LDL size in African Americans, Hispanics, and non-Hispanic whites - The insulin resistance atherosclerosis study

The prevalence of cardiovascular disease (CVD) and atherosclerosis varies a mong several minority ethnic groups in the United States. Recently, small, dense low density lipoprotein (LDL) particle size has been recognized as a risk factor for CVD, We examined LDL size as a possible explanation for dif ferences in CVD rates in 1571 subjects from the Insulin Resistance Atherosc lerosis Study (IRAS), a multiethnic study of insulin resistance and cardiov ascular risk factors. LDL size (Angstrom) was significantly different by et hnic group (African Americans 262.1+/-0.6, Hispanics 257.6+/-0.6, and non-H ispanic whites 259.2+/-0.4, P<0.001). Ethnic differences in LDL size contin ued to be statistically significant after adjustment for upper body adiposi ty, insulin resistance, and glucose tolerance status. However, after furthe r adjustment for other cardiovascular risk factors, especially ethnic diffe rences in triglyceride and high density lipoprotein (HDL) cholesterol level s, the ethnic differences in LDL size were markedly attenuated and in gener al no longer statistically significant. The relation of triglyceride, HDL c holesterol, insulin resistance, and adiposity to LDL size in each ethnic gr oup was similar. LDL size differs by ethnic group, which is independent of obesity or insulin resistance. These ethnic differences appear to be due to ethnic variations in dyslipidemia (especially differences in triglyceride levels); ethnic differences in LDL size are not consistent with previously reported ethnic dissimilarities in CVD or atherosclerosis.