GENETIC PREDISPOSITION AND ENVIRONMENTAL-FACTORS LEADING TO THE DEVELOPMENT OF INSULIN-DEPENDENT DIABETES-MELLITUS IN CHILEAN CHILDREN

This study was designed to examine the hypothesis that some environmen tal factors increase the risk for insulin-dependent diabetes mellitus. Data on dietary history was collected from 80 diabetic children from the Santiago de Chile Registry and from 85 nondiabetic control subject s who were comparable in terms of age, sex, and ethnic characteristics . Early exposure was defined as the ingestion of food sources other th an maternal milk before 3 months of age. To define genetic susceptibil ity to insulin-dependent diabetes mellitus each subject was typed in t erms of HLA DQA1 and DQB1, and the possible conformation of susceptibl e heterodimers was considered as a risk marker. Fewer children were ex clusively breast fed in the diabetic group than in the control group ( 21.55+/-15.05 vs. 33.95+/-20.40 weeks, P<0.01). In addition, exposure to cow's milk and solid foods occurred earlier in the diabetic group t han in the control group (15.90+/-10.95 vs. 21.15 13.65 and 16.85+/-10 .25 vs. 21.20+/-12.35 weeks, P<0.05). Our data show that a short durat ion of breast-feeding and early exposure to cow's milk and solid foods may be important factors in the development of insulin-dependent diab etes mellitus. The high relative risk observed in individuals genetica lly predisposed indicates an interaction effect ge between genetic and environmental components.