Type 2 diabetes and low birth weight - The role of paternal inheritance inthe association of low birth weight and diabetes

Lower birth weight is associated with an increased occurrence of type 2 dia betes in later life. Whether this relationship is explained by environmenta l or genetic factors is unknown. We have examined the potential for genetic influences by determining whether parental diabetes is associated with low er birth weight in 1,608 children of known birth weight and gestational age born between 1941 and 1993 in the Gila River Indian Community in Arizona. The previously described relationships of maternal diabetes to increased bi rth weight and offspring diabetes were observed. In contrast to this we hav e determined novel relationships between low birth weight and paternal diab etes, The offspring of diabetic fathers were, on average, 78 g lighter than the offspring of nondiabetic fathers. For fathers, lower birth weight in t heir offspring was associated with an increased risk of later diabetes, i.e ., fathers of offspring in the lowest quintile of birth weight, who were no t diabetic at the time of birth of their child, had a 1.8-fold increased ri sk of developing diabetes later in life (95% CI 1.2-2.7; P = 0.004). For ch ildren, lower birth weight predicted diabetes in the offspring if paternal but not maternal diabetes was present, but it was not associated with highe r plasma glucose if neither parent had diabetes. We conclude that the risk of diabetes associated with low birth weight is strongly related to the dev elopment of paternal diabetes, suggesting a genetic link between lower birt h weight and later diabetes.