Criterion-related validity of self-reported stair climbing in older adults.

Abstract

Stair climbing is an activity of daily living that might contribute to increase levels of physical activity (PA). To date, there is no study examining the validity of climbing stairs assessed by self-report. The aim of this study was, therefore, to examine the validity of estimated stair climbing from one question included in a common questionnaire compared to a pattern-recognition activity monitor in older adults. A total of 138 older adults (94 women), aged 65-86years (70.9 ± 4.7years), from the IMPACT65 + study participated in this validity study. Estimates of stair climbing were obtained from the European Prospective Investigation into Cancer and Nutrition (EPIC) PA questionnaire. An objective assessment of stair climbing was obtained with the Intelligent Device for Energy Expenditure and Activity (IDEEA) monitor. The correlation between both methods to assess stair climbing was fair (ρ = 0.22, p = 0.008 for PA energy expenditure and ρ = 0.26, p = 0.002 for duration). Mean differences between self-report and the IDEEA were 7.96 ± 10.52 vs. 9.88 ± 3.32 METs-min/day for PA energy expenditure, and 0.99 ± 1.32 vs. 1.79 ± 2.02min/day for duration (both Wilcoxon test p < 0.001). Results from the Bland-Altman analysis indicate that bias between both instruments were -1.91 ± 10.30 METs-min/day and -0.80 ± 1.99min/day, and corresponding limits of agreement for the two instruments were from 18.27 to -22.10 METs-min/day and from 3.09 to -4.70min/day, respectively. Our results indicate that self-reported stair climbing has modest validity to accurately rank old age participants, and underestimates both PAEE and its duration, as compared with an objectively measured method.