[1] Univ Witwatersrand, Fac Hlth Sci, South African Med Res Council, WITS Dev Pathways Hlth Res Unit DPHRU,Dept Paedia, Johannesburg, South Africa
[2] South Australia Hlth, Riverland Acad Clin Excellence, Riverland Mallee Coorong Local Hlth Network, Berri, SA 5343, Australia
[3] Univ Cape Town, Hlth Phys Act Lifestyle & Sport Res Ctr HPALS, FIMS Int Collaborating Ctr Sports Med, Dept Human Biol,Fac Hlth Sci,Div Physiol Sci, ZA-7700 Cape Town, South Africa
[4] South African Med Res Council, Biomed Res & Innovat Platform, ZA-7505 Cape Town, South Africa
[5] Stellenbosch Univ, Fac Med & Hlth Sci, Ctr Cardiometab Res Afr CARMA, Div Med Physiol, ZA-7505 Cape Town, South Africa
[6] Univ Pretoria, Fac Hlth Sci, Dept Obstet & Gynaecol, ZA-0002 Pretoria, South Africa
[7] Univ Manchester, NHS Fdn Trust, Dept Biochem, Manchester M13 9WL, England
[8] South African Med Res Council, Noncommunicable Dis Res Unit, ZA-7505 Cape Town, South Africa
[9] Univ Witwatersrand, Fac Hlth Sci, Sch Clin Med, Dept Anaesthesiol, ZA-2050 Johannesburg, South Africa
[10] Natl Hlth Lab Serv, Dept Chem Pathol, ZA-2192 Johannesburg, South Africa
[11] Univ Witwatersrand, Fac Hlth Sci, ZA-2192 Johannesburg, South Africa
[12] Stellenbosch Univ, Dept Biochem, ZA-7600 Stellenbosch, South Africa
[13] Umea Univ, Dept Publ Hlth & Clin Med, S-90187 Umea, Sweden
[14] Univ Oxford, Oxford Ctr Diabet Endocrinol & Metab, Oxford OX3 7LE, England
[15] Oxford Univ Hosp Trust, Natl Inst Hlth Res, Oxford Biomed Res Ctr, Oxford OX3 7LE, England