The combined GWAS of moderate-to-severe COPD included COPDGene non-Hispanic whites, COPDGene African-Americans, ECLIPSE, NETT/NAS, and GenKOLS (Norway), for a total of 6,633 cases and 5,704 controls. Both individual and overall quantile-quantile (Q-Q) plots showed no evidence of significant population stratification (individual study λGC all ≤ 1.04; overall λGC =1•03; λ 45GC1000 = 1•01, Figure S1). The top results at each of the loci with P < 10−7 are shown in Table 3 and Figure 1. The three most significant SNPs in this meta-analysis were either identical to, or in strong LD – r2 > 0•5 – with the top SNPs previously described at these three loci: 4q22 (FAM13A), 15q25 (CHRNA3/5/IREB2), and 4q31 (HHIP), confirming these previous association results 9,10,12.
