Lung-Function Trajectories Leading to Chronic Obstructive Pulmonary Disease

Abstract

Chronic obstructive pulmonary disease (COPD) is thought to result from an accelerated decline in forced expiratory volume in 1 second (FEV₁) over time. Yet it is possible that a normal decline in FEV₁ could also lead to COPD in persons whose maximally attained FEV₁ is less than population norms. We stratified participants in three independent cohorts (the Framingham Offspring Cohort, the Copenhagen City Heart Study, and the Lovelace Smokers Cohort) according to lung function (FEV₁ ≥80% or 1 over time among the participants according to their FEV₁ at cohort inception and COPD status at study end. Among 657 persons who had an FEV₁ of less than 80% of the predicted value before 40 years of age, 174 (26%) had COPD after 22 years of observation, whereas among 2207 persons who had a baseline FEV₁ of at least 80% of the predicted value before 40 years of age, 158 (7%) had COPD after 22 years of observation (P1 before 40 years of age and had a rapid decline in FEV₁ thereafter, with a mean (±SD) decline of 53±21 ml per year. The remaining half had had a low FEV₁ in early adulthood and a subsequent mean decline in FEV₁ of 27±18 ml per year (P1 in early adulthood is important in the genesis of COPD and that accelerated decline in FEV₁ is not an obligate feature of COPD. (Funded by an unrestricted grant from GlaxoSmithKline and others.)