A prospective study of dietary salt intake and gastric cancer incidence in a defined Japanese population: The Hisayama study

The results of prospective studies of the association between dietary salt intake and gastric cancer occurrence remain controversial. To examine this issue in a cohort study of a general population, 2,476 subjects aged 40 years or older were stratified into 4 groups according to the amount of daily salt intake: namely, <10.0,10.0-12.9,13.0-15.9, and ≥ 16.0 per day and were followed up prospectively for 14 years. During the follow-up period, 93 subjects developed gastric cancer. The age- and sex-adjusted incidence was significantly higher in the second to fourth groups than in the first group (age- and sex-adjusted hazard ratio [95% confidence interval], 2.42 [1.24-4.71] for the second group; 2.10 [1.03-4.30] for the third group; 2.98 [1.53-5.82] for the fourth group). This association remained substantially unchanged even after adjusting for other confounding factors such as age, sex, Helicobacter pylori infection, atrophic gastritis, medical history of peptic ulcer, family history of cancer, body mass index, diabetes, total cholesterol, physical activity, alcohol intake, smoking habit and other dietary factors. In the stratified analysis, a significant salt-cancer association was observed only in subjects who had both Helicobacter pylori infection and atrophic gastritis (age- and sex-adjusted hazard ratio, 2.87 [1.14-7.24]). Our findings suggest that high dietary salt intake is a significant risk factor for gastric cancer; moreover, this association was found to be strong in the presence of Helicobacter pylori infection with atrophic gastritis.