Self-reported smoking status was available for all the 7,623 subjects according to the Framingham SHARe. For determination of the smoking status, a question “Did you smoke cigarettes regularly in the last year?” was asked to a subject. Those answering “yes” are treated as smokers and “no” as non-smokers in this sample. In total, there are 1,172 smokers, among whom 542 are males and 630 females. To be consistent with our GWAS sample, those non-smokers who are younger than 25 were excluded from the analyses. The basic characteristics of the study subjects are presented in Table 1.
