LDL-cholesterol/apolipoprotein B ratio is a good predictor of LDL phenotype B in type 2 diabetes

Low-density lipoprotein cholesterol to apolipoprotein B ratio predicts mortality and cardiovascular events in peritoneal dialysis patients

PURPOSE

The ratio of low-density lipoprotein cholesterol (LDL-C)/apolipoprotein B (apo B) is associated with all-cause mortality and cardiovascular events in chronic kidney disease patients. The aim of this study was to investigate the association between the LDL-C/apo B ratio (LAR) and all-cause mortality and cardiovascular events in peritoneal dialysis (PD) patients.

METHODS

A total of 1199 incident PD patients were enrolled from November 1, 2005 to August 31, 2019. The LAR was used to divide the patients into two groups by X-Tile software and restricted cubic splines using 1.04 as the cutoff. The incidence of all-cause mortality and cardiovascular events at follow-up was compared according to LAR.

RESULTS

Of the 1199 patients, 58.0% were men, the mean age was 49.3 ± 14.5 years, 225 patients had a history of diabetes, and 117 patients had prior cardiovascular disease. During the follow-up period, 326 patients died, and 178 patients experienced cardiovascular events. After full adjustment, a low LAR was significantly associated with HRs for all-cause mortality of 1.37 (95% CI 1.02-1.84, P = 0.034) and for cardiovascular events of 1.61 (95% CI 1.10-2.36, P = 0.014).

CONCLUSION

This study suggests that a low LAR is an independent risk factor for all-cause mortality and cardiovascular events in PD patients, indicating that the LAR may provide significant information when assessing all-cause mortality and cardiovascular risks.

Lipid profile, lipid ratios, apolipoproteins, and risk of cardiometabolic multimorbidity in men: The Kuopio Ischaemic Heart Disease Risk Factor Study

The blood level of lipids, apolipoproteins, and lipid ratios are important predictors of some chronic diseases. However, their association with cardiometabolic multimorbidity (CMM) is less known. We evaluated a wide range of lipid profiles and lipid ratios, including low-density lipoprotein-cholesterol (LDL-C), very-low-density lipoprotein-cholesterol (VLDL-C), high-density lipoprotein-cholesterol (HDL-C), and apoA1 and B, as well triglyceride and total cholesterol with risk of incident CMM. In 1728 men aged 52.5 ± 5.2 years from the Kuopio Ischaemic Heart Disease were included in this study. We defined CMM as coexisting of two or more of stroke, type 2 diabetes mellitus (T2D), coronary heart disease (CHD). A Cox proportional hazard regression method was applied to evaluate the risk of CMM against the exposures. During the mean follow-up of 22.4 years, 335 men suffered from CMM conditions. Higher serum triglyceride and VLDL concentrations were associated with a higher risk of coexisting T2D-CHD (HRs 1.99 (95% CI, 1.12-3.53) and HRs 1.79 (95% CI, 1.04-3.11), respectively. Whereas higher HDL was associated with lower incident [HRs 0.49 (95% CI, 0.40-1.00)]. The HRs for coexisting T2D-CHD was 2.02 (95% CI, 1.01-3.07) for total cholesterol/HDL-C, 1.85 (95% CI, 1.04-3.29) for triglyceride/HDL-C, 1.69 (95% CI, 1.01-2.31) for Non-HDL-C/HDL-C, and 1.89 (95% CI, 1.03-2.46) for apoB/apoA1. In contrast, serum LDL-C/apoB ratios were inversely associated with the risk of coexisting T2D-CHD [HRs 0.50 (95% CI, 0.28-0.90)]. No associations were observed between our exposures and other CMM conditions. In conclusion, elevated triglyceride, VLDL-C, total cholesterol/HDL-C, TG/HDL-C, apoB/apoA1 as well as lower LDL-C/apoB were independently associated with the higher risk of T2D-CHD coexistence.

Low-density lipoprotein cholesterol-to-apolipoprotein B ratio as a potential indicator of LDL particle size and plasma atherogenicity in type 2 diabetes

AIMS

Atherogenic dyslipidemia, associated with small, dense low-density lipoprotein-cholesterol (S-LDL) particles and impaired metabolism of triglycerides (TGs) and high-density lipoprotein-cholesterol (HDL-c), leads to the development of atherosclerosis-related complications of type 2 diabetes mellitus. Based on the hypothesis that an LDL-c-to-apolipoprotein B ratio (LDL/ApoB) < 1.2 may predict the prevalence of S-LDL, this study aimed to evaluate the LDL/ApoB ratio in patients with type 2 diabetes with moderately elevated TG levels.

METHODS

The study population consisted of 121 outpatients with type 2 diabetes (S-LDL group, LDL/ApoB < 1.2, n = 79; L-LDL group, LDL/ApoB > 1.2, n = 42) and 58 healthy subjects. The LDL/ApoB ratio was calculated from the measured LDL-c and ApoB levels in participants with TG levels lower than 4.5 mmol/L. Since TGs and HDL-c are included in the atherogenic index of plasma (AIP), we evaluated the relationship between LDL/ApoB and the AIP.

RESULTS

Higher levels of AIP, TG (both P < 0.0001), and lipid hydroperoxides (LOOH) (P < 0.001) and lower levels of HDL-c, total cholesterol, and non-HDL-c (P < 0.001, <0.01, <0.05, respectively) were found in the S-LDL group compared to the L-LDL group. There were significant relationships between the LDL/ApoB ratio and the AIP, TG (both P < 0.0001), LOOH (P < 0.0005), and HDL-c levels (P < 0.05) in the S-LDL group.

CONCLUSIONS

The prevalence of S-LDL particles (65%) and the close association of LDL/ApoB with the AIP suggest that this ratio may be a potential indicator of increased cardiovascular risk in patients with type 2 diabetes.

Chromosome Xq23 is associated with lower atherogenic lipid concentrations and favorable cardiometabolic indices

Autosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min P = 8.5 × 10-72), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (P = 1.7 × 10-4), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (P = 1.4 × 10-5). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased CHRDL1 gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids.

