Menopausal symptoms and symptom clustering in Chinese women

Maturitas 33 (1999) 219 – 227 www.elsevier.com/locate/maturitas

Menopausal symptoms and symptom clustering in Chinese women Suzanne C Ho a,*, Sieu Gaen Chan a, Yin Bing Yip b, Anna Cheng a, Qilong Yi c, Cynthia Chan a a

Department of Community and Family Medicine, Faculty of Medicine, The Chinese Uni6ersity of Hong Kong, 4 /F, Lek Yuen Health Centre, Shatin, N.T., Hong Kong b Department of Nursing and Health Sciences, Hong Kong Polytechnic Uni6ersity, Hong Kong c Department of Public Health Sciences, Faculty of Medicine, Uni6ersity of Toronto, Toronto, Canada Received 2 March 1999; accepted 23 July 1999

Abstract Objecti6es: this paper aims to report the prevalence of symptoms in the Hong Kong Chinese perimenopausal women; to construct reported symptoms into symptom groupings; and to clarify whether the symptom groups are associated with menopausal status. Methods: a random telephone survey of perimenopausal women aged 44 – 55 years was conducted in 1996. Eligible subjects were identified through telephone dialing of a random sample of the numbers listed in the residents’ telephone directory. Standardized questionnaire, including a 22-item symptom check list, was administered over the telephone. The principal component analysis method followed by varimax rotation was used to examine the relations among the symptoms. Results: differences in the prevalence of menstrual problems across the menopausal status were noted with perimenopausal women having the most complaints. Musculoskeletal conditions were the top complaints reported by the respondents, followed by headaches and psychological symptoms. About 10% of the women complained of hot flushes, and less than 5% of cold sweats. Five symptom clusters, namely psychological, musculoskeletal/gastrointestinal, non-specific somatic, respiratory, and vasomotor, have been identified. After adjustment for age, the analysis of variance showed that psychological, non-specific somatic and vasomotor symptoms were significantly associated with menopausal status, while musculoskeletal and respiratory were of borderline statistical significance. Conclusions: compared with pre- and post-menopausal women, perimenopausal women had the highest reports of symptom complaints. Musculoskeletal complaints were the most prevalent complaints, followed by psychological symptoms. While vasomotor symptoms were significantly associated with menopausal status, their prevalence was comparatively lower than that reported in Caucasian populations. © 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Menopausal symptoms; Symptom clustering; Chinese women

* Tel.: + 852-26928775; fax: + 852-26063500. E-mail address: [email protected] (S.C. Ho) 0378-5122/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 3 7 8 - 5 1 2 2 ( 9 9 ) 0 0 0 5 6 - 0

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1. Introduction Previously, knowledge about menopause has mostly been derived from clinical studies of women attending menopausal clinics for their symptoms, or from women who have had surgical menopause. The generalizability of findings from these studies is limited. More recently, population studies on menopausal symptoms have revealed a high prevalence of vasomotor complaints. However, most of these studies have been conducted in North America and Europe [1 – 6]. Studies in Asia revealed that some of these reported menopausal symptoms may not be universal [2,7 – 9]. Attempts have also been made to identify the symptoms that women experience through the period of menopausal transition, from pre- to post-menopausal years, and to delineate which symptoms may be attributable to menopausal status [5,6]. However, besides the general consensus that hot flushes, night sweats and vaginal changes are associated with menopausal status, the association of other symptom groupings with menopausal status has been unclear [10,11]. Some studies have reported no changes across the menopause [10,12,13], while others have observed an increase in the prevalence of symptoms prior to menopause [14,15]. Greene et al. [16] conducted factor analysis on a list of 30 symptoms reported by women aged 40 to 55 in the United Kingdom. The investigators had identified three symptom clusters and had labelled them as vasomotor, somatic and psychological. Another study by Hunter et al. [10] found seven factors ranging from somatic symptoms, depressed moods to vasomotor symptoms. In 1991, Holte and Mikkelsen [17] factor analysed 21 symptoms in Norwegian women and found five clusters. These reports seem to indicate clustering of symptoms experienced by women through menopause in the Caucasian populations. Avis et al. [2] have addressed the diversity of menopausal symptoms in women aged between 45 and 55 years in three different populations, Manitoba, Massachusetts, and Japan. Factor analyses for symptom groupings had found the vasomotor symptoms — night sweat and hot flushes — did not load on the same factor in the Japanese

sample as were in the United States and Canadian samples. A number of hypotheses including the diversity of socio-cultural influences on menopausal symptomatology have been suggested to explain such differences [18,19]. As there is still limited information on the experience of menopausal symptoms and their groupings in Asian women, the objectives of this paper are to report the prevalence of symptoms in the Hong Kong Chinese perimenopausal women; to construct reported symptoms into symptom groupings; and to clarify whether the symptom groups are associated with menopausal status.

