To prospectively determine the risk of gestational diabetes (GDM) in association with life-course weight characteristics and adult abdominal adiposity.
We investigated the joint and independent impact of birth weight, childhood size by somatotypes, adolescent and adult body mass index (BMI) and abdominal adiposity on GDM risk among 21,647 women in the Nurses’ Health Study II who reported a singleton pregnancy between 1989 and 2001. 1,386 incident GDM cases were reported. Relative risk (RR) was estimated by pooled logistic regression adjusting for age, prematurity, race, smoking status, parental history of diabetes, age of first birth, parity, and physical activity.
Birth weight was inversely associated with GDM risk (P-trend 0.02). Childhood somatotypes at ages 5 and 10 years were not associated with risk. U-shaped associations were found for BMI at age 18 and somatotype at age 20 years. Weight gain between adolescence and adulthood, pre-gravid BMI and abdominal adiposity were positively associated with risk (p-trends all<0.01). Multivariate adjusted RR for GDM from lowest to highest quintile of waist-to-hip ratio were 1.00, 1.50, 1.51, 2.03, 2.12 (P-trend 0.0003). Lower birth weight (<7 pounds) without adulthood overweight (BMI>25 kg/m2) was associated with 20% increased risk (95% CI: 1.02–1.41). However, adulthood overweight alone was related to 2.36 times greater GDM risk (95% CI: 2.12–3.77).
Although lower birth weight is an independent risk factor for GDM, weight gain since early adulthood, and overall and central obesity in adulthood were more strongly associated with elevated GDM risk independent of other known risk factors.