Effects of Virgin Olive Oil and Phenol-Enriched Virgin Olive Oils on Lipoprotein Atherogenicity

The atherogenicity of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins (TRLs) may be more significant than LDL cholesterol levels. Clinical trials which have led to increased high-density lipoprotein (HDL) cholesterol have not always seen reductions in cardiovascular disease (CVD). Furthermore, genetic variants predisposing individuals to high HDL cholesterol are not associated with a lower risk of suffering a coronary event, and therefore HDL functionality is considered to be the most relevant aspect. Virgin olive oil (VOO) is thought to play a protective role against CVD. This review describes the effects of VOO and phenol-enriched VOOs on lipoprotein atherogenicity and HDL atheroprotective properties. The studies have demonstrated a decrease in LDL atherogenicity and an increase in the HDL-mediated macrophage cholesterol efflux capacity, HDL antioxidant activity, and HDL anti-inflammatory characteristics after various VOO interventions. Moreover, the expression of cholesterol efflux-related genes was enhanced after exposure to phenol-enriched VOOs in both post-prandial and sustained trials. Improvements in HDL antioxidant properties were also observed after VOO and phenol-enriched VOO interventions. Furthermore, some studies have demonstrated improved characteristics of TRL atherogenicity under postprandial conditions after VOO intake. Large-scale, long-term randomized clinical trials, and Mendelian analyses which assess the lipoprotein state and properties, are required to confirm these results.

Role of HDL function and LDL atherogenicity on cardiovascular risk: A comprehensive examination

BACKGROUND

High-density lipoprotein (HDL) functionality and low-density lipoprotein (LDL) atherogenic traits can describe the role of both particles on cardiovascular diseases more accurately than HDL- or LDL-cholesterol levels. However, it is unclear how these lipoprotein properties are particularly affected by different cardiovascular risk factors.

OBJECTIVE

To determine which lipoprotein properties are associated with greater cardiovascular risk scores and each cardiovascular risk factor.

METHODS

In two cross-sectional baseline samples of PREDIMED trial volunteers, we assessed the associations of HDL functionality (N = 296) and LDL atherogenicity traits (N = 210) with: 1) the 10-year predicted coronary risk (according to the Framingham-REGICOR score), and 2) classical cardiovascular risk factors.

RESULTS

Greater cardiovascular risk scores were associated with low cholesterol efflux values; oxidized, triglyceride-rich, small HDL particles; and small LDLs with low resistance against oxidation (P-trend<0.05, all). After adjusting for the rest of risk factors; 1) type-2 diabetic individuals presented smaller and more oxidized LDLs (P<0.026, all); 2) dyslipidemic participants had smaller HDLs with an impaired capacity to metabolize cholesterol (P<0.035, all); 3) high body mass index values were associated to lower HDL and LDL size and a lower HDL capacity to esterify cholesterol (P<0.037, all); 4) men presented a greater HDL oxidation and lower HDL vasodilatory capacity (P<0.046, all); and 5) greater ages were related to small, oxidized, cytotoxic LDL particles (P<0.037, all).

CONCLUSIONS

Dysfunctional HDL and atherogenic LDL particles are present in high cardiovascular risk patients. Dyslipidemia and male sex are predominantly linked to HDL dysfunctionality, whilst diabetes and advanced age are associated with LDL atherogenicity.

Measured Versus Calculated Small Dense LDL-Cholesterol and Cardiometabolic Traits in a South African Population

Small-dense low density lipoprotein (sdLDL) is increasingly viewed as a marker for evaluating atherogenic risk, however its clinical uptake is hampered by the cumbersomeness of available methods. Consequently, a number of alternative methods for the estimation of sdLDL have been developed and none have been tested in a population from Africa. We evaluated an equation to estimate sdLDL-C from classic lipid parameters in South Africans. This is a cross-sectional study involving 1550 participants in which direct measurement of sdLDL in 237 participants was performed using a homogeneous enzymatic assay. Their mean age (standard deviation, SD) was 54.2 (14.7) years. 156 (65.8%) were normotolerant, 29 (12.2%) prediabetes, 17 (7.2%) screen detected diabetes and 35 (14.8%) known diabetes. Measured sdLDL values ranged from 0.17 to 3.39 versus-1.85 to 2.52 mmol/L calculated sdLDL. There was a significant positive correlation between the two measurements with a Pearson correlation coefficient of 0.659 (95%CI: 0.581-0.726). In a regression model, the adjusted R² was 0.440 after adding age, 0.441 after further adding gender, then 0.443 with dysglycemia and lastly 0.447 upon adding body mass index. With the exception of HDL-cholesterol levels that decreased across increasing quintiles of calculated sdLDL, our data showed significant correlations between sdLDL and cardiometabolic risk factors, all p values < 0.0001. In conclusion, this study has shown that calculated sdLDL can be efficiently used to approximate population levels of sdLDL; however the modest correlation indicate that at the individual level, it will poorly approximate true sdLDL levels, with possible implications for risk stratification.

Efficacy and safety of a combination of red yeast rice and olive extract in hypercholesterolemic patients with and without statin-associated myalgia

Cholesfytol^®, a lipid-lowering dietary supplement with antioxidant and anti-atherosclerotic properties, combines red yeast rice (RYR) and olive extract (5mg hydroxytyrosol equivalent) and represents an alternative for patients who do not wish or are unable to use chemical statins, including individuals with previous statin-associated muscle symptoms (SAMS). A 2-months observational non-randomized study was performed to evaluate the efficacy, tolerance and safety of Cholesfytol^® (1 tablet/day) in 642 hypercholesterolemic patients (mean age: 59 yrs; total cholesterol (TC) ≥200; LDL-C ≥140mg/dl). Patients were followed by 126 GPs, and included irrespective of SAMS history and/or diabetes. None of the patients were taking statins or other lipid-modifying therapy at inclusion. At baseline, 26% had fasting glucose >100 ≤125mg/dL, and 5% >125mg/dL; 32% (n=194) had a SAMS history; and 21% had atherogenic dyslipidemia (AD). In the entire cohort, pre-treatment TC; non-HDL-C; LDL-C; and TG were 259; 200; 168; 158mg/dL, respectively, and decreased significantly on treatment (-17.5% (TC) and -23.3% (LDL-C)). Fasting glucose and HbA_1c decreased between visits. The reduction in lipids was greater in patients with higher values at baseline. For comparable pre-treatment values, patients with SAMS history had reductions in TC, LDL-C, non-HDL-C, and apoB₁₀₀ slightly less than patients without myalgia. AD patients had greater on-treatment decrease in TG. Overall, 13 patients reported minor side-effects, and 4 patients reporting myalgia had antecedent SAMS. In conclusion, a substantial decrease in LDL-C was obtained with a combination of RYR and olive extract in high-risk hypercholesterolemic patients, without inducing new-onset SAMS.

