Control subjects were 2 years older than case patients, on average, but had a similar gender ratio and ethnic background (Table 2). Compared to case patients, control subjects were less likely to be cigarette smokers, to have a history of COPD or environmental tobacco smoke exposure, or to have a positive family history of lung cancer in their first-degree relatives. Deficient PI1 types were significantly overrepresented among case patients compare to control subjects (p < 0.05) [Table 3]. For the two ELA2 SNP sites, the frequency distribution of alleles and genotypes at Rep_a was similar between case patients and control subjects, but differed at Rep_b. […]