Body mass index change trajectories and gastric cancer risk: Effect modification by sex, age, smoking, and menopausal status in Korean adults aged ≥40 years

by Su Youn Nam, Junwoo Jo This study examined the association between body mass index (BMI) and gastric cancer risk and specifically evaluated effect modification by sex, age, smoking, and menopausal status. A nationwide cohort of cancer-free Korean adults aged ≥40 years who underwent standardized health examinations in 2009 and 2013 was followed through 2017.

BMI was classified into five categories ( 2 ), and BMI changes were grouped into 25 trajectories. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for gastric cancer were estimated using Cox proportional hazards models, with formal interaction testing for key modifiers.

Among 2,800,588 participants (52.8% women), 14,662 incident gastric cancers were identified. Persistent obesity I was consistently associated with an increased gastric cancer risk in total population and most subgroups, including both men and women, both smoking groups, postmenopausal women, and individuals aged < 60 years.