Activity of the antioxidant enzyme paraoxonase in Argentinean children living at high altitude

Background: Children living at high altitude in San Antonio de los Cobres (SAC), Argentina, were shown to have lower high-density lipoprotein cholesterol (HDL-C) levels than Buenos Aires (BA) children. HDL antioxidant capacity is mainly attributed to paraoxonase1 (PON1).

Objective: To compare PON1 activity in indigenous SAC vs. BA children.

Methods: A cross-sectional study compared 158 SAC vs. 97 BA children (6–16 years). Anthropometric data and lipoprotein profile were measured. PON1 was evaluated employing paraoxon (PON) and phenylacetate (ARE) activity.

Results: The prevalence of overweight/obesity was lower in SAC than in BA children (18.3 vs. 30.9%). Triglycerides (1.34 vs. 0.90 mmol/l), apo B (0.84 vs.0.72 g/l), apo A-I (1.33 vs. 1.27 g/l), and ARE activity (100 vs. 90 µmol/ml/min) were higher, while HDL-C (1.16 vs. 1.32 mmol/l) and PON activity (170 vs. 203 nmol/ml/min) were lower in SAC than in BA. Separate multiple linear regression analyses showed that SAC children had significantly higher triglyceride (Beta −0.38), apo B (Beta −0.34), and ARE (Beta −0.36) plus lower HDL-C (Beta 0.33) and PON (Beta 0.25) compared with BA; adjusted for age, gender, and BMI.

Conclusion: SAC showed an unfavorable lipoprotein profile, lower PON and higher ARE activities compared with BA children, suggesting the presence of altered HDL metabolism and antioxidant capacity.

The Mediterranean Diet decreases LDL atherogenicity in high cardiovascular risk individuals: a randomized controlled trial

SCOPE

Traditional Mediterranean diet (TMD) protects against cardiovascular disease through several mechanisms such as decreasing LDL cholesterol levels. However, evidence regarding TMD effects on LDL atherogenic traits (resistance against oxidation, size, composition, cytotoxicity) is scarce.

METHODS AND RESULTS

We assessed the effects of a 1-year intervention with a TMD on LDL atherogenic traits in a random sub-sample of individuals from the PREDIMED study (N = 210). We compared two TMDs: one enriched with virgin olive oil (TMD-VOO, N = 71) and another with nuts (TMD-Nuts, N = 68), versus a low-fat control diet (N = 71). After the TMD-VOO intervention, LDL resistance against oxidation increased (+6.46%, p = 0.007), the degree of LDL oxidative modifications decreased (-36.3%, p<0.05), estimated LDL particle size augmented (+3.06%, p = 0.021), and LDL particles became cholesterol-rich (+2.41% p = 0.013) relative to the low-fat control diet. LDL lipoproteins became less cytotoxic for macrophages only relative to baseline (-13.4%, p = 0.019). No significant effects of the TMD-Nuts intervention on LDL traits were observed versus the control diet.

CONCLUSION

Adherence to a TMD, particularly when enriched with virgin olive oil, decreased LDL atherogenicity in high cardiovascular risk individuals. The development of less atherogenic LDLs could contribute to explaining some of the cardioprotective benefits of this dietary pattern.

Usefulness of the LDL-C/apoB ratio in the overall evaluation of atherogenicity of lipid profile

CONTEXT

The ratio of low-density lipoprotein cholesterol to apolipoprotein-B (LDL-C/apoB) conventionally represents an alternative index of LDL particle size.

OBJECTIVE

This study was undertaken to determine the importance of LDL-C/apoB ratio in the overall evaluation of atherogenicity of lipid profile.

METHODS

The plasma levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apolipoprotein (apo) A-I, apoB and apoE were measured in 186 apparently healthy men using enzymatic and immunoturbidimetric methods.

RESULTS

The subjects with low values of the LDL-C/apoB ratio, indicating a predominance of small dense LDL (sd-LDL) particles in plasma, were characterized by higher TG levels and lower apoE levels.

CONCLUSION

Low levels of apoE are most likely a cause of reduced clearance of TG-rich lipoproteins, which promotes the formation of sd-LDL. Determination of the LDL-C/apoB ratio can be used for monitoring qualitative changes in lipid profile, in addition to traditional lipid variables indicating quantitative changes.

Acute modification in plasma lipid levels in ultramarathon runners

We aimed to evaluate the effects of a 24-h ultramarathon, an aerobic test of high physical load, on lipid profile and apolipoproteins B (ApoB) and A1 (ApoA1) levels, minimally modified low-density lipoprotein (LDL), and oxidised LDL. Prospective evaluation of 16 male athletes who participated in an ultramarathon run, where the objective was to run the greatest distance possible in 24 h. Fourteen participants completed the run. The mean distance achieved was 133.1 km (maximum of 169.6 km). There was a trend in reduction of triglycerides and total cholesterol (P = 0.06 and 0.05, respectively), without significant modifications in high-density lipoprotein, LDL and ApoA1 levels (P = 0.16; 0.55 and 0.67). There was a marked reduction in ApoB levels (P < 0.001), correlated directly to the distance covered (Pearson R = 0.68). Accordingly, an increase in the LDL/ApoB ratio was observed. The stress of this physical activity was not associated to an increase in minimally modified LDL or oxidised LDL. Lipid profile levels were not acutely altered by prolonged physical activity. Similarly, there was no evidence of greater oxidation of LDL over a 24-h period of physical activity. The reduction in ApoB was directly proportional to the distance covered, suggesting an acute positive change in phenotype of LDL molecules.

Estimation of LDL Particle Size Using Lipid Indices: A Population-Based Study of 1578 Schoolchildren

BACKGROUND

Low-density lipoprotein (LDL) is atherogenic and LDL particles are reduced in diameter in the presence of insulin resistance, forming small, dense LDL. This study was conducted to assess the relationship between commonly used lipid indices and LDL particle size and furthermore to clarify the best surrogate lipid markers that could conveniently be used to estimate LDL particle size in children.

