The full GWAS Catalog22 database was downloaded on 31 December 2016. The data were filtered to identify results relevant to any of the 26 PAGE phenotypes, producing a subset of 8,979 unique trait-SNP associations (3,322 unique variants) that were genome-wide significant (P < 5 × 10−8) in the GWAS Catalog. The PAGE results for each of the GWAS Catalog trait-SNP associations was examined to first identify the subset of pairs that replicated (P < 5 × 10−8) in PAGE unconditioned models. Pairs of replicated tag SNPs within 500,000 base pairs of each other were then merged into loci, to count ‘unique’ associated loci. Of the GWAS Catalog tag SNPs that were replicated in PAGE, SNPs that had a Bonferroni-corrected SNP × PC interaction heterogeneity P value (P < 8.71 × 10−5, 0.05/574) were considered to show evidence of significant effect size heterogeneity between ancestries. Effect heterogeneity was also assessed using the multi-ethnic study population of PAGE by first identifying the lead SNP in each locus with the smallest P value in PAGE, totalling 333 SNPs (302 known loci from the
