BODY-MASS INDEX AND THE RISK OF CANCERS OF THE GASTRIC CARDIA AND DISTAL STOMACH IN SHANGHAI, CHINA

The divergent incidence patterns of gastric cardia and distal stomach cancers suggest different etiologies. Although obesity has recently be en linked to cardia cancer in Western populations, its association wit h distal stomach cancer remains unclear. This study examined the relat ion of anthropometric measurements to risk by subsites of stomach canc er in a Chinese population. We identified 1124 population-based cases of stomach cancer, ages 20-69 years, newly diagnosed between December 1988 and November 1989 in Shanghai, China. Controls (n = 1451) were ra ndomly selected from permanent Shanghai residents and frequency-matche d to cases by age and sex. Information on demographic characteristics, height and weight, diet, smoking, and other exposures was obtained by trained interviewers in person. The body mass index (BMI) was calcula ted as weight in kilograms divided by height in square meters and cate gorized into quartiles based on the distribution among controls. Odds ratios and 95% confidence intervals were estimated using logistic regr ession models, simultaneously adjusting for age, education, income, ci garette smoking (men only), alcohol drinking (men only), intake of tot al calories, and chronic gastric diseases. For gastric cardia cancer, the odds ratios among men were 1.4, 1.5, and 3.0 in the second, third, and fourth quartiles of usual BMI (P for trend, <0.01). Among women, elevated risks also were associated with excess weight, but the gradie nt in risk was not smooth. Risk patterns for usual body weight, maximu m BMI, and minimum BMI were similar to those found for usual BMI. For distal stomach cancer, no association with usual BMI was observed amon g men, but a slightly elevated risk was seen among women. Our observat ions in China support recent findings in Western populations that obes ity contributes to the risk of gastric cardia cancer, especially among men.