Income-based inequalities in self-reported moderate-to-vigorous physical activity among adolescents in England and the USA: a cross-sectional study

OBJECTIVE: Quantify income-based inequalities in self-reported moderate-to-vigorous physical activity (MVPA) in England and the USA by sex. DESIGN: Population-based cross-sectional study. PARTICIPANTS: 4019 adolescents aged 11–15 years in England (Health Survey for England 2008, 2012, 2015) and 4312 aged 12–17 years in the US (National Health and Nutrition Examination Survey 2007–2016). MAIN OUTCOME MEASURES: Three aspects of MVPA: (1) doing any, (2) average min/day (MVPA: including those who did none) and (3) average min/day conditional on participation (MVPA active). Using hurdle models, inequalities were quantified using the absolute difference in marginal means (average marginal effects). RESULTS: In England, adolescents in high-income households were more likely than those in low-income households to have done any formal sports/exercise in the last 7 days (boys: 11%; 95% CI 4% to 17%; girls: 13%; 95% CI 6% to 20%); girls in high-income households did more than their low-income counterparts (MVPA: 6 min/day, 95% CI 2 to 9). Girls in low-income households spent more time in informal activities than girls in high-income households (MVPA: 21 min/day; 95% CI 10 to 33), while boys in low-income versus high-income households spent longer in active travel (MVPA: 21 min/week; 95% CI 8 to 34). In the USA, in a typical week, recreational activity was greater among high-income versus low-income households (boys: 15 min/day; 95% CI 6 to 24; girls: 19 min/day; 95% CI 12 to 27). In contrast, adolescents in low-income versus high-income households were more likely to travel actively (boys: 11%; 95% CI 3% to 19%; girls: 10%; 95% CI 3% to 17%) and do more. CONCLUSIONS: Policy actions and interventions are required to increase MVPA across all income groups in England and the USA. Differences in formal sports/exercise (England) and recreational (USA) activities suggest that additional efforts are required to reduce inequalities.