WUNRN
ADOLESCENCE - FOUNDATION FOR FUTURE
HEALTH - ADOLESCENT GIRLS
Summary
Adolescence
is a life phase in which the opportunities for health are great and future
patterns of adult health are established. Health in adolescence is the result
of interactions between prenatal and early childhood development and the
specific biological and social-role changes that accompany puberty, shaped by
social determinants and risk and protective factors that affect the uptake of
health-related behaviours. The shape of adolescence is rapidly changing—the age
of onset of puberty is decreasing and the age at which mature social roles are
achieved is rising. New understandings of the diverse and dynamic effects on
adolescent health include insights into the effects of puberty and brain
development, together with social media. A focus on adolescence is central to
the success of many public health agendas, including the Millennium Development
Goals aiming to reduce child and maternal mortality and HIV/AIDS, and the more
recent emphases on mental health, injuries, and non-communicable diseases.
Greater attention to adolescence is needed within each of these public health
domains if global health targets are to be met. Strategies that place the
adolescent years centre stage—rather than focusing only on specific health
agendas—provide important opportunities to improve health, both in adolescence
and later in life.
Introduction
The
present generation of people aged 10—24 years is the largest in history—with a
population of 1·8 billion,1 they comprise a quarter of the
world's population. Nearly 90% live in low-income and middle-income countries
where they constitute a far greater proportion of the population than in
high-income countries because of higher fertility rates (figure 1).
The growth in adolescent populations coincides with a reduction in infectious
disease, malnutrition, and mortality in infancy and early childhood, shifting
attention to sexual and reproductive health, substance misuse, mental health,
injury, obesity, and chronic physical illness, which become prominent during
adolescence and need very different responses.3, 4
Many
countries have entered a demographic transition in which falling fertility and
longer, healthier life expectancy increase the proportion of people able to
work. A healthy, educated workforce has the potential to shape a country's
economic prospects.5 Conversely, poverty, inadequate
education, mass unemployment, migration, natural disasters, and war result in
social environments that can devastate the health of young people.6—11
Young
people were at the forefront of the social unrest across north Africa and the
Middle East that began in Tunisia in December, 2010. Although many succeeded in
toppling the restrictive regimes that they fought against, they faced serious
threats to their lives and health. Such engagement is a powerful reminder that,
by stark contrast with younger children, adolescents have an increasing
capacity to be active agents of change within their communities.11,
12
It raises concerns about the extent of young people's exposure to violence,
exploitation, and abuse, and suggests the need for greater protection of human
rights.13
Many
of the economic, educational, and political issues that affect young people are
interlinked. Investment in education of adolescents has clear benefits to
individuals and their health, but is also a strategy for enhancing employment,
human rights, social capital, and community wealth.5 The adverse effects of child
marriage and pregnancy at a young age (<18 years) on the health and human
rights of girls is well appreciated, but just as potent is the dislocating
effect of early pregnancy on girls' education, skill development, and social
networks, which all undermine their present and future health and wellbeing,
the health of their children, and their nations' social and economic prospects.14, 15
Key
messages
Societies
typically define adolescence in terms of age and social roles with little
consistency between countries. We focus on adolescents and young adults aged
10—24 years (referred to as young people and youth and hereafter referred to as
adolescents) because this age-group encompasses most individuals who are going
through the biological changes and social-role transitions that historically
defined adolescence (panel). Although the biological sequences of puberty are highly
consistent (table 1),
changes in the timing of puberty, the nature of social-role changes, and the
hopes and aspirations of adolescents across the world are widely affected by
economic and sociocultural factors.
Definitions
of adolescence and young adulthood
Child
Defined
by the Convention on the Rights of the Child (1989) as a person younger than 18
years, unless majority (ie, the legal threshold of adulthood) is attained at a
younger age in a particular country.13
Adolescence
Historically
defined by WHO as the period between ages 10 and 19 years.16 It is derived from the Latin adolescere—the
present participle adolescens means growing up, whereas the past
participle adultus means grown up.
