1 Department of Maternal, Newborn, Child & Adolescent Health & Ageing, World Health Organization, Geneva, Switzerland. Electronic address: baltagv@who.int.
2 Interdisciplinary Division for Adolescent Health (DISA), Lausanne University Hospital (CHUV), Lausanne, Switzerland.
3 Department of Maternal, Newborn, Child & Adolescent Health & Ageing, World Health Organization, Geneva, Switzerland.
4 Interdisciplinary Division for Adolescent Health (DISA), Lausanne University Hospital (CHUV), Lausanne, Switzerland; Faculty of Biology and Medicine, University of Lausanne (UNIL), Lausanne, Switzerland.