A meta-analysis of alcohol drinking and oral and pharyngeal cancers: results from subgroup analyses

To quantify the magnitude of the association between alcohol and oral and pharyngeal cancer (OPC) by sex, smoking habits, type of alcoholic beverage and other factors.

We combined findings from all case-control and cohort studies published until September 2010 and present in this article the results classified by these factors, using a meta-analytic approach. Summary relative risks (RRs) were obtained using random-effects models; heterogeneity was assessed using the χ(2) test.

The association between alcohol and OPC risk was similar in men and women, with similar dose-response relationships. No notable differences were found with respect to geographic area and other factors, both for drinking overall and heavy (≥4 drinks/day) drinking. Among never/non-current smokers, the pooled RRs were 1.32 (95% confidence interval, CI, 1.05-1.67) for drinking, and 2.54 (95% CI, 1.80-3.58) for heavy drinking. The corresponding RRs in smokers were 2.92 (95% CI, 2.31-3.70) and 6.32 (95% CI, 5.05-7.90). The pooled RRs for any drinking irrespective of smoking were 2.12 (95% CI, 1.37-3.29) for wine-, 2.43 (95% CI, 1.92-3.07) for beer- and 2.30 (95% CI, 1.78-2.98) for spirits-only drinking. The corresponding RRs for heavy drinking were 4.92 (95% CI, 2.80-8.65), 4.20 (95% CI, 1.43-12.38) and 5.20 (95% CI, 2.77-9.78).

The alcohol-related RRs are similar with respect to sex, geographic area and type of alcoholic beverage. The association between alcohol and OPC is stronger in smokers than in non-smokers.