Youth
The
UN defines youth as people aged between 15 years and 24 years, a definition
made in the lead up to the International Youth Year of 1985.
Teenager
Refers
to people aged 13—19 years. The term was first used in the USA in the 1920s,
and became widely used within popular culture after World War 2.
Young
people
A
less formally defined term that generally refers to people aged 10—24 years, as
does the composite term adolescents and young adults.16
When
data are reported, the 10—24 year age range is increasingly being divided into
three categories: 10—14 years (early adolescence); 15—19 years (late
adolescence); and 20—24 years (young adulthood) to appropriately examine the
extent of changes in health that take place during these years.17—19
Adulthood
The
age that children and adolescents gain legal rights and accountabilities
varies. 18 years is the legal age of majority in many countries, although not
universally. Even in law, no unified definition of adulthood exists—instead,
laws define adulthood at different ages depending on the activity in question.
Developmental
characteristics of adolescence and young adulthood
We
assess the role of adolescence as a foundation for future health, emphasising
the changing context of health and social development from late childhood to
early adulthood and the place of adolescents within global public health. Our
report is arranged around a conceptual framework that we have developed to
describe the many factors affecting adolescent health and to put into context
the subsequent reports in this Series (figure 2).
The
framework emphasises the crucial importance of a life-course perspective in the
understanding of adolescent health and development (represented by the
horizontal flow of the framework) and the importance of social determinants of
health (vertical flow). The axes intersect around the unique characteristics of
adolescence (the complex interactions between puberty, neurocognitive maturity,
and social-role transitions) to emphasise how these factors affect adolescent
health and development. The text outside the boxes refers to settings and scope
of policies, preventive interventions, and services that affect adolescent
health.
Adolescence
within the life course
Social
disadvantage and negative experiences in infancy and early childhood interfere
with the achievement of normal developmental milestones in later childhood,
such as healthy peer relationships and literacy.21 This can lead to peer rejection,
school disengagement, academic failure, and early uptake of risky behaviours in
adolescence.21—23
Adoption of a life-course perspective promotes the understanding that factors
affecting preconception and early childhood can cumulatively affect
adolescents. Thus, programmes intended to enhance maternal, infant, and child
health will also positively affect the health of adolescents.24 However, although aspects of
adolescent health are known to be related to earlier determinants, less
emphasis has been placed on how adolescent health is also the product of the
biological and social experiences that are specific to this phase of life (figure 2).
Similarly,
policy makers have responded inadequately to the knowledge that health-related
behaviours (ie, behaviours that positively or negatively affect health) and
health outcomes in adolescence have a sustained effect on the future health of
these young people. The life-course approach promotes a different temporal
understanding of prevention because many opportunities for prevention of
non-communicable diseases, mental disorders, and injuries in adults arise from
a focus on risk processes that begin in or before adolescence.3,
5, 15, 25 Many health-related behaviours that usually
start in adolescence (tobacco and alcohol use, obesity, and physical
inactivity) contribute to the epidemic of non-communicable diseases in adults26, 27—eg, in people older than 60 years, high blood
pressure and elevated cholesterol and glucose account for 29% of
disability-adjusted life-years (DALYs); tobacco use accounts for 10%; physical
inactivity for 7%; and being overweight or obese for 7%.17
The
health of pregnant adolescents in particular contributes to the health of the
next generation by affecting developing fetuses. Viral infections such as
rubella and HIV, maternal malnutrition and micronutrient deficiency,28
obesity and gestational diabetes,29—31
and health-related behaviours such as the consumption of alcohol, tobacco, and
psychotropic drugs will affect the health of offspring.32,
33
Impaired fetal growth is more common in pregnancy in girls younger than 18
years and is a potent precursor of adult diabetes.34
Specific transgenerational effects will be particularly severe in countries
where, in terms of nutrition for example, both adolescent malnutrition and
micronutrient deficiency are high and teenage pregnancy is common. For example,
in India, about half of girls aged 15—19 years are underweight and anaemic, and
a similar proportion are married before age 19 years.14 Other countries, such as South
Africa, are grappling with the double burden of both underweight and overweight
adolescents.35
Although it has not yet been described, health-related behaviours of boys
probably also have an effect on the health outcomes of the next generation.
