A second chance in the second decade

Adolescents’ health-related behaviours


Key points

  • Surveys provide information on health-related behaviours among adolescents, but the measures vary between surveys, and on some important issues only a small number of countries have data.
  • In the fraction of countries with survey data, 5% to 15% of younger adolescents (ages 13–15) reported a suicide attempt in the 12 months before the survey.
  • Fewer than one in every four adolescents from countries with survey data meet recommended guidelines for physical activity.
  • Up to one in every three adolescents is obese in some countries.
  • In over half the countries in every region, at least half of younger adolescent boys report serious injuries in the preceding year.
  • In most countries half or more of 15-year-olds who are sexually active report using condoms the last time that they had sex.
  • Cigarette smoking is decreasing among younger adolescents in most high income countries and in some middle and low income countries.

Health-related behaviours and conditions among adolescents

A number of health-related behaviours and conditions begin in adolescence that affect health both at the time and in later years. Some of these behaviours lead to the major causes of mortality and morbidity among adolescents (see Section 3), such as suicide attempts, injuries and the various risks associated with unprotected sexual behaviour, or to conditions such as underweight and other nutrition deficiencies. Other behaviours begun in adolescence contribute to adult noncommunicable diseases, including conditions related to tobacco or alcohol use and overweight or obesity. In the WHO global consultation, adolescents said that they have a variety of reasons for adopting these unhealthy behaviours: enjoying the behaviour, having formed a habit that is now difficult to break, and peer pressure.

Conversely, adolescents’ behaviours can play a positive role in their health and development—behaviours such as healthy eating and adequate physical activity—or may prevent health problems, such as condom use.

Monitoring health-related behaviours and conditions

School-based surveys of adolescents monitor a number of these health-related behaviours, mostly among younger adolescents (15 years and younger) at the country level—in particular:

  • Global School-based Student Health Survey (GSHS)1 (ages 13–17)
  • Health Behaviour of School-Age Children: WHO Collaborative Cross-National Study (HBSC)2 (ages 11, 13 and 15)
  • Global Youth Tobacco Survey (GYTS)3 (ages 13–15).
Countries included in the surveys

For older adolescents (15–19 years), who may be in or out of school, the Demographic and Health Surveys (DHS),4 the STEPwise approach to surveillance (STEPS),5 and the GSHS collect information. The DHS surveys are nationally or sub-nationally representative household surveys that report health-related indicators by 5-year age group, including ages 15–19. The STEPS surveys are also nationally or sub-nationally representative household surveys; they capture information on noncommunicable disease risk factors in 15–19 year olds. The GSHS covers adolescents up to age 17 who are still in school.

This section reports the prevalence of key health-related behaviours and conditions among adolescents from the most recent available surveys, as well as trends where possible. Many countries have not repeated surveys three or more times, however, and so trend analyses are not possible.

Adolescent on bad habits: To party and escape your daily troubles!

male, 15-17, France

I just wanted to test it out, then it became a habit.

female, 15-17, France

I think I am physically and mentally healthy, but I feel emotional pain as a result of many different things that have happened over time.

female, 18-19, Mexico

Physically I am in good health, but mentally only partially because several obstacles find their way along my path, affecting my mental health, and I have to overcome them.

female, 15-17, Canada

Adolescents on definition of health: To find myself comfortable with body, and to feel nothing that could make me feel bad about or within myself.

female, 18-19, Spain

That cigarettes, alcohol and drugs not be in style anymore.

female, 15-17, France

To be in good health not only means taking care of your body (through participating in sports, eating well, etc.) or just the absence of illness; it also equally involves feeling good in your own skin, being happy with your choices in life and doing what you love.

female, 15-17 Canada

Adolescents on definition of health: To have the ability to do things well, without any sort of discomfort or pain. To ensure a comfortable future, without any complications like diabetes or any sort of cardiac disease, etc., caused by what was done in the past.

female, 18-19, Mexico

I love drinking and partying, I do it quite often. I also smoke quite often.

male, 18-19, France

Give us real information about our rights and about sexual health. Also information about nutrition and healthy behaviours.

male, 15-17, Mexico

I love sweets, and I haven’t found a balance between normal and excessive consumption.

female, 18-19. Venezuela

Sometimes it's just hard to pass up on something that tastes so good even if it is bad for your body. I have to remind myself that part of the reason it does taste so good is because of the added artificial flavouring or excess sugar content.

female, 18-19, United States of America

Adolescents on what should be done to improve their health: Raising awareness about sexual identities and orientation.

trans, 12-14, Argentina

Adolescents on bad habits: Sometimes laziness and inactivity, I'm not doing sports, and excessive eating of sweets and harmful foods and soft drinks and fruit after midnight.

female, 15-17, Saudi Arabia

Each individual has his or her own life philosophy. I have my own life philosophy: Enjoy the present moment and take each day at a time. Enjoy the moments of youth that are supposed to be the greatest of our existence. It is the age of excess.

male, 18-19, France

It’s basically a thing you do, in part because of the social aspect of these activities, in part, and this especially counts for the cigarettes, as a stress reliever.

male, 18-19, Denmark

Adolescents on bad habits: it’s a quicker and easier way to satisfy my hunger. I like to eat.

female, 12-14, Peru

When I became sexually active I never wore a condom, and I didn’t know how to use one.

male, 18-19. Mexico

I haven’t learned about what I should and shouldn’t eat.

female, 18-19, Mexico

I feel stress over sexual issues - no one wants to give me information, and I also get anxious because I feel that I am doing something wrong.

male, 15-17, Mexico