2. Methods

2.1. Study population A random telephone survey of perimenopausal women was conducted in 1996. For inclusion in the study, the participants must be Hong Kong Chinese residents and aged 44–55 years of age. Eligible subjects were identified through telephone dialing of a random sample of the numbers listed in the residents’ telephone directory. Identified eligible subjects were considered as non-respondents if they could not be reached after six attempts at different times of the day, or refused to participate in the study. 2125 women were successfully interviewed with a response rate of 40.4%. Women who had stopped menstruating as a result of hysterectomy or radio- or chemotherapy, or women whose menstrual status could not be determined because of the missing data were excluded from the analysis. As such, analysis was performed on 1900 subjects.

2.2. Study questionnaire and symptom check list The questionnaire structure was patterned after the Massachusetts and Manitoba studies on women in midlife [4]. Standardized questionnaire included questions on sociodemographic background; a 22-item symptom check list adapted from Avis et al. [2]; and questions concerning general health and gynecological history. ‘Vaginal

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dryness’ from the original list has been left out because of cultural unacceptability of asking about this item through the telephone. As in the approach developed by Kaufert and Syrotuik [14], and subsequently adopted in the studies conducted in Manitoba and Massachusetts [4], the symptom checklist was included in a section dealing with general health rather than menstrual change. The 22 item checklist was translated into the local Chinese dialect and was extensively tested before it was adopted in the study proper. As experienced in this population and evidenced in previous studies [20], subjects had difficulties responding to continuous measurements. As such, a binary response was adopted. Each woman was asked to respond ‘yes’ or ‘no’ to experience of the symptom in the past two weeks.

2.3. Definition of menopausal status Menopausal status was classified into pre-, periand postmenopausal. Premenopausal women were those still having menses. As responses to menstrual irregularity were doubtful, peri-menopausal status was confined to those with cessation of menstrual period for at least three months within the previous 12 months but not due to hysterectomy, oophorectomy or pregnancy. Postmenopausal status was defined as those having cessation of mensturation for at least 12 months [21].

2.4. Statistical methods The principal component analysis (PCA) method followed by varimax rotation [22] was used to examine the relation among the symptoms. PCA is a variable reduction procedure that results in a small number of components that account for most of the variances in the set of variables [22]. The use of PCA is appropriate for the set of binary variables as the identification of the factors is still exploratory at this stage [23]. As such, no assumption is made of the underlying structure or factors which might exert causal influences on the observed variables.

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In order to determine the meaningful components to be retained, the following procedures and considerations were taken into account. Two of the variables — fluid water retention and urinary tract/bladder infection — were omitted from the analysis because of their very low prevalence in the study population (B3%). As menstrual problem is an obvious problem during menopausal transition, it has also been excluded. Factor analyses were thus based on 19 symptoms. An initial analysis was conducted to estimate the maximum number of stable factors, and three factors with eigenvalues of 1.0 or greater were identified. The scree test [24] was then applied. As recommended by Cattell [24] and also used in the analysis by Lock [20], the factoring stopped at the point where the eigenvalues level off with a horizontal slope. The decision on the final number of factors to be chosen was based on both theoretical grounds and interpretability. The mean number of factors in each symptom group was calculated for the pre-, peri- and postmenopausal women. Finally, the one-way analysis of variance using menopausal status as the independent variable was performed to test for association of the mean symptom scores of each factor with menopausal status.

3. Results

3.1. Characteristics of study population Table 1 compares the distribution of educational attainment, marital and work status of the respondents with that of Hong Kong women of similar age group. The distributions were quite similar except there was a slightly higher proportion of married women in the survey population. 83.3% of women below 50 were premenopausal women while 77% of those aged 50 and above were postmenopausal. The mean ages of women belonging to the pre-, peri- and post-menopausal status were 47.27 (standard deviation= 3.22), 49.26 (standard deviation=6.02), 51.59 (standard deviation= 5.30) respectively. 65.7% of the postmenopausal women were within the first 3 years of menopause.

