Adding salt to food at table as an indicator of gastric cancer risk among adults: a prospective study.

Background: While dietary salt intake has been linked with gastric cancer risk in Asian studies, findings from Western populations are sparse and limited to case-control studies. Our aim was to evaluate the frequency of adding salt to food at table in relation to gastric cancer risk among UK adults.

Methods: We evaluated associations between the frequency of adding salt to food and the risk of gastric cancer in the UK Biobank (N = 471,144) using multivariable Cox regression. Frequency of adding salt to food was obtained from a touchscreen questionnaire completed at baseline (2006-2010). 24-h urinary sodium excretion was estimated using INTERSALT formulae. Cancer incidence was obtained by linkage to national cancer registries.

Results: During a median follow-up period of 10.9 years, 640 gastric cancer cases were recorded. In multivariable models, the gastric cancer risk among participants reporting adding salt to food at table "always" compared to those who responded "never/rarely" was HR = 1.41 (95% CI: 1.04, 1.90). There was a positive linear association between estimated 24-h urinary sodium levels and the frequency of adding salt to food (p-trend <0 .001). However, no significant association between estimated 24-h urinary sodium with gastric cancer was observed (HR = 1.19 (95% CI: 0.87, 1.61)).

Conclusions: "Always adding salt to food" at table was associated with a higher gastric cancer risk in a large sample of UK adults. High frequency of adding salt to food at table can potentially serve as a useful indicator of salt intake for surveillance purposes and a basis for devising easy-to-understand public health messages.