Women's experience of the menopause

..GYNAECOLOGY

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Mini-symposium: Menopause

Women’s experience of the menopause

S. M. McKinlay,

D. J. Brambilla,

N. E. Avis and J. B. McKinlay

Particularly since the early 1970s interest in the menopause has increasingly focussed on its role in the aetiology of some major age-related diseases in women, such as cancer.l cardiovascular disease,2 osteoporosis3 and depression4 Motivation for this interest has arisen, at least in part, from the fact that in Western or advanced societies, the overwhelming majority of women now experience menopause (cessation of menses) and can expect to live approximately 30 years beyond this event. Indeed the expected adult life span for women beyond this natural event is now nearly equivalent to woman’s expected reproductive life span. To date, most of the information on menopause has been based on data from a relatively small proportion of self-selecting women who experience and report problems, utilize health facilities, and are therefore conveniently available as research subjects. What has emerged from these studies of predominantly patient populations is a clinical stereotype of the ‘typical’ menopausal woman, who presents a broad range of often diffuse symptoms and consequently consumes a disproportionate share of health resources.’ Such a characterization is understandable in view of the unrepresentative population from which it is derived. The stereotype is reinforced by pharmaceutical advertisements in professional journal@ and through patient images employed and developed during medical education.7 Such clinical stereotypes appear to have resulted in misdiagnosis and treatment of unrelated, clinically diagnosable conditions, by labeling presenting symptomatology as ‘menopausal’. This was noted as early as 1944* and is clearly evident in recent populationbased studies of the impact of estrogen replacement therapy (ERT) on subsequent mortality.‘*l’ These two S. M. McKinlay, D. J. Brambilla, N. E. Avis, J. B. McKinlay, New England Research Institute, 9 Galen Street, Watertown, MA 02172. USA

studies (British and Swedish respectively) reported elevated risks of suicide among ERT users which most probably reflect inappropriate treatment of clinical depression with estrogens. This paper focuses on key aspects of the normal menopause experience. To address this issue, data and findings from the Massachusetts Women’s Health Study (MWHS) are presented. A description of this study is provided in the first section, followed by sections on: the normal menopause transitions; health care behaviour and symptomatology associated with the menopause; and women’s attitudes to this event. A final section discusses the implications of these findings for medical practice and future medical investigations. The Massachusetts Women’s Health Study Almost all of the population-based research concerning menopause has been cross-sectional or retrospective. These studies have therefore been limited by problems of memory and by the limitation of inference to apparent associations.’ ’ With the notable exception of a longitudinal study of menstrual patterns,12 most of the prospective epidemiological, population-based studies of menopause have been conducted in the 1980~.‘~-‘~ Moreover, with the exception of MWHS,“j all of these studies have either included relatively small numbers from which conclusive evidence could not be obtained on a range of issues’ 3--15 or collected only very limited data.12 The MWHS is the largest and most comprehensive prospective cohort study of mid-aged women reported to date, sampled from a general population. It has sufficient numbers to provide, for the first time, stable estimates of parameters in the experience of a natural (as well as surgical) menopause. The study began with a baseline cross-sectional survey in 1981-I 982 that employed a two-stage cluster

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sampling design. First, 38 (10%) Massachusetts cities/ towns were selected, with probabilities proportional to size, within 12 strata defined by city/town size, per capita income and percent black. Women born in the years 1926-1936, inclusive, were then randomly selected from annually compiled census lists in the selected cities/towns to provide an approximtely self-weighing sample. A total of 8050 completed responses were obtained (using mailed questionnaires and telephone interviews of women who did not respond to three mailings), producing an overall response rate of 77%. From this cross-sectional sample (T,), a cohort of 2570 women was identified, consisting of women who had menstruated in the preceding three months and who had not experienced a removal of the uterus and/ or ovaries. Prospective study of the cohort consisted of telephone contacts every 9 months until six followup contacts (T,-T,) had been completed (follow-up interval, 4.5 years, overall response rate 93%). At each contact, an interview was conducted, including questions related to current health status, current menstrual status, health service utilisation, employment and any changes in selected sociodemographic characteristics. Additional information was collected on social support, life-style behaviours (smoking, alcohol consumption, exercise, etc.) and on attitudes to aging and menopause at selected contacts to reduce the interview burden as well as avoid biased responses. The quality of the data in this study is reflected in the high response rates and in the methodological studies reported elsewhere.‘7p21 The goal of the MWHS was to describe women’s response to menopause as they approached and experienced this event and to identify those health-related, life-style and other social factors which affect this experience. The normal menopausal transitions

