Does the secular increase in body mass in children contribute to the increasing incidence of type 1 diabetes?

Background: The incidence of type 1 diabetes in children has increased in most developed countries after World War II, and simultaneously, normal children have experienced accelerated weight gain and growth. Objective: We set out to explore whether any relationship can be seen between the incidence of childhood type 1 diabetes and changes in linear growth and body mass in Finnish children over a 12-yr period. Methods: Incidence rates for type 1 diabetes in Finnish children under the age of 15 yr were obtained from the National Central Drug Registry. The rates were averaged for 3-yr intervals over the 15-yr period 1979-1993 and related to data on mean height, weight, and body mass index (BMI) in 15-yr-old children generated for the years 1980, 1983, 1986, 1989, and 1992 by the 'Cardiovascular Risk in Young Finns' study. Results: There was a positive correlation between the incidence of childhood type 1 diabetes and mean heights (r = 0.84; p = 0.039), mean weights (r = 0.85; p = 0.036), and mean BMIs (r = 0.87; p = 0.028) in 15-yr-old children over the 12-yr study period. Conclusions: This observation suggests that accelerated linear growth and increasing body mass may contribute to the rising incidence of childhood type 1 diabetes seen in most developed countries since World War II. This effect might be mediated through increased beta-cell stress induced by hyperinsulinemia and decreased insulin sensitivity, associated with rapid linear growth and obesity.