Dark tobacco and lung cancer in Cuba.

A retrospective epidemiologic study of 826 cytologically and/or histologically confirmed lung cancer cases (219 females and 607 males), 979 hospital controls, and 539 neighborhood controls was undertaken in Havana, Cuba, to investigate whether the high lung cancer mortality rates in this country could be explained by the cigarette and cigar consumption habits, including the smoking of dark-tobacco cigarettes. Relative risk(s)(RR) of lung cancer among cigarette smokers were 7.3 in women and 14.1 in men and increased consistently with various measures of exposure to smoke. The findings suggested that duration of smoking, daily number of cigarettes consumed, and inhalation practices have independent effects. Most Cubans smoked dark tobacco. RR were higher for dark-tobacco users than for light-tobacco users (RR = 8.6 vs. 4.6 for women and 14.3 vs. 11.3 for men), but the differences were reduced after adjustment for amount smoked. Cigarette smoking was associated with all histologic types of lung cancer, although the risk for adenocarcinoma was lower than that for the other types. Men who smoked exclusively cigars had a fourfold risk of lung cancer. Mixed smokers (i.e., cigar and cigarette smoker) had a greater RR than cigarette-only smokers (15.0 vs. 14.1), which was perhaps related to the unusually deep and frequent inhalation of cigar smoke. The data support the hypothesis that smoking patterns account for the higher lung cancer mortality in Cuba than in other Latin American countries.