Teenagers' lifestyle and the risk of exposure to hepatitis B virus.

Prevention of lifestyle-related diseases and promotion of physical and mental well-being in adolescents require an understanding of how life situations place adolescents at risk. The most important risk factors for hepatitis B virus (HBV) infection are sexual activity with more than one partner and injecting drug use. Sexual transmission is particularly important in areas of low endemicity, but is increasingly important in areas of high endemicity as young people adopt a 'Western' lifestyle. HBV infection in general is associated with indicators of sexual activity, e.g. number of sexual partners, years of sexual activity and the occurrence of other sexually transmitted diseases (STDs). Risk behaviours are often associated: adolescents who have frequent sexual intercourse also drink more alcohol, smoke more cigarettes, use marijuana more often and wear seat-belts less often when driving than adolescents who have little or no sexual activity. Health education and health promotion are important activities aimed at preventing HBV infection, but the major strategy should be providing immunity from infection before risk-taking behaviour. As for other STDs, this is best achieved by universal vaccination of young adolescents or infants or both.