Perinatal and neonatal determinants of childhood type 1 diabetes. A case-control study in Yorkshire, U.K.
OBJECTIVE: To identify environmental factors that exert their effect in the perinatal and neonatal period and influence the subsequent onset of insulin dependent (type 1) diabetes during childhood. RESEARCH DESIGN AND METHODS: A population-based case-control study of data abstracted from the hospital obstetric and neonatal records of 196 children with type 1 diabetes and 325 age- and sex-matched control subjects. Analysis of matched sets by conditional logistic regression was conducted for a range of perinatal and neonatal factors. RESULTS: A significantly raised risk was observed for illnesses in the neonatal period (OR 1.61, 95% CI 1.06-2.44), the majority of which were infections and respiratory difficulties. Exclusive breast feeding as the initial feeding method was significantly protective (OR 0.65, 95% CI 0.45-0.94). There were no significant associations with high- or low-birth weight, being firstborn or small-for-dates. All factors significant (5% level) for the entire dataset, that is, maternal age, type 1 diabetes in mothers, preeclampsia, delivery by cesarean section, neonatal illnesses, and initial breast feeding were modeled and the OR remained significant for all variables other than cesarean section. CONCLUSIONS: The findings are based on medical record data that cannot be subject to biased recall of mothers. Neonatal illnesses increased and initial breast feeding decreased the risk of childhood type 1 diabetes. Further determinants of risk are mothers with type 1 diabetes, older mothers, and preeclampsia during pregnancy.