BACKGROUNDChronic obstructive pulmonary disease (COPD) is thought to result from an accelerated decline in forced expiratory volume in 1 second (FEV 1 ) over time. Yet it is possible that a normal decline in FEV 1 could also lead to COPD in persons whose maximally attained FEV 1 is less than population norms. METHODSWe stratified participants in three independent cohorts (the Framingham Offspring Cohort, the Copenhagen City Heart Study, and the Lovelace Smokers Cohort) according to lung function (FEV 1 ≥80% or <80% of the predicted value) at cohort inception (mean age of patients, approximately 40 years) and the presence or absence of COPD at the last study visit. We then determined the rate of decline in FEV 1 over time among the participants according to their FEV 1 at cohort inception and COPD status at study end. RESULTSAmong 657 persons who had an FEV 1 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 FEV 1 of at least 80% of the predicted value before 40 years of age, 158 (7%) had COPD after 22 years of observation (P<0.001). Approximately half the 332 persons with COPD at the end of the observation period had had a normal FEV 1 before 40 years of age and had a rapid decline in FEV 1 thereafter, with a mean (±SD) decline of 53±21 ml per year. The remaining half had had a low FEV 1 in early adulthood and a subsequent mean decline in FEV 1 of 27±18 ml per year (P<0.001), despite similar smoking exposure. CONCLUSIONSOur study suggests that low FEV 1 in early adulthood is important in the genesis of COPD and that accelerated decline in FEV 1 is not an obligate feature of COPD. (Funded by an unrestricted grant from GlaxoSmithKline and others.) a bs tr ac t

No abstract

Rationale Club cell secretory protein-16 (CC16) is the major secreted product of airway Club cells, but its role in the pathogenesis of COPD is unclear. We measured CC16 airway expression in humans with and without COPD and CC16 function in a cigarette smoke (CS)-induced COPD mice model. Methods Airway CC16 expression was measured in COPD patients, smokers without COPD, and non-smokers. We exposed wild-type (WT) and CC16-/- mice to CS or air for up to 6 months, and measured airway CC16 expression, pulmonary inflammation, alveolar septal cell apoptosis, airspace enlargement, airway MUC5AC expression, small airway remodeling, and pulmonary function. Results Smokers and COPD patients had reduced airway CC16 immunostaining that decreased with increasing COPD severity. Exposing mice to CS reduced airway CC16 expression. CC16-/- mice had greater CS-induced emphysema, airway remodeling, pulmonary inflammation, alveolar cell apoptosis, airway MUC5AC expression, and more compliant lungs than WT mice. These changes were associated with increased nuclear factor-κB (NFκB) activation in CC16-/- lungs. CS-induced acute pulmonary changes were reversed by adenoviral-mediated over-expression of CC16. Conclusions CC16 protects lungs from CS-induced injury by reducing lung NFκB activation. CS-induced airway CC16 deficiency increases CS-induced pulmonary inflammation and injury and likely contributes to the pathogenesis of COPD.

Rationale: Wood smoke-associated chronic obstructive pulmonary disease (COPD) is common in women in developing countries but has not been adequately described in developed countries. Objectives: Our objective was to determine whether wood smoke exposure was a risk factor for COPD in a population of smokers in the United States and whether aberrant gene promoter methylation in sputum may modify this association. Methods: For this cross-sectional study, 1,827 subjects were drawn from the Lovelace Smokers' Cohort, a predominantly female cohort of smokers. Wood smoke exposure was self-reported. Postbronchodilator spirometry was obtained, and COPD outcomes studied included percent predicted FEV 1 , airflow obstruction, and chronic bronchitis. Effect modification of wood smoke exposure with current cigarette smoke, ethnicity, sex, and promoter methylation of lung cancer-related genes in sputum on COPD outcomes were separately explored. Multivariable logistic and poisson regression models were used for binary and rate-based outcomes, respectively. Measurements and Main Results: Self-reported wood smoke exposure was independently associated with a lower percent predicted FEV 1 (point estimate [6 SE] 20.03 6 0.01) and a higher prevalence of airflow obstruction and chronic bronchitis (odds ratio, 1.96; 95% confidence interval, 1.52-2.52 and 1.64 (95% confidence interval, 1.31-2.06, respectively). These associations were stronger among current cigarette smokers, non-Hispanic whites, and men. Wood smoke exposure interacted in a multiplicative manner with aberrant promoter methylation of the p16 or GATA4 genes on lower percent predicted FEV 1 . Conclusions: These studies identify a novel link between wood smoke exposure and gene promoter methylation that synergistically increases the risk for reduced lung function in cigarette smokers.

Patients with COPD and/or CS-exposed mice have pulmonary and renal endothelial cell injury linked to increased endothelial cell AGEs and RAGE levels. Albuminuria could identify patients with COPD in whom angiotensin-converting enzyme inhibitor therapy improves renal and lung function by reducing endothelial injury.

Hispanic ethnicity is inversely associated with cross-sectional and longitudinal spirometric COPD phenotypes even after adjustment for smoking. Native American genetic ancestry may account for this "Hispanic protection."

Health care utilization among COPD patients is approximately twice that of age- and sex-matched controls, with much of the difference attributable to smoking-related diseases. In this health maintenance organization, inpatient costs were similar to and outpatient costs were much higher than national averages for COPD patients covered by Medicare.

Background COPD is a heterogeneous disease, but there is little consensus on specific definitions for COPD subtypes. Unsupervised clustering offers the promise of “unbiased” data-driven assessment of COPD heterogeneity. Multiple groups have identified COPD subtypes using cluster analysis, but there has been no systematic assessment of the reproducibility of these subtypes. Objective We performed clustering analyses across ten cohorts in North America and Europe in order to assess the reproducibility of 1) correlation patterns of key COPD-related clinical characteristics and 2) clustering results. Methods We studied 17,146 individuals with COPD using identical methods and common COPD-related characteristics across cohorts (FEV1, FEV1/FVC, FVC, BMI, MMRC score, asthma, and cardiovascular comorbid disease). Correlation patterns between these clinical characteristics were assessed by principal components analysis (PCA). Cluster analysis was performed using k-medoids and hierarchical clustering, and concordance of clustering solutions was quantified with normalized mutual information (NMI), a metric that ranges from 0 to 1 with higher values indicating greater concordance. Results The reproducibility of COPD clustering subtypes across studies was modest (median NMI range 0.17 – 0.43). For methods that excluded individuals that did not clearly belong to any cluster, agreement was better but still suboptimal (median NMI range 0.32 – 0.60). Continuous representations of COPD clinical characteristics derived from PCA were much more consistent across studies. Conclusions Identical clustering analyses across multiple COPD cohorts showed modest reproducibility. COPD heterogeneity is better characterized by continuous disease traits coexisting in varying degrees within the same individual, rather than by mutually exclusive COPD subtypes.