INTERNATIONAL RENAL-CELL CANCER STUDY .1. TOBACCO USE

The relationship between renal-cell cancer (RCC) and tobacco use was i nvestigated in an international, multicenter, population-based case-co ntrol study. Coordinated studies were conducted in Australia, Denmark, Germany, Sweden and the United States using a shared protocol and que stionnaire. A total of 1,732 cases (1,050 men, 682 women) and 2,309 co ntrols (1,429 men, 880 women) were interviewed for the study. No assoc iation was observed between risk and use of cigars, pipes or smokeless tobacco. A statistically significant association was observed for cig arette smoking, with current smokers having a 40% increase in risk [re lative risk (RR)= 1.4, 95% confidence interval (CI) 1.2-1.7]. Risk inc reased with intensity (number of cigarettes) and duration (years smoke d). Among current smokers the RR for pack-years rose from 1.1 (95% CI 0.8-1.5) for < 15.9 pack years to 2.0 (95% CI 1.6-2.7) for > 42 pack y ears (p for trend < 0.001). Long-term quitters (> 15 years) experience d a reduction in risk of about 15-25% relative to current smokers. Tho se who started smoking late (> 24 years of age) had about two-thirds t he risk of those who started young (less than or equal to 12 years of age). Overall, the findings of this pooled analysis confirm that cigar ette smoking is a causal factor in the etiology of RCC. (C) 1995 Wiley -Liss, Inc.()