INS and metabolic syndrome: Obesity was reported to significantly influence the development of PreDM in the Northeast Chinese population.26 A higher proportion of PreDM was also found among men in the US population.27 Low HDL cholesterol level in patients with PreDM and MetS is a risk factor for heart disease, stroke,28 and T2D.29 Previous study reported that HDL cholesterol could enhance skeletal muscle absorption of glucose22 and that it promoted insulin secretion from pancreatic beta cells.