
The cohort of women examined in this study were interviewed as part of a household interview survey conducted in 197OG71 by the Center for Health Research, of the Northwest Region of Kaiser Permanente, and resurveyed via a mail-out questionnaire in 1985586. The initial household interview survey achieved a 92% response rate, yielding a beginning cohort of 1140 women. The cohort of women were between the ages of 18 and 65 in 1970-71. Over the 15 years of the study period about half of the cohort was lost to follow-up (there were 103 documented deaths), yielding a final cohort of 556. Four hundred and eighty women had discontinued membership in the health plan over the 15 years of the study. However, they were included in the follow-up survey and there was a 26% response rate among those women who had discontinued health plan membership. There was an 8 1% response rate among respondents still enrolled in the health plan. The cohort members who remained in the study have sociodemographic characteristics very similar to the entire cohort, with one exception. The cohort members who remained in the study were older than the average initial cohort member. medical records have been The respondents’ routinely abstracted for research purposes since enrollment. or since January 1967 if enrollment was prior to this date. The dependent variables in this analysis are self-reported health status at follow-up and serious morbidities occurring subsequent to the interview date. Three diagnoses are examined: ischemic heart disease (ICDA 9th edition 410414) stroke (ICDA 430438) and malignancy (ICDA 140-208, except 173). For each morbidity, the analysis excludes subjects whose morbidity predated the initial interview. The outcome variable of selfreported health status is a three-value variable. Respondents at follow-up indicated how they would rate their health: excellent, good, or fair/poor. Over the 15year period there were 46 diagnoses of ischemic heart disease, 47 diagnoses of malignancies, and 24 diagnoses of stroke in the study population. The morbidity rates are adjusted for health plan
Discontinuities in female employment and marital status eligibility. Seventy-eight percent of the study population were enrolled in the health plan for the full 15-year period. Only 3% had less than 10 years of health plan eligibility over the study period. Predictor and control variables The predictor variables are measures of the stability of employment and marital status over the 1j-year study period. Months of‘ employment. This variable is a simple count of the number of months of employment from 1971 through 1985. In the follow-up survey respondents reported each of their paid positions during this period, the length of time employed, and whether the position was full- or part-time. In this analysis, no differentiation is made between full- and parttime employment. Thus the number of months of employment in each five-year time period within the 15-year study period was ascertained. For some of the analysis the first 5 or 10 years of employment history is used to predict morbidity in the subsequent 10 or 5 years. In other parts of the analysis the stability of employment for the full 15 years is examined. In addition to these variations, different forms of the variable ‘months of employment’ are also used in the analysis. For example, the full variable of number of months of employment (O-180) is used in the univariate and bivariate portions of the analysis. However, for the multivariate portion of the analysis, dummy variables are constructed using the trichotomy of: no months of employment during the study period; full months of employment during the study period (e.g. 180 months within a 15-year period); and some employment with less than full months during observation period. Where dummy variables are used, the reference category is some employment with less than full months. Total entrances into employment. This variable is a simple count of the number of times that women reported entering paid employment for either the first time or after a minimum of a 2-month hiatus. This variable was constructed from the employment history reported in the follow-up survey. Women who were employed at baseline, then, could have zero entrances if they either never had a two-month hiatus in work or left the work force and did not reenter during the study period. This variable ranges from 0 to 5. Marital status stability. This variable is a summary of marital status changes over the study period. The full variable has the categories: married at baselineremained married through 15 year study period; unmarried at baseline-remained unmarried through study period; changed marital status once during study period; changed marital status two or more times during the study period. For the multivariate analysis, dummy variables are constructed using the category married and remained married as the reference category.