Puberty
and social-role transitions
The
onset of puberty has long been accepted as the starting point of adolescence,
and key social-role transitions such as completion of education, employment,
marriage, and childrearing historically signalled the end. Until the industrial
revolution in the 1800s, the achievement of physical maturity generally
paralleled social-role maturity.36
Even until the early 20th century, the delay between physical and social-role
maturity was very short.
The
decreasing age of onset of puberty that took place throughout the 20th century
seemed to be related to improvements in childhood hygiene, nutrition, and
health. This trend had largely ceased by the 1960s in high-income countries
when the mean age of menarche stabilised at about 12—13 years.37
In these countries, the increase in the age at which adult social roles and
responsibilities were adopted began at about the same time, which has made it
less clear when adolescence now ends. Not only do young people now spend longer
in education and marry and have children later22,
38 but also contemporary social-role transitions,
such as completion of education, employment, marriage, and childrearing, are
increasingly less defined and linear than they were historically.38
Despite its widespread legal significance, the age of 18 years clearly no
longer signifies adulthood in many parts of the world (panel).
The
combination of children beginning puberty earlier and taking on
characteristically adult roles at an older age than they did historically has
increased the length and indeed changed the shape of adolescence. These secular
trends, evident in all but the poorest of countries,39, 40
are further affected by regional social determinants (economic, cultural, and
political) and by risk and protective factors. For example, in the
Arabic-speaking countries of north Africa and west Asia, high costs of marriage
and secure housing have contributed to an increase in the age at which people
are getting married.41
Additionally, increasing industrialisation, globalisation, urbanisation, and
access to digital media are reducing the influence that families and communities
traditionally had on the transition to adulthood by decreasing parental
control, social support for families, and social cohesion. At the very least,
there seems to be less agreement between generations and within different
communities across the world about the accepted timing and pathways to adult
roles.
The
biology of adolescent development
Like
early childhood, adolescence is a sensitive period in which both normative and
maladaptive patterns shape future trajectories. Part of this sensitivity
relates to the social embedding of health risks and the biological changes
before, during, and beyond adolescence.
100
years ago, puberty was widely thought merely a process of physical maturation
that propelled individuals into different social contexts that affected their
health.42
We now appreciate that puberty is a highly programmed and biologically driven
process that affects behaviour, emotional wellbeing, and health in complex
ways. For example, the timing of puberty rather than chronological age is most
associated with the increase in health-related behaviours and mental health
states during adolescence.43
These changes in behaviour and mental health might be partly related to
changes, started at puberty, in the regulation of oxytocin in girls and
vasopressin in boys, which have been linked to social attachment, pair-bonding,
and parenting behaviour across species.44
Although the processes have not yet been elucidated, family and social factors
such as parental health and marital tension and the presence of a stepfather
also affect pubertal timing.45—47
There
is growing interest in understanding how puberty affects the developing brain.
