The Canadian Respiratory Research Network (CRRN) has recently been established to study the origins and evolution of airways disease in the population. The CRRN is funded by the Institute of Cardio-respiratory Health (ICRH), an institute of the CIHR. The Physiology platform will support the other CRRN platforms (biology, imaging, population health, knowledge transfer) by providing a comprehensive characterization of the nature and extent of physiological impairment of respiratory function in smokers at risk for airways disease and in those with early or mild airway obstruction. The planned studies of the physiology group (core sites located at Queen's University, University of British Columbia and McGill University) will initially focus on smoking-related lung injury in those at risk for COPD and in those meeting spirometric criteria for mild airway obstruction, with or without respiratory symptoms. The primary aim of this initial study is to identify and validate sensitive test(s) of peripheral airway dysfunction that may qualify as physiological biomarkers for use in future CRRN studies.

INCLUSION CRITERIA:

Stable patients with GOLD grade 1 mild COPD will be included in the study if they have: a post-bronchodilator FEV1≥80 %predicted and an FEV1/FVC ratio <0.7 and <LLN; ≥40 years of age; and a cigarette smoking history ≥10 pack-years or ≥10 years of exposure to other inhaled substances (i.e., second hand smoke and/or biomass). Symptomatic (category B) subjects will have a Baseline Dyspnea Index (BDI) total score ≤9, a modified Medical Research Council (MRC) dyspnea score ≥2, or a COPD Assessment Test (CAT) score ≥10. Asymptomatic (category A) subjects will have a BDI>9, modified MRC<2 or CAT<10, no history of seeking medical care for respiratory symptoms, and no history of using respiratory medications. Symptomatic current or ex-smokers (>10 pack-year history) who do not meet criteria for COPD (e.g., post-bronchodilator FEV1<80%predicted and FEV1/FVC<0.7, with both measurements also <LLN) and who are on no respiratory medication will be included. Symptomatic will be defined as: BDI≤9, modified MRC≥2 or CAT>10. Healthy, age- and sex-matched, non-smoking (<2 pack-year history) participants with normal spirometry will be used for comparison purposes.

EXCLUSION CRITERIA:

• presence of clinically significant comorbidities that could contribute to dyspnea or exercise limitation (i.e., unstable heart disease, a pulmonary disease other than COPD, uncontrolled diabetes, neuromuscular or orthopedic impairment);
• history/clinical evidence of asthma;
• contraindications to exercise testing;
• <40 years of age;
• body mass index <18.5 or >=35 kg/m2.

Subjects will include 30 participants from each of the following four subgroups: GOLD grade 1A COPD, GOLD grade 1B COPD, symptomatic smokers who do not meet spirometric criteria for COPD, and age- and sex-matched healthy non-smoking controls. Subjects will be recruited from the Canadian Chronic Obstructive Lung Disease (CanCOLD) study cohort and, once that source has been exhausted, from each site's database of previous or potential research study participants. The CanCOLD Study cohort was recruited from the COLD Study sample, which was a random sample of adults ≥40 years of age who had pre- and post-bronchodilator spirometry performed in order to estimate the prevalence of COPD in Canada.