rate available on each of the three questionnaires (<5 cigarettes/day in 1982 and 1992, <10 cigarettes/day in 1997). After ascertainment for heavy and light smoking, 1,500 heavy smokers and 1,500 light smokers were selected for genotyping. Of these, 2,847 smokers (1,452 heavy smokers and 1,395 light smokers) passed genotyping quality control and were included in this study. Both current and former smokers were included in the analysis.
