Epidemiology of Age at Natural Menopause

Background: The menopausal transition may affect womens quality of life. Hormone therapy (HT) has been shown to be effective in alleviating menopausal symptoms, such as hot flashes. The age at natural menopause (ANM) is of clinical relevance since earlier menopause is associated with increased morbidity and mortality. It is therefore important to identify means to ensure a healthy menopause. More than a decade ago HT use rates plummeted, however the current situation on its use is unclear. Factors associated with ANM and HT use vary across populations; little is known on such factors in Canada. Obesity after middle age has deleterious health consequences; yet the relationship between absolute and relative weight, BMI and waist circumference (WC), and ANM is inconclusive. Objectives: 1) To investigate the role of changes in anthropometric measures on ANM. 2) To elucidate factors associated with ANM in Canada, and 3) to examine the prevalence and characteristics of HT use. Methods: To answer objective 1, data from the Coronary Artery Risk Development in Young Adults (CARDIA) study were used. To answer objectives 2 and 3, secondary data analysis was conducted on baseline data from the Canadian Longitudinal Study on Aging (CLSA). Multinomial logistic, and Cox Proportional hazard regressions were performed. Results: Baseline WC and > 5 % loss of baseline weight were modest predictors of ANM in middle-aged women. Premenopausal hypertension and blood pressure indicators were also significantly related to an earlier ANM. Median ANM was 51 years. Having no partner, low household income and education levels, current and former smoking, and cardiovascular disease (CVD) were associated with an earlier ANM, while current employment, alcohol consumption, and obesity were associated with later ANM. Current HT use was 9.5%. Older age, non-white ethnic background, current employment, regular smoking, obesity, and breast cancer were negatively associated with current HT use. Alcohol consumption and presence of allergies or mood disorders were positively associated with current HT use. Conclusion: Menopausal age is in part determined by modifiable factors. These findings may be used to inform opportunities regarding menopause management, and help in prevention, assessment, and early management of chronic disease risk during the menopausal transition.