Adolescents and young adults, particularly girls and young women, are increasingly seen as driving forces in global health and international development.1 The physical, cognitive, social, and emotional capabilities acquired during adolescence underpin wellbeing throughout the life-course, including the capacity to engage effectively in work and leisure, family life, and communities.2 Equally, failure to acquire these capabilities during adolescence can have adverse long-term effects on individuals, families, and communities.
Powerful global forces are shaping this transformational life phase. Improvements in childhood nutrition and control of infectious diseases have reduced the age of puberty in many countries.3, 4 Conversely, the adoption of adult roles, including stable partnerships and marriage, parenthood, employment, and leaving home are occurring later in life.5 Changing economic patterns, driven by globalisation, technology, and climate change, are reshaping the nature of jobs, requiring increased periods of education before employment.6 Changing cultural and social norms around gender, child marriage, and attitudes to violence, together with the rapid spread of digital and social media, are now shaping social development across the adolescent years.7
In low-income and middle-income countries (LMICs), many specific factors affect both the health and social development and the capabilities of adolescents. To date, adolescents have benefited less than younger children from the epidemiological transition from communicable to non-communicable diseases as the main contributors to the burden of disease. For adolescents aged 15–19 years, the disease burden remains twice as high in LMICs (excluding China) as in the rest of the world. This increased burden arises from preventable and treatable problems, including HIV and other infectious diseases, poor sexual and reproductive health, undernutrition, and unintentional injury.5 Child marriage is a crucial factor: in 42 LMICs, 36% of women aged 20–24 years were married or in union before 18 years of age, compared with 1–2% of women in high-income countries.8 Rates of interpersonal violence are nearly 2·5 times as high in 75 LMICs as in the rest of the world.9 The availability of quality education and employment for adolescents in LMICs also remains limited.
Action and investment to ensure that adolescents and young adults develop the capabilities for adult life is now a pressing agenda.10 On Sept 25, 2015, the UN adopted the Sustainable Development Goals,11 with specific targets to be achieved by 2030. These targets include reducing poverty and ending extreme poverty, ensuring healthy lives and promoting wellbeing at all ages, achieving inclusive and equitable access to education, and empowering women. Achieving these targets will not be possible without large-scale investments to build the capabilities of adolescents.
Key messages
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Coordinated investments in adolescent health and wellbeing provide high economic and social returns and are among the best investments that can be made by the human community to achieve the UN's Sustainable Development Goals and the Global Strategy for Women's, Children's and Adolescents' Health.
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Investment of US$5·2 per capita each year across 75 low-income and middle-income countries in programmes to improve physical, mental, sexual, and reproductive health and to reduce road traffic injuries will show economic and social benefits at ten times their costs by saving 12·5 million lives, preventing more than 30 million unwanted pregnancies, and averting widespread disability.
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At a cost of $3·8 per capita each year, programmes will substantially reduce child marriage, while showing benefits of about six times the costs.
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Initiatives to improve secondary school enrolment and quality of education are central to health, wellbeing, and human capital and have long-lasting benefits on health and welfare over the life-course. Investment of $22·6 per capita each year will generate economic benefits of about 12 times the costs by 2030, even before considering the broader health and social benefits of such interventions.
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These investments are most urgent for adolescent girls in low-income countries where gender inequity is often high. For many programmes, the greatest benefits will be seen in girls, but road safety programmes are especially important for boys. Improved secondary education will have substantial effects on the position of girls in low-income countries, but the full economic benefits of this transformation will take time to be realised.
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The evidence from this study suggests that large-scale investments in adolescents should be considered an essential element in life-course and intergenerational strategies for health and wellbeing, but a substantial body of further research is needed to fully understand the benefits and costs of some of the interventions considered here.
The 2016 Lancet Commission5 on adolescent health and wellbeing recommended increased investments to transform health, education, family, and legal systems to support the acquisition of the physical, cognitive, social, and emotional capabilities that underpin wellbeing across the life-course. Such investments can yield “a triple dividend of benefits”5 around essential capabilities during adolescence, future adult-health trajectories, and the welfare of the next generation of children.
This Health Policy paper complements the findings of the Lancet Commission and other reports12 by considering the economic and social benefits of specific investments addressing major determinants of adolescent health and capability. However, as the Commission itself noted, knowledge about interventions to improve adolescent wellbeing is limited in several areas, such as child marriage and intimate partner violence. Therefore, we had two objectives: the first was to analyse the costs and benefits of interventions that promote healthy physical growth and social development during adolescence, and the second was to identify key gaps in existing knowledge and hence identify areas in which further research is required. We considered five areas for intervention: physical, mental, and sexual health; secondary schooling; child marriage; violence against women; and road traffic injury.