Distribution of low-density lipoprotein particle size in healthy Korean adult males

Association between triglyceride-glucose index and low-density lipoprotein particle size in korean obese adults

BACKGROUND

Small dense low-density lipoprotein cholesterol (sdLDL-C) is the lipoprotein marker among the various lipoproteins that is most strongly related to atherosclerosis. Insulin resistance (IR) can alter lipid metabolism, and sdLDL-C is characteristic of diabetic dyslipidemia. Therefore, this study sought to inspect the relationship between the triglyceride-glucose (TyG) index and mean low-density lipoprotein (LDL) particle size.

METHODS

In this study, a total of 128 adults participated. The correlation coefficients between various lipoproteins and the TyG index were compared using Steiger's Z test and the Spearman correlation. The independent link between the TyG index and mean LDL particle size was demonstrated by multiple linear regression analysis. To identify the TyG index cutoff value for the predominance of sdLDL particles, receiver operating characteristic curves were plotted.

RESULTS

Mean LDL particle size correlated more strongly with the TyG index than did very low-density lipoprotein, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Regression analysis demonstrated that mean LDL particle size had a strong association with the TyG index (β coefficient = -0.038, P-value < 0.001). The TyG index optimal cutoff value for sdLDL particle predominance and the corresponding area under the curve (standard error: 0.028, 95% confidence interval: 0.842-0.952) were 8.72 and 0.897, respectively, which were close to the cutoff value of diabetes risk in Koreans.

CONCLUSIONS

Mean LDL particle size is more strongly correlated with the TyG index than do other lipid parameters. After correcting for confounding variables, mean LDL particle size is independently linked with the TyG index. The study indicates that the TyG index is strongly related to atherogenic sdLDL particles predominance.

Predominance of small dense LDL differentiates metabolically unhealthy from metabolically healthy overweight adults in Korea

OBJECTIVE

The purposes of this study were (1) to determine the association between lipoprotein subfraction profiles and metabolically healthy overweight (MHO) phenotype, as defined by visceral adiposity; and (2) to identify the strongest predictor of metabolic health among the lipoprotein measurements.

MATERIALS/METHODS

This cross-sectional study was comprised of 462 overweight patients, who were classified as MHO or non-MHO based on their visceral adipose tissue (VAT) area to subcutaneous adipose tissue area (SAT) ratio (VAT/SAT ratio). Serum lipoprotein subfraction analyses and other metabolic parameters were measured.

RESULTS

Among the overweight participants, two hundred fifty-five individuals (53.7%) had the MHO phenotype. After adjusting for age, sex, medication, lifestyle factors, and confounding metabolic characteristics, the non-MHO group showed significantly higher lipid levels and a greater prevalence of unfavorable lipid profiles. LDL subclass pattern type B was the most significant predictor of the non-MHO phenotype (odds ratio 2.70; 95% CI 1.55-4.69), while serum LDL cholesterol level was not a significant predictor of the non-MHO phenotype.

CONCLUSIONS

Lipoprotein subfraction particle measurements were significantly associated with the non-MHO phenotype and a higher VAT/SAT ratio, with small dense LDL predominance being the most significant predictor of MHO phenotype. These findings will help identify MHO and non-MHO phenotypes and perhaps lead to a development of cost-effective individualized treatments.

The association of the Clock 3111 T/C SNP with lipids and lipoproteins including small dense low-density lipoprotein: results from the Mima study

BACKGROUND

The clock molecule plays major roles in circadian rhythmicity and regulating lipid and glucose metabolism in peripheral organs. Disruption of the circadian rhythm can lead to cardiometabolic disorders. The existence of small dense low-density lipoprotein (sdLDL) in the circulation, an abnormality of lipid metabolism, in part associated with lifestyle, is also one of risk parameters for cardiometabolic disorders. The 3111 T/C single nucleotide polymorphism (SNP) of the Clock gene has been reported to be associated with lifestyle including morning/evening preference. We investigated whether the Clock 3111 T/C SNP may affect lipids and lipoproteins including sdLDL.

METHODS

In 365 community-dwelling subjects (170 men and 195 women, mean age 63 ± 14 years), the 3111 T/C SNP was genotyped using a fluorescent allele-specific DNA primer assay system. The levels of sdLDL were measured with the electrophoretic separation of lipoproteins employing the Lipoprint system.

RESULTS

The frequency of the Clock 3111 C allele was 0.14. The area of sdLDL did not differ between the subjects with obesity and those without. In carriers of T/T homozygotes, the area of sdLDL was significantly higher compared with carriers of the C allele (T/C or C/C) (1.7 ± 3.4 vs. 0.8 ± 1.9%; p < 0.05). A multiple regression analysis showed that the area of sdLDL was significantly and negatively correlated with the Clock 3111 T/C SNP (β = -0.114, p < 0.05), independently of age, sex, body mass index, and exercise habits.

CONCLUSION

Our findings indicated that the Clock 3111 T/C SNP might be associated with the existence of sdLDL.

The Trp64Arg polymorphism of the beta3-adrenergic receptor gene is associated with increased small dense low-density lipoprotein in a rural Japanese population: the Mima study

The presence of small dense low-density lipoprotein (sdLDL) is closely associated with an increased risk of developing coronary artery disease. The Trp64Arg polymorphism of the beta(3)-adrenergic receptor (beta(3)-AR) gene is a genetic marker for obesity-related traits. However, any possible association between this polymorphism and sdLDL profiles is unclear. The objective of this study is to investigate the effects of the polymorphism of the beta(3)-AR gene on LDL particle size and sdLDL in a rural Japanese population. Among 277 subjects, body mass index, blood pressure, fasting serum insulin levels, and insulin resistance index (fasting glucose x fasting insulin/405) were determined. The polymorphism of the beta(3)-AR gene was assessed by polymerase chain reaction-restriction fragment length polymorphism using buccal samples. Low-density lipoprotein particle size and sdLDL were measured with the electrophoretic separation of lipoproteins on the LipoPrint System (Quantimetrix, Redondo Beach, CA). The frequency of the beta(3)-AR allele was 0.19. In Arg carriers (Trp/Arg or Arg/Arg), the mean value of LDL particle size was smaller than that of non-Arg carriers (Trp/Trp) (P < .05). The area percentage of sdLDL was higher in Arg carriers (P < .05) than in non-Arg carriers. A multiple regression analysis showed that the area percentage of sdLDL was correlated with the polymorphism of the beta(3)-AR gene (P < .05), independently of age, sex, body mass index, smoking, and insulin resistance index. The present findings suggest that the beta(3)-AR gene polymorphism plays a role in the genetic predisposition to increased sdLDL, independently of insulin resistance.