Abstract 3753: Is Isolated Low HDL-C An Atherogenic Phenotype? The Amish Family Calcification Study
Background: While the inverse relationship between HDL-C and coronary heart disease (CHD) is well established, few data have specifically evaluated the atherogenic impact of “isolated” low HDL-C. We hypothesized that if low HDL-C promoted atherosclerosis, then an increased presence of coronary artery calcification (CAC) would be observed, irrespective of LDL-C.
Methods: In addition to completing a questionnaire addressing CHD risk factors and measuring fasting lipids and lipoproteins, electron beam computed tomography was used to detect the presence of CAC in asymptomatic Amish subjects as part of the Amish Family Calcification Study (AFCS). Isolated low HDL-C was defined as HDL-C less than 40 (men) and 50 (women) mg/dL in association with LDL-C less than < 130 mg/dL.
Results: CAC and lipid measurements were performed in 1,069 subjects (mean age 56.6 ± 13 years; 55% women). Compared to the low LDL-C, high HDL-C (referent) group, risk of CAC was significantly increased with high LDL-C (≥130 mg/dL), irrespective of whether HDL-C was high (≥50 mg/dL in women or ≥ 40 mg/dL in men) or lower (Table⇓). In contrast, the likelihood of having detectable CAC was not significantly increased in the presence of “isolated” low HDL-C even after adjustment for age, sex, BMI, SBP, DBP, current smoking, and family structure (adjusted OR, 1.1). Notably, inferences were the same even if lower LDL cutpoints (<100 mg/dL) were used to define “isolated” low HDL-C.
Conclusions: Low HDL-C is not associated with increased CAC in the absence of elevated LDL-C. As such, these data raise the possibility that an “isolated” low HDL-C may not in itself promote subclinical coronary atherosclerosis as measured by CAC.