A high weight gain early in life is associated with an increased risk of type 1 (insulin-dependent) diabetes mellitus.

Growth during the first years of life in relation to type of feeding in infancy was retrospectively studied in an unselected population-based group of 297 children who had been diagnosed with Type 1 (insulin-dependent) diabetes mellitus before the age of 15 years (probands) and 792 individually-matched referent subjects. Reliable data were collected from child welfare clinics. Probands weighed slightly less at birth but their weight gain at 6, 9, 18 and 30 months of age was significantly greater (p < 0.02) than that of referent children. The weight gain of children who had never been breast-fed was more marked than that of breast-fed children; this was found for both probands and referent children. But also among exclusively breast-fed children (> 2 months), probands gained significantly more in weight from birth up to 18 and 30 months of age than exclusively breast-fed referent children. Early weight gain appears to be a risk factor for development of Type 1 diabetes. The lower weight gain in breast-fed compared to non-breast-fed children may explain the protective effect of breast feeding against Type 1 diabetes observed in several studies.