Vitamin Information Center

Adolescent Health and Development
ADALINE ZENOBIA MUYEED
Senior Technical Officer, Strategic Information,
Family Health International, Arlington, VA, USA
amuyeed@jhsph.edu
Definition
Adolescence is defined as the period between childhood
and adulthood when multiple developmental processes
occur. These areas of development include physical
growth, pubertal maturation, cognitive transitions, and
psychosocial and social maturation. Early, middle, and
late adolescence are defined in pediatrics by sub-categories
of chronological age: early adolescence is characterized
as ages 11–14; middle adolescence, ages 15–17; and late adolescence as 18–21 years of age. However,
young people between the ages of 10 and 24 years
are considered, especially in light of the fact that the age
at which young people assume adult roles is increasing
globally. Although chronological age is an important
indicator of adolescent development and provides
an objective and practical measure, it does not account
for individuals on different developmental trajectories
in terms of physical, cognitive, and psychosocial maturation.
The notion of “adolescence”, defined as an exploratory
period between childhood and adulthood when young
people typically have few responsibilities, has been said
to be relevant mainly to advanced economies; young
people (both men and women) in other parts of the
world move directly from childhood to taking on adult
roles. However, as compared with 20 years ago, there
is evidence that a large number of young people (the
total population of 10–24 year olds is estimated to have
reached 1.5 billion worldwide by 2005) are now entering
adolescence earlier and healthier, are more likely to
stay in school longer, to postpone entry into the labor
force, and to delay marriage and childbearing (National
Research Council and Institute of Medicine 2005).
A focus on adolescence is therefore gaining more attention
worldwide. The need to help young people transition
to successful adult roles such as work, citizenship,
marriage, and parenthood is being advocated.
Basic Characteristics
Adolescent Development
Physical Growth and Maturation Adolescents experience
rapid acceleration in physical growth (increase
in height and weight;  physical maturation), and
pubertal and sexual maturation ( pubertal maturation),
including further development of reproductive
organs and development of secondary sexual characteristics
(such as breast development in girls, genital
development in boys, and pubic hair in both). Age at
 menarche is the most commonly reported indicator
of sexual maturity in girls. Other physical manifestations
include changes in body composition, and
the quantity and distribution of fat and muscle. There
are also changes in circulatory and respiratory systems
which lead to increased strength and tolerance for exercise.
The growth spurt occurs about 2 years earlier in
girls compared with boys. These physiological changes occur between the ages of 9 and 16; however, there is
inter-individual variation in the timing and tempo of
these events (Steinberg 1993).
Cognitive Transitions From early adolescence
onwards, adolescent thinking is characterized by increased
knowledge, multi-dimensional thinking, and
the ability for hypothetical reasoning ( cognitive
development). Piaget described a shift from concrete to
abstract thinking (such as the ability to see various sides
of an issue and the perspective of others). The ability to
think abstractly is made possible by cognitive advances
that emerge between the ages of 11 and 20 years (Keating
1990). A liability of this developmental shift can be
an overestimation of abilities.
Psychological and Social Transitions Adolescents
grapple with issues of identity development, achievement,
autonomy, intimacy, and sexuality during the
adolescent period ( psychosocial development). The
process of identity formation can take various paths
(with a variable degree of exploration, seeking of alternatives,
and sense of commitment), and some of these
tend to be more adaptive than others. There are multiple
domains of self-evaluation and self-description including
scholastic and athletic achievement, and physical
appearance, etc. The process of individuation, and
increasing autonomy during this period, although culturally
variable, can be the basis of potential conflict
with authority figures, including parents. There is a line
of research studying the effectiveness of different types
of parenting style on teens, including democratic, autocratic
and permissive styles, which allow a different
degree of autonomy and negotiation. The choice and
effectiveness of the various styles may be based on cultural
preferences and social context.
Adolescence is a time of life when people expand their
circle of significant others to include peers and other
adults ( social transition). Young people also begin
to navigate through social institutions such as school.
Parents, guardians, teachers, classmates, and friends are
important socializers. Social acceptance and integration
become salient, and we see the development of friendships;
in particular with larger  peer groups and/or
more intimate relations, such as in close friendships.
There is a shift from same sex to opposite sex interest,
and young people may begin dating, experience romantic
relationships and become sexually active. Adolescent Health
Good physical and mental health, as well as the knowledge
and means to sustain good habits, are key for
healthy development in adolescents as many health
compromising behaviors emerge during this period. It
is known that the major causes of mortality and morbidity
