Effect of Antibiotics Taken for other Illnesses on Incidence of Helicobacter Pylori Infection in Children

Purpose This analysis estimated rate ratios for the effect of antibiotic exposure on the incidence of a first detected H. pylori infection in children. We hypothesized that antibiotics taken for common infections decrease the incidence of H. pylori infections that persist long enough to be detected. Methods The Pasitos Cohort Study (1998–2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. We screened children for infection at target intervals of 6 months from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Reported exposure was defined in two ways: 1) any systemic antibiotic use in the immediately preceding at-risk interval (interval-specific exposure) and 2) average number of courses across all at-risk intervals (average exposure). Cox proportional hazards regression models included country of residence, motherʹs education, and prenatal care adequacy. We defined infection onset time as the midpoint between last negative and first positive test. For model checking, we also estimated rate ratios with an interval-censored survival model using a Weibull distribution. Results Of 589 children with complete data, 247 had a first detected infection during 15,762 person-months at risk; ≥1 antibiotic courses were reported at 48% of 1,920 visits. Rate ratios (95% CI) comparing 0 to >0 courses were 1.0 (0.79–1.3) for interval-specific and 0.45 (0.34–0.61) for average exposure. Across interval-specific exposure levels, estimates showed weak effects; rate ratios comparing low and high average exposure to none were 0.38 (0.27–0.55) and 0.50 (0.37–0.69), respectively. Interval-censored models produced similar results. Conclusion Incidental antibiotic exposure was associated with a decreased rate of detected acquisition of childhood H. pylori infection when measured as the average across at-risk person-time. Reasons for inconsistent effects across exposure definitions and levels need further study.