Differences in the Effect of Physical Activity on the Prevention of Gastric Cancer According to Sex

Purpose: Physical activity (PA) is considered a potentially effective factor in the primary prevention of gastric cancer (GC). As body mass index (BMI) and waist circumference (WC) differ by sex, particularly with age, this study aimed to investigate the impact of PA on GC development, considering BMI and WC variations by sex. Materials and Methods: We analyzed the impact of PA on GC development using Cox proportional hazard regression in a cohort of 314,525 Korean individuals from the National Health Insurance Service–Health Screening database, using data from 2009–2019. Additionally, subgroup analyses were conducted based on BMI and WC. The models were adjusted for age, sex, smoking status, alcohol consumption, BMI, and comorbidities. Results: The effect of PA on the prevention of GC development was relatively evident in males. The high PA group (metabolic equivalents of task, METs/week of 500–999) showed a lower risk of GC compared to the group with METs/week of 0 (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.79–0.98). Especially in males with WC <90 cm and BMI <23 kg/m², a lower risk of GC was observed in the group with METs/week of 1–499 compared to the group with METs/week of 0 (HR, 0.80; 95% CI, 0.67–0.96). In contrast, no consistent association was observed between PA levels and risk of GC in females. Conclusions: Moderate PA had a preventive effect on GC development in males, particularly in those with low BMI and WC. However, this effect was not observed in females.