title: Physical activity and fatigue in chronic obstructive pulmonary disease - A population based study.
abstract: BACKGROUND
  In subjects with chronic obstructive pulmonary disease (COPD), symptoms of fatigue, concomitant heart disease and low physical activity levels are more frequently described than in subjects without COPD. However, there are no population-based studies addressing the relationship between physical activity, fatigue and heart disease in COPD. The aim was to compare physical activity levels among subjects with and without COPD in a population based study, and to evaluate if concomitant heart disease and fatigue was associated to physical activity.
  
  
  METHODS
  In this, 470 subjects with COPD and 659 subjects without COPD (non-COPD) participated in examinations including structured interview and spirometry. A ratio of the forced expiratory volume in one second (FEV1)/best of forced vital capacity (FVC) and vital capacity (VC) < 0.7 was used to define COPD. Physical activity was assessed with the International Physical Activity Questionnaire (IPAQ), and fatigue with the Functional Assessment of Chronic Illness Therapy - Fatigue scale (FACIT-F).
  
  
  RESULTS
  The prevalence of low physical activity was higher among subjects with FEV1 < 80% predicted compared to non-COPD subjects (22.4% vs. 14.6%, p = 0.041). The factors most strongly associated with low physical activity in subjects with COPD were older age, OR 1.52, (95% CI 1.12-2.06), a history of heart disease, OR 2.11 (1.10-4.08), and clinically significant fatigue, OR 2.33 (1.31-4.13); while obesity was the only significant factor among non-COPD subjects, OR 2.26 (1.17-4.35).
  
  
  CONCLUSIONS
  Physical activity levels are reduced when lung function is decreased below 80% of predicted, and the factors associated with low physical activity are different among subject with and without COPD. We propose that the presence of fatigue and heart disease are useful to evaluate when identifying subjects for pulmonary rehabilitation.
authors.affiliation: Department of Neuroscience, Physiotherapy, Uppsala University, Uppsala, Sweden; Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden. Electronic address: mikael.andersson@neuro.uu.se.
authors.forename: Mikael
authors.initials: M
authors.lastname: Andersson
authors.affiliation: Department of Health Sciences, Luleå University of Technology, Luleå, Sweden.
authors.forename: Caroline
authors.initials: C
authors.lastname: Stridsman
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine, The OLIN Unit, Umeå University, Umeå, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Rönmark
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Sweden.
authors.forename: Anne
authors.initials: A
authors.lastname: Lindberg
authors.affiliation: Department of Neuroscience, Physiotherapy, Uppsala University, Uppsala, Sweden; Department of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden.
authors.forename: Margareta
authors.initials: M
authors.lastname: Emtner
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D011159:Population Surveillance; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013147:Spirometry; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014797:Vital Capacity
keywords: COPD; Epidemiology; Physical activity; Population-based study