High Density Lipoprotein Cholesterol (HDLc): Is Too Much of a Good Thing Harmful?

High Density Lipoprotein Cholesterol (HDLc): Is Too Much of a Good Thing Harmful? Recent reports have raised co Recent reports have raised concern that very high HDLc may not protect against cardiovascular disease (CVD), potentially due to altered particle structure/function. As persons with type 1 diabetes exhibit increased CVD risk despite elevated mean HDLc, we assessed the relationship between HDLc and subfractions with coronary artery disease (CAD) in childhood onset type 1 diabetes. Participants from the Epidemiology of Diabetes Complications Study who were free of CAD (301 men, 298 women; mean age, 27.1 and diabetes duration, 18.9 years) were studied. CAD was defined as angina, ischemic ECG changes, confirmed MI, angiographic stenosis [underline][gt][/underline]50%, revascularization or CAD death. Cholesterol in the HDL fraction and HDL3 subfraction was measured enzymatically after precipitation with heparin/manganese and dextran sulfate respectively. During 18 years of follow-up, 29.6% of men and 25.5% of women had a CAD event. CAD incidence increased in both genders below 47 mg/dL (i.e. the bottom 2 quintiles in men, the bottom quintile in women). Little risk gradient was seen for men above 47 mg/dL; in women risk increased above 80 mg/dL. These patterns largely reflected the HDL3-CAD association (Figure 1); HDL2 was not related to CAD. The linear, inverse, HDL-CAD association in men persisted after multivariable adjustment (HR=0.97, 95% CI=0.94-0.99), whereas the U-shaped association in women remained after adjustment for ApoA1 and ApoB (p=0.03) but not after further adjustments. There was a linear independent association for HDL3 in men (p=0.06); in women, the lower 2 (HR=1.87, 95% CI=1.06-3.29) and highest (HR=2.29, 95% CI=1.19-4.42) quintiles were associated with increased risk. Very high ([gt]80 mg/dL) HDLc does not appear to protect against CAD in type 1 diabetes. While this association was only seen in women, gender specificity could not be determined as only 2 men had HDL [gt]80 mg/dL.[figure1] TINA COSTACOU, RHOBERT W. EVANS, TREVOR JOHN ORCHARD 98-OR Pittsburgh, PA Diabetic Dyslipidemia