Body mass index and risk of gastric cancer: A 30-year follow-up study in the Linxian general population trial cohort.

Although a number of previous studies have noted either positive or no association for body mass index (BMI) and gastric cancer risk, little evidence exists in the Chinese population. We prospectively examined the associations of BMI with risk of gastric cancer in the Linxian General Population Trial cohort, with 29 584 healthy adults enrolled in 1985 and followed through to the end of 2014. Body weight and height were measured during physical examination at baseline and BMI was calculated as weight in kilograms divided by height in meters squared. Body mass index from 138 subjects was missing, and a total of 29 446 participants were included in the final analysis. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals. During 30 years of follow-up, we confirmed 1716 newly diagnosed gastric cardia adenocarcinoma (GCA) cases and 626 new gastric non-cardia adenocarcinoma (GNCA) cases. Overall, compared to the lowest quartile (BMI <20.32 kg/m2 ), subjects in the fourth quartile (BMI ≥23.31 kg/m2 ) subjects had lower risk of developing GNCA (hazard ratio, 0.65; 95% confidence interval, 0.51-0.83). Age- and sex-specific analyses showed that this protective effect was only observed in men and older (52 + years) persons. No associations were observed for BMI with GCA incidence. Higher BMI was associated with decreased risk of GNCA in this population, particularly in men and older persons. Future studies are needed to confirm these findings. The trial is registered with ClinicalTrials.gov: NCT00342654.