LAUSR

Background: Limited data suggest normalization of lung function decline with smoking cessation and slower decline with smoking reduction; yet, mechanistic studies suggest ongoing risk. Aims: To test whether former and “light” smoking are associated with accelerated lung function decline compared to never smoking. Methods: The NHLBI Pooled Cohorts Study harmonized spirometry and other measures from US population-based cohorts. Smoking status was self-reported as never, former, or current at each exam. Light current smoking was defined as Results: 25,552 participants from 6 cohorts (mean age 53 years) contributed 70,411 spirometry exams over a median of 7 years. Forty percent were never smokers (NS), 28% sustained former smokers (FS), 10% sustained current smokers (CS), and 23% reported variable status. In adjusted models, compared to NS, FS demonstrated 1.8 mL/year faster FEV1 decline (95% CI, 1.3-2.4) and 19% faster FEV1/FVC decline (95% CI, 14%-24%); these were 20% and 25% of effect sizes for CS. Lung function decline was faster in current light smokers than NS or FS (P Conclusions: Former and light smoking were associated with faster lung function decline than never smoking.