Work-related risk factors for laryngeal cancer.

The authors conducted a case-control study to identify employment-related risk factors for laryngeal cancer. Richmond County, Georgia, and the contiguous counties were chosen as the study area because the 1950-1969 laryngeal cancer mortality rate for white males in Richmond County was almost double the corresponding rate for the entire United States, and because a large proportion of the working population was employed in industries for which excess risk among workers had been reported. All persons with newly diagnosed squamous cell carcinoma of the larynx treated in the area hospitals were identified. Potential controls were selected from patients admitted to these hospitals during the same time period as the cases, excluding those patients admitted for cancer, lung disease, or employment-related disease. Eighty-five control subjects were individually matched to 42 cases for sex, age, area of residence, and smoking and alcohol-drinking history. From lifetime employment histories, laryngeal cancer rate ratios were estimated comparing the incidence rate among subjects who had ever worked in an occupation with the incidence rate among subjects who had never worked in that occupation. Among the 10 occupations in which at least 15 subjects had worked, the authors found rate ratio estimates above 3.0 for farmers, textile processors who separated, filtered or dried textile fibers, and for all laborers and maintenance personnel.