1101
Included in all the multivariate analyses are three control variables; age, education, and baseline selfreported health status. Self-reported health status is a three-value variable. Respondents rated their health as: excellent, good, or fair/poor. By controlling for baseline self-reported health, the effect of the stability of the role (employment or marital status) may be observed while removing the effect of initial health status. Also examined in relationship to months of employment are family and occupational variables. Number of children as well as parental status (whether or not there are any children in the home under the age of 19 at baseline), and baseline marital status are examined in relationship to months of employment over the study period. In addition, occupational status, an ordinal five value variable reflecting occupational prestige, is examined in relationship to stability of employment. Design and statistical
analysis
The study utilizes a longitudinal cohort design. Employment and marital status stability for the study are used to predict morbidity and health status outcomes over a 15-year period. Cox proportional hazards regression models are used to assess the relative risk of morbidity over the study period. An important feature of this statistical method is that it provides for varying lengths of observation. In this investigation, respondents free of morbidity at baseline are observed until a morbidity is diagnosed, disenrollment occurs, or the study period concludes. These nonparametric models allow the hazards of death and disease incidence to be arbitrary functions of follow-up time but require the proportional effects of predictors on hazards to be independent of followup time. That is, the effects of each predictor variable are assumed in the Cox model to be the same over the entire period of observation. The SAS SUGI procedure PHGLM was used [16]. This procedure handles censoring due to health plan disenrollment and includes a goodness-of-fit test of the proportional hazards assumption. The exponential function of the Cox regression coefficient is the relative hazard of the outcome for a unit of difference in the predictor variable [17]. The analysis begins with a univariate and “ivariate assessment of the research variables. The frequency distributions of the main predictor variables are presented along with the intercorrelations of sociodemographic factors and predictor variables. The multivariate analysis is carried out using several different permutations. One of these permutations is to examine the first 5 years of employment history as a predictor of morbidity in the last 10 years, and also to examine the first 10 years of employment history as a predictor of morbidity in the last five years. TO examine discontinuities in employment as predictors of morbidities in a concurrent time frame would leave the direction of causality in question. That is, it
1102
JUDITHH. HIBBARDand CLYDER. POPE Table
I. Months of employment the study period
0 months l-36 months 37-72 months 73-1 IO months II I-148 months 149-192 months 192 months
Table 3. Marital
over
N
%
256 28 30 31 26 I7 I68
46.0 50 5.4 5.6 4.7 3.1 14.5
status changes over the study period
Married at baseline no changes Unmarried at baseline no changes Married at baseline unmarried at follow-up Unmarried at baseline married at follow-up Two or more marital status changes
would not be clear whether morbidity came first and caused the discontinuities in employment or whether the discontinuities caused the morbidity. The other permutations of the multivariate analysis are elaborated on in the findings section. FINDINGS Table 1 shows a frequency distribution of the months of employment reported during the l5-year study period. Almost half of the population (46%) remained outside the work force during the entire period of observation. Only 14.5% of the population was employed for the full 192 months. About 40% of the population was employed for some period although not the entire time period. Table 2 shows the number of entrances into paid employment over the study period. For women employed at baseline, 78% had no new entrances. That is, they either stayed in employed positions the entire period of observation (76% of the 222 women) or left paid employment at some point in the study period and did not re-enter (24% of 222 women). Among women not employed at baseline, only about 4% entered the work force during the study period. Thus, while Table 1 suggests a fair amount of discontinuity in employment histories, the data in Table 2 suggests that women are not continually exiting and entering the work force. What is not reflected in either of these tables is job mobility. That is, changes in jobs without a hiatus in working are not included. Table 3 shows the stability of marital status in the study population over the 15-year period. The majority of the women were married at baseline and remained in the same marriage over the study period (65.9%). Almost 17% of the population had at least one marital status change and 5.3% had two or more marital status changes over the study period.
Employed al baseline 0 entrances= I entrance 2 entrances 3 entrances or more
78.0% 17.0% 3.0% 2.0%
(222) (49) (9) (5)
Nonemployed at baseline 96.0% 3.0% 0.4% 0.4%
“An entrance refers to either a new entrance entrance following at least a two-month employment.
at
(256) (8) (I) (I) or to an hiatus in
65.9% 12.0%
16
13.8%
I6 29
2.9% 5.3%
Table 4 shows the correlations between the number of months of employment and socio-demographic and health status factors. Age is positively related to the number of months employed during the study period. That is, older women had more months of employment. Education is also positively correlated with the number of months of employment. While education is significantly related to months of employment, occupational status is not. The three variables relating to family roles are significantly related to months of employment. Women who were unmarried at baseline had more months of employment, as did women with no or with fewer children at home. Baseline self-reported health status is not significantly related to the number of months of employment over the study period. The multivariate analysis examining morbidity outcome is carried out in a variety of ways. First, the relative hazards are examined both for the individual morbidities, and for the occurrence of any of the three morbidities. Second, the full variable of months of employment is used as well as the dummy variables (no employment, discontinuous employment, and continuous employment) to predict subsequent morbidity. Third, family role variables are added to the control variables in the equation. These family role variables include baseline marital status (married or unmarried) and parental status (whether there are children under the age of 19 in the household). Finally, the first 5 years of employment history is used to predict morbidities in the last 10 years of the study, as well as the first 10 years of employment history to predict morbidity in the last 5 years. Not all of these permutations in the analysis are shown. In Table 5 the relative hazards of morbidity are shown for women with discontinuity in their employment patterns in the first 10 years of the study as Table
4. Months
of employment and s&o-demographic characteristics of cohort Correlation coefficient
Table 2. Number of entrances’ into paid employment over the study period by employment status at baseline
362 66
Age Education Occupational status Number of children Marital status at baseline (married or unmarried) Parental status (no vs any children) Baseline health status (3-value self-report) ‘P co.05 **P
X2
0.07’ 0.07’ 0.04 -0.17” l
** *
“S.
