Risk factors for oral cancer in Brazil: a case-control study

ABSTRACT

A case-control study of risk factors for carcinomas of the tongue, gum, floor, and other specified parts of the mouth was conduced in three metropolitan areas in Brazil; Säo Paulo (Southeast), Curitiba (South), and Goiânia (Central-West). We analyzed information on demographics, occupational history, environmental exposures, tabacco smoking and alcohol drinking habits, diet, oral and other health characteristics obtained from interviews with 232 cases and 464 hospital non-cancer controls matched on 5-year age group, sex hospital catchment area, and trimester of admission. Tobacco and alcohol consuption were the strongest risk factors irrespective of the anatomical site. The adjusted relative risks (RR) for ever vs. never smokers were 6.3, 13.9, and 7.00, for industrial-brand cigarrettes, pipe and hand-rolled cigarrettes, respectively. A strong correlation was seen between number of pack-years and risk. The RR for the heaviest vs. the lowest consumption categories (>100 vs. <1 pack-years) was 14.8 Risk levels generally decreased to that of never smokers after 10 years since smoking cessation. The risk associated with alcohol was mostly evident for wine (cancer of the tongue) and "cachaça" (all sites), a hard liquor distilled from sugar cane. Other important risk factors were "chimarräo" drinking (a type of mate), use of a wood stove for cooking, and frequent consumption of charcoal-grilled meat and manioc. Oral hygiene chacarcteristics represented correlates of disease risk