Conference Report From the 10th World Congress on the Menopause

Professor Lorraine Dennerstein, AO MBBS, PHD, DPM, FRANZCP


July 03, 2002

In This Article

How to Evaluate Population-based Studies

Population-based studies can provide us with knowledge of which domains of health are affected by the menopausal transition rather than aging. By studying women in their own naturalistic setting, these investigations also determine the effect of factors other than hormonal change. The results are then generalizable to the ethnic group and location studied. In evaluating cohort studies, the clinician should examine the following:

  • The derivation of the sample (look for a randomized sampling technique rather than a convenience sample such as a clinic sample likely subject to a number of biases)

  • Sample size (need at least 400 subjects at outset to provide enough power to detect change)

  • Baseline age young enough to include measures before major change in hypothalamic-pituitary ovarian axis; women should still be menstruating at the time of the baseline measure

  • Documentation of use during the study of any hormonal therapies, including hormone replacement therapy (HRT) and oral contraceptives, and of surgery that may compromise ovarian functioning, such as hysterectomy

  • Type of study (cross-sectional studies are of limited value, because they are unable to separate out effects of age from that of menopausal hormonal change or to assess the effects of premorbid functioning)

  • Use of validated measures and statistical techniques that can unravel the complex inter-relationships between outcomes and determinants

The length of prospective follow-up is crucial. Dr Janet Guthrie, Office for Gender and Health, University of Melbourne, Victoria, Australia[4] presented information from the Melbourne Women's Midlife Health Project indicating that after 9 years of follow-up of a cohort of women aged 45-55 at baseline (mean age, 48 years), not quite 50% of the women had reached final menstrual period (FMP), 20% had taken up HRT before reaching final menstruation, 12% had undergone surgical menopause, and a similar number were still menstruating. Dr. Sherry Sherman,[5] Director of the Osteoporosis and Menopause Program of the National Institute on Aging, used data from the US multicenter Study of Women Across the Nation (SWAN) to demonstrate that both the mean age of menopause and the length of the menopausal transition differed according to the length of the follow-up.

The 10th World Congress on the Menopause featured presentations from a number of cohort studies that met the above criteria for methodologic rigor. These presentations were interspersed throughout the different seminars of the Congress, where they provided complementary information to that of clinical trials. As well, there was a specific seminar documenting the natural menopausal transition and women's health. Results reported here use the new definitions of reproductive aging developed at the Staging Reproductive Aging Workshop (STRAW),[6] held July 22-24, 2001 in Park City, Utah, under the auspices of the National Institutes of Health and the American Society for Reproductive Medicine and the North American Menopause Society.


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