Alcohol drinking outside meals and cancers of the upper aero-digestive tract

In our integrated series of case-control studies conducted in Italy and Switzerland (324 oral, 397 pharyngeal, 271 oesophageal, 506 laryngeal cancers and 3,263 controls), individuals who also drank alcoholic beverages outside meals showed an increased risk compared to those who drank at meals only. At any alcohol intake level, subjects also drinking between meals showed a more elevated risk of developing an upper aero-digestive tract cancer than subjects drinking only at meals. After adjustment for potential covariates, and, after allowance for the number of daily drinks to adjust for different alcohol-intake levels, the odds ratios for subjects reporting drinking outside meals were 1.5 (95% confidence interval [Cl]: 1.0-2.2) for oral, 1.8 (95% Cl: 1.3-2.5) for pharyngeal, 1.7 (95% Cl: 1.2-2.5) for oesophageal and 1.2 (95% Cl: 0.9-1.7) for laryngeal cancers. Our findings show that drinking pattern with respect to food consumption may influence alcohol carcinogenesis in the upper digestive and respiratory tract. An "alcohol washing effect" by chewing and swallowing is suggested.