The following definitions of natural and surgical menopause are now well-established in the medical and epidemiological literature.22.23 Natural menopause is defined retrospectively after 12 consecutive months of amenorrhea in the absence of a cause (such as pregnancy, lactation). This definition is consistent with the only prospective study of menstrual patterns in normal women.” Surgical menopause is defined as the occurrence of any surgical procedure which stops menstruation. Women in this category are often further subdivided into those having the uterus and possibly one ovary removed and those having both ovaries removed. Cessation of ovarian function can only be detected in the former sub-group through repeated assessment of gonadotropin and/or circulating estrogen levels. In addition to these two events, a period of menstrual change, first identified by Treloar,i2 which occurs immediately prior to natural menopause has been increasingly referenced as the perimenopause. In the MWHS, this period was defined after reports, in two consecutive

interviews, of either a change in cycle regularity and/or periods of amenorrhea of 11 months or less. It is now well-established tht the median age at natural menopause or last menstrual period (LMP) is between 50 and 52 years in Caucasian populations. 18*24 All reports of mean ages at LMP, including that reported by Treloar,’ 2 are negatively biased and consistently understate the true mean age.24q2s Trends in the age-specific prevalence of peri- and postmenopause (excluding surgical menopause) are illustrated from MWHS data in Figure 1. The median ages at LMP and at inception of perimenopause estimated from these data were 51.3 years and 47.5 years respectively, yielding an estimate of nearly 4 years for the median duration of perimenopause. Among factors thought to affect the timing of a natural menopause, only current cigarette smoking resulted in a significant difference. A median difference of 1.8 years between current and non-smokers was extremely large and consistent with other reports.’ 8-24 The lack of difference between non-smokers and quitters reported in this and other studies24 is consistent with an immediate toxic impact on ovarian function caused by some as yet unidentified product of smoking.26 It is also consistent with other reports that smokers are more likely to experience menstrual irregularity27 and infertility.28q29 When the effect of smoking is controlled in multivariate analysis, the apparent associations with socioeconomic status, parity and obesity do not remain. These latter factors are highly correlated with smoking behaviour and/or each other. Similar analyses of factors associated with perimenopause were conducted for the first time in this study. Nulliparous women and smokers were likely to start perimenopause earlier. Smokers and women starting perimenopause at a later age were more likely to have shorter periods of perimenopause. Nearly 10% of the cohort experienced less than 6 months of menstrual irregularity or ceased menstruating abruptly. Health care behaviour and symptomatology

Reporting rates of three frequently cited symptoms, hot flashes, cold sweats and insomnia, were considered in relation to the two transitions (to peri- and to natural postmenopause). Initial cross-tabulations indi-

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49 50 51 52 Age (Years) at TO

Percent Postmenopause 0

53

54

55

Percent Perimenopause

Median Age at Inception of Perimenopause: 47.5 years Median Age at Menopause (LMP): 51.3 years

Fig. 1 - Percentage distributions, by age, at T, for two menopausal transitions, excluding surgical menopause: MWHS 1981-82 (n=5547)

