[1] Maastricht Univ, Maastricht, Netherlands
[2] Maastricht Univ, Res Sch CAPHRI, Dept Hlth Promot, Maastricht, Netherlands
[3] Univ Cape Town, Rondebosch, South Africa
[4] Univ Cape Town, Sch Publ Hlth & Family Med, Rondebosch, South Africa
[5] Univ Cape Town, Child & Adolescent Psychiat, Rondebosch, South Africa
[6] South African Med Res Council, Hlth Syst Res Unit, Cape Town, South Africa