Body mass index following natural menopause and hysterectomy with and without bilateral oophorectomy.

OBJECTIVE: The directional and temporal nature of relationships between overweight and obesity and hysterectomy with or without oophorectomy is not well understood. Overweight and obesity may be both a risk factor for the indications for these surgeries and a possible consequence of the procedure. We used prospective data to examine whether body mass index (BMI) increased more following hysterectomy with and without bilateral oophorectomy compared with natural menopause among middle-aged women. METHODS: BMI was assessed annually for up to 10 years in the Study of Women's Health Across the Nation (SWAN (n=1962)). Piecewise linear mixed growth models were used to examine changes in BMI before and after natural menopause, hysterectomy with ovarian conservation and hysterectomy with bilateral oophorectomy. Covariates included education, race/ethnicity, menopausal status, physical activity, self-rated health, hormone therapy use, antidepressant use, age and visit before the final menstrual period (FMP; for natural menopause) or surgery (for hysterectomy/oophorectomy). RESULTS: By visit 10, 1780 (90.6%) women reached natural menopause, 106 (5.5%) reported hysterectomy with bilateral oophorectomy and 76 (3.9%) reported hysterectomy with ovarian conservation. In fully adjusted models, BMI increased for all women from baseline to FMP or surgery (annual rate of change=0.19 kg m(-2) per year), with no significant differences in BMI change between groups. BMI also increased for all women following FMP, but increased more rapidly in women following hysterectomy with bilateral oophorectomy (annual rate of change=0.21 kg m(-2) per year) as compared with following natural menopause (annual rate of change=0.08 kg m(-2) per year, P=0.03). CONCLUSION: In this prospective examination, hysterectomy with bilateral oophorectomy was associated with greater increases in BMI in the years following surgery than following hysterectomy with ovarian conservation or natural menopause. This suggests that accelerated weight gain follows bilateral oophorectomy among women in midlife, which may increase risk for obesity-related chronic diseases.