A cohort study of reproductive risk factors, weight and weight change and the development of diabetes mellitus

Aims: Reproductive factors (parity, miscarriages, terminations), oral contraceptive use, hormone replacement therapy, body weight at first pregnancy and weight gain following pregnancy may be associated with a long-term risk of diabetes. The aim of this study is to investigate the independent risks of reproductive factors and body weight for diabetes in later life. Methods: This is a retrospective cohort study of 1257 parous women who had a first pregnancy between 1951 and 1970. Reproductive history, weight and height were measured at the time of first pregnancy, then assessed by questionnaire in 1997 for all women. A clinical examination and an analysis of blood samples were undertaken for 992 women. The main outcome was incidence of diabetes based on medical history, medication and random glucose measurement. Results: Sixty of the 1257 (4.8%) women developed diabetes. Body mass index at index pregnancy and after 28-48 years follow-up were both significantly associated with risk of diabetes, this increased with greater weight gain. There was a non-significant increased risk of diabetes associated with stillbirths and miscarriages after age and BMI adjustment. Conclusions: In parous women, higher BMI at index pregnancy, weight gain during follow-up and BMI in later life strongly predict diabetes risk.