Animal data show that hormonal events during puberty exert major effects on
brain maturation and behaviour that alter the perceptions, motivations, and
behavioural repertoire of these animals and enable reproductive behaviour and
independence.48 Although little is known about
the relation between puberty and neural development in people, investigators
have tentatively suggested that pubertal hormones might also affect the structure
and function of the developing human brain.48
Advances
in MRI have enabled the identification of changes in the cortical grey matter
of the brain that take place in a region-specific and non-linear manner
throughout adolescence and into early adulthood.49, 50
Across the frontal, temporal, and parietal cortices, transformations of grey
matter conform to an inverted-U-shaped developmental trajectory, with increases
in volume during childhood reaching a peak in early adolescence with a
subsequent decrease in volume in early adulthood.49, 51
This trajectory is thought to arise from dendritic outgrowth and synaptogenesis
(corresponding to increased grey matter volume in MRI) with subsequent synaptic
pruning (decreased grey matter volume).52
This fine tuning of synaptic connections provides an opportunity for brain
remodelling in response to social, emotional, and behavioural exposures, such
as substance misuse. MRI studies show an overall increase in white matter from
childhood to adolescence, which then slows and stabilises in early to
mid-adulthood depending on the brain region in question. This increase is
attributable to progressive age-related axonal myelination or increasing axonal
calibre, both of which enhance the speed of neuronal transmission.53
The
prefrontal cortex—the site of executive control functions, including planning,
emotional regulation, decision making, multitasking, and self-awareness—is one
of the brain regions that undergoes the most protracted development in human
beings. The prefrontal cortex starts to develop very early in life and
continues after adolescence until the individual is well into their 20s.49,
54
This brain development might explain the steady improvement in self-control
from childhood to adulthood. By contrast, the limbic system, which governs
reward processing, appetite, and pleasure seeking, develops earlier in
adolescence than does the prefrontal cortex.55 The greatest disparity in
maturation between the limbic system and prefrontal cortex is during early to
mid-adolescence. Heightened risk-taking at this time could be explained by a
developmental imbalance that favours behaviours driven by emotion and rewards
over more rational decision making.48,
55
The
reason why adolescents can be poor decision makers was thought to be because
they were less intellectually mature; however, data suggest that adolescents
can make surprising decisions despite knowledge of risks. Adolescents seem to
be more affected than adults by exciting or stressful situations when making
decisions—so-called hot cognitions—especially in the presence of peers.56 Increased activity in the
nucleus accumbens—a region associated with reward, pleasure, and other
emotional responses—seems linked to these behaviours.57
This is consistent with the notion of sensation seeking—the willingness to take
risks to attain new, varied, and stimulating experiences—an important mediator
for risky behaviour and which increases between age 10 and 15 years, suggesting
this behaviour is affected by puberty.56,
58
Such knowledge reinforces policies supporting graded exposure to risk, such as
a limit to the number of passengers allowed in a car with a young driver.59
The wider implications of the nature and timing of adolescent neurocognitive
maturation on policies and programming are only starting to be explored.60
The
effects of social context on health
Both
structural determinants of health (eg, national wealth and income inequality,
access to education and health-care services, employment opportunities, and sex
inequality) and proximal or intermediate determinants of health (eg,
connectedness of adolescents to family and school) affect health-related behaviours
and states in adolescence.61
Whereas many social determinants contribute to an individual's health across
their lifetime, some have particular salience during adolescence. Social
determinants of health that specifically affect adolescents consist of policies
and environments that support access to education, provide relevant resources
for health (eg, contraception), and create opportunities to enhance young
people's autonomy, decision-making capacities, employment, and human rights.
Similar
to proximal determinants of health is the notion of risk and protective
factors. However, these operate within the individual and their family, peers,
school, and community. By interacting with structural determinants of health,
risk and protective factors across these domains affect adolescents' engagement
in health-related behaviours—both positively and negatively.24, 62,
63
For example, risk factors within the individual domain that relate to
intelligence, sexual orientation, or personality can result in negative peer
relationships, such as bullying, which increase the likelihood of various
health-related behaviours, including substance misuse, unsafe sex, depression,
antisocial and illegal activities, and dangerous driving.64,
65
Thus, beyond academic achievement, schools are an important social environment
for adolescents that promote peer connections, emotional control, and health.
