What Happens After Menopause? (WHAM): A prospective controlled study of cardiovascular and metabolic risk 12 months after premenopausal risk-reducing bilateral salpingo-oophorectomy.

OBJECTIVE To prospectively measure cardiometabolic risk 12 months after premenopausal risk-reducing bilateral salpingo-oophorectomy (RRBSO) compared to a similar age comparison group, and the effects of Hormone Therapy (HT) on cardiometabolic risk. METHODS Prospective observational study of 95 premenopausal women planning RRBSO and 99 comparisons who retained their ovaries. At baseline and 12 months, blood pressure (BP), Body Mass Index (BMI), waist and hip circumference, fasting total, HDL and LDL cholesterol, triglycerides, high-sensitivity C-reactive protein, glucose and insulin were measured and HOMA-IR was calculated. Chi-square tests, t-tests and adjusted logistic regression models were used to compare groups. RESULTS Baseline cardiometabolic phenotypes were similar between groups but more RRBSO participants were overweight/obese with higher waist/hip ratios. By 12 months, BP and cardiometabolic phenotypes were largely unchanged. Paired t-tests showed statistically significant increases in BMI (p = 0.037) and weight (p = 0.042) and larger increases in waist circumference (p < 0.001) and waist-hip ratio (p = 0.009) after RRBSO vs comparisons. However, these were not significant when adjusted for baseline values. After RRBSO 60% initiated Hormone Therapy (HT). Paired t-tests demonstrated that non-HT users had a significantly greater mean increase in waist circumference of 4.3 cm (95% CI 2.0-6.5) compared to 1.3 cm in HT users (95% CI -0.2-2.7, p < 0.001), which remained significant when adjusted for baseline values (p = 0.02). At 12 months, mean waist circumference was 2.94 cm greater in non-HT users compared to HT users. CONCLUSIONS Cardiometabolic risk markers are largely unchanged 12 months after RRBSO. Hormone Therapy after RRBSO may prevent against an increase in waist circumference.