Agreement Between Self-Reported and Device-Based Sedentary Time among Eight Countries: Findings from the ELANS.

The purpose of this study was to analyze the agreement between self-reported and device-based sedentary time among eight countries in Latin America. As part of the Latin American Study of Nutrition and Health (ELANS), data were collected from 2524 participants (18-65 years) across eight countries. Participants reported time spent sedentary in different activities (computer use at home, videogame use, reading, sitting down to chat with friends/relatives or listening to music, speaking on the phone, watching TV, and riding in a car). Overall sitting time was assessed using a single item from the International Physical Activity Questionnaire (IPAQ). Device-based sedentary time was assessed using Actigraph GT3X accelerometers. Self-reported overall sitting time (227.1 min/day) produced the lowest values of the three assessment methods, followed by self-reported sum of different types of sedentary behavior (364.1 min/day) and device-based sedentary time (568.6 min/day). Overall, correlation coefficients and ICC varied from weak to moderate (rho: 0.25-0.39; ICC: 0.21:0.39) between self-reported sum of different types of sedentary behavior, self-reported overall sitting time, and device-based sedentary time. The Bland-Altman plots indicated low to moderate agreement between self-reported overall sitting time and device-based sedentary time by sex. Self-report measures underestimate sedentary behavior and overall sitting time when compared with device-based measures. The weak and moderate level of agreement between methods indicates that caution is required when comparing associations between different self-report and device-based measures of sedentary behavior with health outcomes.