Country-level social mobility and inequalities in adolescent health behaviours in 32 countries

Background Higher family affluence is associated with healthier behaviours in adolescents, but the strength of this association varies across countries. Differences in social mobility at the country-level, i.e. the extent to which adolescents develop a different socioeconomic status (SES) than their parents, may partially explain why the association between family affluence and adolescent health behaviours is stronger in some countries than in others. Methods Using data from adolescents aged 11-15 years from 32 different countries, participating in the 2017/2018 wave of the Health Behaviour in School-aged Children (HBSC) study (N = 185,086), we employed multilevel regression models with cross-level interactions to examine whether country-level social mobility moderates the association between family affluence and adolescent health behaviours (i.e. moderate-to-vigorous physical activity, vigorous physical activity, healthy foods consumed, unhealthy foods consumed, having breakfast regularly, weekly smoking). Results Higher family affluence was more strongly associated with higher levels of physical activity in countries characterized by high levels of social mobility (cross-level interaction linear regression coefficient 0.34; 95% CI 0.08 to 0.60; p = 0.009 for moderate-to-vigorous physical activity, and 0.31; 0.11 to 0.50; p = 0.002 for vigorous physical activity). No cross-level interactions were found for any of the other health behaviours. Conclusions Our findings suggest that differences in social mobility at the country-level may contribute to cross-national variations in socioeconomic inequalities in adolescent physical activity. Further research can shed light on the mechanisms linking country-level social mobility to inequalities in adolescent physical activity to identify targets for policy and interventions. Key messages • This is one of the first studies to investigate country-level social mobility in relation to health equity. Inequalities in adolescent physical activity were steeper in socially mobile countries. • Stronger efforts to engage adolescents from low-affluent families in physical activity may be necessary in countries characterized by high levels of social mobility.