Many fatal diseases in adults got started with poor health habits at a young age. For example, if you use tobacco as a teenager, you're more likely to get heart disease, cancer or stroke when you're an adult. Tobacco can also give you bad breath, wrinkles and stained teeth while you're still young. Most people who become addicted to tobacco are addicted before they're 18. By not using tobacco, you lower your chances of getting heart disease or cancer, or having a stroke. Other healthy behaviors include avoiding injuries, alcohol and other drugs, and not having sexual intercourse. A healthy diet and regular physical exercise may help you to live a longer and healthier life.

Will the habits I have now really make a difference when I'm older?

Yes. Sixty-five percent of all deaths in adults are caused by heart disease, cancer and stroke. Many of the behaviors that result in these conditions begin at a young age.

What can I do now to keep myself healthy all through my life?

• Avoid using any type of tobacco product. Try not to breathe second-hand cigarette smoke.

• Always use your seat belt in a car or truck.

• Don't drink and drive. Don't get into a car with a driver who has been drinking alcohol or using drugs.

• Wear protective headgear, such as motorcycle or bike helmets.

• Never swim alone.

• Talk to your parents or your doctor if you're feeling really sad or if you're thinking about harming yourself.

• Get regular exercise.

• Eat a healthy diet.

• Avoid situations where violence or fighting may cause you to be physically injured.

• If you have sex, use protection to avoid pregnancy and sexually transmitted diseases.

• See your doctor regularly for preventive care.

What is preventive care?

For teenagers, preventive care may include the following things:

• Screening by your doctor to find out your risk for certain health problems.

• Health information about ways to avoid unnecessary risks to your health.

• Measurements of height, weight, cholesterol levels and blood pressure.

• Tests to check your general health or to find certain diseases.

• Immunizations (“shots”) to reduce your risk of getting common diseases such as mumps and tetanus.

At my age, what should I especially be concerned about?

Nearly three out of four deaths among teenagers and young adults are caused by four things: car accidents, unintentional physical injury, homicide and suicide. Cancer and heart disease can also affect you at this age. Unwanted pregnancy and sexually transmitted diseases (including HIV and AIDS) also cause you social and personal problems, in addition to harming your health.

Do young men have different health risks than young women?

Yes. Young men don't wear seat belts as often as young women do. They're also more likely to carry weapons, to get into physical fights, to use smokeless tobacco or marijuana, to drink alcohol heavily, and to have more sexual partners than young women do. Young women try to commit suicide more often than young men and use unhealthy weight-loss methods more often than young men.

Should I talk to my doctor if I'm worried about my health or my body?

Yes. It's important to talk to your doctor if you have any concerns about your health or your body.