Public health surveillance of physical activity in adolescents and adults in Namibia: a cross-sectional validation of activity questionnaires against accelerometry

Hilde L Nashandi, John J Reilly, Xanne Janssen

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Background: Monitoring population-level physical activity is crucial for examining adherence to global guidelines and addressing obesity. This study validated self-reported moderate-to-vigorous physical activity (MVPA) against an accurate device-based method in Namibia.

Methods: Adolescent girls (n = 52, mean age 16.2 years [SD 1.6]) and adult women (n = 51, mean age 31.3 years [SD 4.7]) completed the PACE+/GPAQ self-report questionnaires and were asked to wear an Actigraph accelerometer for 7 days. Validity of self-reported MVPA was assessed using rank-order correlations between self-report and accelerometry, and classification ability of the questionnaires with Mann–Whitney tests, kappa's, sensitivity and specificity.

Results: In the adolescents, Spearman's rank coefficients between self-reported MVPA (days/week) and accelerometry measured MVPA were positive but not significant (r = 0.240; P = 0.104). In the adults, self-reported MVPA (minutes/day) was moderately and significantly correlated with accelerometer-measured MVPA (r = 0.396; P = 0.008). In both groups, there was fair agreement between accelerometry and questionnaire-defined tertiles of MVPA (adolescents κ = 0.267; P = 0.010; adults κ = 0.284; P = 0.008), and measured MVPA was significantly higher in the individuals self-reporting higher MVPA than those reporting lower MVPA.

Conclusions: The PACE+ and GPAQ questionnaires have a degree of validity in adolescent girls and adult females in Namibia, though more suitable for population than individual level measurement.
Original languageEnglish
Article numberfdaa067
JournalJournal of Public Health
Early online date16 Jun 2020
Publication statusE-pub ahead of print - 16 Jun 2020


  • accelerometer
  • Africa
  • exercise
  • Global Physical Activity Questionnaire
  • obesity
  • physical activity
  • validity
  • adolescent girls
  • adult women

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