Small Dense Low-density Lipoprotein and Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death worldwide and small dense low-density lipoprotein (sdLDL) has been suggested to be a potential risk factor for cardiovascular disease (CVD). We reviewed published studies on formation and measurement of sdLDL, as well as relationship between LDL subfractions and CVD. sdLDL particle formation is highly dependent on triglycerides (TG) levels, and the physicochemical properties of sdLDL particles provide a potential for increased atherogenicity. Various conditions (e.g. hypertriglyceridemia, diabetes mellitus, metabolic syndrome, chronic renal failure and HIV infections) with increased cardiometabolic risk are associated with increased sdLDLs. Most studies suggest that sdLDL particles are associated with increased prevalence of clinical and subclinical CVDs, as well as non-coronary forms of atherosclerosis. Moreover, LDL size seems to be an important determinant of the progression of CVD. Therapeutic modulation (mostly fibrates, but also some statins, as well as niacin and thiazolidinediones) of small LDL size, number and distribution may decrease CVD risk. However, no definitive causal relationship is yet established, probably due to the close association between sdLDL and triglycerides and other risk factors.

Higher levels of serum triglyceride and dietary carbohydrate intake are associated with smaller LDL particle size in healthy Korean women

The aim of this study was to investigate the influencing factors that characterize low density lipoprotein (LDL) phenotype and the levels of LDL particle size in healthy Korean women. In 57 healthy Korean women (mean age, 57.4 +/- 13.1 yrs), anthropometric and biochemical parameters such as lipid profiles and LDL particle size were measured. Dietary intake was estimated by a developed semi-quantitative food frequency questionnaire. The study subjects were divided into two groups: LDL phenotype A (mean size: 269.7A, n = 44) and LDL phenotype B (mean size: 248.2A, n = 13). Basic characteristics were not significantly different between the two groups. The phenotype B group had a higher body mass index, higher serum levels of triglyceride, total-cholesterol, LDL-cholesterol, apolipoprotein (apo)B, and apoCIII but lower levels of high density lipoprotein (HDL)-cholesterol and LDL particle size than those of the phenotype A group. LDL particle size was negatively correlated with serum levels of triglyceride (r = -0.732, P < 0.001), total-cholesterol, apoB, and apoCIII, as well as carbohydrate intake (%En) and positively correlated with serum levels of HDL-cholesterol and ApoA1 and fat intake (%En). A stepwise multiple linear regression analysis revealed that carbohydrate intake (%En) and serum triglyceride levels were the primary factors influencing LDL particle size (P < 0.001, R2 = 0.577). This result confirmed that LDL particle size was closely correlated with circulating triglycerides and demonstrated that particle size is significantly associated with dietary carbohydrate in Korean women.

Smaller Mean LDL Particle Size and Higher Proportion of Small Dense LDL in Korean Type 2 Diabetic Patients

BACKGROUND: Small dense low density lipoprotein (sdLDL) has recently emerged as an important risk factor of coronary heart disease. METHODS: The mean LDL particle size was measured in 203 patients with type 2 diabetes mellitus (T2DM) and 212 matched subjects without diabetes using polyacrylamide tube gel electrophoresis. Major vascular complications were defined as stroke, angiographically-documented coronary artery disease or a myocardial infarction. Peripheral vascular stenosis, carotid artery stenosis (> or =50% in diameter) or carotid artery plaque were considered minor vascular complications. Overall vascular complications included both major and minor vascular complications. RESULTS: Diabetic patients had significantly smaller mean-LDL particle size (26.32 nm vs. 26.49 nm) and a higher percentage of sdLDL to total LDL compared to those of subjects without diabetes (21.39% vs. 6.34%). The independent predictors of sdLDL in this study were serum triglyceride level and body mass index (odds ratio [OR], 1.020 with P<0.001 and OR 1.152 with P<0.027, respectively). However, no significant correlations were found between sdLDL and major vascular complications (P=0.342), minor vascular complications (P=0.573) or overall vascular complications (P=0.262) in diabetic subjects. CONCLUSION: Diabetic patients had a smaller mean-LDL particle size and higher proportion of sdLDL compared to those of subjects without diabetes. Obese diabetic patients with hypertriglyceridemia have an increased risk for atherogenic small dense LDL. However, we could not verify an association between LDL particle size and vascular complications in this study.

Plasma LDL Particle Sizes Affect the Blood Lipid Profile and Dietary Intakes among Korean Adults / 대한지역사회영양학회지

The purpose of this research was to examine the relationship between the plasma LDL particle size and blood lipid profile, dietary factors and anthropometric values (body mass index, waist circumference and waist/hip ratio). The subjects were 173 adults aged 23 to 81 years, selected from the Outpatient Clinic and Cardiovascular Department of the Seoul Municipal Hospital. Dietary data were obtained using a 3-day food record and analyzed using Korean and US nutrient databases. The subjects were divided into three groups by LDL particle size:type A (large buoyant LDL, > 25.5 nm, n = 96), type I (Intermediate LDL, 25.2 < or = - < or = 25.5 nm, n = 18), and type B (small dense LDL, < 25.2 nm, n = 59) groups. The type B group had higher age, waist circumference, and waist/hip ratio (WHR) than the type A and type I groups. Serum concentration of triglyceride, Apo B, LDL/HDL cholesterol ratio and atherogenic index were significantly higher in the type B group as compared to those in the other two groups. HDL cholesterol level and Apo A-I/Apo B ratio were significantly lower in the type B group than the other two groups. The plasma LDL particle size was highly correlated with triglyceride (r = -0.450), Apo B (r = -0.402) and HDL cholesterol (r = 0.418). However, there was no correlation between plasma LDL particle size and dietary intakes. This study showed that small dense LDL was an important biochemical risk factor that was associated with other risk factors.