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3.2. Pre6alence of menopausal symptoms Table 2 shows the symptom prevalences as well as their overall ranking. It was obvious that perimenopausal women had the most complaints compared with women of other menopausal status. Musculoskeletal conditions were the top complaints reported by the respondents, followed by headaches and psychological symptoms such as insomnia, nervous tension and depression. Overall, about 10% of the women experienced hot flushes and 5% complained of cold sweats. Problems like fluid retention and urinary tract infection were relatively unimportant in this population with less than 3% having these complaints.

3.3. Factor groupings Principal component analysis with varimax rotation was applied to a symptoms check list containing 19 complaints experienced in the past 2 weeks. Several factor solutions were attempted. According to the criteria of eigenvalue greater than 1 and a loading factor of at least 0.45, factor analysis produced three factors which did not include ‘loss of appetite’ and ‘cold sweat’. The three factors explained 42.5%

Table 1 Comparison of the socio-demographic factors between Hong Kong By-census 1996 and the study respondents Socio-demographic factors

HK By-census 1996

Present survey

Marital status Married (%) Non-married (%)

(N=317 355) 86 14

(N= 2125) 94 6

Education attainment No formal education (%) Primary level (%) Secondary level (%) Teritary level (%)

(N =283 777) 11 45 43 8

49 36 7

Work status Working (%) Non-working (%)

(N=301 777) 48 52

40 60

8

of the common variances. A scree test was then used, and factor solutions with three to five factors were examined. The five-factor solution accounting for 52.5% of the variance in the sample seemed to give the best solutions both theoretically and empiracally Table 3. The symptom ‘pins and needles’ sensation has not been included because of a factor loading less than 0.45%. Psychological symptoms group was the first factor extracted. It alone accounted for 31% of the common variance with an eigenvalue of 5.8842. Factor 1 was associated with psychological complaints, notably difficulty in concentration and nervous tension, including rapid heart beat, insomnia and mood lability like feeling blue. Musculoskeletal and gastrointestinal complaints were associated with Factor 2. Non-specific somatic complaints like lack of energy, dizzy spells and headaches were associated with Factor 3. Factor 4 was associated with respiratory complaints like persistent cough, sore throat and shortness of breath. Cold sweat was highly associated with Factor 5. The symptom ‘hot flushes’ was loaded onto Factor 2 with a loading factor of 52 and also onto Factor 5 with a loading of 59. It was included as Factor 5 because of a slightly higher loading and also better biological interpretability.

3.4. Association of factors with menopausal status Table 4 shows the mean score values (with an answer to ‘yes’ scoring one and ‘no’ scoring zero) for each factor according to menopausal status. Perimenopausal women were found to have the highest score compared with women of the other two status. The differences in the mean values were found to be statistically significant by the analysis of variance. The Student–Newman–Kauls test also revealed that the scores in perimenopausal women were different from that of the other two menopausal status for all of the five symptom groups. The differences of the mean scores for factors 2 and 4 were of border line statistical significance after adjustment for age.

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Table 2 Symptoms experienced in previous two weeksa Symptoms

Backaches Aches or joint stiffness Headaches Trouble sleeping Nervous tension Feeling blue Upset stomach Dizzy spells Menstrual problem Rapid heartbeat Difficulty in concentration Lack of energy Sore throat Hot flushes Shortness of breath Diarrhea and/or constipation Loss of appetite Pins and needles sensation Cold sweats Persistent cough Fluid water retention Urinary tract/bladder infection

Menopausal status

P-value

Pre (N= 1258) (%)

Peri (N= 92) (%)

Post (N = 540) (%)

All (N =1900) (%)

27.19 25.20 25.76 20.99 19.00 16.85 16.77 15.74 16.69 14.07 12.40 12.64 10.65 8.74 9.38 8.03 8.90 7.95 4.45 3.34 2.31 1.83

33.70 41.30 29.35 20.65 26.09 29.35 19.57 25.0 53.26 16.30 20.65 16.30 11.96 21.74 21.74 13.04 10.87 14.13 4.35 7.61 6.52 0.00