cated strong associations among the three, as expected from prior multivariate analyses.30-33 Roughly half of those who reported hot flashes at each contact also reported cold sweats. Insomnia was more than twice as likely to be reported by women who experienced hot flashes than others. probably reflecting sleep disturbance from hot flashesisweats at night. An increase in symptom reporting in the perimenopause is due to an increase in all symptom reporting, not just reporting of hot fashes and is clearly transitory. Figure 2 summarizes a complex analysis of 1178 women in the cohort who were premenopausal (menstruating regularly) at T,,. The point at which perimenopause is defined is represented as a point of discontinuity as it is imbedded in the four perimenopausal points ( - 3. - 2. -- I. 0). Three contacts (27 months) before perimenopause is defined. the rate of hot flashes is approximately IO%, which can be considered to represent a baseline population rate for this phenomenon (hot flashes are not exclusive to women or to menopause). This rate increases slowly as irregularity in menses is observed, before the transition to perimenopause. The rapid increase to a peak rate of about 50% in the contact before natural menopause is defined. represents peak reporting in the early months of amenorrhea (3-9 consecutive months of amenorrhea reported). By the fourth postmenopausal contact (about 4 years after LMP) the rate of hot flashes has declined to 20%. This decline represents 75’?;1 of the difference between baseline and peak rates. This study also provided some evidence that the rate of hot Rash reporting is related to the duration of perimenopause. In particular. women who were perimenopausal for only one contact reported a peak rate of 3950. and were consistently less likely to report hot flashes before. during and after the menopause than were women with a longer perimenopause. To demonstrate the lack of association between this major sign of menopause and efforts to seek medical care, two additional rates were estimated and superimposed on Figure 2. Women in the cohort were asked if they had seen or talked to a physician since the prior interview. concerning menstrual or menopausal

Fig. 2 - Relationship between hot flashes reported in 2 weeks and physician contact for menstrual problems or menopause symptoms in 9 months

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concerns. Reasons which involved acute menstrual problems only were included as ‘menstrual consult.’ Those reasons that included bothersome hot flashes or more vaguely worded ‘menopausal symptoms’ were coded as ‘menopausal consult.’ Even though the consultation rates reflect a period of 9 months, and the hot flash reporting was for a period of only 2 weeks. the parallel trends of hot flash reporting and menopausal consults is remarkable. The large difference in rates is somewhat misleading as women may consult a physician only once. even though the symptoms persist for several months or years. When women in the cohort who reported hot flashes at least once during the perimenopause were investigated, nearly 50% reported a menopausal consult in the same period, compared with 33% who did not report hot flashes. These rates probably still represent overestimates of consultation for hot flashes specifically. as the definition used includes broader ‘menopausal symptom’ codes. The rate of reporting of menopausal consults among those with hot flashes also varied with the number of perimenopausal contacts. from 25.6% for those with one perimenopausal contact. to 5840 for 5 6 such contacts. The important finding here. is that the majority of women in this 1J.S. study did not seek help for menopause-related symptoms. Another analysis, reported elsewhere. ’ ” demonstrated that. after 27 months of observation in the MWHS cohort. five indicators of current health status were best explained by the subject’s education and/or employment status and prior health. Only surgical menopause was important in explaining restricted activity -- and then only marginally reflecting residual disability up to 9 months or more following this procedure. No other indicators of menopausal change. including symptomatology, were related to these current health measures. The models are summarized in Table I. A similar analysis of utilization behaviourlh also showed that only surgical menopause was related to 2 of the 5 measures of health care use. This is consistent with an analysis of Manitoba Health Service data which shows that prior frequent use of health services is the primary predictor of subsequent hysterectomy.35 Evidence on the prevalence of vaginal dryness or atrophy immediately following menopause has not been consistently reported in population-based studies. Data on sexual activity have not been reported from population-based samples to date and are required in order to assess whether vaginal dryness is a direct result of estrogen depletion or a result of reduced or changed patterns of sexual activity. Population-based studies, including the MWHS. have consistently shown that depression is not related to menopause_31 -33.35.36 but is rather part of a transitory perimenopausal increase in symptomatology that may be typical of a subgroup of women who tend to report more symptomatology and use more medical services (following the early thesis of Neugarten & Kraines”‘).

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Table 1 - Discriminant models, which explain five health outcomes from 27 months of observation, cohort of 2570 Massachusetts women, 1981-1984 Dependent Variable

Independent Variable Group Sociodemographic

Self-assessed health

Physical symptoms

Psychologic symptoms

Restricted activity

New chronic conditions

Variable

Variable

Variable

Variable

Variable

Employment change*

Education

Education*

Employment change*

Education

Employment change

Marital status

Education

Self-assessed health*

Employment change

Psychologic symptoms*

Self-assessed health*

Psychologic symptoms*

Physical symptoms

Restricted activity*

Restricted activity

Self-assessed health

Physical symptoms

Chronic conditions

Lay consultation

Physical symptoms

Employment change

Marital status Health status (T,)

