We used cross-trait LD-Score regression to estimate the bivariate genetic correlations between MD, AD, and AC using GWA summary statistics (Bulik-Sullivan et al., 2015a). For each pair of traits, the genetic covariance is estimated using the slope from the regression of the product of z-scores from two GWA studies on the LD score. The estimate represents the genetic covariation between the two traits based on all polygenic effects captured by SNPs. To correct for multiple testing, we adopted a Bonferroni corrected P-value threshold of significance of 0.05/ 6 = 0.0083.
