Adolescent Health Series Published April 25, 2012

Today's 1.8 billion adolescents are more exposed to harmful alcohol consumption, sexually transmitted diseases, and other risks than in the past, and face other new challenges such as social media. The Lancet's second Series on Adolescent Health, launched to coincide with the 45th Session of the United Nations Commission on Population and Development, argues that it is now time to put the young person, not the specific issue, centre stage. Four papers analyse the role of adolescence as a foundation for future health, the social determinants of adolescent health, the potential of the worldwide application of prevention science, and the current availability of data on 25 suggested core indicators in all countries. • Adolescence: a foundation for future health • Adolescence and the social determinants of health • Worldwide application of prevention science in adolescent health • Health of the world's adolescents: a synthesis of internationally comparable data