in youth are behavior related, and therefore can
be prevented. In the United States, for example, youths
between the ages of 15 and 25 are more likely to suffer
from unintentional injuries (such as motor vehicle
accidents, drowning and sports/recreational-related
incidents), homicide, violent crimes, and suicide. Other
health related problems that are prevalent in youth
include alcohol use, tobacco use, illicit drug use, obesity/
weight problems, eating disorders, teenage pregnancy
and childbearing, and sexually transmitted infections,
including HIV. There are regional variations in
causes of death; for example, HIV/AIDS is the main
cause of death in youth in Sub-Saharan Africa, whereas
deaths from non-communicable diseases are more
prevalent in other regions, as discussed earlier (National
Research Council and Institute of Medicine 2005).
Pregnancy and childbirth-related mortality and morbidity
due to early childbirth (in Sub-Saharan Africa and
South Asia) and abortion (in all developing regions)
are substantial. Health compromising behaviors have
a grave impact on individuals, societies and economies
in the long-run
Mental health illnesses pose a major burden of disability
worldwide. In the US, mental and addictive disorders
(including anxiety disorders, disruptive disorders,
mood disorders, and substance use disorders) are
prevalent in one out of five 9–17 year olds (USDHHS
1999). Mood disorders such as depression, for example,
are known to be associated with academic, social, and
behavioral problems (including suicide) during adolescence.
Risk factors such as poverty, violence, and trauma,
among others, contribute to mental illness in youth
worldwide. There is a need to address the stigma associated
with adolescent mental health. Global policies
that will integrate mental health policy into the overall
healthcare system and assess the global treatment
gap are programmatic challenges are being advocated
by the World Health Organization (WHO) (WHO
2005). It is important to promote preventive interventions,
as they have been shown to cause sustained reduction
of depression and feelings of hopelessness, but also
aggressive and delinquent behavior, and alcohol, tobacco
and drug use (WHO 2003).
Health Interventions
Steps can be taken to help young people navigate successfully
through themultiple transitions and influences
of adolescence, and remain healthy. Different approaches
have been undertaken to understand and enable positive
health and development in youth. These include
developmental, ecological, and life cycle approaches,
among others. Contemporary developmental theory and
research stresses the dynamics of individual-context
relations in understanding behavior and developmental
change. Ecological approaches address the individuallevel
(such as timing of puberty, temperament, and
age), micro-level (the immediate relationships such as
parents, peer, and teachers), environmental (the home,
school, and neighborhood), and broader macro-level
influences and forces (such as cultural factors, poverty,
political instability, and the media) that influence adolescent
health and development for successful intervention.
The life cycle approach requires the understanding
that promoting and sustaining the health and development
of youth begins in childhood, and continues
throughout the life of individuals. It is useful to end
with the WHO conceptual framework, which presents
a wide array of enabling factors that begin early in life
to promote healthy adolescent development. These factors include promotion of healthy behaviors, life-long
learning and education during adolescence, preceded
by good nutrition, a safe environment, and healthy
development, beginning in childhood (TheWorld Bank
Group 2006).
Cross-References
 Cognitive Development
 Menarche
 Peer Group
 Physical Maturation
 Psychosocial Development
References
Keating D (1990) Adolescent Thinking. In: Feldman S, Elliott G
(eds) At the Threshold: The Developing Adolescent. Harvard
University Press, Cambridge, MA, pp 54–89
National Research Council and Institute of Medicine (2005)
Growing Up Global: The Changing Transitions to Adulthood
in Developing Countries. Panel on Transitions to Adulthood
in Developing Countries. Lloyd CB (ed) Committee on Population
and Board on Children, Youth, and Families. Division
of Behavioral and Social Sciences and Education. The
National Academic Press, Washington, DC
Steinberg L (1993) Biological Transitions. In: Steinberg L (ed)
Adolescence, 3rd edn. McGraw-Hill, New York, pp 22–55
US Department of Health and Human Services (USDHHS)
(1999) Mental Health: A Report of the Surgeon General,
Substance Abuse and Mental Health Services Administration,
Center for Mental Health Services, National Institutes
of Health, National Institutes of Mental Health
The World Bank Group (2006) Children and Youth Web-site.
http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/
EXTCY/0,,menuPK:396453~pagePK:149018~piPK:
149093~theSitePK:396445,00.html
World Health Organization (WHO) (2003) Investing in Mental
Health. Department of Mental Health and Substance Dependence,
Noncommunicable Diseases and Mental Health,
World Health Organization, Geneva, p 28
World Health Organization (WHO) (2005) Child and Adolescent
Mental Health Initiatives of the Department of Mental Health
and Substance Use. WHO Press, Switzerland

The human body is an amazing factory, with all kinds of parts working together to make chemicals necessary for good health. But one thing it can’t make on its own is vitamin D. Research shows that defect can be troubling, especially among children.

