.050) in the early-onset group. Using multivariate regression, female gender was associated with 5.7% lower FEV(1)% predicted in the low exposure group (p=0.012) and a similar trend was observed in the early-onset group (p=0.057). The number of pack-years was not significantly associated with lung function in female subjects with COPD in this study, and the dose-response relationship between smoking and lung function differed by gender at lower levels of smoking exposure