neglect that occurs to children under 18 years of age. It includes all types of physical and/or emotional ill-treatment, sexual abuse, neglect, negligence and commercial or other child exploitation, which results in actual or potential harm to the child's health, survival, development or dignity in the context of a relationship of responsibility, trust, or power. Exposure to intimate partner violence is also sometimes included as a form of child maltreatment. Child maltreatment is a global problem with serious lifelong consequences, which is, however, complex and difficult to study. There are no reliable global estimates for the prevalence of child maltreatment. Data for many countries, especially low- and middle-income countries, are lacking. Current estimates vary widely depending on the country and the method of research used. Approximately 20% of women and 5–10% of men report being sexually abused as children, while 25–50% of all children report being physically abused. Consequences of child maltreatment include impaired lifelong physical and mental health, and social and occupational functioning (e.g. school, job, and relationship difficulties). These can ultimately slow a country's economic and social development. Preventing child maltreatment before it starts is possible and requires a multisectoral approach. Effective prevention programmes support parents and teach positive parenting skills. Ongoing care of children and families can reduce the risk of maltreatment reoccurring and can minimize its consequences. Youth Following the World Health Organization, youth are defined as people between the ages of 10 and 29 years. Youth violence refers to violence occurring between youths, and includes acts that range from bullying and physical fighting, through more severe sexual and physical assault to homicide. Worldwide some 250,000 homicides occur among youth 10–29 years of age each year, which is 41% of the total number of homicides globally each year ("Global Burden of Disease", World Health Organization, 2008). For each young person killed, 20–40 more sustain injuries requiring hospital treatment. Youth violence has a serious, often lifelong, impact on a person's psychological and social functioning. Youth violence greatly increases the costs of health, welfare and criminal justice services; reduces productivity; decreases the value of property; and generally undermines the fabric of society. Prevention programmes shown to be effective or to have promise in reducing youth violence include life skills and social development programmes designed to help children and adolescents manage anger, resolve conflict, and develop the necessary social skills to solve problems; schools-based anti-bullying prevention programmes; and programmes