Supplementary Table 3 shows the selected genome-wide significance thresholds, the methods of investigating heterogeneity across studies, and the replication processes applied in the eligible met-analyses. In all meta-analyses, investigators used primarily P-value thresholds to claim genome-wide significance. In two of them, they used additionally Bayesian methods (Bayes factor and posterior probability of association). The P-values thresholds used were P=5×10−8 for 123 meta-analyses; P=5×10−7 for 8 meta-analyses; P=1×10−8 for 3 meta-analyses; P=7.2×10−8 for 2 meta-analyses; and P=2.5×10−8, P=4×10−7 and P=1.6×10−7 for each one of the remaining 3 meta-analyses. Methods of investigating heterogeneity were reported in 103 meta-analyses. These pertained to Cochran’s Q test alone (n=37), I2 alone (n=27), or both Q and I2 (n=37), while one meta-analysis reported Q, I2 and τ2 and another one had used the Breslow-Day test. Cochran’s Q statistic follows a χ2 distribution and tests whether the observed differences in results are compatible with chance. I2 measures the percentage of variability in effect estimates that is attributed to heterogeneity rather than chance (28). Heterogeneity in GWA studies can be attributed to differences between the included studies such
