Prevalence of behavioural risk factors for cardiovascular disease in adolescents in low-income and middle-income countries: an individual participant data meta-analysis

Background Although overt manifestations of cardiovascular disease (CVD) rarely emerge before adulthood, CVD risk factors are often present in adolescents. However, the prevalence and magnitude of behavioural CVD risk factors in adolescents in low-income and middle-income countries remains unclear. We estimated the magnitude and co-occurrence of behavioural CVD risk factors in adolescents aged 12-15 years for 65 low-income and middle-income countries between 2003 and 2011. Methods We extracted Global School-Based Student Health Surveys (GSHS) datasets from the Centers for Disease Control and Prevention (CDC) website. Pooled prevalence estimates of current tobacco use, alcohol use, low fruit and vegetable intake, low physical activity, obesity and co-occurrence of CVD risk factors for WHO regions and overall, was calculated with random-effects meta-analysis. We explored potential sources of heterogeneity for each CVD risk factor through random- effects meta-regression analysis. Findings Between 2003 and 2011, of 169 369 adolescents, 12.1% (95% CI 10.2-14.1) used tobacco, 15.7% (12.3-19.5) used alcohol, 74.3% (71.9-76.5) had low fruit and vegetable intake, 71.4% (69.5-73.3) reported low physical activity and 7.1% (5.6-8.7) were obese. The pooled regional prevalence of exposure to three or more CVD risk factors was lowest in the southeast Asian region (3.8%, 95% CI 1.2- 7.5) and highest in the western Pacific region (18.6%,12.8-25.3). Substantial heterogeneities within and across regions were not fully explained by major study characteristics. Interpretation In low-income and middle-income countries, adolescents carry a substantial burden of behavioural CVD risk factors, which tend to co-occur. Surveillance, prevention, detection, and control initiatives are a global health priority.