Reducing Socioeconomic Inequalities in Adult Cardiovascular Disease Risk by Targeting Unhealthy Movement Behaviours During Adolescence: A Protocol

Populations with lower socioeconomic position (SEP) are at increased risk of developing cardiovascular disease (CVD). Movement behaviours, including physical activity, sedentary behaviour, and sleep, contribute to socioeconomic gradients in CVD risk, as low-SEP populations are less likely to meet evidence-informed recommendations for these behaviours. Adolescence represents a sensitive period for establishing lifelong health behaviours, with CVD risk beginning to accumulate before adulthood. This study will model the potential effect of adolescent movement behaviour interventions on socioeconomic inequalities in adult CVD risk. We will conduct a population-based cohort study of adolescents from the Add Health study, recruited in 1994-1995 from the US and followed into adulthood. Unhealthy movement behaviours, including a low level of moderate-to-vigorous physical activity, a high level of recreational screen time, and short sleep duration, will be operationalized based on the 24-hour Movement Guidelines and measured twice during adolescence (ages 12-24 years). Parental educational attainment and family financial hardship will be used to capture SEP in adolescence. The outcome will be the 30-year risk of CVD, assessed in adulthood (ages 33-41 years) using a validated risk score that incorporates objectively measured biomarkers, demographic information, and self-reported health indicators. We will perform causal decompositions to quantify the change of socioeconomic inequalities in adult CVD risk under 2 interventional scenarios: (i) elimination (unhealthy movement behaviours are eliminated in the whole population of adolescents); and (ii) equalization (the distributions of unhealthy movement behaviours for low-SEP adolescents are equalized to those of high-SEP adolescents). This study will provide insights into how modifying adolescent movement behaviours may contribute to reducing socioeconomic inequalities in CVD risk.