Marital status

Physical symptoms* Psychologic symptoms* Restricted activity Chronic conditions

Lay consultation Lay consultation Utilization behavior (T,)

Prescribed medication

Surgical menopause

Menstrual change status *contribute most to explaining variance

Attitudes to menopause

Finally, to underscore the normalcy of menopause for the majority of women, population-based studies have been reporting low rates of regret or negative attitudes for two decades.31*38*3gRecent analyses of attitudes to cessation of menses, in the MWHS, measured at T, and T, are summarized in Table 2. Less than 3% expressed regret at T,, reducing still further at Tg. The overwhelming majority, nearly 3/4, expressed neutral or positive feelings at T,, increasing to over 85% at T,. The shift in attitude, as women approached and experienced menopause, was overwhelmingly towards neutral or positive feelings. These trends were independent of actual changes in menstrual status experienced by the cohort. Summary and conclusion

The results of the MWHS and other population-based studies reviewed here present a profile of menopause experience in mid-aged women which is dramatically different from the impression gained in a physician’s office. In a remarkable book on menopause, published in Table 2 - Percentage of women reporting each feeling at T, (1985-86) according to feeling at T, (1981-82) (n=2164)* Feeling T,

N

Regret

Mixed

Regret Mixed Neutral Relief Total

62 510 738 854 2164

25.8 2.9 1.4 I.1 50

33.9 26.9 6.0 4.8 243

Feeling T, Neutral 22.6 35.9 57.1 20.4 792

*This n is reduced by drop-out and missing data.

Relief 17.7 34.3 35.6 73.8 1079

1897,40 a physician Currier noted that: (1) the menopause lacks scientific attention; (2) there is apparently no menopause in animals and symptomatology varies widely across ethnic groups; (3) there is evidence of pre-disposing factors in women presenting severe menopausal symptoms and (4) in industrialized societies, ‘highly bred’, ‘civilized’ women and ‘those with many troubles and ills’ appeared to be the primary sufferers while for the majority of women menopause is uneventful. Although these comments were based on unsystematic observation, they have been largely ratified by recent population-based research, nearly a century later. In particular, it is clear that women who present with ‘menopausal’ symptomatology are more likely to have reported prior poor health, independently of menopause. 16v41Women who experience some form of surgical menopause tend to be frequent users of medical care prior to this surgery - often for other, related surgery, such as breast tumors (malignant or benign)’ 6,34 - are more likely to be depressed prior to the surgery and are likely to experience continued ill health months after the surgery. Physicians, presented with middle-aged women in their office, must be concerned to take careful histories, including other potentially stressful aspects of their lives which may be affecting their health. From both MWHS and other studies41-43 the stressful impact on women’s health of, for example, adolescent children, a disabled spouse, caring for frail parents or parentsin-law, dealing with widowhood, divorce and/or reentry into the work force, is considerable. The relative contribution of menopause as an additional stressor in this context is negligible. What appear to be presented as ‘menopausal’ symptoms may often be indi-

WOMEN’S

caters of other underlying disease or conditions which are quite unrelated to menopause itself. The detrimental impact of smoking on menopause is well documented and there is growing evidence of menstrual disturbance and infertility resulting from this habit in younger women. When this is combined with the known high risk of smoking for heart disease in women, the need to discourage cigarette smoking particularly in older women assumes new importance and should be integrated into clinical practice. Apart from the highly selective characteristics of women presenting with ‘menopausal’ complaints, the findings reviewed here have important implications for medical research. I;j’r.st. results of studies of women who x-e identified as patients in the medical care system cannot be generalized to 011women. Secorzd, women with some form of surgical menopause must be studied separately from those with a natural menopause. and observations from these two groups cannot be directly combined. The surgical group is younger, of poorer health and/or uses medical care more frequently. Results from reports which do not acknowledge these caveats should be reviewed with some caution.

