by Nicola Reavley, George C Patton, Susan M Sawyer, Elissa Kennedy, and Peter Azzopardi
A series of systematic reviews was conducted to assess current knowledge on the effectiveness of prevention interventions outside formal health care settings across nine areas of health targeting adolescents directly. They included both specific health outcomes and health risks. Some responses are not directly targeted at young people but may have particular benefits for them compared with other age groups.
Sexual and Reproductive Health, Including HIV/AIDS
More than any other area of health, a country’s cultural, religious, legal, political, and economic contexts affect the sexual and reproductive health of adolescents, and actions for sexual and reproductive health need to take these contexts into account. The evidence suggests that implementing multicomponent interventions, that act in two or more settings, improves sexual and reproductive health and reduces the impact of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). For example, high-quality, comprehensive sex education is more likely to prevent pregnancy and reduce the prevalence of sexually transmitted infections (STIs) or HIV/AIDS if it is combined with the provision of contraceptives. Legislation to protect adolescents from early marriage and pregnancy, is more likely to be effective if accompanied by actions to encourage favorable community and professional attitudes. Although evidence exists to show the impact on safe-sex behaviors of interventions to promote universal health coverage, relatively little exists to show their impact on STI or HIV/AIDS prevalence. The quality of training for providers is likely to be an important factor in the success of such interventions, and studies targeting marginalized or vulnerable adolescents, including those not in school, are needed.
Infectious and Vaccine-Preventable Diseases
Vaccination against infectious diseases has received far less attention in adolescents than in children. Yet adolescents are also important for ensuring completion of immunization schedules (such as measles-rubella and hepatitis B vaccine), administering booster doses (such as diphtheria-tetanus), and ensuring primary immunization (such as for human papillomavirus). Rubella vaccination is important for adolescent girls given intergenerational risks, although hepatitis B vaccine is important for both genders, given its adult burden. Other vaccines to consider according to local prevalence of disease and cost are tuberculosis, influenza, and meningitis vaccines.
Lack of basic knowledge has hindered responses to common infectious diseases in adolescents. In contrast to diarrheal disease in children, the etiological agents, proportion of vaccine-preventable morbidity and mortality, and comorbidities are largely unknown in adolescents. Similarly, adolescent tuberculosis has received little attention, even though it is the leading contributor to the burden of infectious disease in young adults in multiburden countries.
Adolescents in Sub-Saharan Africa also carry a substantial burden of malaria. In high-transmission areas, rates are higher in adolescent girls than in boys, with pregnant girls experiencing additional risks. In endemic regions, people are exposed to malaria earlier in life and more frequently. In these settings, partial immunity develops relatively early, and the risk of severe malaria in adolescence declines. However, in areas of lower transmission, clinical disease is more common in adolescents and young adults. As infection in endemic areas is controlled and the development of childhood immunity becomes less likely, the risk of malaria in adolescents and young adults increases. In low-transmission regions, the incidence of malaria among adolescents reflects their use of individual preventive interventions, such as insecticide treated bednets. A study from Nigeria, where an estimated 50 percent of the community experiences an episode of malaria each year, showed that only 8.5 percent of students ages 13–18 years reported sleeping under insecticide treated bednets.
Undernutrition
No adolescent-specific evidence exists of the benefit of interventions for the prevention of undernutrition. Interventions do not typically target adolescents alone or report age-disaggregated outcomes. However, good evidence exists about interventions targeting nutrition-related risks that commonly affect adolescents. These risks include iron-deficiency anemia, protein-energy malnutrition, and other micronutrient deficiencies. Energy and iron requirements increase during puberty and are required for optimal growth.
Interventions to reduce protein-energy malnutrition, including balanced protein-energy supplementation, cash transfers, and improved household food storage systems, may be particularly beneficial in adolescents. As adolescence is a period of rapid growth, it is plausible that interventions that support catch-up growth in young children might also promote catch-up growth in stunted adolescents, although further research is required to confirm this.
The additional iron necessary to meet menstruation-related needs places adolescent girls at increased risk of iron-deficiency anemia. Iron fortification of staple foods, such as flour, can reduce iron deficiency anemia at a population level by up to 63 percent and has been shown to be cost-effective. Interventions addressing food insecurity may also improve iron levels.
