Air pollution and type 1 diabetes in children

Background: Over the past decade, there has been a worldwide largely unexplained increase in the incidence of type 1 diabetes in young children. This study explores the quantitative role of exposure to specific air pollutants in the development of type 1 diabetes in children. Methods: A total of 402 children were retrospectively studied. Zip code-related, time-specific birth-to-diagnosis exposure to five ambient air pollutants was obtained for 102 children with type 1 diabetes and 300 healthy children receiving care at a single hospital. Pollution exposure levels were created by summing up zip code-specific pollution data and dividing by months of exposure from birth to diagnosis. Analysis employed chi(2), two-tailed independent sample t-test and unconditional logistic regression. Results: Odds ratio (OR) was significantly high for cumulative exposure to ambient ozone (O-3) and sulfate (SO4) in cases compared with controls, OR = 2.89 [95% confidence interval (CI) = 1.80-4.62] and OR = 1.65 (CI = 1.20-2.28), respectively, even after adjustment for several potential confounders. Passive smoking was more frequent in children with diabetes (30 vs. 10%, p = 0.001). Attending day care and breast feeding in infancy were less frequent in children with diabetes (14 vs. 23%, p = 0.025; 59 vs. 78%, p = 0.001). Family history of diabetes, autoimmune disease and drug abuse was more frequent in cases (p < 0.01). Conclusion: Cumulative exposure to ozone and sulfate in ambient air may predispose to the development of type 1 diabetes in children. Early infant formula feeding and passive smoking in the household may precipitate or accelerate the onset of type 1 diabetes.