Consumption of salt and high-salt foods and the risks of oral, pharyngeal, and oesophageal cancers: the JACC Study

Abstract

The association between salt and salted food consumption and oral, pharyngeal, and oesophageal cancers remains inconclusive. To address this, we conducted a large-scale nationwide cohort study in Japan, a region globally recognised for its high-salt consumption. In a baseline survey conducted from 1988 to 1990, salt consumption was evaluated using a self-administered food frequency questionnaire in a sample of 42,535 participants aged 40–79 years. Over a median 14.4-year follow-up period, 145 incident cases of oral (n=43), pharyngeal (n=17), and oesophageal (n=85) cancers were observed. A Cox proportional hazards model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) after adjusting for age, sex, smoking status, alcohol consumption, and fruit and vegetable consumption. High-salt consumption was associated with a higher risk of oral, pharyngeal, and oesophageal cancers combined; the multivariable HR for the highest versus lowest tertiles of salt consumption was 1.67 (95% CI: 1.08–2.61, P-trend = 0.01). An excess risk was primarily observed for oral and oesophageal cancers. Among the salt sources, miso soup consumption was positively associated with the combined risk of oral, pharyngeal, and oesophageal cancers; however, the consumption of other high-salt foods was not. In conclusion, high-salt consumption was associated with a higher combined risk of oral, pharyngeal, and oesophageal cancers.