29.82 29.27 21.64 20.36 16.36 15.09 15.27 12.55 0.18 11.82 12.00 10.91 11.82 11.64 8.73 10.18 8.36 8.00 6.00 4.73 1.45 1.82

28.26 27.16 24.74 20.79 18.58 16.95 16.47 15.26 13.68 13.53 12.68 12.32 11.05 10.21 9.79 8.89 8.84 8.26 4.89 3.95 2.26 1.74

0.257 0.002 0.101 0.956 0.069 0.003 0.523 0.006 0.001 0.317 0.061 0.289 0.737 0.001 0.001 0.120 0.729 0.111 0.362 0.068 0.010 0.425

a P value from the chi-square test comparing the distribution of subjects with and without symptoms in women with different menopausal status.

4. Discussion The present study is based on a populationbased non-clinical sample of Hong Kong Chinese women aged 44–55 years. Of the 2125 women interviewed, 10.5% were excluded because of surgical menopause. The moderate response rate was mainly due to the very specific age and sex requirements. However, the socio-demographic characteristics of the study population were quite comparable with that of the Hong Kong general population of similar age, except there was a slightly higher proportion of married women in the study population. Again, this could be due to the lower willingness of single women to respond to telephone surveys. Among the 1900 respondents included in the analysis, 4.8% were perimenopausal. A similar proportion of perimenopausal women was found

in a study in Beijing [25] using similar definitions. According to the very specific criteria used to define perimenopause, this group of women were more likely to be immediately prior to menopause. This narrow definition may explain the significantly higher prevalence of symptom complaints in this group of women. The Beijing study also reported similar findings. A cohort study of 2570 women in Massachusetts reported an increase in symptom reporting rates during perimenopausal period, especially immediately prior to menopause [5]. As suggested by McKinlay [26], major physiological changes occurring may contribute to the increase in symptom complaints during this period. The symptoms could be roughly divided into musculoskeletal, psychological, general malaise and estrogen deficiency related complaints. Approximately 1/4 of women had musculoskeletal

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complaints like low back pain and or pain/stiffness. Such prevalence was also found in Japanese women, and also in studies carried out in Manitoba and Massachusettes [7,2]. Other studies have also revealed that the incidence of low back pain was higher in perimenopausal women [27,28]. Psychological symptoms like headaches, insomnia, nervous tension, depression and non-specific somatic conditions were experienced by 12 – 27% of the respondents. Such prevalence was quite comparable to that reported in Japan, but comparatively lower than that found in the Manitoba and Massachusetts studies where about 1/4 to 1/3 of women had these complaints [7]. It is unknown if mood changes in perimenopausal women are related to estrogen deficiency [5,6,9]. There have been suggestions that decline in ovarian function or hormonal deficiency cause psychological and somatic complaints [29], while others do not support such an association [30]. Avis et al. [1] have reported that women with negative attitudes have

higher prevalence of symptom reporting. Longitudinal studies [31] seem to support that social, psychological and health factors accounted for more of the psychological symptoms than menopausal status. Life events related to illness or death of elderly parents, children growing up and leaving home, unemployment are most often experienced by women in midlife. Thus, interpersonal stress and changes in reproductive hormones may interplay and result in the negative mood states found during this period of life [32,33]. Population-based cross-sectional and prospective studies carried out in the West have suggested that only vasomotor symptoms (hot flushes and night sweats) were clearly associated with the menopause [5,16,34,35]. Complaints of hot flushes and night sweats averaged around 50–60% in these populations. In our population, the report of vasomotor symptoms were low — 10.2% for hot flushes and about 5% for cold sweats. The

Table 3 Symptom groups, rotated factor loading, eigenvalue and variance Rotated factor loading

1. Psychological Difficulty in concentration Nervous tension Rapid heartbeat Trouble sleeping Feeling blue

72 66 60 59 50

2. Musculosketetal and gastrointestinal Diarrhea and/or constipation Aches or joint stiffness Backaches Upset stomach

61 58 57 51

3. Non-specific somatic complaints Lack of energy Dizzy spells Headaches

76 74 50

4. Respiratory Persistent cough Sore throat Shortness of breath

79 60 48

5. Vasomotor Cold sweats Loss of appetite Hot flushes

78 59 55

Eigenvalue

Cumulative variance

5.8842

31.0

1.1515

37.0

1.0419

42.5

0.9634

47.6

0.9346

52.5

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Table 4 Mean (standard deviation) score values of the five factors by menopausal status Factor

