Great interest has been shown in the age of the menopause, the time at which the ovaries run out of egg cells and hormone production declines. A recently published UK based survey provides more information on factors which influence the age of both natural and surgical menopause.
Beginning in the mid-1960s, Pokoradi and colleagues recruited approximately 23,000 women (mean age, 29 years) through general practitioners’ practices. In the mid-1990s, women who were still participating were sent questionnaires asking about pregnancies, hormone use, surgery, menopausal status, cigarette smoking, alcohol use, weight, medical problems, physical activity, and date of their last period.
Data from 5113 eligible responses were analyzed. The average age at menopause was 47.2 years (49 years for natural menopause and 42.4 years for surgical menopause). Among those with early natural menopause, cigarette smoking (15 or more packs per year) was more common, but alcohol consumption, physical activity, and body mass index (BMI) at age 30 years had no effect on age at menopause. Women with early natural menopause were more likely to have used contraceptive pill in the past and to have had sterilisation or symptoms associated with endometriosis. They were less likely to have used hormone replacement therapy.
Women who had surgical menopause were more likely to be manual workers with a trend for higher BMI. They were more likely to have undergone tubal sterilisation and to have had at least 1 episode of endometriosis, menorrhagia (very heavy periods), or dysmenorrhea (very painful periods). Diabetes, thyroid problems, or a diagnosis of autoimmune disease was not associated with the timing of natural or surgical menopause.
This study has shown a younger average age for menopause than previously reported. Similar to other reports, the adverse effects of smoking were evident. Smoking exposes the egg cells to toxic effects, and by destroying them faster, the egg cell pool is depleted sooner. This is yet another reason for women to consider smoking cessation.
The impact of past contraceptive pill use in this study is puzzling and has not been confirmed by others. Besides providing effective contraception, contraceptive pill use is also associated with numerous noncontraceptive benefits. These effects need to be balanced against a potential adverse impact on the age of natural menopause. Additional studies will need to explore this association to establish or refute it.
Tubal ligation (sterilisation) is known to affect ovarian reserve by reducing blood supply to the ovaries, thereby advancing the age of natural menopause. Benign gynaecologic problems (eg, endometriosis, fibroids) may be managed medically but if those measures fail (especially in the perimenopausal years), surgical treatment may be required. In the perimenopausal years, surgery is usually definitive and involves hysterectomy plus removal of the ovaries, hence surgical menopause. Endometriosis may lead to scarring, which may negatively influence ovarian activity and, therefore, the onset of natural menopause. Increased weight was correlated with surgical menopause. Obese women are more likely to have bleeding irregularities and endometrial thickening or cancer that would require surgical treatment.
Besides genetic predisposition, it seems that certain modifiable lifestyle factors and benign conditions will influence the timing of menopause. It is important to be aware of these factors so that women can make informed choices about their lifestyle and management of some gynaecology conditions.
Pokoradi AJ, Iversen L, Hannaford PC. Factors Associated With Age of Onset and Type of Menopause in a Cohort of UK Women. Am J Obstet Gynecol. 2011;205:34.e1-13