Apolipoprotein C-III Levels and Interrelation with Other Risk Factors in Residents of the Marmara Region

In 259 participants of the Turkish Adult Risk Factor Survey, the role of apolipoprotein C-III (apoCIII) in high-dens ity lipoprotein (HDL) and nonHDL apoCIII (nh apoCIII = total minus HDL apoCIII) as markers of triglycerides and HDL-cholesterol and of prevalent coronary heart disease (CHD) risk was studied cross-sectionally in a population sample of the Marmara region. Total and HDL-linked apoCIII were measured by turbidimetric immunoassay. Other ri sk variable measurements and CHD diagnosis were by standard techniques of the main survey. Mean concentrations for nh apoCIII in norınolipidemic men and women were 7.8±3.2 and 7.7±3.6 mg/d!, in hypertriglyceridemic men and women 17.6±6.6 ve 16.3±6.7 mg/dl, respectively. Mean HDL-Iinked apoCIII in normolipidemic subjects were 0. 83±0.5 and 1 .0±0.5 mg/di, in men and women with high triglyceride Jevels 0.94±0.5 mg/d!. Compared to Western populations, nh apoCIII appeared to be by one-half higher, and HDL apoCIII by two-thirds lower, representing an adverse lipoprotein profile, and suggesting a redistribution of apoCIII from HDL to apoB-containing lipoproteins in the fasting state. nh apoCIII was correlated closely notably with triglycerides and apo B, but also with levels of total, LDL-, and HDLcholesterol, anthropometric measures and blood pressures in both genders. In addition, nh apoCIII was significantly correlated with C-reactive protein levels in women. Presumably due to limited size of the cohort, neither nh apoCIII, nor HDL- linked apoCIII proved to be significantly associated with prevalent CHD. It was concluded that Turkish adults probably exhibit a defect in TRL metabolism characterized by a major redistribution of apoCIII from HDL to VLDL and remnants . NonHDL apoCIII concentrations closely reflect plasma triglycerides. Canfirmation of these findings and the assessment of the question as to whether this adverse profile is associated with augmented CHD risk should await further studies.