METHODS

We determined LDL particle diameter by gradient gel electrophoresis in 1578 children aged 10-12 years. At the fasting state, the relationships between measured LDL particle size and lipid variables [total cholesterol (TC), triglycerides (TG), LDL-cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), atherogenic index [(TC-HDL-C)/HDL-C, TG/HDL-C, LDL-C/HDL-C, and LDL-C/apolipoprotein B (Apo B) and non-HDL-C (TC-HDL-C)] were analyzed.

RESULTS

The LDL particle diameter was 26.64 (mean) ± 0.48 (SD) nm in boys (n = 820) and 26.66 ± 0.49 nm in girls (n = 758); there was not a statistically significant difference. There were statistically significant correlations between LDL particle size and TG or HDL-C concentrations (r = 0.28∼0.37), but the correlations with LDL-C and ApoB were very weak. The combined lipid measures, such as atherogenic index, TC/HDL-C, TG/HDL-C, and LDL-C/HDL-C showed moderate correlations (r = 0.33∼0.38) with LDL particle size; however, the correlation of non-HDL-C with LDL particle size was weak (r = 0.18∼0.19). Simple HDL-C measure appeared to be of comparable value to combined lipid measures.

CONCLUSIONS

Our data indicate that various lipid indices are not superior to HDL-C levels alone as a clinical tool for estimating LDL particle size. Non-HDL-C was less valuable in this aspect.

Atherogenic dyslipidemia in children: evaluation of clinical, biochemical and genetic aspects

The precursors of atherogenic dyslipidemia (AD) are not well defined. Therefore, we investigated 62 non-obese, non-diabetic AD and 221 normolipemic children. Anthropometric parameters, blood pressure and biochemical measures were obtained in index children, their parents and all available siblings. The heritability (h²) of anthropometric and biochemical traits was estimated by SOLAR. Rare and common variants in APOA1 and LPL genes were screened by re-sequencing. Compared to normolipemic, AD children showed increased body mass index, waist circumference, plasma glucose, insulin, ApoB, HOMA-IR, hs-CRP and lower adiponectin (p<0.001 for all). Metabolic syndrome was present in 40% of AD while absent in controls. All traits (except adiponectin and hs-CRP) showed a strong familial aggregation, with plasma glucose having the highest heritability (89%). Overall, 4 LPL loss-of-function mutations were detected (p.Asp9Asn, p.Ser45Asn, p.Asn291Ser, p.Leu365Val) and their cumulative prevalence was higher in AD than in control children (0.073 vs. 0.026; P=0.038). The LPL p.S447* gain-of-function mutation, resulted to be less frequent in AD than in control children (0.064 vs. 0.126; P=0.082). No variant in the APOA1 gene was found. Our data indicate that AD is a rather common dyslipidemia in childhood; it associates with metabolic abnormalities typical of insulin resistant state and shows a strong familial aggregation. LPL variants may contribute to the development of AD phenotype.

The apolipoprotein B/apolipoprotein A-I ratio as a potential marker of plasma atherogenicity

Background. The apolipoprotein (apo) B/apoA-I ratio represents the balance between apoB-rich atherogenic particles and apoA-I-rich antiatherogenic particles, and this ratio is considered to be a marker of cardiovascular risk. Although many studies have demonstrated the importance of the apoB/apoA-I ratio in predicting the presence or absence of cardiovascular disease, less is known about apoB/apoA-I ratio as a marker of plasma atherogenicity. Methods. A total of 157 normolipidemic men aged 20–59 years were included in the study. The plasma levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apoA-I, apoB, and apoE were determined after a 12 h fasting period. Results. The median of the apoB/apoA-I ratio in the studied normolipidemic subjects was 0.52, with values ranging from 0.19 to 2.60. The percentage of subjects with the apoB/apoA-I ratio exceeding 0.9 (the accepted risk value of cardiovascular disease) was 19.1%. The subjects with apoB/apoA-I>0.9 were characterized by higher TG levels and atherogenic index of plasma (AIP) and lower values of ratio of low-density lipoprotein cholesterol (LDL-C) to apoB (LDL-C/apoB) and apoE levels compared with men with apoB/apoA-I<0.9. Conclusion. Despite normolipidemia, the subjects with the unfavorable apoB/apoA-I ratio had more atherogenic lipid profile.

The association between the apolipoprotein A1/ high density lipoprotein -cholesterol and diabetes in Taiwan - a cross-sectional study

BACKGROUND

Traditional lipid indices have been associated with type 2 diabetes, but it remains uncertain which lipid index is the best discriminator for diabetes. In this study, we aimed to assess lipoproteins, traditional lipid variables, and other variables to discover their association with diabetes in the Taiwanese population.

METHODS

Data from a nationwide cross-sectional population-based survey of 3087 men and 3373 women in 2002 were analyzed in this study. All participants were assessed for anthropometry, glycosylated hemoglobin, fasting sugar and lipid profiles with triglycerides, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), and apolipoprotein A1 (ApoA1) and B (ApoB). The ratio of LDL-C/HDL-C, ApoB/ApoA1, ApoB/LDL-C and ApoA1/HDL-C and other variables were analyzed to determine their potential roles in type 2 diabetes in the Taiwanese population. The Odds ratios (ORs) of the risk variables for diabetes were estimated using logistic regression and were adjusted for confounding factors.

RESULTS

The increased ratio of ApoA1/HDL-C was significantly associated with diabetes in men (top tertile vs. lowest: OR 2.98; 95% CI: 1.12 - 7.92; P-trend = 0.030) and women (top tertile vs. lowest: OR 2.15; 95% CI: 1.00 - 4.59; P-trend = 0.047). A modest increased diabetic risk was evident with ApoB/LDL-C in women (top tertile vs. lowest: OR 2.03; 95% CI: 1.07- 3.85; P-trend = 0.028), but not in men (top tertile v. lowest: OR 1.69; 95% CI: 0.79- 3.62; P-trend = 0.198).

CONCLUSIONS

ApoA1/HDL-C had a significant linear association with diabetes in both sexes and was superior to other lipid and lipoprotein variables among the general Taiwanese population.