Adolescent Pregnancy
Adolescent pregnancy places girls at increased risk of undernutrition; children born to adolescent girls are more likely to have low birth weight, independent of socioeconomic or maternal preconception nutritional status. Preconception interventions, such as multiple-micronutrient supplementation or iron and folic acid supplementation continuing into pregnancy, deworming to reduce nutrient loss, and antenatal nutrition counseling and education, can play a role in preventing undernutrition and poor health outcomes in offspring. Delaying first pregnancies, spacing subsequent births, and increasing young women’s access to education and health care or control over household resources are likely to be central in preventing adversity. Delaying the first pregnancy is essential in stunted adolescent girls.
Unintentional Injury
Much of the disease burden of adolescent unintentional injury is related to RTIs. Adolescents and young adults, particularly those in LMICs, are at high risk; they are more likely to be vulnerable road users, such as pedestrians, cyclists, and motorcyclists. Moreover, in young men in particular, developmental immaturity, risky behavior, and poor decision making increase the risks.
In HICs, improvements in road design, equipment and maintenance, traffic control, vehicle design and protective devices, driver training and regulation, police enforcement and sanctions, public education and information, and postcrash care have significantly reduced the burden of injury, including in adolescents. More targeted actions include the following:
- Graduated licensing systems that extend the learning period, increase low-risk supervised driving, and regulate exposure to high-risk settings, such as driving at night without supervision, driving with other young passengers, or using alcohol during an initial licensing period. Robust testing of competence before issuing licenses is generally an essential element.
- Legislation and enforcement of mandatory helmet wearing for motorcyclists in countries where a high proportion of adolescents and young adults ride motorcycles.
- Investment in pedestrian safety in regions where pedestrian injuries are common, such as Sub-Saharan Africa. Effective actions include the imposition of lower speed limits on lengths of road where pedestrians mix with other traffic and enforcement of these limits, regulation including police enforcement of the behavior of drivers and riders at pedestrian crossings, improved pedestrian facilities such as footpaths and crossings, separation of pedestrians and vehicles, and increased visibility of pedestrians.
Although education programs have shown some benefits, school-age driver education programs that focus on selecting driving instructors and offering theory and practical tests should be avoided, as they may encourage earlier driving and lead to greater risk of accident.
Intersectoral coordination, underpinned by strong information systems, clear governance, civil society advocacy, and a capacity to implement effectively within different sectors, is central to achieving reductions in RTIs.
Violence
Violent behavior in adolescents and young adults develops because of complex interactions among individual, relationship, community, and societal factors. Individual risk factors include substance use, impulsivity, low educational attainment, and childhood aggression. Relationship risk factors include peer involvement in problem behavior, family conflict, poor family management, child abuse, and pro-violent parental attitudes and behavior. Communities with poor social cohesion, low socioeconomic status, high residential mobility, drug trafficking, and unemployment also increase the risk of violence. Societal risk factors include inequality, availability of weapons, and laws and cultural norms that support violence.
Adolescent-specific violence prevention strategies are implemented in three principal settings: schools, communities, and families, and policy interventions are most often targeted to the broader community. Universal school-based interventions have shown some evidence of effectiveness in reducing violent or aggressive behavior, with similar impacts in schools in areas characterized by lower socioeconomic status and high crime rates.
School-based interventions are likely to be more effective in at-risk adolescents, with beneficial effects in mixed groups and boys-only groups. Family-focused interventions seek to promote parent-child communication and improve parenting skills, such as providing children with information about the positive and negative consequences of their behavior. Some interventions use a combined family and school approach. Although good evidence exists of the impact of parenting interventions targeted to younger children, less research has been conducted among adolescents. However, family-focused and family- and school-based interventions have shown beneficial effects. Limited evidence exists on the effectiveness of community-based social development interventions that target risk factors for violence.
Most evidence of the effectiveness of policy interventions comes from studies conducted in the broader population. Reducing the availability and harmful use of alcohol and reducing the access to weapons (for example, laws against owning and carrying weapons, fines for carrying weapons, policies on school-based weapons) have been shown to reduce violence in adolescents and young adults.
Reducing the violence-related burden of disease in young people is likely to require a multifaceted approach that is integrated with policies directed at social and political risk factors, such as inequality, lack of access to education, unemployment, availability of weapons and laws, and cultural norms that support violence. This is likely to be particularly important in countries in which many adolescents are not in school.
Early adolescence is a period in which gender role differences intensify and boys and girls begin to explore intimate relationships. Interventions at this stage offer opportunities to promote attitudes and behaviors that reduce the risk of interpersonal and sexual violence.
