title: Prevalence of airflow obstruction and reduced forced vital capacity in an Aboriginal Australian population: The cross-sectional BOLD study.
abstract: OBJECTIVE
  Mortality and hospital separation data suggest a higher burden of chronic obstructive pulmonary disease (COPD) in indigenous than non-indigenous subpopulations of high-income countries. This study sought to accurately measure the true prevalence of post-bronchodilator airflow obstruction and forced vital capacity reduction in representative samples of Indigenous and non-Indigenous Australians.
  
  
  METHODS
  This study applies cross-sectional population-based survey of Aboriginal and non-Indigenous residents of the Kimberley region of Western Australia aged 40 years or older, following the international Burden Of Lung Disease (BOLD) protocol. Quality-controlled spirometry was conducted before and after bronchodilator. COPD was defined as Global initiative for chronic Obstructive Lung Disease (GOLD) Stage 2 and above (post-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1 /FVC) ratio <0.7 and FEV1  < 80% predicted).
  
  
  RESULTS
  Complete data were available for 704 participants. The prevalence of COPD, adjusted for age, gender and body weight in Aboriginal participants (7.2%, 95% confidence interval (CI) 3.9 to 10.4) was similar to that seen in non-Indigenous Kimberley participants (8.2%, 95% CI 5.7 to 10.7) and non-Indigenous residents of the remainder of Australia (7.1%, 95% CI 6.1 to 8.0). The prevalence of low FVC (<80% predicted) was substantially higher in Aboriginal compared with non-Indigenous participants (74.0%, 95% CI 69.1 to 78.8, vs 9.7%, 95% CI 7.1 to 12.4).
  
  
  CONCLUSIONS
  Low FVC, rather than airflow obstruction, characterizes the impact of chronic lung disease previously attributed to COPD in this population subject to significant social and economic disadvantage. Environmental risk factors other than smoking as well as developmental factors must be considered. These findings require further investigation and have implications for future prevention of chronic lung disease in similar populations.
authors.affiliation: Cairns Hospital, The Esplanade, Cairns, Queensland, Australia.
authors.forename: Nathania A J B
authors.identifier: http://orcid.org/0000-0002-4123-8598
authors.initials: NA
authors.lastname: Cooksley
authors.affiliation: Rural Clinical School Of Western Australia, University of WA and Kimberley Aboriginal Medical Services Council, Broome, Western Australia, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Atkinson
authors.affiliation: Department of Respiratory and Environmental Epidemiology, Woolcock Institute of Medical Research, Sydney, New South Wales, Australia.
authors.forename: Guy B
authors.initials: GB
authors.lastname: Marks
authors.affiliation: Department of Respiratory and Environmental Epidemiology, Woolcock Institute of Medical Research, Sydney, New South Wales, Australia.|Sydney Local Health District, Sydney, New South Wales, Australia.
authors.forename: Brett G
authors.identifier: http://orcid.org/0000-0002-7375-0019
authors.initials: BG
authors.lastname: Toelle
authors.affiliation: Health Promotion Strategy Unit, Northern Territory Government, Darwin, Northern Territory, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Reeve
authors.affiliation: School of Medicine, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: David P
authors.initials: DP
authors.lastname: Johns
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Abramson
authors.affiliation: School of Biomedical Sciences, Charles Sturt University, Orange, New South Wales, Australia.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Burton
authors.affiliation: Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: Alan L
authors.initials: AL
authors.lastname: James
authors.affiliation: School of Medicine, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Wood-Baker
authors.affiliation: School of Medicine, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: E Haydn
authors.initials: EH
authors.lastname: Walters
authors.affiliation: School of Medicine, Oregon Health and Sciences University, Portland, Oregon, USA.
authors.forename: A Sonia
authors.initials: AS
authors.lastname: Buist
authors.affiliation: Baker IDI Central Australia, Alice Springs Hospital, Alice Springs, Northern Territory, Australia.
authors.forename: Graeme P
authors.initials: GP
authors.lastname: Maguire
mesh_terms: D000368:Aged; D001993:Bronchodilator Agents / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D044382:Population Groups; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000379:methods; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D014797:Vital Capacity; D014904:Western Australia / Q000453:epidemiology
chemical_list: D001993:Bronchodilator Agents
keywords: chronic obstructive pulmonary disease; indigenous population; race; respiratory function test; vital capacity