We used METAL software (Willer et al. 2010) to combine the p values and effect size estimates from the SAGE and COGA association results. METAL selects the reference allele for each marker and calculates the z-statistic characterizing the evidence for association. The z-statistic summarizes the magnitude and direction of the effect relative to the reference allele. Overall statistic and p-values were then calculated from the weighted sum of the individual statistics.
