Criterion validity of a 10-category scale for ranking physical activity in Norwegian women

• Main Authors: Borch Kristin B, Ekelund Ulf, Brage Søren, Lund Eiliv
• Format: Article
• Language: English
• Published: BMC 2012-01-01
• Series: International Journal of Behavioral Nutrition and Physical Activity
• Subjects: Accelerometry; combined sensor; heart rate; physical activity; self-report; validation
• Online Access: http://www.ijbnpa.org/content/9/1/2

<p>Abstract</p> <p>Background</p> <p>Accurate measurement of physical activity (PA) is critical to establish dose-response relationships with various health outcomes. We compared the self-administered PA questionnaire from the Norwegian Women and Cancer Study (NOWAC) with a criterion method in middle-aged Norwegian women.</p> <p>Methods</p> <p>A sample of 177 randomly recruited healthy women attended two clinical visits approximately 4-6 months apart. At each visit, the women completed the NOWAC PA questionnaire (NOPAQ), rating their overall PA level on a 10-category scale (1 being a <it>"very low" </it>and 10 being a <it>"very high" </it>PA level) and performed an 8-minute step-test to estimate aerobic fitness (VO₂max). After each visit, the women wore a combined heart rate and movement sensor for 4 consecutive days of free-living. Measures of PA obtained from the combined heart rate and movement sensor, which were used as criterion, included individually calibrated PA energy expenditure (PAEE), acceleration, and hours/day of moderate-to-vigorous intensity PA (MVPA). These were averaged between visits and compared to NOPAQ scores at visit 2.</p> <p>Results</p> <p>Intra-class correlation coefficients for objective measures from both free-living periods were in the range of 0.65-0.87 (<it>P </it>< 0.001), compared to 0.62 (<it>P </it>< 0.001) for NOPAQ. There was a moderate but significant (<it>P </it>< 0.001) Spearman's rank correlation coefficient in the range of 0.36-0.46 between NOPAQ and objective measures of PA. Linear trends for the association between the NOPAQ rating scale with PAEE, hours/day of MVPA and VO₂max <it>(P </it>< 0.001) were also demonstrated.</p> <p>Conclusions</p> <p>Self-reported PA level measured on a 10-category scale appears valid to rank PA in a female Norwegian population.</p>