Differences in metabolomic and transcriptomic profiles between responders and non-responders to an n-3 polyunsaturated fatty acids (PUFAs) supplementation

Studies have demonstrated large within-population heterogeneity in plasma triacylglycerol (TG) response to n-3 PUFA supplementation. The objective of the study was to compare metabolomic and transcriptomic profiles of responders and non-responders of an n-3 PUFA supplementation. Thirty subjects completed a 2-week run-in period followed by a 6-week supplementation with n-3 PUFA (3 g/d). Six subjects did not lower their plasma TG (+9 %) levels (non-responders) and were matched to 6 subjects who lowered TG (-41 %) concentrations (responders) after the n-3 PUFA supplementation. Pre-n-3 PUFA supplementation characteristics did not differ between the non-responders and responders except for plasma glucose concentrations. In responders, changes were observed for plasma hexose concentrations, docosahexaenoic acid, stearoyl-CoA-desaturase-18 ratio, and the extent of saturation of glycerophosphatidylcholine after n-3 PUFA supplementation; however, no change in these parameters was observed in non-responders. Transcriptomic profiles after n-3 PUFA supplementation indicate changes in glycerophospholipid metabolism in both subgroups and sphingolipid metabolism in non-responders. Six key genes in lipid metabolism: fatty acid desaturase 2, phospholipase A2 group IVA, arachidonate 15-lipoxygenase, phosphatidylethanolamine N-methyltransferase, monoglyceride lipase, and glycerol-3-phosphate acyltransferase, were expressed in opposing direction between subgroups. In sum, results highlight key differences in lipid metabolism of non-responders compared to responders after an n-3 PUFA supplementation, which may explain the inter-individual variability in plasma TG response.

Low-density lipoprotein cholesterol to apolipoprotein B ratio is independently associated with metabolic syndrome in Korean men

The low-density lipoprotein cholesterol to apolipoprotein B (LDL-C/apo B) ratio is associated with cardiovascular risk factors and the prevalence of metabolic syndrome. The aim of this study was to assess the relationship between LDL-C/apo B ratio and metabolic syndrome in Korean men. This study included 499 men (mean age, 49.1 years) without metabolic syndrome at baseline who were followed for an average of 2.9 years. Subjects were divided into 4 groups according to baseline LDL-C/apo B ratio quartiles: greater than 1.243 in group I, 1.164 to 1.243 in group II, 1.070 to 1.163 in group III, and less than 1.070 in group IV. The incidence of metabolic syndrome at follow-up was compared according to LDL-C/apo B ratio group. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. The overall incidence of metabolic syndrome was 9.6%: 1.6% in the highest quartile (group I), 9.7% in group II, 11.2% in group III, and 16.0% in the lowest quartile (group IV) (P = .001). In multivariable regression analysis model adjusting for age, lifestyle status, homeostasis model assessment of insulin resistance, LDL-C, and high-sensitivity C-reactive protein, groups II, III, and IV had significantly increased odds ratio for the incidence of metabolic syndrome compared with the highest LDL-C/apo B quartile (group I). The LDL-C/apo B ratio is independently associated with metabolic syndrome in Korean men, indicating that this ratio may provide additional information when assessing cardiometabolic risks and predicting future development of metabolic syndrome.

The role of niacin in raising high-density lipoprotein cholesterol to reduce cardiovascular events in patients with atherosclerotic cardiovascular disease and optimally treated low-density lipoprotein cholesterol: baseline characteristics of study participants. The Atherothrombosis Intervention in Metabolic syndrome with low HDL/high triglycerides: impact on Global Health outcomes (AIM-HIGH) trial

OBJECTIVES

The study aims to report the baseline characteristics of the fully randomized AIM-HIGH study population.

BACKGROUND

Residual risk persists despite aggressive low-density lipoprotein cholesterol (LDL-C) reduction in patients with atherosclerotic cardiovascular (CV) disease, many of whom have atherogenic dyslipidemia (low levels of high-density lipoprotein cholesterol (HDL-C), elevated triglycerides, and small dense LDL particles).

METHODS

All study participants had established CV disease and atherogenic dyslipidemia. Participants received simvastatin (or simvastatin plus ezetimibe) at a dose sufficient to maintain LDL-C at 40 - 80 mg/dL (1.03-2.07 mmol/L) and were randomized to receive extended-release niacin or matching placebo. The primary end point is time to the first occurrence of coronary heart disease death, nonfatal myocardial infarction, ischemic stroke, hospitalization for acute coronary syndrome or symptom-driven coronary or cerebral revascularization with average follow-up of 4.1 years.

RESULTS

Between 2006 and 2010, 8,162 individuals signed consent to be screened, 4,275 began study drug run-in, and 3,414 were randomized to treatment. Mean age at entry was 64 ± 9 years, 85% were men, and 92% were white. As expected, risk factors were prevalent with 34% having diabetes; 71%, hypertension; and 81%, metabolic syndrome. Most participants had coronary artery disease (92%), whereas 11% had peripheral arterial disease; and 12%, cerebrovascular disease. Previous coronary revascularization occurred in 82%, and 54% reported a prior myocardial infarction. Among participants on a statin at entry (94%), mean baseline LDL-C was 71 mg/dL (1.84 mmol/L); mean HDL-C, 34.9 mg/dL (0.90 mmol/L); and median triglycerides, 161 mg/dL (1.82 mmol/L).

SUMMARY

AIM-HIGH enrolled a high-risk group of patients with established atherosclerotic CV disease and atherogenic dyslipidemia. This study should determine whether there is incremental clinical benefit of niacin in reducing cardiovascular events in patients who have attained optimal on-treatment levels of LDL-C with a statin.

Assessment of the validity of the frequently used lipid indices for predicting LDL peak particle diameter in a large cohort of 1955 normal and dyslipidemic subjects

OBJECTIVES

To assess the relationship between commonly used lipid indices and LDL peak particle diameter (LDL-PPD) in a large cohort of 1955 subjects.

DESIGN AND METHODS

Four statistical methods were used for comparison: correlation, concordance analysis, kappa statistics and receiver operating characteristic curve (ROC) analysis.

RESULTS

Plasma triglyceride (TG) levels, TG/HDL-C, LDL-C/apoB, total cholesterol (TC)/TG, LDL-C/TG, and TG/apoB ratios were best correlated with LDL-PPD but none of these ratios accounted for more than 45% of the variation in LDL-PPD. Moreover, across the range of the lipid indices and LDL-PPD quintiles, just under 40% of the values were concordant, with kappas varying between 0.20 and 0.25. Finally, plasma TG levels and the lipid ratios yielded areas under the ROC curve between 0.78 and 0.80.

