Participants’ DNA samples were genotyped using the Illumina Human1M array, the Illumina Human OmniExpress 12V1 array, the Illumina 2.5M array (Illumina, San Diego, CA), or the Smokescreen genotyping array (Baurley et al., 2016). Data were imputed to 1000 Genome Phase 3, and single nucleotide polymorphisms (SNPs) with a genotyping rate < 0.95 or that violated Hardy-Weinberg equilibrium (p < 10−6) or with minor allele frequency < 0.01 were excluded from analysis.
