Age at menopause, reproductive life span, and type 2 diabetes risk: results from the EPIC-InterAct study.

OBJECTIVE: Age at menopause is an important determinant of future health outcomes, but little is known about its relationship with type 2 diabetes. We examined the associations of menopausal age and reproductive life span (menopausal age minus menarcheal age) with diabetes risk. RESEARCH DESIGN AND METHODS: Data were obtained from the InterAct study, a prospective case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition. A total of 3,691 postmenopausal type 2 diabetic case subjects and 4,408 subcohort members were included in the analysis, with a median follow-up of 11 years. Prentice weighted Cox proportional hazards models were adjusted for age, known risk factors for diabetes, and reproductive factors, and effect modification by BMI, waist circumference, and smoking was studied. RESULTS: Mean (SD) age of the subcohort was 59.2 (5.8) years. After multivariable adjustment, hazard ratios (HRs) of type 2 diabetes were 1.32 (95% CI 1.04-1.69), 1.09 (0.90-1.31), 0.97 (0.86-1.10), and 0.85 (0.70-1.03) for women with menopause at ages <40, 40-44, 45-49, and ≥55 years, respectively, relative to those with menopause at age 50-54 years. The HR per SD younger age at menopause was 1.08 (1.02-1.14). Similarly, a shorter reproductive life span was associated with a higher diabetes risk (HR per SD lower reproductive life span 1.06 [1.01-1.12]). No effect modification by BMI, waist circumference, or smoking was observed (P interaction all > 0.05). CONCLUSIONS: Early menopause is associated with a greater risk of type 2 diabetes