Sedentary behavior in children by wearable cameras: development of an annotation protocol

INTRODUCTION: There is increasing evidence that not all types of sedentary behavior have the same harmful effects on children's health. Hence, there has been a growing interest in the use of wearable cameras. The aim of this study is to develop a protocol to categorize children's wearable camera data into sedentary behavior components. METHODS: Wearable camera data were collected in 3 different samples of children in 2014. A development sample (3 children aged 4-8 years) was used to design the annotation protocol. A training sample (4 children aged 10 years) was used to train 3 different coders. The independent reliability sample (14 children aged 9-11 years) was used for independent coding of wearable camera images and to estimate inter-rater agreement. Data were analyzed in 2018. Cohen's kappa was calculated for every rater pair on a per-participant basis. Means and SDs were then calculated across per-participant kappa scores. RESULTS: A total of 41,651 images from 14 participants were considered for analysis. Inter-rater agreement over all raters over all the sedentary behavior components was almost perfect (mean kappa=0.85, 95% CI=0.83, 0.87). Inter-rater reliability for screen-based sedentary behavior (mean kappa=0.72, 95% CI=0.62, 0.82) and nonscreen sedentary behavior (kappa=0.69, 95% CI=0.65, 0.72) showed substantial agreement. Inter-rater reliability for location (kappa=0.91, 95% CI=0.88, 0.93) showed almost perfect agreement. CONCLUSIONS: A reliable annotation protocol to categorize wearable camera data of children into sedentary behavior components was developed. Once applied to larger samples in children, this protocol can ultimately help to better understand the potential harms of screen time and sedentary behavior in children.