To create vitamin D, which plays an important role in bone health and development, the body needs exposure to sunlight. As some countries move into autumn, the days get shorter and colder and exposure to sunlight decreases, making the colder months of the year a crucial time to watch vitamin D intake. Supplements can play an important role but one question is, how much?

Most of a child’s bone mass is built up early. A vitamin deficiency can prevent a child from building adequate bone mass now, and they won’t be able to make it all up later.

Although a study released this week found that vitamin D deficiencies are common in children around the world, there is minimal data on how much supplementation is necessary or safe.

Vitamin D is a fat — soluble vitamin directly or indirectly involved in several key body processes: regulating calcium and phosphorus levels in the blood, promoting bone formation and mineralisation, restricting parathyroid hormone secretion and promoting anti-tumour activity.

A review of medical literature on the vitamin published last year in The New England Journal of Medicine found that vitamin D is also associated with a reduced risk of type 1 diabetes in children, and may inhibit future hip fracture.

The main source of vitamin D is sunlight, which the body uses to convert vitamin D into a useable form. It’s also found naturally in eggs and fatty fish like salmon or tuna, and milk and some breakfast cereals are fortified with the vitamin.

The Institute of Medicine recommends that children get 200 IUs of vitamin D daily, but some experts say that up to 800 IUs is better.

The new study found that high doses of the vitamin were safe for children, whether taken over the short-term or for a longer period of time, and helped increased bone mass in 10 to 17 year olds.

A study released this summer found that even children who are otherwise healthy can have low levels of vitamin D, resulting in low levels of bone mineral content.

The risk for low vitamin D levels begins in infancy —breast milk, like cow’s milk, is naturally low in vitamin D. And if a mother doesn’t have enough vitamin D, her breast milk won’t either.

A vitamin D deficiency can affect bone growth even if there are no obvious problems.

A bottle of vitamin supplements
The American Academy of Paediatrics says that rickets, bone softening that can lead to fractures and deformity, in infants due to low vitamin D intake is seen in several US states.

The agency recommends that breast-fed infants receive vitamin D supplement drops.

Children at risk
“It is recommended that all infants, including those who are exclusively breastfed, have a minimum intake of 200 IUs of vitamin D per day beginning during the first two months of life,” said a clinical report for the health agency done by Dr Lawrence Gartner and Dr Frank Greer.

“In addition, it is recommended that an intake of 200 IUs of vitamin D per day be continued throughout childhood and adolescence, because adequate sunlight exposure is not easily determined for a given individual.”

The risks to bone health don’t end in infancy.
A Canadian study released last year found that despite guidelines for its prevention, vitamin D-deficiency rickets in childhood is still seen in the country, with an annual incidence of 2.9 cases per 100,000.

Children living in countries where exposure to sunlight is low had the highest incidence, and most of the affected children had medium to dark skin tones and had been breast fed.

“Since there were no reported cases of breast-fed children having received regular vitamin D (400 IU/d) from birth who developed rickets, the current guidelines for rickets prevention can be effective but are not being consistently implemented,” the study concluded.

Adequate vitamin D levels in the blood are important because the body can’t absorb dietary calcium without vitamin D, so in its absence it steals calcium from the bones, which increases the risk of rickets, osteoporosis and fractures.

This also places teenagers at risk because they have weaker bones that are more likely to fracture.

Children at particular risk include infants who are breast-fed exclusively and don’t receive supplementation, children who use sunscreen in summer, children who don’t use sunscreen in the summer but spend less than 15 minutes a day in direct sunlight, children who receive no supplementation in the winter, and children with chronic diseases that affect fat malabsorption, such as cystic fibrosis or celiac disease, according to the Hospital for Sick Children.

TORONTO (Reuters) - The human body is an amazing factory, with all kinds of parts working together to the make the chemicals necessary for good health. But one thing it can’t make on its own is vitamin D. Research shows that defect can be troubling, especially among children.

To create vitamin D, which plays an important role in bone health and development, the body needs exposure to sunlight. As we move into autumn, the days get shorter and colder and our exposure to sunlight decreases, making the colder months of the year a crucial time to watch vitamin D intake. Supplements can play an important role but one question is, how much?

