Income inequality and adherence to 24-hour movement guideline recommendations among adolescents: a multilevel growth curve analysis using longitudinal data from three waves of the Cannabis, Obesity, Mental health, Physical activity, Sedentary behaviour and Smoking (COMPASS) study (2016-2019).

Background: There is a paucity of literature regarding income inequality and adolescent movement behaviours (physical activity, sedentary behaviours, sleep). This study examined whether income inequality was associated with meeting Canadian 24-Hour Movement Guidelines (24HMG) recommendations among adolescents over time.

Methods: Longitudinal data from adolescents (n=9299) in the Cannabis, Obesity, Mental health, Physical activity, Sedentary behaviour and Smoking study (2016-2017 to 2018-2019) were linked with income data at the census division (CD) level from the 2016 Canadian Census. Adolescents (aged 13-19 years) reported on their physical activity, sleep duration and screen time via questionnaire. Gini coefficients were calculated at the CD level using after-tax household income from the 2016 Canadian Census. Multilevel logistic regression analyses were performed to test the association between income inequality and meeting several 24HMG recommendations.

Results: The joint effect (income inequality*time) was significant for meeting the sleep duration recommendation (2017-2018 OR=0.83, 95% CI 0.74, 0.92; 2018-2019 OR=0.77, 95% CI 0.70, 0.86; p<0.0001), meeting any two recommendations over time (2017-2018 OR=0.97, 95% CI 0.86, 1.09; 2018-2019 OR=0.85, 95% CI 0.75, 0.97; p=0.0402) and meeting combined sleep and physical activity recommendations (2017-2018 OR=0.93, 95% CI 0.82, 1.06; 2018-2019 OR=0.82, 95% CI 0.71, 0.94; p=0.0200). Joint effects (income inequality*time) were not significant (p>0.05) for screen time or physical activity independently of sleep.

Conclusion: Adolescents attending schools in areas with greater income inequality may be at higher risk for inadequate sleep and combined short sleep and physical inactivity.