Analyses of SNP-based heritability hSNP2 and genetic correlation (rG) were conducted using the cross-trait linkage disequilibrium (LD) score regression approach and LD score regression software (LDSC) (Bulik-Sullivan et al., 2015b; open-source LDSC pipeline, version 1.0.1, github.com/bulik/ldsc) which requires GWAS summary statistics in samples of unrelated individuals. The approach estimates rGs by replacing the χ2 with the z scores from both studies and the genetic covariance is then estimated using the slope from the regression of both z scores on LD scores. Normalizing genetic covariance by hSNP2 yields the genetic correlation. Multiple testing was adjusted using false discovery rate (FDR) correction.
