[Body mass index and the risk of gastric cancer in males: a prospective cohort study].

Objective

To investigate the association between BMI and gastric cancer risk in Chinese males.

Methods

Data on body weight, body height and incidence of gastric cancer were collected on a biennial basis in males in Kailuan Cohort during 2006-2015. In addition, electronic databases of hospitals affiliated to Kailuan Group, insurance system of Kailuan Group and medical insurance system of Tangshan were used for supplementary information. Males with normal body weight (18.5 kg/m(2)≤BMI<24.0 kg/m(2)) were used as controls. Cox proportional hazards regression model was used to evaluate the association between baseline BMI and the risk of gastric cancer in males through the calculations of hazard ratio and 95% confidence interval.

Results

A total of 109 600 males were included and 272 new gastric cancer cases were identified in Kailuan male cohort study, with a follow-up of 860 399.79 person-years during 2006-2015. The median follow-up period was 8.8 years. When compared with normal weight, the hazard ratios (HR) of underweight (BMI≤18.5 kg/m(2)) for gastric cancer risk were 2.11 (95%CI: 1.23-3.62) after adjusting for potential confounding factors (age, education level, smoking status, alcohol drinking status, dust exposure, salty food intake, tea drinking status). However, overweight or obesity showed no significant association with gastric cancer risk. The stratified analyses based on age, education level, status on smoking, alcohol drinking, tea drinking and dust exposure indicated that underweight showed significant association with gastric cancer risk in those with older age, those with high education level, non-smokers, non-alcohol drinkers, non-tea drinkers and those with dust exposure.

Conclusion

Underweight might increase the risk of gastric cancer in males in China, and this positive association might be associated with age, education level, status on smoking, alcohol-drinking, tea-drink, and dust exposure.