Evidence for the prevention of intimate-partner and sexual violence in adolescents and young adults is largely lacking. In many cases, particularly in LMICs, studies are of poor quality, with small sample sizes, varied outcome measures, and short follow-up periods. The most common types of interventions targeted to this age group are educational and skills-based interventions, which can be effective in changing attitudes but which appear to have little impact on violent behavior. Moreover, most of these interventions have been implemented in schools and tertiary institutions in HICs, particularly the United States. Community-based programs to promote gender-equitable norms are the most common interventions in LMICs, but the evidence for their effectiveness is mixed.
Programs are needed that more fully address the risk factors for intimate-partner and sexual violence, alcohol misuse, family-derived attitudes to violence, and social norms, such as those that condone violence and gender inequality. They need to be tailored to local contexts, include families where appropriate, target persons at high risk, and be subject to rigorous evaluation. Legislative and judicial responses are important, but they are unlikely to reduce intimate-partner and sexual violence in isolation.
Mental Disorders
Most mental disorders begin before age 25 years, most often at ages 11–18 years. Although not all adolescent mental health problems persist into adulthood, particularly if the episodes are brief, those that do often have lifelong impacts. This has led to increased emphasis on early intervention, either in primary health care or, in some countries, through adolescent-focused mental health services. Although access to health services has increased in some places, evidence that these increases have led to detectable improvements in adolescent mental health is largely lacking.
Although prevention of mental disorders is increasingly seen as a public health priority, evaluation studies have focused mainly on taking effective clinical treatments, such as cognitive-behavioral therapies, and applying them to the general population of adolescents or to at-risk subgroups to test if they prevent the development of disorders. A systematic meta-review and meta-analysis of randomized controlled trials of prevention interventions for depression or anxiety in children and adolescents showed that these interventions produced a minimal to moderate reduction in symptoms in the short term, but no effect beyond 12 months of follow-up.
Innovative approaches are needed, including those that focus on developmental mental health risks such as bullying and interpersonal violence. Exploration is also needed into the role of digital and social media as risk factors and as potential avenues for preventive interventions.
Suicide
The risk factors for suicide in adolescents include suicidal behavior in families, depression, alcohol abuse, use of hard drugs, mental health problems, suicidal behavior of friends, family discord (especially for females), poor peer relationships, living apart from parents, antisocial behavior (especially in females), sexual abuse, physical abuse, and unsupportive parents. Contagion—when a suicidal act increases the likelihood of other suicides in a community—is a further factor in up to 60 percent of suicides in adolescents and young adults. Deliberate self-harm is also common in adolescents, particularly in females, and heightens the risks for subsequent suicide.
Adolescent suicide prevention strategies typically include one or more of the following goals: increased help-seeking for suicidal thoughts and behaviors; identification and referral of at-risk young people by health professionals, teachers, parents, or peers; reduction of risk factors for suicide; and promotion of mental health. School-based interventions are the most commonly evaluated interventions in the adolescent age group; although some evidence shows that universal interventions improve attitudes toward suicide, these gains are unlikely to be maintained at follow-up, and iatrogenic effects remain largely untested. Gatekeeper training, which teaches specific groups of people to identify people at high risk of suicide and refer them for treatment, also improves knowledge and attitudes toward suicide and builds confidence in providing help.
Evidence is mixed on the effectiveness of universal school-based interventions, gatekeeper training, public education and mass media interventions, screening or intervention-after-suicide programs, and clinical treatments on help-seeking behavior, help-giving behavior, suicidal ideation, or suicide attempts in adolescents.
Evidence from studies among the broader population suggests that training health practitioners to recognize depression and evaluate suicide risks and restricting access to lethal methods show some benefits for preventing suicide.
Many studies of suicide prevention interventions are of poor quality, and evidence for effective interventions to prevent suicide in young people is largely lacking, particularly in LMICs. Reducing the suicide-related burden of disease in young people is likely to require a multifaceted approach that focuses on restricting access to means and training health practitioners, particularly in depression and substance use. Help-seeking behavior is likely to differ between males and females, and future evaluations of preventive actions should address gender differences.
Source
Reavley N, Patton GC, Sawyer SM, et al. Health and Disease in Adolescence. In: Bundy DAP, Silva Nd, Horton S, et al., editors. Child and Adolescent Health and Development. 3rd edition. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2017 Nov 20. Chapter 18. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525258/ doi: 10.1596/978-1-4648-0423-6_ch18