NOS3 and type 2 diabetes mellitus: [64] In this context, variation in other genetic or environmental factors such as nutrition that may contribute to the prevalence of type 2 diabetes in the two racial groups, as well as the significant difference in allele frequencies for the G894T variant, may at least partially account for the disparity in the association between the NOS3 SNP and diabetes risk in obese subjects when white and African American participants were compared.