Like some aspects of reproductive function, menopausal symptoms appear to exhibit seasonal variation, according to new research from Menopause: The Journal of the North American Menopause Society. The study assessed the impact of season and proximity to the final menstrual period (FMP) on frequency of symptom reporting.
The authors included 955 participants from the Study of Women’s Health Across the Nation, a cohort study that followed a multiethnic sample as the transition from premenopause to postmenopause over a 10-year period. Participants filled out menstrual calendars daily to capture days when spotting or bleeding occurred. Women answered questions about hormone therapy (HT) use and gynecological procedures that could affect their bleeding reports monthly and also completed a short survey about whether they had experienced symptoms (hot flashes, night sweats, and trouble sleeping) in the past month.
FMP was defined as the first day of the bleeding episode that was followed by at least 12 months of amenorrhea. Hot flashes, night sweats, and trouble sleeping were coded as a binary variable (yes/no) for each month of observation. HT use varied by time and was coded based on current use (yes/no) for each month of observation.
The authors found that 5 to 10 years before the FMP, approximately 20% of women reported hot flashes and night sweats. During that period, approximately 40% reported trouble sleeping. These numbers rose approximately 4 years before the FMP with a sharp jump in prevalence of hot flashes (~60%) and night sweats (~40) coincident with the FMP.
In terms of seasonality, the authors noted that a peak in hot flash reports was observed in July, while January had a trough in hot flash reports. Women had 66% greater odds of a hot flash at their seasonal peak compared to their seasonal minimum in both the unadjusted model and the model adjusted for smoking, race, age at FMP, and body mass index. The corresponding odds for night sweats and sleep problems were 50% and 24%, respectively. The authors also noted that odds of reporting all three symptoms increased as women approached the FMP.
The authors believe their findings indicate that menopausal symptoms exhibit seasonal variation based on summer and winter. They believe their findings indicate the need for physicians to recognize the summer months as a critical period for managing their patients’ symptoms.