CONCLUSIONS

The present study does not support the concept that plasma TG levels and the commonly used lipid indices may be considered as adequate surrogates for the small dense LDL phenotype. Our data also indicate that various lipid indices are not superior to plasma TG levels alone as a clinical tool for prediction of the small dense LDL phenotype.

Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial

Background

To evaluate the metabolic effects of two weight loss diets differing in macronutrient composition on features of dyslipidemia and post-prandial insulin (INS) response to a meal challenge in overweight/obese individuals.

Methods

This study was a parallel-arm randomized 4 mo weight loss trial. Adults (n = 50, 47 ± 7 y) matched on BMI (33.6 ± 0.6 kg/m², P = 0.79) consumed energy restricted diets (deficit ~500 kcal/d): PRO (1.6 g.kg^-1.d^-1 protein and < 170 g/d carbohydrate) or CHO (0.8 g.kg^-1.d^-1 protein and > 220 g/d carbohydrate) for 4 mos. Meal challenges of respective diets were utilized for determination of blood lipids and post-prandial INS and glucose response at the beginning and end of the study.

Results

There was a trend for PRO to lose more weight (-9.1% vs. -7.3%, P = 0.07) with a significant reduction in percent fat mass compared to CHO (-8.7% vs. -5.7%; P = 0.03). PRO also favored reductions in triacylglycerol (-34% vs. -14%; P < 0.05) and increases in HDL-C (+5% vs. -3%; P = 0.05); however, CHO favored reduction in LDL-C (-7% vs. +2.5%; P < 0.05). INS responses to the meal challenge were improved in PRO compared to CHO (P < 0.05) at both 1 hr (-34.3% vs. -1.0%) and 2 hr (-9.2% vs. +46.2%), an effect that remained significant after controlling for weight or fat loss (both P < 0.05).

Conclusion

A weight loss diet with moderate carbohydrate, moderate protein results in more favorable changes in body composition, dyslipidemia, and post-prandial INS response compared to a high carbohydrate, low protein diet suggesting an additional benefit beyond weight management to include augmented risk reduction for metabolic disease.

Association of low-density lipoprotein particle size and ratio of different lipoproteins and apolipoproteins with coronary heart disease

BACKGROUND

Worldwide coronary heart disease (CHD) is estimated to be the leading cause of death. Current knowledge about prevention of CHD is mainly derived from developed countries. Therefore, this study aimed to find out the association of CHD with ratios of different lipoproteins and apolipoproteins, LDL particle size, as well as different traditional risk factors in Asian Indian population in Eastern part of India.

METHODS

Case-control study of 100 patients with CHD and 98 healthy controls were age and sex matched. After clinical evaluation, blood samples were collected for biochemical assays.

RESULTS

Multivariate logistic regression analysis found apoB (OR 2.96; 95% CI 1.02-8.54), apoB/HDL-c (OR 4.14; 95% CI 1.33-12.83), nonHDL-c (OR 5.41; 95% CI 2.08-14.10), apoB/apoAI (OR 6.64; 95% CI 2.37-18.57), and LDL particle size (9.59; 95% CI 2.92-31.54) were independently associated with CHD. Area under the ROC curves derived from the model (AUROC 0.947; 95% CI 0.916-0.977) are significantly higher than any other variables.

CONCLUSIONS

Findings from the multivariate analysis, apoB, apoB/HDL-c, nonHDL-c, apoB/apoAI, and LDL particle size are potent indicators and useful for diagnosis of predisposed CHD.

Plasma lipoproteins and triacylglycerol are predictors of small, dense LDL particles

Recently published data suggest that the assessment of LDL subfraction profiles may contribute to the determination of the cardiovascular risk. In this study, we tested the ability of various metabolic parameters to estimate the presence or the preponderance of small, dense LDL particles (sdLDL). One hundred and fifty individuals attending the Outpatient Clinics of the University Hospital of Ioannina for suspected metabolic abnormalities were included in the study. Individuals were excluded if they were found to be diabetic or if they had a history of cardiovascular disease. Patients with thyroid dysfunction, liver or kidney diseases as well as those receiving drugs that may interfere with lipids or glucose metabolism were also excluded from the study. The ability of the various parameters to identify individuals with pattern B LDL phenotype or, alternatively, with measurable quantities of sdLDL particles was tested with the calculation of the areas under the ROC curves. The ratio of triglycerides to HDL-C was the best predictor of the presence of the pattern B LDL phenotype. Nevertheless, when the variable of interest was the presence of measurable quantities of sdLDL subfractions, the ratio of apoB to apoAI had the best predictive ability. In conclusion the ratios of apoB to apoAI and of triglycerides to HDL-C can reliably predict the presence of measurable quantities of sdLDL particles and of the pattern B LDL phenotype, respectively. However, since the quantitative determination of sdLDL concentrations may contribute to the determination of the cardiovascular risk, whereas the role of the LDL particle size remains controversial, apoB to apoAI ratio could provide more valuable information compared to markers that simply predict the presence of the pattern B LDL phenotype.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Does low-density lipoprotein size add to atherogenic particle number in predicting the risk of fatal myocardial infarction?

The lipoprotein-related risk of coronary artery disease is determined principally by the balance between atherogenic lipoprotein particles, i.e., the lipoprotein that contain apolipoprotein-B (apo-B), and the antiatherogenic particles, i.e., high-density lipoprotein particles that contain apo-A-I. However, there is also considerable evidence that patients with predominantly small dense low-density lipoprotein (LDL) have more adverse clinical outcomes than do those with large buoyant LDL. The AMORIS study prospectively examined the relative importance of lipoprotein lipids versus apolipoproteins on the risk of fatal myocardial infarction in a large Swedish cohort. This updated analysis includes 69,029 men and 57,167 women who were followed for a mean of 10.3 years. Our objective was to determine whether LDL size as reflected by the LDL cholesterol/apo-B ratio added significant predictive power to apo-B or the apo-B/apo-A-I ratio. Although apo-A-I added significantly to the predictive power of apo-B, categorical and continuous multivariate analyses showed that this is not the case for LDL size. The strongest single lipoprotein-related risk factor was the apo-B/apo-A-I ratio. In conclusion, these results provide further confirmation of the importance of determining apo-B and apo-A-I in routine clinical practice.

