We use linkage disequilibrium score regression (LDSC)27 (see Methods) to estimate SNP-based heritability (h2 SNP) in EAs and AAs, where sample sizes are large enough to provide robust estimates for each trait (Fig. 2a). For AUDIT-C, the h2 SNP is 0.068 (s.e. = 0.005) in EAs: 0.068 (s.e. = 0.005) in males and 0.099 (s.e. = 0.037) in females. In AAs, the h2 SNP is 0.062 (s.e. = 0.016): 0.058 (s.e. = 0.018) in males. For AUD, the h2 SNP is 0.056 (s.e. = 0.004) in EAs: 0.054 (s.e. = 0.004) in males and 0.110 (s.e. = 0.038) in females. The h2 SNP for AUD is 0.100 (s.e. = 0.022) in AAs: 0.104 (s.e. = 0.023) in males. Robust estimates of h2 SNP are unavailable in AA and LA females due to the small sample size.
