Exposure to Helicobacter pylori –positive Siblings and Persistence of Helicobacter pylori Infection in Early Childhood

Objectives: Cross‐sectional studies suggest that Helicobacter pylori may be transmitted between siblings. The present study aimed to estimate the effect of an H pylori –infected sibling on the establishment of a persistent H pylori infection. Materials and Methods: The authors used data collected from a Texas–Mexico border population from 1998 to 2005 (the “Pasitos Cohort Study”). Starting at age 6 months, H pylori and factors thought to be associated with H pylori were ascertained every 6 months for participants and their younger siblings. Hazard ratios were estimated from proportional hazards regression models with household‐dependent modeling. Results: Persistent H pylori infection in older siblings always preceded persistent infection in younger siblings. After controlling for mother's H pylori status, breast‐feeding, antibiotic use, and socioeconomic factors, a strong effect was estimated for persistent H pylori infection in an older sibling on persistent infection in a younger sibling (hazard ratio 7.6, 95% confidence interval 1.6–37], especially when the difference in the age of the siblings was less than or equal to 3 years (hazard ratio 16, 95% confidence interval 2.5–112). Conclusions: These results suggest that when siblings are close in age, the older sibling may be an important source of H pylori transmission for younger siblings.