Very recently, three other large smoking genetics consortia published their meta-analysis findings that confirm locus 1 (representing not only rs16969918 but also rs1051730 and other SNPs) as the locus most associated with smoking quantity, genome-wide [12]–[14]. All three studies used linear regression to test for association with either quantitative CPD value [14] or categorical CPD (1–10, 11–20, 21–30, and 31+) [12], [13]. Those consortia also report results from conditional analyses in which a locus 1 SNP was included as a covariate, paralleling our joint analyses.
