Physical activity is not related to risk for incident early menopause, according to a prospective cohort study published in Human Reproduction.
To determine whether physical activity influenced menopausal timing, researchers followed 107,275 female registered nurses from 1989 to 2011, each of whom was premenopausal and physically active at baseline. Every 2 years, individuals self-reported their menopause status via questionnaire. Time per week participating in physical activities was also self-reported; researchers used these data to calculate metabolic task hours per week at baseline, updating it every 4 years.
To assess for early menopause, researchers asked participants to report if and when their menstrual cycles had permanently ceased, and whether this was caused by surgery, radiation or chemotherapy, or natural occurrence. Of the total population, 2786 women experienced incident early menopause.
Compared with women who reported participating in lower levels of physical activity overall, those who reported higher activity were slightly younger, had lower body mass index at baseline, and had lower parity. Furthermore, greater physical activity was associated with slightly longer duration of oral contraceptive use as well as higher intake of alcohol, vegetable protein, and vitamin D.
Based on age-adjusted hazard models, the researchers concluded that physical activity was not associated with risk for early menopause. Compared with women who reported <3 metabolic task hours per week, those who reported ≥42 metabolic task hours per week had a hazard ratio of early menopause of 0.92 (95% CI, 0.81-1.06; P =.34). Likewise, neither moderate nor strenuous activity in adolescence or young adulthood was related to early menopause risk, and associations did not vary based on body mass index or smoking status.
Certain limitations to this study were noted, including potential misclassification as a result of self-reporting of physical activity rather than objective measurement.
“Although physical activity has been shown to have wide ranging positive health effects overall,” the researchers concluded, “results of this large, prospective study do not support an important role of physical activity with regard to risk [for] early menopause.”
Zhao M, Whitcomb B, Purdue-Smithe AC, et al. Physical activity is not related to risk of early menopause in a large prospective study [published online August 21, 2018]. Hum Reprod. doi:10.1093/humrep/dey267