Perinatal and Antibiotic Exposures and the Risk of Developing Childhood-Onset Inflammatory Bowel Disease: A Nested Case-Control Study Based on a Population-Based Birth Cohort.

The role of early-life environmental exposures on Inflammatory Bowel Disease (IBD) onset remains unclear. We aimed to quantify the impact of perinatal conditions and antibiotic use in the first 6 and 12 months of life, on the risk of childhood-onset IBD, in a birth cohort of the region Friuli-Venezia Giulia (Italy). A nested case-control design on a longitudinal cohort of 213,515 newborns was adopted. Conditional binomial regression models were used to estimate Odds Ratios (OR) with 95% confidence intervals (CI) for all analyzed risk factors. We identified 164 individuals with IBD onset before the age of 18 years and 1640 controls. None of the considered perinatal conditions were associated with IBD. Analyses on antibiotic exposure were based on 70 cases and 700 controls. Risks were significantly higher for children with ≥4 antibiotic prescriptions in the first 6 and 12 months of life (OR = 6.34; 95%CI 1.68-24.02 and OR = 2.91; 95%CI 1.31-6.45, respectively). This association was present only among patients with Crohn's disease and those with earlier IBD onset. We found that perinatal characteristics were not associated to IBD, while the frequent use of antibiotics during the first year of life was associated to an increased risk of developing subsequent childhood-onset IBD.