Socioeconomic patterning of children's accelerometer-assessed physical activity intensities and adiposity : a pooled analysis of individual-level data for 26,915 children and adolescents from 36 European cohorts

Abstract

Background: Childhood obesity is increasing globally with widening socioeconomic inequalities. It is unclear if differences in the accumulation and intensity distribution of children’s physical activity is contributing to these rising disparities. We investigated if the intensity patterning of physical activity differs between socioeconomic groups across Europe and if this relationship differs by national level income inequality and age to help explain obesity disparities. Methods: We pooled and harmonised individual-participant accelerometer-assessed activity and socioeconomic position (SEP) data from 36 European child studies. Included participants were between 5 to 16 years of age with valid accelerometer data (≥480 minutes of daily wear time on 3 days), parental education and anthropometric measurements. Study-level multivariable linear regression models were run to assess differences in moderate-vigorous physical activity (MVPA), vigorous physical activity (VPA) and adiposity by socioeconomic position (by parental education). Effects were pooled in random effect meta-analyses.

Findings: 26,915 participants (mean age: 10·1y [SD:1.2]; 51·7% female) from 16 European countries met the inclusion criteria. Meta-analyses revealed proportionally more average daily minutes of VPA were performed by children from a higher socioeconomic position (High vs low SEP, b: 0·57, 95%CI: 0·28, 0·85 mins), despite lower overall levels of physical activity (MVPA; b: -1·51, 95%CI: -2·36, -0·67 mins). Higher intensity activity in children from a higher socioeconomic position was paralleled by lower levels of adiposity measured by BMI z-score (b: -0·20, 95%CI: -0·24, -0·16). Stepwise differences were apparent moving from low to medium to high socioeconomic position [e.g. BMI z-score: (Low vs Med SEP; b: -0·10, 95%CI: -0·14, -0·07) (Low vs High SEP; b: -0·20, 95%CI: -0·24, -0·16)]. Inequalities in VPA and BMI z-score widened with age and were not affected by national level income inequality. Interpretation: Lower levels of adiposity in children from a higher socioeconomic position are paralleled by relatively higher amounts of VPA despite overall lower levels of MVPA. Physical activity promotion efforts should focus on providing opportunities for less affluent children to be vigorously active.