The "lipid accumulation product" performs better than the body mass index for recognizing cardiovascular risk: a population-based comparison

BACKGROUND

Body mass index (BMI, kg/m2) may not be the best marker for estimating the risk of obesity-related disease. Consistent with physiologic observations, an alternative index uses waist circumference (WC) and fasting triglycerides (TG) concentration to describe lipid overaccumulation.

METHODS

The WC (estimated population minimum 65 cm for men and 58 cm for women) and TG concentration from the third National Health and Nutrition Examination Survey (N = 9,180, statistically weighted to represent 100.05 million US adults) were used to compute a "lipid accumulation product" [LAP = (WC-65) x TG for men and (WC-58) x TG for women] and to describe the population distribution of LAP. LAP and BMI were compared as categorical variables and as log-transformed continuous variables for their ability to identify adverse levels of 11 cardiovascular risk factors.

RESULTS

Nearly half of the represented population was discordant for their quartile assignments to LAP and BMI. When 23.54 million with ordinal LAP quartile > BMI quartile were compared with 25.36 million with ordinal BMI quartile > LAP quartile (regression models adjusted for race-ethnicity and sex) the former had more adverse risk levels than the latter (p < 0.002) for seven lipid variables, uric acid concentration, heart rate, systolic and diastolic blood pressure. Further adjustment for age did not materially alter these comparisons except for blood pressures (p > 0.1). As continuous variables, LAP provided a consistently more adverse beta coefficient (slope) than BMI for nine cardiovascular risk variables (p < 0.01), but not for blood pressures (p > 0.2).

CONCLUSION

LAP (describing lipid overaccumulation) performed better than BMI (describing weight overaccumulation) for identifying US adults at cardiovascular risk. Compared to BMI, LAP might better predict the incidence of cardiovascular disease, but this hypothesis needs prospective testing.

A potential role of apolipoprotein B in the risk stratification of diabetic patients with dyslipidaemia

Diabetic dyslipidaemia is characterised by retention of atherogenic particles, which are depleted of cholesterol. Therefore, calculating or measuring LDL or VLDL cholesterol may not reflect the actual number of these atherogenic particles. We examined the potential role of apolipoprotein B in the risk stratification of Omani patients with type 2 diabetes and dyslipidaemia. Two hundred and twenty-one subjects with type 2 diabetes and 67 healthy controls were recruited. Diabetic subjects had significantly higher serum levels of triglycerides (P<0.0001), non-HDL cholesterol (P<0.0001), and total/HDL cholesterol ratio (P<0.04) and lower levels of HDL cholesterol (P<0.0001) and lipoprotein(a) compared to nondiabetic subjects. The ratio of apoB/LDL cholesterol ratio was significantly higher (P<0.002) among diabetic compared to nondiabetic subjects. Sixty percent of the diabetic subjects with abnormal apoB of >1.2g/L had an LDL cholesterol of less than 4.2 mmol/L compared to 7% of the nondiabetic subjects (sensitivity; 40% versus 93%, respectively). Furthermore, diabetic subjects with ischaemic heart disease (IHD) had significantly higher (P<0.003) apoB/non-HDL cholesterol ratio compared to those without IHD. These findings suggest that the ratios of apoB/LDL cholesterol and apoB/non-HDL cholesterol may have a role in the risk stratification of diabetic patients with dyslipidaemia.

Distribution of LDL particle size in a population-based sample of children and adolescents and relationship with other cardiovascular risk factors

BACKGROUND

Smaller, denser LDL particles are associated with an increased risk for cardiovascular diseases (CVD). In youths, data on the distribution of LDL particle size and on its association with other CVD risk factors are limited.

METHODS

We determined LDL peak particle size by nondenaturing 2%-16% gradient gel electrophoresis in a representative sample of 2249 youths 9, 13, and 16 years of age who participated in a school-based survey conducted in 1999 in the province of Quebec, Canada. Standardized clinical measurements and fasting plasma lipid, glucose, and insulin concentrations were available.

RESULTS

The LDL peak particle size distribution was gaussian. The 5th, 50th (median), and 95th percentiles by age and sex were 255.5-258.6, 262.1-263.2, and 268.1-269.5 A, respectively. The prevalence of the small, dense LDL phenotype (LDL peak particle size <or=255 A) was 10% in participants with insulin resistance syndrome (IRS), in contrast to 1% in those without IRS. In a multiple regression analysis, the association of LDL size with other CVD risk factors [apolipoprotein B, HDL-cholesterol (HDL-C), triglyceride (TG), and insulin concentrations, and body mass index] was strongest with TG and HDL-C concentrations: a 1 SD increase in log(e)-transformed TG concentration was associated with a 1.2 A reduction in LDL size, and a 1 SD increase in HDL-C was associated with a 1.1 A increase in LDL size.

CONCLUSIONS

Although the small, dense LDL phenotype is less prevalent in youths than adults, its prevalence is clearly increased in childhood IRS. Metabolic correlates of LDL size are similar in youths and adults.

Clinical significance of the physicochemical properties of LDL in type 2 diabetes

Atherosclerosis is the leading cause of death in type 2 diabetes. LDL cholesterol and atherosclerosis are related, both in healthy people and those with diabetes; however, people with diabetes are more prone to atheroma, even though their LDL cholesterol levels are similar to those in their non-diabetic peers. This is because LDL particles are modified in the presence of diabetes to become more atherogenic. These modifications include glycation in response to high plasma glucose levels; oxidative reactions mediated by increased oxidative stress; and transfer of cholesterol ester, which makes the particles smaller and denser. The latter modification is strongly associated with hypertriglyceridaemia. Oxidatively and non-oxidatively modified LDL is involved in plaque formation, and may thus contribute to the accelerated atherosclerosis. This review discusses the techniques currently used to determine the physicochemical properties of LDL, and examines the evidence that modification of these properties plays a role in the accelerated atherosclerosis associated with type 2 diabetes.

