Different Associations between High Density Lipoprotein Cholesterol and Cardiovascular Diseases in Diabetic and Non-diabetic People: A Prospective Community-based Study

Abstract Background: Experimental studies found that the functionality of high density lipoprotein cholesterol (HDL-C) may be lost in the presence of diabetes mellitus (DM). We prospectively tested whether DM modified the association between HDL-C concentrations and cardiovascular disease (CVD). Methods: Included were 91,354 Chinese adults (8,244 participants with DM and 83,110 participants without DM) without use of lipid-lowering drugs and free of CVD or cancer at baseline (2006). The primary endpoint of interest was a composite of CVD (myocardial infarction, ischemic stroke and hemorrhagic stroke). Cumulative average HDL-C concentrations were calculated from all available HDL-C measures at baseline (2006) and during the follow-up period (2008, 2010, 2012 and 2014). Results: During a mean of 10.4 year of follow-up, there were 5,076 CVD events identified. Presence of DM significantly modified the association between HDL-C concentrations and CVD risk ( P interaction =0.003). The association between HDL-C concentrations and CVD followed a U-shaped curve in individuals without DM (P nonlinearity <0.001). The adjusted hazard ratio (HR) of CVD was 1.25 (95% confidence interval (CI): 1.06-1.48) for HDL-C concentrations <1.04 mmol/L and 1.80 (95% CI: 1.56-2.07) for HDL-C concentrations >2.07 mmol/L, relative to the lowest risk group (HDL-C concentrations of 1.30-1.42mmol/L). In participants with DM, higher HDL-C concentrations were associated with a higher risk of CVD, in a dose-response manner (P nonlinearity =0.44; P trend <0.001). The adjusted HR of CVD was 1.63 (95%CI: 1.20-2.20) for HDL-C concentrations >2.07 mmol/L, relative to HDL-C concentrations of 1.30-1.42mmol/L. Conclusion: High HDL-C concentrations were paradoxically associated with increased risk of composite CVD outcomes in individuals with or without DM. However, low HDL-C concentrations failed to predict future CVD risk in individuals with DM.