Most of a child’s bone mass is built up early. A vitamin deficiency can prevent a child from building adequate bone mass now, and they won’t be able to make it all up later. Although a study released this week found that vitamin D deficiencies are common in children around the world, there is minimal data on how much supplementation is necessary or safe.

Vitamin D is a fat-soluble vitamin directly or indirectly involved in several key body processes: regulating calcium and phosphorus levels in the blood, promoting bone formation and mineralization, restricting parathyroid hormone secretion and promoting anti-tumor activity. A review of medical literature on the vitamin published last year in The New England Journal of Medicine found that vitamin D is also associated with a reduced risk of type 1 diabetes in children, and may inhibit future hip fracture.

The main source of vitamin D is sunlight, which the body uses to convert vitamin D into a useable form. It’s also found naturally in eggs and fatty fish like salmon or tuna, and milk and some breakfast cereals are fortified with the vitamin. The Institute of Medicine recommends that children get 200 IUs of vitamin D daily, but some experts say that up to 800 IUs is better.

This week’s study found that high doses of the vitamin were safe for children, whether taken over the short-term or for a longer period of time, and helped increased bone mass in 10-17-year olds.

Vitamin D deficiency is particularly a problem for North Americans, research shows, due in part to the higher latitudes at which they live. As well, because of concerns about skin cancer, many people now wear sunscreen, which inhibits the body’s ability to use sunlight to make the vitamin. The Hospital for Sick Children in Toronto says that sunscreen with an SPF above 8 blocks all vitamin D production through the skin. And darker-skinned individuals living in Canada and the United States may be at particular risk because they have more melanin in their skin, which means they need more sunlight than a lighter-skinned person to make the same amount of vitamin D.

A study released this summer found that even children who are otherwise healthy can have low levels of vitamin D, and resulting low levels of bone mineral content. More than 12 percent of the 400 kids studied by researchers at the Children’s Hospital in Boston had levels of vitamin D in their blood low enough to qualify them as deficient, and 40 percent of the children had less than the recommended level
The risk for low vitamin D levels begins in infancy - breast milk, like cow’s milk, is naturally low in vitamin D. And if a mother doesn’t have enough vitamin D, her breast milk won’t either.

A vitamin D deficiency can affect bone growth even if there are no obvious problems. The American Academy of Pediatrics says that rickets (), bone softening that can lead to fractures and deformity, in infants due to low vitamin D intake is seen in several U.S. states. The agency recommends that breast-fed infants receive vitamin D supplement drops.

“It is recommended that all infants, including those who are exclusively breastfed, have a minimum intake of 200 IUs of vitamin D per day beginning during the first 2 months of life,” said a clinical report for the health agency done by Drs. Lawrence Gartner and Frank Greer. “In addition, it is recommended that an intake of 200 IUs of vitamin D per day be continued throughout childhood and adolescence, because adequate sunlight exposure is not easily determined for a given individual.”

The risks to bone health don’t end in infancy. A Canadian study released last year found that despite guidelines for its prevention, vitamin D-deficiency rickets in childhood is still seen in the country, with an annual incidence of 2.9 cases per 100,000. Children living in the northern part of the country, where exposure to sunlight is the lowest, had the highest incidence, and most of the affected children had medium to dark skin tones and had been breast fed.

“Since there were no reported cases of breast-fed children having received regular vitamin D (400 IU/d) from birth who developed rickets, the current guidelines for rickets prevention can be effective but are not being consistently implemented,” the study concluded.

Adequate vitamin D levels in the blood are important because the body can’t absorb dietary calcium without vitamin D, so in its absence it steals calcium from the bones, which increases the risk of rickets, osteoporosis and fractures. This also places teenagers at risk because they have weaker bones that are more likely to fracture.

Children at particular risk include infants who are breast-fed exclusively and don’t receive supplementation, children who use sunscreen in the summer, children who don’t use sunscreen in the summer but spend less than 15 minutes a day in direct sunlight, children who receive no supplementation in the winter, and children with chronic diseases that affect fat malabsorption, such as cystic fibrosis or celiac disease, according to the Hospital for Sick Children.

Because natural sources are so rare, it’s difficult to get adequate vitamin D in the diet. One tablespoon of cod liver oil has 1,360 IUs, a serving of cooked salmon has 360, a cup of fortified milk has 98 and a whole egg has 20. Fifteen minutes of direct sunlight is enough for many people to reach their needs for vitamin D, but darker-skinned people need longer exposure and because winter sunlight in North America is indirect, supplementation may be recommended.

Do you supplement with extra vitamin D? Let us know: HealthMatters@reuters.com