Helicobacter pylori infection in families of patients with early gastric cancer: household clustering, spousal concordance, and associated factors

The prevention and control strategies for Helicobacter pylori (H. pylori) are gradually shifting from individual-based care to family-based management approaches. However, household infection patterns and associated factors among families of patients with early gastric cancer (EGC) remain to be elucidated. This family-based study was conducted at Nanjing Drum Tower Hospital from June to December 2024, targeting cohabiting family members of EGC patients. Inclusion criteria required family members to have lived together for at least 10 months per year, with a minimum of two members and no upper limit on household size. An infected household was defined as having at least one member testing positive for H. pylori. The study investigated household H. pylori infection patterns and associated factors. A mixed-effects model was employed to analyze H. pylori infection status among early gastric cancer patients and their family members, accounting for family-level clustering. Among the 125 enrolled early gastric cancer patients, 118 (94.3%) were infected with H. pylori, while 7 (5.6%) tested negative. Spearman correlation analysis revealed weak positive correlations between the severity of atrophic gastritis and both the household infection rate (r s = 0.23, P = 0.009) and the number of infected family members (r s = 0.27, P = 0.002). In Poisson and negative-binomial mixed-effects models, the association between current H. pylori infection in the EGC patient and the number of infected family members was positive but not statistically significant (both IRR 1.18, 95% CI 0.52–2.68; P = 0.687). Among the 125 enrolled households, 4 (3.2%) showed no infections, 84 (67.2%) had partial infections, and 37 (29.6%) had full-family infections. Among the 153 couples, 67 (43.8%) had both partners infected, 22 (14.4%) had neither partner infected, and in the remaining couples, only one partner was infected. At the household level, higher annual income was associated with a lower risk of infection (aOR = 0.26, 95% CI: 0.08–0.80, p = 0.019). At the individual level, older age, occupations such as farming or freelancing, exposure to infected household members, and a history of gastrointestinal discomfort were significant risk factors for infection ( P < 0.05). In unadjusted analyses, joint infection was more frequent among couples with longer cohabitation; this association was attenuated after age adjustment. A high infection burden and household clustering of H. pylori infection were observed among EGC-centred households. Patients with EGC may provide a practical starting point for family-based H. pylori screening, with guideline-based management for infected cohabiting family members.