No evidence for association of insulin receptor substrate-1 Gly972Arg variant with type 2 diabetes mellitus in a mixed-ancestry population of South Africa.

Background: The most common single-nucleotide polymorphism in the insulin receptor substrate-1 (IRS1) gene is Gly972Arg, which is associated with a 25% increased risk of developing diabetes. The mixed-ancestry population of South Africa (SA) has one of the highest prevalences of type 2 diabetes mellitus (T2DM) in Africa.

Objective: To report the frequency of IRS1 Gly972Arg and investigate its associations with cardiometabolic traits.

Proliferator-activated receptor gamma Pro12Ala interacts with the insulin receptor substrate 1 Gly972Arg and increase the risk of insulin resistance and diabetes in the mixed ancestry population from South Africa.

Background: The peroxisome proliferator-activated receptor gamma (PPARG), Pro12Ala and the insulin receptor substrate (IRS1), Gly972Arg confer opposite effects on insulin resistance and type 2 diabetes mellitus (T2DM). We investigated the independent and joint effects of PPARG Pro12Ala and IRS1 Gly972Arg on markers of insulin resistance and T2DM in an African population with elevated risk of T2DM. In all 787 (176 men) mixed-ancestry adults from the Bellville-South community in Cape Town were genotyped for PPARG Pro12Ala and IRS1 Gly972Arg by two independent laboratories.

High prevalence of diabetes mellitus and metabolic syndrome in a South African coloured population: baseline data of a study in Bellville, Cape Town.

Objective: The coloured population has the second-highest prevalence of diabetes in South Africa. However, the data were based on a study conducted almost 20 years ago in a peri-urban coloured population of the Western Cape. We aimed to determine the prevalence of diabetes mellitus and metabolic syndrome in an urban coloured population in South Africa.