We lifted the SNP positions from HapMap 2 NCBI build 36, Human Genome references 18 to the Human Genome references 19 positions based on dbSNP build 138. Following conversion, there were meta-analysis results available for quantity smoked (2,342,540 SNPs), ever smoking (2,339,474 SNPs), smoking cessation (2,340,171 SNPs) and age at initiation (2,341,140 SNPs). The SNPs passed the TAG consortium's quality criteria (see Supplementary Table 3 in 13).
