Prospective cohort study evaluating the relationship between salted food intake and gastrointestinal tract cancer mortality in Japan.

PURPOSE To investigate whether a high salted food intake increases the risk of gastrointestinal tract cancer mortality. METHODS We conducted a prospective study of 6830 Japanese inhabitants to evaluate the association between salted food consumption and the risk of gastrointestinal tract cancer mortality. Data were obtained from a prospective cohort study in Japan. Salted food consumption, determined from a baseline questionnaire, was classified into the two categories of 'low intake' and 'high intake'. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CI). FINDINGS Total of 174 gastrointestinal tract cancer deaths (47 esophagus cancer, 87 stomach cancer, 23 colon cancer and 17 rectal cancer) were observed during 94996 person-years of follow-up, with a mean follow-up period of 8.9 years. After adjustment for age, body mass index, physical activity, smoking, alcohol, history of diabetes mellitus and dietary items, including vegetables, fruit, tea, red meat and processed meat, the HR for stomach cancer in males with high salt intake was 2.05 (95% CI:1.25 - 3.38) whereas that of rectal cancer was 3.58 (95% CI: 1.08 - 11.89). In contrast, no association was seen in females. Further, no association was seen between higher salted food consumption and esophagus and colon cancer in either sex. CONCLUSIONS A significant association was seen between higher salted food consumption and stomach and rectal cancer mortality in men, but not in women. No association was seen between higher consumption and esophagus and colon cancer mortality in either men or women.