Accelerometer data treatment for adolescents: Fitting a piece of the puzzle

This study aimed to assess the differences in participant retention and associations between physical activity and key variables when a range of accelerometer data inclusion criteria are employed. Data were drawn from 204 adolescents of Pacific Island heritage (survey, body composition, 7-day accelerometry) and their parents (date of birth, socioeconomic status) between October 2014 and February 2016 in Auckland, New Zealand. Data wear time criteria for inclusion were as follows: A) > = 10 h/weekday or > = 8 h weekend day, > = 5 days (at least one weekend day); B) > = 10 h/weekday or > = 8 h weekend day, > = 4 days; C) > = 7 h/day, > = 3 days; D) > = 10 h/day, > = 1 day. Overall, 49%, 62%, 88%, and 96% of participants met the criteria, respectively. Adjusted odds of meeting each criterion were examined using a multivariable logistic regression model. Almost 50% of participants were excluded by the most stringent inclusion criteria. Increased body fat percentage and proportion of time in moderate-to-vigorous activity were associated with decreased odds of meeting Criterions A and B. This research contributes to a growing understanding of the impact of differing accelerometer reduction approaches to sample retention and bias in adolescent physical activity research.