Results of a new epidemiological analysis of more than 108,000 women observed a lower risk of early menopause among women who had at least one pregnancy lasting at least six months and among those who had breastfed their infants. Further, risk was lowest among those who breastfed exclusively. The work is by first author and doctoral at the University of Massachusetts Amherst School of Public Health and Health Sciences student Ms. Christine Langton, with her advisor Dr. Elizabeth Bertone-Johnson, Professor of Epidemiology and chair of the Department of Health Promotion and Policy.
These two factors, pregnancy (parity) and breastfeeding, generally prevent ovulation and may slow the natural depletion of ovarian follicles over time, the authors point out. Thus pregnancy and breastfeeding are believed to lower the risk of early menopause, which is defined as the end of menstruation before age 45. Early menopause is associated with increased risk of cardiovascular disease, cognitive decline and osteoporosis. Details of the analysis appear in the online open-access journal JAMA Network Open.
Ms. Langton and colleagues suggest that while their results did not demonstrate a clear dose-response for breastfeeding, their findings are consistent with the hypothesis that a biological mechanism is influenced by longer breastfeeding. Also, findings from other studies support that optimal benefits from breastfeeding exclusively, for both mother and baby, reach a threshold between six and 12 months.
The authors believe theirs is the first prospective cohort study to look at the relationship between breastfeeding and risk of early menopause. They point out that only one other study had examined the relationship of parity (number of children) to risk of early natural menopause.Tags: Friday Letter Submission, Publish on January 31