School-based interventions that create strong engagement between students and
teachers and a feeling of emotional safety result in reduced substance misuse,
violence, and other antisocial behaviours in adolescents.66
This finding is consistent with the positive youth development approach, which
focuses on adolescents' assets and developmental strengths, whether internal to
the individual (eg, intelligence), or external (eg, peers and school).67,
68
Together
with differential protection of human rights, the complex interaction of social
determinants of health and risk and protective factors with the biological and
social-role transitions of adolescence explains the growing disparities between
the health of adolescents in different regions and countries. These same
factors also affect the experience of growing up within the same country, where
adolescents can have highly heterogeneous life experiences and diverse health
outcomes. In Australia, for example, adolescents with an indigenous ethnic
origin, from a refugee background, or who are incarcerated or homeless have
worse health outcomes than do their mainstream peers.69—72
Changes
in the adolescent burden of disease
Changes
in the biological and social transitions that define adolescence have important
links to health (figure 2),
although the processes by which this happens are complex and still not wholly
understood. For example, the timing of puberty is linked to the onset of sexual
activity and the risks of teenage pregnancy and sexually transmitted
infections.73
That adult roles and responsibilities are now achieved at an older age in many
high-income countries also has implications for sexual health, but for
different reasons. In these countries, where the age of first sexual
intercourse is about 16 years, the period of vulnerability to sexually
transmitted infections caused by premarital sexual intercourse has extended
from only a few years to more than a decade. The heightened sensitivity to
peers during adolescence affects adolescents' experimentation with
health-related behaviours, such as substance misuse.74,
75
The timing of puberty also affects substance misuse—eg, young people who begin
drinking in early adolesence are more likely to become alcohol dependent within
10 years and to have lifetime alcohol dependence than those who begin drinking
at an older age.76
The increase in the length of adolescence has also changed the importance of
these behaviours. For example, because marriage and childrearing contribute to
the reduction in many risk behaviours,77
the trend for people to marry and have children at an older age is especially
potent when combined with the early onset and heavy consumption of alcohol,
which is increasingly seen in girls as well as boys.78,
79
Additionally, youth unemployment, which is at very high levels in several
countries, increases the risks for substance misuse and mental disorders in adolescence.
The subsequent effects on social confidence, skills, and financial resources
will probably have far-reaching results well into adulthood.
Overall,
the health of adolescents has improved to a lesser extent than that of younger
children.80
In a longitudinal study of 50 countries, childhood mortality was reported to
have declined by more than 80% in the past 50 years.18
By contrast, adolescent mortality has only marginally improved. A notable
example is in Brazil, where more adolescents die from violence than do children
younger than 5 years from infectious diseases.14
Although
engagement in some risky behaviours might be thought a normal aspect of
adolescent development, some have immediate negative effects and many are
preventable.24 The leading risk factors for
incident DALYS in young people aged 10—24 years are alcohol (7% of DALYs),
unsafe sex (4%), iron deficiency (3%), lack of contraception (2%), and illicit
drug misuse (2%).17 At least 15% of the worldwide
disease burden is accounted for by DALYs in 10—24 year olds, which challenges
the widespread belief that adolescence is a healthy time of life.
An
analysis of worldwide patterns of mortality reported that 2·6 million young
people aged 10—24 years died in 2004, with mortality increasing from early to
mid-adolescence and into young adulthood.19 The rate and causes of death
differed substantially by age, sex, and region, with mortality rates almost
four times higher in low-income and middle-income countries than in high-income
countries. The leading causes of death were injuries (both unintentional, such
as road traffic accidents, and self-inflicted, such as suicide); maternal
causes; communicable, nutritional, and perinatal diseases (eg, tuberculosis,
meningitis, and HIV/AIDS); and non-communicable diseases (such as diabetes and
cancer). Irrespective of region, most adolescent deaths are preventable and
thus strongly justify worldwide action to enhance adolescent health. Incident
disability also increases with age throughout adolescence.17 The contribution of mental
disorders to the non-fatal burden of disease rises sharply throughout
adolescence and is the largest contributor to the burden of disease in young
people aged 10—24 years (45%), ahead of unintentional injuries (12%) and
infectious and parasitic diseases (10%).17
Emerging
drivers of adolescent health
In
addition to the well established influences of parents and peers during
adolescence, various new drivers are emerging. Marketing of unhealthy products
and lifestyles (eg, tobacco, alcohol, and foods high in fat, sugar, and salt)
clearly targets young people. Analogous to an infectious disease epidemic, mass
media can be viewed as a vector that carries attitudes and products to an
increasing number of hosts, resulting in outbreaks of previously uncommon
behaviours. The extent of such epidemics results from the relation between
economic, sociocultural, and public-policy environments.81
For example, tobacco marketing to men, and then increasingly to young women,
largely brought about the rise in smoking that peaked around the mid-1960s in
men in high-income countries, and about a decade later in women.82 As a result of ever-tightening
policy environments, the tobacco epidemic is now well past its peak in countries
such as Australia, Canada, the UK, and the USA, with substantial declines in
adolescent smoking seen over the past 15 years in these regions.
