The second paper in The Lancet Series on Adolescent Health addresses the social determinants that affect health in this age group. It concludes that the most effective interventions to improve adolescent health are likely to be structural changes to improve access to education and employment for young people and to reduce the risk of transport-related injury. But a wide range of other factors are also at play, including a country's national wealth, income inequality, and the presence of safe and supportive families and schools. The second paper is by Professor Russell Viner, UCL Institute of Child Health, University College London, London, UK, and Professor Sir Michael Marmot, University College London, London, UK, and colleagues.
Structural determinants are the fundamental structures that generate social stratification, such as global and national economic, political, and social welfare systems, and education systems. Proximal, also called intermediate, determinants are the circumstances of daily life, from the quality of the family environment and peer relationships, through availability of food, housing, and recreation, to access to education.
The authors note that greater national wealth was strongly associated with better health across most outcomes in both sexes, with the exception of reported injuries, exposure to violence, and smoking. However, among low-income countries, there is a five-times variation in male adolescent mortality and a ten-times variation in teenage birth rate despite similar national wealth, suggesting that cultural, religious, or other social factors strongly moderate the effects of structural determinants such as wealth. Nations with greater income inequality also have poorer adolescent health across all outcomes.
The authors emphasise the importance of education in adolescent health. In developing countries, up to a third of lower secondary school age adolescents don't attend school, compared with just 1 in 25 in the USA, Canada, and Western Europe. The authors say: "Within-country studies show that completion of secondary school provides great benefits for adolescents, improving health and wellbeing, increasing their capacity and motivation to prevent pregnancy, empowering them to take responsibility for their own lives, and for improving the lives of others. Education also improves survival of their children." Countries with higher numbers of adolescents in school see lower rates of male and female overall mortality, lower male injury mortality, and lower female non-communicable disease mortality, as well as lower HIV prevalence and teenage pregnancy rates. The school environment itself is also vital: there is emerging evidence that connections within school protect against a wide range of health risk behaviours in low-income and middle-income countries. Programmes that improve secondary school environment and connectedness are among the most promising large-scale interventions for improving health outcomes in adolescence. The structure of the local neighbourhood that adolescents socialise within is also key, with studies from countries such as the UK, Lebanon, and Brazil showing that communities offering greater support and opportunities for participation have better adolescent health outcomes.
Sex inequalities are present in many aspects of health in adults in high-income countries. European data and data from Canada and the USA have shown notable sex inequalities from early adolescence: girls consistently have poorer wellbeing indicators, such as self-rated health, psychosomatic complaints or symptoms, and life satisfaction, whereas boys have higher levels of injury and being overweight. There is strong evidence that ethnic origin affects health in adolescents, with evidence strongest for high-income countries and relating to mental health, obesity, substance misuse, and sexual health and teenage pregnancy.
Families remain key factors in the lives of adolescents, as in earlier childhood. Studies from the USA show that adolescents who feel connected to their family are more likely to delay sexual initiation, report lower levels of cigarette, alcohol, and marijuana use, and are less likely to engage in violence. Similar findings have been shown in Europe, Brazil, the Caribbean, and Turkey. Parents who are more actively involved in and knowledgeable about their child's activities generally have adolescents who are less likely to engage in problem behaviour. Conversely, young people whose parents smoke, drink alcohol, or engage in violence are more likely to engage in these behaviours. Other adolescents or 'peers' can have strongly positive or negative effects on adolescents health. These peers can offer support or protection against problem behaviours, or in a negative context increase the risk of smoking, alcohol use and other behaviours. Access to social media is providing both opportunities to promote opportunities for and also risks to adolescent health. The authors say: "Although many forms of information technology promote educational and social development, exposure to violent and sexualised content linked with advertising for cigarettes and alcohol has been shown to increase problems of violence, cigarette and alcohol use, and early initiation of sexual behaviour in susceptible adolescents and other young people."
The authors note there is substantial evidence across cultures that young people in lower socioeconomic positions are more likely to engage in unhealthy behaviours, irrespective of ethnic origin. One exception is smoking, where relationships with socioeconomic position vary markedly between countries, being unrelated to socioeconomic status in many countries, higher amongst poorer adolescents (e.g. the USA) or even higher among wealthier adolescents (as in many European countries but also amongst many low-income and middle-income countries).
The researchers make several recommendations to improve prospects for adolescent health and wellbeing, echoing those of the WHO Commission on the social determinants of health. The conditions of daily life for young people should be improved—the circumstances in which adolescents grow, live, work, and age. Governments need to tackle the inequitable distribution of power, money, and resources particularly with relationship to adolescents. Structural changes are needed to empower young people and increase wealth available to older adolescents and young adults as they move towards autonomy. Reduced barriers to youth employment, changes in national employment policy, student support, and taxation can be highly effective in reducing youth poverty. The authors say: "The great burden of injury mortality and morbidity in young people highlights the need for action at the structural level. Changes to transport infrastructure and road safety policy can substantially affect young people's health, as can gun control." They further recommend raising awareness of social determinants of health, and workforce training in this area.
They conclude: "The strongest determinants of adolescent health worldwide are structural factors such as national wealth, income inequality, and access to education. Furthermore, safe and supportive families, safe and supportive schools, together with positive and supportive peers are crucial to helping young people develop to their full potential and attain the best health in the transition to adulthood. Improving adolescent health worldwide requires improving young people's daily life with families and peers and in schools, addressing risk and protective factors in the social environment at a population level, and focusing on factors that are protective across various health outcomes. The most effective interventions are probably structural changes to improve access to education and employment for young people and to reduce the risk of transport-related injury."
Professor Russell Viner, UCL Institute of Child Health, University College London, UK. T) +44 (0) 20 7905 2190, but please email to arrange interview. E) rviner@ucl.ac.uk
For Professor Sir Michael Marmot, University College London, UK, please contact Felicity Porritt T) +44 (0)7739 419219 E) m.marmot@ucl.ac.uk
Journal
The Lancet