The details of the SpiroMeta consortium analysis (including contributing studies, spirometry details and methods) are described elsewhere15. In brief, this was an inverse variance weighted fixed effects meta-analysis of 17 studies with imputation to 1000 Genomes Project Phase 1 reference panel. Within each study, FEV1, FVC and FEV1/FVC were adjusted for age, age2, sex, height and population structure, separately for ever and never-smokers. Inverse normal transformed residuals were then tested for association within each smoking stratum assuming an additive genetic effect and then meta-analysed. Genomic control was applied to account for residual population structure. We only included SpiroMeta meta-analysis results in the meta-analysis in this study if Neffective > 70% (i.e. >70% of 38,199), where Neffective is the effective sample size after scaling for imputation quality15.
