Characteristics associated with requested and required accelerometer wear in children

Objective: To investigate characteristics associated with wearing an accelerometer for the required and requested time among 8-year-old to 10-year-old children.

Design: Cross-sectional.

Setting: 60 Bristol and North Somerset primary schools taking part in the 'Active for Life Year 5' randomised controlled trial (RCT) in 2011.

Participants: 2048 children, aged 8-10 years, invited to wear an accelerometer for 5 days of recording.

Primary outcome measure: Numbers meeting required wear-time for inclusion in main RCT analysis (≥8 h/day ≥3 days) and numbers meeting requested wear-time (≥8 h/day for all 5 days).

Results: 817 (40%) of the children wore the accelerometer for the requested time and 1629 (80%) for the required time. In adjusted multivariable analyses the odds of wearing the accelerometer for the required time were greater in females as compared with males (OR 1.76 (1.42-2.18)), those with higher scores for reporting their mother restricted time on sedentary behaviours (1.26 (1.04-1.52) per increase of 1 on a 1-4 scale) and in children from schools with larger year group sizes (1.01 (1.00-1.02) per additional child). Living in a neighbourhood with higher levels of deprivation (0.49 (0.33-0.72) comparing highest to lowest third of the deprivation score) or reporting higher levels of weekday outdoor play (0.97 (0.94, 1.00) per 30 min more) were associated with reduced odds of meeting required time. Results were essentially the same for requested wear-time. Other characteristics, including child body mass index, were not associated with required or requested wear-time.

Conclusions: Only 40% of children wore the accelerometer for the requested time but 80% fulfilled the required criteria to be included in the main study analyses. Knowing which characteristics are associated with accelerometer wear could help target interventions to increase wear-time.