title: IPAQ interview version: convergent validity with accelerometers and comparison of physical activity and sedentary time levels with the self-administered version.
abstract: OBJECTIVE
  This study aimed to assess convergent validity of International Physical Activity Questionnaire (IPAQ) interview (long form, last seven days), and to examine differences in reported physical activity and sedentary time between the self-administered and interview versions of the long IPAQ (last seven days); and whether these differences depend on gender, age, educational level and weight status.
  
  
  METHODS
  In total, 542 Belgian adults (45.3% male, 43.8±12.1 years) completed the IPAQ self-administered version. Data of these adults were compared with data of 542 adults (45.2% male, 43.5±12.3 years) who completed the IPAQ interview version and wore an accelerometer for seven consecutive days. Samples were matched on gender, age, education, neighborhood characteristics and time of data collection.
  
  
  RESULTS
  Convergent validity of the IPAQ interview version was moderate for total physical activity (Spearman ρ=0.37, P<0.001) and high for sedentary time (Spearman ρ=0.67; P<0.001). Bland-Altman plots showed that systematic and proportional biases were present for total physical activity; for sedentary time only systematic bias was present. Adults who completed the self-administered IPAQ reported higher means for most types of physical activity and less sedentary time than those who completed the IPAQ interview version. Differences between the two IPAQ versions were larger in males, lower-educated, older and overweight/obese adults.
  
  
  CONCLUSIONS
  Convergent validity of assessing total physical activity using IPAQ interview was similar to previous studies examining validity of the IPAQ, but stronger results were found for sedentary time. In general, and especially in males, lower-educated, older and overweight/obese adults, the use of the IPAQ interview version assessed by trained researchers, should be recommended to collect self-reported data on physical activity and sedentary time.
authors.affiliation: Research Foundation Flanders (FWO), Brussels, Belgium - delfien.vandyck@ugent.be.
authors.forename: D
authors.initials: D
authors.lastname: Van Dyck
authors.forename: G
authors.initials: G
authors.lastname: Cardon
authors.forename: B
authors.initials: B
authors.lastname: Deforche
authors.forename: I
authors.initials: I
authors.lastname: De Bourdeaudhuij
mesh_terms: D061725:Accelerometry / Q000379:methods*; D000328:Adult; D000368:Aged; D001530:Belgium; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires