Intrauterine exposure to diabetes conveys risks for type 2 diabetes and obesity: a study of discordant sibships

Intrauterine exposure to diabetes is associated with an excess of diabetes and obesity in the offspring, but the effects of intrauterine exposure are confounded by genetic factors. To determine the role of the intrauter-ine diabetic environment per se, the prevalence of dia-betes and the mean BMI were compared in siblings born before and after their mother was recognized as having diabetes. Nuclear families in which at least one sibling was born before and one after the mother was diagnosed with type 2 diabetes were selected. Conse-quently, the siblings born before and after differed in their exposure to diabetes in utero. A total of 58 sib-lings from 19 families in which at least one sibling had diabetes were examined at similar ages (within 3 years). The risk of diabetes was significantly higher i