LUNG-CARCINOMA IN AFRICAN-AMERICANS AND WHITES - A POPULATION-BASED STUDY IN METROPOLITAN DETROIT, MICHIGAN

BACKGROUND. African Americans are at higher risk for lung carcinoma th an whites in the United States. This racial disparity is greater among younger people. The authors evaluated whether racial differences in l ung carcinoma risk can be explained by differences in cigarette smokin g behaviors. METHODS. For this study, 5588 population-based cases of A frican Americans and whites with pathologically confirmed lung carcino ma, diagnosed between 1984 and 1987, were identified through the Metro politan Detroit Cancer Surveillance System. Also identified were 3692 population-based controls. Logistic regression methods were used to ev aluate the risk of lung carcinoma associated with race both within cig arette smoking category and after adjustment for cigarette-smoking beh aviors. RESULTS. The difference in lung carcinoma incidence between Af rican Americans and whites was explained almost entirely by difference s in smoking habits among study participants age 55-84 years. However, among males age 40-54 years, African Americans were 2-4 times more li kely to develop lung carcinoma of any histologic type than whites even after adjustments were made for smoking habits. Similar excesses in r isk among African American females age 40-54 years were demonstrated o nly for squamous cell and small cell carcinomas (odds ratios [OR] and 95% confidence intervals [CI] = 3.7 [1.5-8.9] and 2.7 [1-7.3], respect ively). Also, in this younger age group, African American male nonsmok ers and smokers of 1-40 pack-years had a significantly higher risk of lung carcinoma than white males belonging to the same age group with a similar cigarette-smoking history (ORs and 95% CIs = 8 [2-32.8] and 3 .1 [1.9-5.4] respectively). CONCLUSIONS. Elevated risk for lung carcin oma among younger (but not among older) African Americans, particularl y among males, exists both within cigarette smoking exposure level and beyond that associated with smoking habits. This may indicate a high risk group particularly susceptible to lung carcinogens, or it may ind icate unique exposures not yet identified. (C) 1997 American Cancer So ciety.