Maternal exposure to air pollution and type 1 diabetes--Accounting for genetic factors.

BACKGROUND Genetic and non-genetic factors probably act together to initiate and accelerate development of type 1 diabetes [T1D]. One suggested risk factor contributing to development of T1D is air pollution. OBJECTIVE The aim of the study was to investigate whether maternal exposure during pregnancy to air pollution, measured as nitrogen oxides [NOx] and ozone, in a low-dose exposure area was associated with the child developing T1D. METHOD In Scania (Skåne), 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 had been 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. RESULTS Ozone as well as NOx exposures were associated with T1D. When the highest exposure group was compared to the lowest group an odds ratios of 1.62 (95% confidence interval [CI] 0.99-2.65) was observed for ozone in the second trimester and 1.58 (95% CI 1.06-2.35) for NOx in the third trimester. CONCLUSION This study indicates that living in an area with elevated levels of air pollution during pregnancy may be a risk factor for offspring T1D.