title: Level of agreement between methods for measuring moderate to vigorous physical activity and sedentary time in people with obstructive sleep apnea and obesity.
abstract: BACKGROUND
  There is ambiguity about what measures to use to best identify physical activity and sedentary behavior, and agreement between methods for measuring physical activity and sedentary behavior in people with obstructive sleep apnea syndrome (OSAS) and obesity has not been evaluated.
  
  
  OBJECTIVE
  The objective of this study was to examine the level of agreement between an accelerometer and a self-report questionnaire (International Physical Activity Questionnaire [IPAQ]) or a logbook for measuring time spent on moderate to vigorous physical activity and time spent sedentary in people with OSAS and obesity.
  
  
  METHODS
  This prospective study was a psychometric evaluation of agreement between measurement methods.
  
  
  METHODS
  Thirty-nine people who were obese (body mass index: X=36.1 kg/m², SD=4.35) and had moderate to severe OSAS (apnea-hypopnea index of ≥15) were consecutively recruited from a sleep clinic in Sweden. All were treated with continuous positive airway pressure and were waiting for a follow-up sleep evaluation.
  
  
  RESULTS
  Agreement between the measurement methods was limited. For physical activity, the mean difference between the accelerometer and the IPAQ was 47 minutes, and the mean difference between the accelerometer and the logbook was 32 minutes. Agreement was limited for sedentary time as well; the mean difference between the accelerometer and the IPAQ was 114 minutes, and the mean difference between the accelerometer and the logbook was 86 minutes.
  
  
  CONCLUSIONS
  The small sample size may affect the interpretation and generalizability of the results.
  
  
  CONCLUSIONS
  The results imply that the methods cannot be used interchangeably. A combination of an accelerometer and a daily logbook seems to provide a detailed description of physical activity and sedentary behavior.
authors.affiliation: Department of Neuroscience, Section of Physiotherapy, Uppsala University, Box 593, BMC, Uppsala S-75124, Sweden. helena.igelstrom@neuro.uu.se
authors.forename: Helena
authors.initials: H
authors.lastname: Igelström
authors.forename: Margareta
authors.initials: M
authors.lastname: Emtner
authors.forename: Eva
authors.initials: E
authors.lastname: Lindberg
authors.forename: Pernilla
authors.initials: P
authors.lastname: Asenlöf
mesh_terms: D061725:Accelerometry; D000328:Adult; D000368:Aged; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009765:Obesity / Q000150:complications / Q000503:physiopathology; D011446:Prospective Studies; D011594:Psychometrics; D057185:Sedentary Behavior; D057566:Self Report; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology; D013997:Time Factors