Application of different accelerometer cut-points to estimate preschool children's sedentary time in preschool

Abstract: The accelerometers, such as the Actigraphs, are used in measuring preschool children’s sedentary time. There are several cut-points age-specifically designed for preschool children, and most of these cut-points have different count per minute (cpm) estimate for sedentariness. The aim of this study was to assess preschool children’s sedentary minutes derived from four different validated cutpoints recommended to use for preschool children. A pilot study of the DAGIS project was conducted in 2014. The 3-6-years old children from two different preschools (N=23) wore accelerometers (Actigraph wGTX3-BT) during one day (appr. 4 hours) in preschool. The four validated cut-points were compared: Sirard (<1204 cpm), Evenson (<100 cpm), Butte’s vector magnitude (VM) (<820 cpm) and Butte’s X-axis (<240 cpm). The sleep time was extracted from the analyses (appr. 30 minutes). Overall, the mean minutes of sedentariness were 173 (Sirard), 122( ButteX-axis), 106 (Evenson) or 96 (Buttes VM) minutes. According to Friedman’s repeated measures ANOVA, there was a statistically significant difference in sedentary minutes depending on the cutpoints, χ2(3) = 65.035, p = 0.000. Post hoc analyses revealed that Butte’s VM minutes differed to Butte’s x-axis and Sirard. Evenson’s minutes differed to Butte’s and Sirard’s. There were no significant differences between Butte’s x-axis and Sirard’s minutes, and between Butte’s VM and Evenson’s minutes. The amount of measured sedentary time is depended on the cut-points used. The variation should be acknowledged when comparing results conducted by accelerometers. The consensus about proper cut-points should be achieved, which helps to design proper sedentary recommendations.