Regular smoking or excessive drinking in adolescence has immediate and long-term health consequences. Children who establish smoking habits in early adolescence increase their risk of cardiovascular diseases, respiratory illnesses and cancer. They are also more likely to experiment with alcohol and other drugs. Alcohol misuse is itself associated with a range of social, physical and mental health problems, including depressive and anxiety disorders, obesity and accidental injury (Currie et al., 2008).

Nutrition is important for children’s development and long-term health. Eating fruit during adolescence, for example, in place of high-fat, sugar and salt products, can protect against health problems such as obesity, diabetes, and heart problems. Moreover, eating fruit when young can be habit forming, promoting healthy eating behaviours for later life.

Undertaking physical activity in adolescence is beneficial for health, and can set standards for adult physical activity levels, thereby indirectly influencing health outcomes in later life. Research supports the role that physical activity in adolescence has in the prevention and treatment of a range of youth health issues including asthma, mental health, bone health and obesity. More direct links to adult health are found between physical activity in adolescence and its effect on overweight and obesity and related diseases, breast cancer rates and bone health in later life. The health effects of adolescent physical activity are largely dependent on the activity type, e.g. water physical activities in adolescence are effective in the treatment of asthma, and exercise is recommended in the treatment of cystic fibrosis (Hallal et al., 2006; Currie et al., 2008).

Children who are overweight or obese are at greater risk of poor health in adolescence and in adulthood. Being overweight in childhood increases the risk of developing cardiovascular disease or diabetes, as well as related social and mental health problems. Excess weight problems in childhood are associated with an increased risk of being an obese adult, where certain forms of cancer, osteoarthritis, a reduced quality of life and premature death can be added to the list of health concerns (Currie et al., 2008; WHO Europe, 2007).

Tobacco is the second major cause of death in the world, after cardiovascular disease, and is directly responsible for about one in ten adult deaths worldwide, equating to about 6million deaths each year (Shafey et al., 2009). It is a major risk factor for at least two of the leading causes of premature mortality – circulatory diseases and a range of cancers. In addition, it is an important contributory factor for respiratory diseases, while smoking among pregnant women can lead to low birth weight and illnesses among infants. It remains the largest avoidable risk to health in OECD countries.

The global health burden related to excessive alcohol consumption, both in terms of morbidity and mortality, is considerable in most parts of the world (Rehm et al., 2009; WHO, 2004b). It is associated with numerous harmful health and social consequences, including drunkenness and alcohol dependence. High alcohol intake increases the risk for heart, stroke and vascular diseases, as well as liver cirrhosis and certain cancers. Foetal exposure to alcohol increases the risk of birth defects and intellectual impairments. Alcohol also contributes to death and disability through accidents and injuries, assault, violence, homicide and suicide, and is estimated to cause more than 2 million deaths annually. It is, however, one of the major avoidable risk factors for disease.

The growth in overweight and obesity rates among adults is a major public health concern. Obesity is a known risk factor for numerous health problems, including hypertension, high cholesterol, diabetes, cardiovascular diseases, respiratory problems (asthma), musculoskeletal diseases (arthritis) and some forms of cancer.