[1] Natl Hlth Lab Serv NHLS, Dept Chem Pathol, Cape Town, South Africa
[2] Stellenbosch Univ, Cape Town, South Africa
[3] Univ Cape Town, Dept Med, Cape Town, South Africa
[4] South African Med Res Council, Non Communicable Dis Res Unit, Cape Town, South Africa
[5] SAMRC, Dept Biomed Sci, CPUT Cardiometabol Hlth Res Unit, Cape Town, South Africa
[6] Cape Peninsula Univ Technol, CPUT Cardiometabol Hlth Res Unit, SAMRC, Dept Biomed Sci, Cape Town, South Africa