Validity of active Australia physical activity questions in older adults

Abstract

Introduction: The Active Australia physical activity survey (AAS) is used for physical activity (PA) surveillance in the general Australian adult population. Given the ageing of the population and the health benefits of PA for older adults, this group should be included in PA surveillance and, for comparison with younger adults, be asked the same PA surveillance questions. However, the appropriateness of the AAS for older adults has not been evaluated. Our aim was to examine the criterion validity of the AAS questions in older adults. Three criterion measures were used: pedometer step counts, body mass index (BMI), and self-reported physical function. Methods: Participants were 51 community-dwelling adults, aged 65–89 years, who reported the ability to walk at least 100 m. They completed a self-administered version of the AAS as part of a larger study of older adults. They also completed a physical function survey (SF-36 function scale) and had their weight and height measured, for calculating BMI. During the 7 days prior to the interview, participants each wore a YAMAX Digiwalker SW200 pedometer and recorded their daily steps in a diary. Using the AAS data, daily walking minutes and daily total PA minutes (walking, moderate-intensity PA, vigorous-intensity PA) were compared with the three criterion measures using Spearman rank-order correlations. Results: 26 men and 25 women (mean age = 72 years, SD = 6) completed the AAS. Median daily walking minutes were 34.4 (IQR 17.1, 60.0), and median daily total PA minutes were 72.9 (IQR 35.6, 120.0). Both walking minutes and total PA minutes were significantly correlated with pedometer steps (Spearman correlation r = 0.42, for each, p < 0.01). Total PA minutes were significantly correlated with physical function scores (r = .38, p < 0.001), but walking minutes were not (r = 0.14). Neither walking minutes nor total PA minutes were significantly correlated with BMI (r = −0.13 and −0.15, respectively). Conclusions: This initial examination of the psychometric properties of the AAS for older adults suggests that this surveillance tool has adequate criterion validity for ambulatory older adults.