Sibship size, Helicobacter pylori infection and chronic atrophic gastritis: A population-based study among 9444 older adults from Germany

Abstract

Background: Early-life social environment has been suggested to play an important role during the development of Helicobacter pylori-related gastric diseases. We aimed to assess the association of sibship size with H. pylori infection and chronic atrophic gastritis (CAG) in a population-based study from Germany. Methods: In the baseline examination of ESTHER, a study conducted in Saarland, serological measurements of pepsinogen I and II and H. pylori antibodies were taken in 9444 participants aged 50-74 years. Information on potential risk factors and medical history were obtained by self-administered standardized questionnaire. Results: A strong dose-response relationship between sibship size and H. pylori seroprevalence was observed (P < 0.01). Adjusted odds ratios (ORs) 95% confidence interval (CI) for H. pylori seropositivity for subjects with 4, 5, 6 and 7 or more siblings compared with subjects without siblings were 1.45 (1.20-1.77), 1.83 (1.50-2.22) and 1.84 (1.47-2.31), respectively. A large sibship size was also associated with an increased risk of CAG with an adjusted OR of 1.42 (1.01-2.01) for 7 or more compared with less than or equal to 2 siblings. This association was attenuated but not entirely elimi- nated after additional adjustment for H. pylori infection. Notably, a significant association between large sibship size and CAG was also found among H. pylori-negative subjects. Conclusions: Our results suggest that large sibship size is associated with increased H. pylori prevalence and CAG risk. The association with CAG risk may be mediated at least in part by H. pylori infection. However, mechanisms other than H. pylori infection may contribute to the 'sibling effect' as well. © The Author 2009; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.