Abstract
BACKGROUND: It remains unclear whether Helicobacter pylori (H. pylori) serostatus modifies the obesity-mortality relationship. This study aimed to evaluate the interaction between H. pylori serostatus and visceral obesity indicators in relation to mortality. METHODS: Data were analyzed on 2,161 adults of the National Health and Nutrition Examination Survey (NHANES) 1999–2000 cycle, and followed up through 2018. Logistic regression adjusted for multiple covariates evaluated the relationship between visceral obesity and H. pylori seropositivity. Cox regression with restricted cubic splines (RCS), stratified by H. pylori serostatus, were used to evaluate survival outcomes. RESULTS: Waist-triglyceride index (WTI) and visceral adiposity index (VAI) were both significantly related to H. pylori seropositivity, and only WTI showed an interaction with serostatus in relation to mortality. Among seropositive individuals, the highest WTI tertile was associated with a 66% higher risk of all-cause mortality than the lowest (95% CI: 1.149–2.397; P = 0.007). No significant association was observed in seronegative individuals. CONCLUSIONS: Our findings demonstrated that H. pylori serum status was the effect modification factor associated with visceral obesity and mortality. This increased risk was evident at high visceral adiposity, as measured by WTI. Therefore, WTI may help identify high-risk individuals among those with H. pylori seropositivity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-026-12915-5.