The identified genetic factors gave estimated effect sizes consistent with those for well-established risk factors for pulmonary function decline. Carrying one copy of an implicated reference allele resulted in a FEV1 difference ranging from 50 to 70 mL. These effect sizes correspond to approximately 2.8–3.9 years of age-related decline in pulmonary function based on a mean decline of about 18 mL/year and to approximately 1.7–2.3 years of active smoking-related decline based on a mean decline of about 30 mL/year51. Second-hand smoke exposure has also been associated with decline in FEV1 (15 mL decline for a 10-year exposure in the home and 41 mL decline for a 10-year workplace exposure)52. For FEV1/FVC, carrying one copy of an implicated reference allele resulted in a difference ranging from 0.30 to 1%. The lower effect size estimates are comparable with the mean FEV1/FVC decline related to second-hand smoking (0.35 for a 10-year exposure in the home and 0.14 for a 10-year workplace exposure)52. These comparisons demonstrate that the identified genetic factors have a moderate impact on pulmonary function. Individuals carrying these polymorphisms will have
