Infant feeding, early weight gain, and risk of type 1 diabetes

OBJECTIVE - To evaluate whether the increased risk of type 1 diabetes confe rred by an early introduction of cow's milk supplements can be mediated by accelerated growth in formula-fed infants. RESEARCH DESIGN AND METHODS - All children less than or equal to 14 years o f age who were diagnosed with type 1 diabetes from September 1986 to April 1989 were invited to participate in the study. Birth date- and sex-matched control children were randomly selected from the Finnish Population Registr y. At least three weight measurements from the first year of life were obta ined for 435 full-term diabetic subjects and 386 control subjects from well -baby clinics and school health care units. RESULTS - Increase in body weight was greater in the diabetic girls than in the control girls, and the difference increased from 111 g (95% CI 0-218, P = 0.04) at 1 month of age to 286 g (95%, CI 123-450, P = 0.0006) at 7 mon ths. For boys, the difference in weight between the diabetic subjects and t he control subjects remained stable during infancy (difference 95 g, 95% CI -2-205, P = 0.09). Increased weight was associated on average with a 1.5-f old risk of type 1 diabetes. Early introduction of formula feeding (<3 vs. greater than or equal to 3 months) was also associated with an increased ri sk of type 1 diabetes after adjustment for the individual weight gain curve (adjusted odds ratio 1.53, 95% CI 1.1-2.2). No evidence for interaction wa s observed. CONCLUSIONS - These observations indicate that an early exposure to cow's m ilk formula-feeding and rapid growth in infancy are independent risk factor s of childhood type 1 diabetes.