Identifying ActiGraph non-wear time in pregnant women with overweight or obesity

Abstract Objectives Non-wear time algorithms have not been validated in pregnant women with overweight/obesity (PW-OW/OB), potentially leading to misclassification of sedentary/activity data, and inaccurate estimates of how physical activity is associated with pregnancy outcomes. We examined: (1) validity/reliability of non-wear time algorithms in PW-OW/OB by comparing wear time from five algorithms to a self-report criterion and (2) whether these algorithms over- or underestimated sedentary behaviors. Design PW-OW/OB (N = 19) from the [anonymous] randomized controlled trial wore an ActiGraph GT3x + for 7 consecutive days between 8–12 weeks gestation. Methods Non-wear algorithms (i.e., consecutive strings of zero acceleration in 60-second epochs) were tested at 60, 90, 120, 150, and 180-min. The monitor registered sedentary minutes as activity counts 0−99. Women completed daily self-report logs to report wear time. Results Intraclass correlation coefficients for each algorithm were 0.96−0.97; Bland–Altman plots revealed no bias; mean absolute percent errors were Conclusions The 60, 90, 120, 150, and 180-min algorithms are valid and reliable for estimating wear time in PW-OW/OB. However, implementing algorithms with a higher threshold for consecutive zero counts (i.e., ≥150-min) can avoid the risk of misclassifying sedentary data.