The
tobacco industry is now vigorously investing in advertising campaigns in
middle-income and low-income countries that historically had very low rates of
smoking, especially in women.83, 84
Not surprisingly, these countries are undergoing an increase in male smoking,85 with substantial yearly
increases in cigarette smoking per person in countries such as China (8·0%),
Indonesia (6·8%), and Syria (5·5%).83
Tobacco in other forms, such as smokeless (chewing) tobacco and waterpipe
smoking, is also marketed to young people86—nearly
one in five of the world's adolescents aged 13—15 years use tobacco, and more
than one in ten use tobacco in a form other than cigarettes.87 A major concern is the rapid
rise in female smoking as marketing and globalisation lead to a decrease in
traditional cultural prohibitions against this practice.82,
85 Men are four times more likely than women to
smoke,88
whereas boys aged 13—15 years are now only 2·3 times more likely to smoke than
girls their age,87
and in many countries sex differences in adolescent smoking rates no longer
exist.89
Young
people are the earliest adopters of information and communication technology
such as mobile phones, the internet, instant messaging, and social networking
sites including Facebook and Twitter, both in low-income and middle-income
countries as well as high-income regions.5, 14 The expanded social environment provided by new
forms of social media has both real and perceived risks and benefits. New
social media provide a powerful voice for young people to actively engage with
one another or to circumvent more traditional and controlled forms of media and
communication. The extent to which various governments have attempted to
restrict access to new media—such as internet censorship and restrictions to
social networking sites imposed in China,90
Libya, and Iran—reinforces the perceived power of such communication. Arguably,
young people's engagement with new social media has enabled adults to
appreciate the capacity of the young to be active catalysts for community
change, a part they have long played. However, young people are susceptible to
the physical effects of intense engagement with media (eg, decreased physical
activity and sleep disturbance), to new variations of old difficulties (eg,
cyber-bullying and pornography) and to previously unknown behaviours, such as
sexting (the act of sending sexually explicit messages or photographs by mobile
phone).
Adolescence
is a sensitive time for social learning through imitation of behaviours,
especially by peers. The ubiquitous nature of new media has arguably changed the
very notion of the peer group. Certainly, it has changed the speed at which
sociocultural norms are affected91
and has contributed to the rise of what were previously less common attitudes,
aspirations, and behaviours.92
Social contagion received attention more than 200 years ago as a result of a
cluster of suicides after publication of a popular novel in which a young man
committed suicide.93
Copycat suicides are even more probable now, in view of the power of new media
to emotively and graphically publicise suicides.94
Social contagion has been invoked as contributing to behaviours that range from
the very uncommon (eg, school shootings95)
to the more widespread (eg, deliberate self harm96).
The extent of publicity around such behaviours further contributes to new
norms.
The
rising influence of social media has resulted in great interest in how it can
be used to promote the health of adolescents, and a growing number of trials
suggest positive effects of interventions that make use of information and
communication technology.97
Population-focused social marketing approaches seem to have particular salience
in changing community values and attitudes in the young. For example, the South
African multimedia so-called edutainment programme Soul City has helped
change social norms about HIV/AIDS and domestic violence, contributed to
increases in individuals' knowledge about condom use and domestic violence, and
widely contributed to the empowerment of local communities.98
For such interventions to be effective, knowledge of prevention science will no
longer be sufficient; new skills and alliances will be needed to exploit
opportunities for health, such as social marketing, information technology, and
creative design. One such alliance, the television network MTV's
Staying Alive Ignite campaign, aims to prevent the spread of HIV by
changing attitudes, behaviours, and national norms. Based on a confronting
television drama, the accompanying multimedia campaign challenges young people
in Kenya, Trinidad and Tobago, and Ukraine to ignite a wide social movement to
stop the spread of HIV.
