APOE and type 2 diabetes mellitus: At molecular level, we further investigated the transcriptional control mechanism at the −491A/T-spanning region of APOE. At physiological level, we examined the association of APOE promoter polymorphisms −491A/T (rs449647), −219G/T (rs405509) and +113G/C (rs440446) with the risk of type 2 diabetes.