Table 2.
Characteristics of studies included in review
| Study | Year | Location | Cohort | Population | Selection | COPD Definition |
|---|---|---|---|---|---|---|
| Qiu et al. [23] | 2012 | Multi-centrea | ICGN | Family-cohort of probands of COPD patients and healthy siblings/parent with >5 pack-year history of smoking | Information not available | Post-bronchodilator FEV1/FVC <0.7 and FEV1 < 70% predicted |
| Boston (USA) | EOCOPD | Family-cohort of probands of COPD patients with varying severity, prior to age 53, exclusion of AAT deficiency (confirmed by serum analysis), all family members had potential to be enrolled (independent of smoking status) | Cases identified from Lung Transplant/Reduction Surgical Programs at Brigham and Women’s Hospital and Massachusetts General Hospital. Pulmonary Clinics at these hospitals and associated hospitals served as additional source of participants [32] | Post-bronchodilator FEV1/FVC < 0.7 and FEV1 < 70% predicted | ||
| Bell et al. [22] | 2012 | UK | Twins UK | Healthy unselected volunteers who are a twin (MZ, DZ and singleton) representing the general population | Participants recruited from media campaigns, initially only middle-aged women were included in the registry but from 1995 onwards, men and women >18 years of age were also recruited [28] | Analysed lung function only (no COPD diagnosis) – FEV1 and FVC |
| Lepeule et al. [25] | 2012 | USA | Normative Ageing | Healthy male participants at enrolment, containing smokers and ex-smokers (Veterans Administration 1963 closed-cohort) | Enrolled after an initial health screening determined that they were free of known chronic medical conditions | Analysed lung function – FEV1, FVC, MMEF (did not specify pre-/post-bronchodilator) |
| Lange et al. [26] | 2012 | Boston (USA) | Normative Ageing | Healthy male participants at enrolment, containing smokers and ex-smokers (Veterans Administration 1963 closed-cohort) | Enrolled after an initial health screening determined that they were free of known chronic medical conditions | GOLD stage II or higher (pre-bronchodilator FEV1/FVC < 0.7 and FEV1 < 80% predicted) |
| Marioni et al. [21] | 2015 | Scotland (UK) | Lothian Birth | Childhood inception cohort of ‘healthyb’ participants with varying lung function, containing smokers, ex-smokers and never smokers | Individuals born in 1936 in the Lothian area were identified using the Community Health Index (registered at a general practitioner) or through media advertisements. The majority of the cohort were participants in the Scottish Mental Survey 1947 [27] | Analysed lung function only (no COPD diagnosis)- FEV1 |
| Wielscher et al. [24] | 2015 | Austria | N/A | COPD patients, GOLD 0 COPD patients and healthy controls | Selection of patient from Medical University of Vienna, 2008-2012 | Post-bronchodilator FEV1/FVC <0.7 |
Abbreviations: ICGN International COPD Genetics Network
aMulti-centre: Cambridge, Copenhagen, Denver, Harvard, Holland, Italy, Liverpool, Nebraska, Spain, Vancouver EOCOPD: Early-onset COPD (Boston), AAT: Alpha-1-Antitrypsin, UK: United Kingdom, MZ: Monozygotic twin, DZ: Dizygotic twin, USA: United States of America, GOLD: Global Initiative for Chronic Obstructive Lung Disease
bHealthy: participants free from chronic disease at enrolment, GOLD stage 0: FEV1/FVC ratio > 0.7 but with respiratory symptoms