Infections in Early Life and Development of Type 1 Diabetes

Abstract

Infections in Early Life and Development of Type 1 DiabetesViral infections, particularly enteroviruses, 1 have been hypothesized to cause type 1 diabetes (T1D). 2 Recent studies suggest that respiratory tract infections are associated with increased T1D risk if they are encountered within the first 6 months. 3 We explored associations between infection types during the first 2 years and between respiratory tract infections in the first 6 months and T1D in a population-based cohort.Methods | The Kassenärztliche Vereinigung Bayern processes claims data for all statutorily insured patients in Bavaria, Germany (approximately 85% of the total Bavarian population).Infants born between 2005 and 2007 were included and observed until March 2015 or last contact with a physician.Diagnoses of infection, T1D, and juvenile idiopathic arthritis (JIA, as a control autoimmune disease) were obtained using International Classification of Diseases, Tenth Revision, codes recorded in 3-month age intervals over 2 years (eg, birth to 2.9 months).Infections were categorized by symptoms (respiratory, gastrointestinal, dermal, and eye) and causes (viral, bacterial, and mycoses).Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals of time to T1D diagnosis by infection event, adjusting for sex and calendar month of birth.Infections were treated as binary time-varying covariates with nonexposure to a specific infection in a quarterly interval as reference category.Kaplan-Meier analysis was used to estimate cumulative risks of T1D and JIA by respiratory tract infections or viral respiratory tract infections in the first 6 months.Differences were assessed by the log-rank test.Statistical analyses were conducted using SAS (SAS Institute), version 9.3, and R (R Foundation), version 3.0.3.Statistical significance was determined at the 5% level (2-sided).