Dietary diversity score and incident peptic ulcer in Chinese older adults: a prospective cohort study

Objective To examine the association between dietary diversity score (DDS) and incident peptic ulcer among older Chinese adults. Methods We analyzed four waves of CLHLS data (2008–2018) from 13,274 ulcer-free adults aged ≥65 years with complete covariate data. DDS (0–9) was derived from a 9-item food frequency questionnaire. Cox proportional hazards models and restricted cubic splines were used to estimate hazard ratios, adjusting for sociodemographic, lifestyle, and health-related covariates. Sensitivity analyses included competing-risk models, lagged exposure updates, hospital-confirmed diagnoses, and multiple imputation. Results In fully adjusted models, each 1-point increase in DDS was associated with a lower risk of incident ulcer (HR = 0.944, 95% CI 0.904–0.986; p = 0.009). Compared with the lowest tertile, the highest tertile had a 24% lower risk (HR = 0.757, 95% CI 0.618–0.927; p = 0.007), with an approximately linear dose–response relationship ( p for nonlinearity = 0.655). The association was consistent in most subgroups but was absent among participants with disability in activities of daily living ( p for interaction = 0.004). Findings were robust across sensitivity analyses, although the association attenuated to null after 3 years of follow-up and in the 6-year landmark analysis, suggesting that the effect was mainly evident during early follow-up. Conclusion Higher dietary diversity was associated with a lower risk of incident peptic ulcer among older Chinese adults, particularly during early follow-up and among functionally independent individuals. Randomized trials are needed to confirm causality and evaluate the intervention potential of dietary diversity.