LDSC-based genetic correlation (rG) analyses between OA (gSEM results) and 37 brain related traits (Fig. 3, Supplementary Table 11) yielded 21 significant results (Bonferroni threshold of p < 1.35 × 10–3). The highest rGs were with cannabis use disorder (rG = 1.0452, p = 9.40 × 10–6) and alcohol dependence (rG = 0.8183, p = 4.82 × 10–10); smoking traits (rG = − 0.4928 to 0.6043, p = 1.82 × 10–49 to 0.44) and other psychiatric disorders (rG = − 0.2482 to 0.4849, p = 0.79 to 1.82 × 10–49) were more modest. Expected inverse genetic correlations were also evident for age of initiation of cigarette smoking (rG = − 0.4928, p = 5.97 × 10–17) and cognitive/educational traits (rG = − 0.3722 to − 0.4033, p = 1.00 × 10–4 to 1.40 × 10–22). There were no genetic correlations between OA and brain volume traits.