Adolescents
and global health agendas
The
Millennium Development Goals have driven global health policy for the past
decade. Adolescence has become an important focus because improvement of
adolescent health is central to the achievement of worldwide targets associated
with maternal health, child mortality, and HIV/AIDS. The Millennium Development
Goals continue to provide a very important opportunity to focus on sexual and
reproductive health, which are fundamental to improvement of young people's
health—maternal mortality is one of the leading causes of death in adolescent
girls and young women in Africa and southeast Asia;19 more than a third of girls still
undergo child marriages;15 and adolescents are at the heart
of the HIV/AIDS epidemic (table 2).103
Examples
of global public health goals and the contribution of adolescence
However,
adolescents are central to the success of many other emerging health agendas.
The growing worldwide focus on mental health is an important opportunity to
target adolescent health, because adolescence is when many psychiatric
disorders begin,118
and neuropsychiatric disorders, including substance misuse, contribute to
nearly half of non-fatal DALYs in people aged 10—24 years.17 Undoubtedly, there can be no
improvement in mental health without a focus on adolescent health.
The
global health agenda on injury prevention could be used to achieve major health
benefits for adolescents because this age-group disproportionately contributes
to all-age injuries.111
Road traffic accidents, suicide and homicide, violence and war, drownings, and
fire-related incidents account for about 40% of all youth mortality, by
contrast with people older than 25 years for whom these injuries account for
only 10% of deaths.19
The
substantial rise in tobacco use in adolescents will result in devastating
effects on adult health in low-income and middle-income countries for many
decades.85
The success of tobacco control policies that focused on access (eg, pricing and
taxation) emphasises that many interventions promoting adolescent health are
the result of population-targeted campaigns.24 Urgent implementation of the
Global Framework Convention on Tobacco Control119—a
treaty to reduce the availability of, and interest in, tobacco for young
people—is necessary.
The
rising burden of non-communicable diseases has resulted in an increased
worldwide focus on tobacco control and other risk factors for adult disease,
such as obesity, low levels of physical activity, and alcohol consumption.26,
27
Policy resonance is being driven mainly by arguments about the worldwide burden
of non-communicable diseases, which now account for two in every three deaths,
including in low-income and middle-income countries,120
and about the efficiencies that could be achieved by clinically oriented
secondary prevention interventions targeting common risk factors in adults.
Despite the estimation that 70% of premature deaths in adults are largely
caused by behaviours started in adolescence that share common risk factors,1
little articulation has taken place within the non-communicable disease agenda
about the importance of adolescents as a target for universal prevention.
Recognition
of adolescent health
Within
child health, decades of clinical experience have stimulated research that has
in turn affected national and global public policy, public health, and models
of clinical practice within key domains of interest (eg, infant mortality and
pneumonia). These efforts have contributed to the growth and integration of
child public health. Collaborations, networks, advocacy, and funding
organisations that stretch beyond health have resulted in national and
worldwide investment and initiatives that have led to substantial improvements
in child health.
Adolescent
health is a much younger discipline by comparison. Although the International
Pediatric Association was established in 1910, the International Association of
Adolescent Health was not established until 1987. In many low-income countries,
the life stage of adolescence is only just being recognised.39,
121 In the USA, adolescent medicine emerged as a
distinct medical specialty about 50 years ago and has contributed to
improvements in clinical practice, public health, and prevention science.122
Other high-income countries have only very recently adopted adolescent medicine
as a specialty, which explains why many health professionals have insufficient
training and skills to work effectively with adolescents.123,
124
The training needs of clinicians and public health practitioners in low-income
and middle-income countries are only starting to be appreciated.121,
125
The
current generation will take a different path through their adolescent years
from previous generations and will face new challenges to their health along
the way. How they negotiate these years will have a powerful effect on their
future health and their countries' economic and social prospects. We make the
following recommendations to promote the health of adolescents and to ensure
that adolescence is indeed a strong foundation for future health.
