Unique contributions of ISCOLE to the advancement of accelerometry in large studies

Abstract

Accelerometry has become a mainstay approach for objectively monitoring children's physical activity and sedentary time in epidemiological studies. The magnitude of effort underlying successful data collection, management and treatment is prodigious and its complexity has been associated with increasingly diverse methodological choices that, while defensible relative to specific research questions, conspire to undermine the ability to compare results between studies. Although respecting widespread calls for best practices, it is also important to openly share tools and resources supporting potential improvements to research practice and study design, thus allowing others to replicate, further improve, and/or otherwise build on this foundation. The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) is a large multinational study that included accelerometer-based measures of physical activity, sedentary time and sleep. This review summarizes the unique contributions of ISCOLE to the advancement of accelerometry in large studies of children's behavior, and in particular: (1) open-access publication of the ISCOLE accelerometry Manual of Operations; (2) 24-h waist-worn accelerometry protocol; (3) identification and extraction of nocturnal total sleep episode time (with open access to editable SAS syntax); (4) development of the first interpretive infrastructure for identifying and defining an evolved list of sleep-related variables from 24-h waist-worn accelerometry; (5) provision of a detailed model for reporting accelerometer paradata (administrative data related to accelerometry); and (6) cataloging the most detailed and defensible list of accelerometry-derived physical activity and sedentary time variables to date. The novel tools and resources associated with these innovations are shared openly in an effort to support methodological harmonization and overall advancement of accelerometry in large epidemiological studies.

International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE): Contributions to Understanding the Global Obesity Epidemic

“…This section summarizes some of the methodological advances that were developed during the planning and implementation of ISCOLE. As described above, we have made all of our protocols and algorithms publicly available, and we have summarized our contributions to the use of accelerometry in large studies in detail elsewhere [11,12].…”

Multiple lifestyle behaviours and overweight and obesity among children aged 9–11 years: results from the UK site of the International Study of Childhood Obesity, Lifestyle and the Environment

“…Accelerometry can also be used to provide a proximal indicator of sleep duration. Using the protocol developed via the ISCOLE study, 32 nocturnal sleep duration was quantified using a published automated algorithm. 33 Briefly, total sleep duration was estimated using the total minutes from all nocturnal sleep episodes, identified using a combination of the Sadeh algorithm 34 and the inclinometer function to determine the probability of sleep for each individual minute.…”

Calibration and Cross-Validation of the ActiGraph wGT3X+ Accelerometer for the Estimation of Physical Activity Intensity in Children with Intellectual Disabilities

“…This study calibrated and cross-validate the first accelerometer cut points for the classification of sedentary, moderate, and vigorous intensity activity in children with intellectual disabilities, and empirically demonstrated the need for population-specific cut points. Due to the associated health outcomes of sedentary behaviour and MVPA, and the need for more standardised objective measurement [ 30 , 31 ], the current recommendation is to use a vertical axis cut point of 100 cpm for sedentary and the Evenson et al [ 32 ] cut point of ≥ 2296 cpm for MVPA in typically developing children [ 33 , 34 ]. However, as the sedentary and MVPA cut points developed in this study are notably different to these recommended cut points, it is important that the measurement of physical activity in children with intellectual disabilities is viewed independent of typically developing research.…”