It was previously shown that the CYP2A6 alleles are associated with smoking-related lung cancer in a Japanese population [12]. Therefore, we also assessed the association between the CYP2A6 locus and chronic obstructive pulmonary disease (COPD; 982 cases and 4,480 controls), lung cancer (997 cases and 6,491 controls) and arteriosclerosis obliterans (ASO; 499 cases and 10,975 controls) in our GWAS and replication sample sets. Compared with the reference haplotype, we observed significant associations of the deletion haplotype with COPD (OR = 0.2, 95%CI 0.14–0.27, ) and lung cancer (OR = 0.33, 95%CI 0.25–0.45, ), as well as a suggestive association with ASO (OR = 0.53, 95%CI 0.36–0.77, ) (Table 2). Similarly, we observed significant associations of the mutant haplotype with COPD (OR = 0.38, 95%CI 0.3–0.49, ) and lung cancer (OR = 0.55, 95%CI 0.44–0.69, ) (Table 2).
