Rationale: Chronic obstructive pulmonary disease (COPD) has its origin in early life, and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) proposes a pre-disease state "pre-COPD".
Objective: We tested the hypothesis that susceptible young adults identified with chronic bronchitis and subtle lung function impairment will develop COPD later in life.
Methods: We followed random non-obstructive individuals aged 20-50years from two population-based cohorts from different smoking eras, the Copenhagen General Population Study from 2003(N=5497) and Copenhagen City Heart Study from 1976-78(N=2609), for 10 and 25years for development of COPD(forced expiratory volume in one second[FEV1]/forced vital capacity[FVC]<0.70) and COPD GOLD 2-4 (additionally FEV1<80% predicted).
Measurements and main results: After 10 years follow-up, 28% developed COPD and 13% COPD GOLD 2-4 in individuals susceptible to COPD compared to 8% and 1% in those without any susceptibility to COPD. Correspondingly, after 25years, 22% versus 13% developed COPD and 20% versus 8% developed COPD GOLD 2-4. More than half of incident COPD cases developed from a susceptible state. Compared to those without susceptibility to COPD, multivariable adjusted odds ratios in those susceptible to COPD were 3.42(95% confidence interval:2.78-4.21) for COPD and 10.1(6.77-15.2) for COPD GOLD 2-4 after 10years, and 1.54(1.23-1.93) and 2.12(1.64-2.73) after 25years. The ability of a COPD risk score consisting of the susceptibility state to COPD with smoking and asthma as risk factors to predict COPD later in life was high.
Conclusions: Our study suggests the existence of a pre-disease state of COPD, which can be used for early identification of susceptible individuals at risk for COPD later in life.
Keywords: Airway Obstruction; Chronic Bronchitis; Early Diagnosis; Forced Expiratory Volume; Spirometry.