Abstract
BACKGROUND: In the U.S., the incidence of lung cancer varies by race, with rates being highest among black men. There are marked differences in smoking behavior between blacks and whites, but little is known regarding how these differences contribute to the racial disparities in lung cancer. PURPOSE: To compare the lung cancer risk associated with smoking in 14,610 blacks and whites in the prospective cohort Atherosclerosis Risk in Communities study. METHODS: Smoking characteristics were ascertained at baseline and three follow-up visits in 1990-1992, 1993-1995, and 1996-1998 (response rates were 93%, 86%, and 80%, respectively), as well as from annual telephone interviews. Data were analyzed in the fall of 2012. Multivariable-adjusted proportional hazards models were used to calculate hazard ratios and 95% CIs for lung cancer. RESULTS: Over 20 years of follow-up (1987-2006), 470 incident cases of lung cancer occurred. Lung cancer incident rates were highest in black men and lowest in black women. However, there was no evidence to support racial differences in the associations of smoking status, intensity, or age at initiation with lung cancer risk (all p(interaction)≥0.25). The hazard ratio for those who started smoking at age ≤12 versus >22 years was 3.03 (95% CI=1.62, 5.67). Prolonged smoking cessation (≥10 years) was associated with a decrease in lung cancer risk, with equivalent benefits in whites and blacks, 84% and 74%, respectively (p(interaction)=0.25). CONCLUSIONS: Smoking confers similar lung cancer risk in blacks and whites.