Pre (N =1258)

Peria (N =92)

Post (N =550)

Unadjusted Pvalueb

Adjusted Pvaluec

1. Psychological 2. Musculosketetal and gastrointestinal 3. Non-specific somatic complains 4. Respiratory 5. Vasomotor

0.166 (0.2628) 0.192 (0.2641)

0.229 (0.2945) 0.272 (0.2545)

0.152 (0.2577) 0.211 (0.2741)

0.039 0.019

0.027 0.057

0.180 (0.2993) 0.074 (0.1897) 0.078 (0.1821)

0.238 (0.3343) 0.125 (0.2146) 0.139 (0.2537)

0.151 (0.2803) 0.087 (0.2086) 0.084 (0.1997)

0.018 0.041 0.015

0.009 0.069 0.018

a Mean score values of perimenopausal women were significantly different from that of the other two menopausal status by the Student–Newman–Keuls test for all five factors. b P-value from ANOVA. c Adjusted for age.

prevalence of these complaints were quite similar to findings from a study carried out in Japan [7]. Previous studies conducted in both clinical and non-clinical settings in the local population have also reported low prevalences of vasomotor complaints [9,36]. As in the Japanese population [7], there are no precise words in the Hong Kong Cantonese speaking population for hot flushes. Description has to be made to describe the sudden onset of this body status. As suggested by Lock [7], the lack of the precise words may lead to the unawareness and thus the lower prevalence of the symptoms. On the contrary, in the Beijing population where the condition is more prevalent (37%), a term for this condition does exist [25]. Studies in Thai perimenopausal women [29] also reported higher prevalence of vasomotor symptom than that found in women in Hong Kong and Japan. Therefore, although the complaints of vasomotor symptoms are generally lower, the extent of the experience is not consistent among Asian women in different localities. Reasons for the generally lower complaints in Asian women are lacking. Suggestions have been made on genetic factors, body composition, dietary intake of phytoestrogens and cultural meaning attached to menopause [7,3,35,36,37]. Further investigations of the influence of these factors on menopausal experience are required to tease out the specific mechanisms responsible for the generally lower vasomotor complaints in Asian women.

4.1. Symptom clustering Analyses for symptom groupings were based on 19 items, after excluding the obvious menopause associated menstrual problem and symptoms with very low prevalence. The PCA revealed five symptom clusters which are clinically meaningful. As reported in other studies [30,38], psychological symptoms were the first extracted factor group. Our findings also resembled the US study with psychological symptoms accounting for the most variance [2]. While other studies have reported vasomotor symptoms to be the second loaded factor [38,39], this symptom group was the fifth loaded factor in our study. The one way analysis of variance has revealed that all five symptom clusters were significantly related to menopausal status. Musculoskeletal/ gastrointestinal and respiratory symptom groups became only of marginal significance after adjustment for age. The symptom ‘vaginal dryness’ has been left out from the symptom list because of the cultural inappropriateness of including this in a telephone survey. However, studies conducted by Mikkelsen and Holte [40] in 200 Norwegian women aged 45–55 years, and later on, in a representative sample of around 1900 women [17], have identified that ‘vaginal dryness’ was included in the factor labelled vasomotor complaints. This was the only factor related to menopausal development. As a contrast to studies in Caucasian populations, both psychosomatic and vasomotor

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symptoms were related to menopausal status in our study. There have been some suggestions that depression may be linked to subsequent complaints of vasomotor symptoms. The relatively uncommon report of vasomotor complaints does not seem to support such an association in our population.

4.2. Implications of findings for health promotion There has been low level of use of hormonal replacement therapy and treatment sought for menopausal symptoms in our population [8,9,41 – 43]. However, our study has indicated that women at menopausal transition do experience increased level of complaints in the psychological, non-specific somatic and vasomotor symptom groups. Psychosomatic problems seem to play a major role in the menopausal syndrome in our population. More research is needed to delineate the predictors of these symptoms. Moreover, health education, promotion and treatment programmes, multi-disciplinary in approach, need to be developed to cater for the expanding number of women going into menopause.

Acknowledgements The authors would like to acknowledge the partial support of the Health Services Research Committee for this study; and would also like to thank Daisy Fung and Sharon Kwok for typing the manuscript.

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