Recommendations
Embrace
adolescence within the life course
What
happens during adolescence is central to many emerging global health agendas.
In view of this prominence, these agendas are unlikely to be successful without
a greater focus on adolescence. Even when the contribution of adolescents to
the wider agenda is indisputable, such as in international HIV/AIDS
initiatives, it is often overlooked in terms of policy and programming. To
rectify this omission, much greater appreciation of the importance of
adolescence within a life-course perspective is needed.
Develop
a cross-cutting agenda
Social
determinants of health that are distinctly influential during adolescence
combined with common risk and protective factors suggest that efforts to
improve health issues will probably be effective if they are part of a
cross-cutting agenda focused on adolescent health as a whole, rather than in
terms of different diseases. An international agenda on adolescent health would
place the developmental phase of adolescence centre stage rather than any one
health issue, but would build on and contribute to the interventions taking
place within distinct disease entities (so-called vertical silos). This agenda
would focus attention on the common determinants of health that promote both
risk and protective factors in young people's lives. It would also promote the
implementation of adolescent-friendly health systems and services that are able
to effectively respond to the specific needs of young people.4, 126
Importantly, it would support investments in preventive interventions that
extend well beyond the health sector24,
127
through alignment with education, employment, sex equality, and human rights
initiatives.
Make
adolescents and their health visible
Good
information systems are an important step towards making adolescents and their
health more visible to policy makers, researchers, donors, and development
partners. The insufficient prominence of adolescent health could be a result of
inadequate information systems,128,
129
which shows inadequate acknowledgment of adolescence as a developmental stage
and a failure to appreciate the dynamic nature of health across adolescence. No
doubt, this is compounded by inconsistent age definitions—eg, age categories
that view young people aged 15—19 years as adults (eg, 0—14 years, 15—64 years)
effectively render adolescence invisible, and are usually inconsistent with the
age criteria of relevant services such as health and education.130
The value of reporting data for three categories across adolescence (10—14
years, 15—19 years, and 20—24 years) is clear from publications that have
raised awareness of the greatly changing health profile across this
developmental period.17—19
Give
adolescents a stronger voice
Greater
engagement of young people, whether as consumers of health services or
recipients of preventive intervention programmes, will help to ensure the
relevance of interventions that set out to target this diverse population. If
adolescents are given a voice by being involved in the identification of their
health issues and development of appropriate solutions, they will also be more
visible to their communities, stakeholders, and decision makers.
Increase
the capacity of the specialty
Despite
growing worldwide interest in adolescent health and medicine,4,
5,
14,
15,
25 local, national, and global capacity is
insufficient to shape the necessary attitudes and skills of the next generation
of public health practitioners, prevention scientists, policy makers, and
clinicians. Functional capacity will be provided by greater investments in
people and organisations.
Funding
to support the development of academic centres of excellence in adolescent health,
such as the Leadership in Adolescent Health programme in the USA,25
is necessary to develop sufficient public health, prevention science, advocacy,
and policy skills within adolescent health. This development would foster
proficiency within the major categories of adolescent public health (eg, sexual
health, tobacco use, substance misuse, mental health, and injuries). A strong
focus on adolescent health within undergraduate and postgraduate health
programmes is urgently needed, as is reorientation of existing professionals to
the specialty.
Achievement
of the necessary worldwide investments in adolescent health would be greatly
aided by more visible advocacy efforts, especially in relation to governments,
donors, and development partners. In the short term, reorientating child-health
advocacy groups to be more inclusive of adolescents would be helpful, but in
the medium term, more focused initiatives on adolescents are needed.