Tobacco, alcohol, and diet in the etiology of laryngeal cancer: a population-based case-control study.

Cancer of the larynx constitutes an increasingly important problem in Polish males during the last 25 years. A population-based case-control study of laryngeal cancer among people under 65 years of age was conducted in Lower Silesia, a province in Southwest Poland, from 1986 to 1987, with 249 newly-diagnosed cancer cases and 965 controls. The estimated relative risk (RR) for smoking and alcohol are both very high: for smoking more than 30 cigarettes, RR = 59.7 (95 percent confidence interval [CI]: 13.0-274); for drinking vodka regularly for more than 30 years, RR = 10.4 (95 percent CI: 4.0-27.2). Exposures to alcohol and tobacco show a clear multiplicative effect in all categories of exposure. The risk was shown to be reduced by quitting smoking (RR = 0.3, 95 percent CI: 0.14-0.64, after 10 years) or by having a history of intermittent smoking. Poor nutrition was also identified as a strong independent risk factor. However, data quality regarding this factor is not as high as for tobacco and alcohol. Smoking alone accounts in this study for an estimated 95.2 percent of all the cases of laryngeal cancer.