To evaluate heritability, genetic correlation and polygenic scoring, we generated ancestry-stratified GWAS meta-analysis results for each of the four continental groups: AFR, AMR, EAS and EUR (Supplementary Table 2 lists ancestry-stratified loci). Heritability and cross-phenotype genetic correlations were generally similar in sign and modest in magnitude in each ancestry (Fig. 2a and Supplementary Tables 8 and 9). Smoking phenotypes were moderately genetically correlated with each other (|rg| = 0.30–0.63) and with DrnkWk (|rg| = 0.16–0.27). Genetic correlations for the same phenotype between each of the largest contributing cohorts and all remaining cohorts (restricted to EUR ancestries only) were generally high for each smoking phenotype (mean rg of 0.93) and DrnkWk (mean rg of 0.72), indicating that these measures were reliable across cohorts (Supplementary Table 9).
