MATERNAL EXPOSURE TO AIR POLLUTION AND THE RISK OF THE CHILD DEVELOPING TYP1 DIABETES

Genetic and non-genetic factors act probably together to initiate and accelerate development of Type1 Diabetes [T1D]. One suggested risk factor contributing to development of T1D is air pollution. The aim of the study was to investigate if maternal exposure during pregnancy to air pollution, measured as nitrogen oxides [NOx], traffic density and ozone, in a low dose exposure area was associated with her child developing T1D. In Scania, the most southern county in Sweden, 84 039 infants were born during the period 1999-2005. By the end of April 2013, 324 of those children were diagnosed with T1D. For each of those T1D children three control children were randomly selected and matched for HLA genotype and birth year. Individually modelled exposure data at residence during pregnancy were assessed for nitrogen oxides [NOx], traffic density and ozone. Ozone as well as NOx exposures were associated with T1D. When the highest exposure quartile was compared to the lowest quartile an odds ratio of 1.70 (95% confidence interval [CI] 1.01 to 2.87) was observed for ozone in the second trimester and 1.57 (95% CI 1.06-2.34) for NOx in the third trimester. This study indicates that living in an area of elevated levels of air pollution during pregnancy may be a risk factor for T1D. The major strengths of this study is that we in a population-based prospective study have been able to, for the first time, analyze the association of air pollution during pregnancy and risk of childhood development of T1D after controlling for the genetic risk of disease.