Association between vasomotor symptom frequency and weight gain in the Study of Women's Health Across the Nation

OBJECTIVE: The menopause transition is associated with weight gain in women. We examined whether changes in vasomotor symptom (VMS) frequency precede weight changes. METHODS: This longitudinal retrospective analysis included data from the multisite, multiethnic Study of Women's Health Across the Nation. Women in premenopause or perimenopause aged 42 to 52 years at baseline self-reported VMS frequency (hot flashes/night sweats) and sleep problems at up to 10 annual visits. Menopause status, weight, body mass index, and waist circumference were compared across visits. The primary objective was to measure the association between VMS frequency and weight gain using a lagged approach with first-difference regression models. Secondary objectives were to statistically quantify mediation by sleep problems and moderation by menopause status and explore the association between cumulative, 10-year VMS exposure and long-term weight gain. RESULTS: The primary analysis sample included 2,361 participants (12,030 visits; 1995-2008). Increased VMS frequency across visits was associated with subsequently increased weight (0.24 kg), body mass index (0.08 kg/m(2)), and waist circumference (0.20 cm). Cumulative exposure to a high frequency of VMS (≥6 d/2 wk) over 10 consecutive annual visits was associated with increases in weight measures, including a 3.0-cm increase in waist circumference. Contemporaneous sleep problems mediated no more than 27% of waist circumference increases. Menopause status was not a consistent moderator. CONCLUSIONS: This study demonstrates that increases in VMS, onset of a high frequency of VMS, and persistent VMS symptoms over time may precede weight gain in women.