Prenatal and Postnatal Exposure to Antibiotics and the Risk of Type 1 Diabetes in Finnish Children: A Registry-based Study.

Objective: To study whether prenatal and postnatal exposure to antibiotics is associated with the risk of type 1 diabetes in childhood.

Study Design: This case cohort study included 2869 children diagnosed with type 1 diabetes by the end of 2009 who were born between January 1, 1996, and December 31, 2008, in Finland and a reference cohort (n = 74 263) representing 10% of each birth cohort. Exposure to antibiotics was assessed in different time periods. The data were derived from Special Reimbursement Register, Drug Prescription Register, and Population Register and analyzed with weighted Cox proportional hazards regression models.

Results: Exposure to any antibiotics before or during pregnancy, in the neonatal ward, during the first year of life, or during the 2 first years of life, was not associated with the risk of type 1 diabetes in the offspring. Exposure to macrolides in the year preceding pregnancy (adjusted hazard ratio [HR], 1.17; 95% CI, 1.02-1.33) and to sulfonamides and trimethoprim during pregnancy (adjusted HR, 1.91; 95% CI, 1.07-3.41) was associated with an increased risk of type 1 diabetes in the offspring. Exposure to sulfonamides and trimethoprim during first 2 years of life was associated with a decreased risk of type 1 diabetes (adjusted HR, 0.84; 95% CI, 0.73-0.97). The number of antibiotic purchases among mothers or children was not associated with type 1 diabetes risk.

Conclusions: Prenatal and postnatal exposure to antibiotics in general did not increase the risk of type 1 diabetes in the offspring. However, the type of antibiotic and timing of exposure may play a role in type 1 diabetes risk.