Discontinuities Table 5. Number
of months
of enmlovment
in female employment and marital status
in first 10 years as predictors
of morbidity
amona
1103
wmen
in last 5 “ears of studv Deriod
Adjusted relative hazards” of malignancy, stroke or ischemic heart disease No employment as compared to some months of employment Full number of months of employment as compared to smne months ‘Adjusted
for age, education,
and baseline self-reported
of marital
(0.7-3.2) (0.5-3.0)
95%C.I. 95% Cl.
health.
compared to the hazards of morbidity for women with either no employment or full employment. What is shown in Table 5 is the hazard of the occurrence of any of the three morbidities (stroke, ischemic heart disease, or a malignancy). There is apparently no statistically significant increased hazard of morbidity associated with discontinuous employment patterns over continuously employed or continuously unemployed. All the other permutations to the analysis mentioned above also yielded similar nonsignificant findings. An analysis that examined the total number of entrances into employment was also carried out. This variable was not a significant predictor of morbidity, either independently or additively with the months of employment variables. Finally, the months of employment over the full 15 years is examined as a predictor of selfreported health at follow-up. In this analysis, as in the previous one, baseline self-reported health, age, and education are used as control variables. In this analysis also, months of employment (or the dummy variables) fail to predict follow-up self-reported health status. The last portion of the analysis examines marital status stability and health and morbidity outcomes. The relative hazards of morbidity associated with martial status stability are shown in Table 6. As in Table 5, the relative hazards are for any of the three morbidities examined. However, unlike the relative hazards shown in Table 5, these hazards are calculated for the entire 15-year study period. The reference category in this analysis is married and remained married over the study period. There is apparently no increased hazard of morbidity associated with remaining unmarried or having one or more marital status changes as compared to being continuously married. This finding is true when looking at marital status stability as a sole predictor as well as when months of employment is included in the equation. However, in the analysis examining self-reported health status reported at follow-up, it does appear that those women with two or more marital status changes are significantly more likely to report poorer Table 6. Number
R.H. 1.5 R.H. 1.3
of employment
status changes as uredictors
health than women who were continuously married (1 = 2.6, P < 0.01). The other categories of marital stability were also compared to women who were continuously married, and no other statistically significant differences were noted. CONCLUSIONS
The findings confirm that women’s work patterns are characterized by discontinuities, and that these discontinuities are related to women’s domestic and family obligations. The degree of discontinuity is somewhat less than reported in others studies [l, 151. The design of this study may be biased toward subjects with stable work patterns. Women who moved from the area because of job changes may have been lost to follow-up. Women are most likely to return to employment when their children reach school age. Thus, it was surprising that of those women not employed at baseline, only 4% entered the labor force during the study period. However, among those employed at baseline 40% (I 16) left the labor force at least once during the study period. The long-term trend is for women to pursue a more continuous pattern of labor force participation throughout adulthood [2]. As work patterns evolve, employment will likely become a more stable and permanent facet of women’s lives. The results suggest that employment discontinuities are not related to subsequent morbidities or to self-rated health. Thus, there is no evidence to suggest that employment discontinuities, in themselves, are a major stressor in women’s lives. These findings are consistent with those of McKinlay et al. [13] who found no health effects associated with intermittency in employment. Discontinuities in marital status (at least two changes) is related to poorer self-reported health. This is true whether or not they are accompanied by discontinuities in employment. However, marital discontinuities were not related to morbidity outcomes. The self-reported health effect may reflect a of morbiditv
anmne women in 15 Years of studv oeriod Adjusted relative hazards” of malignancy. stroke or ischemic heart disease
Unmarried at baseline married at baseline One change in marital married at baseline Two or more changes married at baseline “Adjusted
with no changes over study as compared with no changes Over study period status as compared to with no changes Over study period in marital status as compared to with no changes over study period
for age, education,
and baseline self-reported
health.
to R.H. 0.92
95% C.I.
(0.3-2.8)
R.H. 1.0
95% c. 1.
(0.k2.9)
R.H. 0.8
95% c. 1.
(0.1-6.3)
1104
JUDITH H. HIBBARD and CLYDE R. POPE
more general feeling about the quality of life as well as actual health deficits. Thus, further research which examines the health effects beyond self-reported measures would be desirable. Thus, of the discontinuities that characterize women’s lives examined in this investigation, marital instability is the only one that appears to be related to subsequent health. Instability in this more intimate aspect of life likely has more pervasive life consequences for women than changes in employment. In addition, there may be a greater element of choice in the discontinuities associated with employment than with the discontinuities associated with marital status. That is, if discontinuities in employment represent a strategy to reduce the stress associated with family obligations, then the changes are likely to be freely chosen. On the other hand, some marital discontinuities (widowhood and divorce) among middle-aged women are very likely to be unwelcome and unchosen life changes. Further research that examines the reasons for employment discontinuities and satisfaction with employment status changes is needed to understand the impact of this type of discontinuity in women’s lives. Similarly, are marital status changes which are freely chosen less likely to lead to poorer health than marital status changes that are unwelcome? While the evidence produced to date suggests employment discontinuities have no direct health effect, the question of how these changes may affect women’s health indirectly should also be investigated. That is, if intermittency affects women’s long-term occupational opportunities and earnings, is there an indirect effect on women’s health through reduced material circumstances and reduced life chances? Finally, as more women enter retirement the question of the degree to which women’s employment patterns affect adjustment to retirement and health in the post retirement years becomes important. Some of the questions surrounding work histories and postretirement adaptation and health will be examined, since the authors plan to follow the cohort studied in this investigation into their retirement years. Acknowledgement-This research is supported from the National Institute on Aging, AG03824,
by a grant USDHHS.
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