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background and climacteric symptoms. Psychiat Sot Sci 1982: 2: 41-45 McKinlay JB, McKinlay SM. Brambilla DJ. Health status and utilization behavior associated with menopause, Am J Epidemiol 1987; 125(l): 110-121 Brambilla D, McKinlay SM. A comparison of responses to mailed questionnaires and telephone interviews in a mixed mode health survey. Am J Epidemiol 1987; 1?.6(5): 962 -997 Brambilla DJ. McKinlay SM. A prospective stud) of factors affecting age at menopause. In press Jr of Chn Epidemlol. 1989 Brambilla DJ. McKinlay SM. A comparison of response to telephone and face-to-face intervIews in a longitudinal study. Accepted for presentation at the !989 Public Health conference on Records and Statistics and 10 hc puhlishcd in Conference Proceedings. 19X9 Brambilla D, McKinlay SM. McKinlay JB. ltcm nonresponse and response bias in mixed mode surveys. In: Proceedings 01 the 1987 Public Health Conference on Records and Statistics. DHHS Pub. No. (PHS) X8 1214 Brambilla DJ and McKinlay SM. Bifano N. ‘tnd Clapp R Validation of self-reported cancer incidence. Accepted for presentation at Fifth Conference on Health Survey Research Methods and to be published in the conference proceedings, 19x9 World Health Organization Scientific Group. Research on Menopause, WHO Technical Scrtice Report Series 670 Geneva: World Health Organization. 19X I Kaufert P. Women and their health in the middle years. a Manitoba project. Sot Sci Med 1984: 18: 279-2X1 McKinlal SM. Bifano NL. McKinlay. JB. Smoking and age at menopause. Annals of Int Med 1985; lll3(3): 350-356 McKinlay SM. Jefferys M, Thompson B. An investigation of the age at onset of the menopause. J Biosoc Sci 1972: 4: 161 -173 Mattison DR. The mechamsms of action ot’ reproductne toxins. Am J Indus Med 1983: 4: 65-79 Hammond EC. Smoking in relation to phbslcal complaints. Arch of Envir Health 1961: 3: 2X-46 Baird DD. Wilcox AJ. Cigarette smoking associated with delayed conception. JAMk 1985: 253(20): 2979. 19X3 Olsen J. Rachootin P. Schiodt AV. Damsbo N. Tobacco use. alcohol consumption and infertility Int .I Epidemiol 19X3; I:(z): 179 -1X-t Thompson B. Hart SA. Durno D. Menopausal age dnd symptomatology in a general practice. J BIOSOCSCI 1077; 5: 71 McKinlay SM. JetTerys M. The menopausal s>ndromc. Br J Prev Sot Med 1974: 2X: 10% I I5 Greene JB. A factor analjtlc stud! of cllmdctcrlc \!mpt<>mb. J Psvchosom Res 1976: 20: 425 340 Green JG. Cooke DJ. Life stress and symptoms at the climactetium. Br J Psychiat 1980; 136: 48691 Roos NP. Hysterectomies in one Canadian Provmcc: A neu look at risks and benefits. Am J Pub 1lealth. Vol.. 7.1. No. I. 19X4: 39-46 Mikkelsen A. Holte A. A factor-analytic htud!: of chmacterlc symptoms. Psychiat Sot Sci 1989; 7: 35 39 McKinlay JB. McKinlay SM. Brambllla DJ The rrlativc contributions of endocrine changes and socral circumstances to depression in m&aged women. J Health Sot Behav 1987: ‘8: 345-63 Neugarten BL. Krames RJ. Menopausal \kmptorn\ 111nomen of various ages. Psychosom Med 1964: 27, 266-173 Neugarten BL. Wood V. Kraines RJ. Loomis B. Women’s attitudes towards the menopause. an update Mnturitas 1986: 8: 47. 56 Leiblum SR. Swartzman LC. Women’s attitudes to\\drd the menopause: an update. Maturitas 1986: X: 47-56 Currier AF. The Menopause. Appleton. NY: IX97 McKinlay SM. McKinlay JB. The Impact of menopause and social facrors on health. In: Hammond C. Haselun F. Schiff 1. eds. Menopause: Evaluation. Treatment and Health Concerns. New York: Alan Liss. 198X Anesheusel C: Marital and employment role-\tram. social support. and depression among adult women. In Stress. Social Support and Women. 1986: 99% I I4 Verbrugge L. Multiple roles and physlcal health of women and men. .[ Health 19X3: 74: 16-30