Abstract
PURPOSE: We evaluated the validity and sensitivity to change of a workplace questionnaire to assess sedentary behavior (SB) during and outside work. METHODS: Participants wore an activPAL and completed an SB questionnaire at two time points (baseline and 3-month follow-up). Ecological momentary assessments were used to assess workplace location (at desk vs. away from desk). Intraclass correlation coefficients, mean difference, root of mean square error, kappa agreement, and Bland-Altman plots assessed validity. Sensitivity to change after 3 months of intervention was assessed using the standardized effect size. RESULTS: Data from 546 participants (age = 45.1 ± 16.4 years, 24.9% males, 72.7% white) were analyzed. Intraclass correlation coefficients ranged from 0.08 to 0.23. SB was overestimated d¯(95%CI)[] by 47.9 (39.2, 56.6) min during work hours but underestimated for both non-work hours and nonworkdays by -38.3 (-47.4, 29.1) and -106.7 (124.0, -89.5) min, respectively. Participants slightly underestimated SB by -3.4 (-12.6, 5.7)% when at their desk but overestimated SB by 2.8 (-2.4, 8.0)% when not at their desk. The questionnaire demonstrated similar standardized effect size (>0.6) to the activPAL for sedentary and standing time. CONCLUSIONS: Agreement between the questionnaire and activPAL was on par with other self-report measures. The questionnaire yielded valid estimates of at/away from desk SB and was sensitive to change.