Emerging cardiovascular risk factors in subclinical hypothyroidism: lack of change after restoration of euthyroidism

Subclinical hypothyroidism (SH) is a frequent condition that may be associated with increased cardiovascular risk. There is current interest in determining the effect, if any, of substitutive therapy with l-thyroxine (L-T4) on cardiovascular risk factors in SH and, particularly, on those associated with emerging cardiovacular risk, such as apolipoprotein (apo) B, lipoprotein (Lp) (a), total homocysteine (t-Hcy), and C-reactive protein (CRP). Thus, the aim of this study was to assess the impact of euthyroidism restoration on these emerging risk factors in SH. Forty-two patients diagnosed with SH were consecutively recruited before treatment. These patients were treated with L-T4 for 3 to 6 months with the dose necessary to restore euthyroidism. Lp(a), fasting and postmethionine (n = 28) t-Hcy, and CRP did not change with substitutive therapy, regardless of the respective baseline values, and the decrease in apo B paralleled that of low-density lipoprotein (LDL) cholesterol. Similarly, no treatment effect was observed on homocysteine or CRP in patients with thyrotropin-stimulating hormone (TSH) >10 mIU/L. Monitoring of emerging risk factors did not offer additional arguments for treating patients with SH and, thus, is not justified in their clinical management.

Substitution of transdermal estradiol during oral estrogen-progestin therapy in postmenopausal women: effects on hypertriglyceridemia

OBJECTIVE

We investigated effects of changing from oral estrogen to transdermal estradiol on the lipid and lipoprotein profile of postmenopausal women who developed hypertriglyceridemia (serum concentrations exceeding 150 mg/dL) during estrogen-progestin therapy.

DESIGN

Sixty-one postmenopausal Japanese women receiving 0.625 mg of conjugated equine estrogen plus 2.5 mg of medroxyprogesterone acetate daily for 12 months had developed serum triglyceride concentrations exceeding 150 mg/dL after 12 months of treatment. Thirty-six of them, chosen randomly for study, were assigned at random to either a group that continued this oral regimen or another that changed to transdermal estradiol while continuing 2.5 mg of oral medroxyprogesterone acetate for the next 3 months (n = 18 for each). Blood lipids were compared between groups.

RESULTS

Serum concentrations of triglyceride and very-low-density lipoprotein triglyceride decreased significantly after changing to transdermal estradiol (triglyceride, from 226.0 +/- 43.9 to 110.5 +/- 44.1 mg/dL, P < 0.01). No changes were seen in concentrations of low-density lipoprotein cholesterol or high-density lipoprotein cholesterol.

CONCLUSION

Changing to transdermal estradiol may improve triglyceride metabolism in women who developed hypertriglyceridemia during oral estrogen-progestin therapy, with minimal effect on cholesterol profiles.

Effects of pioglitazone and glimepiride on glycemic control and insulin sensitivity in Mexican patients with type 2 diabetes mellitus: A multicenter, randomized, double-blind, parallel-group trial

BACKGROUND

Pioglitazone and glimepiride improve glycemic control in patients with type 2 diabetes mellitus by different mechanisms. Pioglitazone is a thiazolidinedione that reduces insulin resistance, and glimepiride is a sulfonylurea insulin secretagogue.

OBJECTIVE

The goals of this study were to compare changes in measures of glycemic control and insulin sensitivity in Mexican patients with type 2 diabetes who received pioglitazone or glimepiride for 1 year.

METHODS

This was a multicenter, 52-week, double-blind, parallel-group trial. Patients were randomized to receive monotherapy with either glimepiride (2 mg QD initially) or pioglitazone (15 mg QD initially). Doses were titrated (maximal doses: pioglitazone 45 mg, glimepiride 8 mg) to achieve glycemic targets (fasting blood glucose < or =7 mmol/L and 1-hour postprandial blood glucose < or =10 mmol/L). Insulin sensitivity (primary end point) was evaluated in terms of the Homeostasis Model Assessment for Insulin Sensitivity (HOMA-S), the Quantitative Insulin Sensitivity Check Index (QUICKI), and fasting serum insulin (FSI) concentrations. Glycemic control was evaluated in terms of glycosylated hemoglobin (HbA(1c)) values and fasting plasma glucose (FPG) concentrations. Patients were encouraged to maintain their individual diet and exercise regimens throughout the study.

RESULTS

Two hundred forty-four patients (125 women, 119 men; all but 1 Hispanic) were randomized to receive pioglitazone (n = 121) or glimepiride (n = 123). In the intent-to-treat sample, pioglitazone and glimepirede produced comparable reductions in HbA(1c) from baseline to the end of the study (-0.78% and -0.68%, respectively). The pioglitazone group had significantly higher HbA(1c) values compared with the glimepiride group after 12 weeks of therapy (8.66% vs 7.80%; P = 0.007) but had significantly lower values after 52 weeks (7.46% vs 7.77%; P = 0.027). Pioglitazone significantly reduced FPG compared with glimepiride (-0.6 vs 0.6 mmol/L; P = 0.01). Pioglitazone therapy was associated with significant increases in insulin sensitivity (reduced insulin resistance), whereas glimepiride had no effect. HOMA-S values changed 18.0% for pioglitazone and -7.9% for glimepiride (P < 0.001), QUICKI values changed a respective 0.013 and -0.007 (P < 0.001), and FSI values were -21.1 and 15.1 pmol/L (P< 0.001). Both drugs were well tolerated, with pioglitazone associated with more peripheral edema (number of treatment-emergent cases: 35/121[28.9%] vs 17/123 [13.8%]; P = 0.005) and fewer hypoglycemic episodes (19 [15.7%] vs 38 [30.9%]; P = 0.024). The incidence of weight gain was not significantly different between treatment groups.

CONCLUSIONS

These data suggest that long-term treatment with pioglitazone enhances insulin sensitivity relative to glimepiride in Mexican patients with type 2 diabetes and that pioglitazone may have a more sustained antihyperglycemic effect.

Effect of improving glycemic control on low-density lipoprotein particle size in type 2 diabetes

The current study sought to assess the effect of improving glycemic control in type 2 diabetes on the components of diabetic dyslipidemia, especially low-density lipoprotein (LDL) size. A total of 33 type 2 diabetic patients (48.5% women, age 59.6 +/- 11.1 years, body mass index [BMI] 28.9 +/- 4.9, diabetes duration 6 [0 to 40] years, 40.7% on insulin) were seen at the hospital because of poor glycemic control (hemoglobin A(1c) [HbA(1c)] 10.33% +/- 1.89%). Triglyceride, LDL-cholesterol (LDLc, Friedewald/ ultracentrifugation), high-density lipoprotein HDL-cholesterol (HDLc, direct method), apolipoproteins AI (apoAI) and B (apoB) (immunoturbidimetry), and LDL size (gradient gel electrophoresis) were measured at baseline and after improvement in glycemic control (decrease >/= 1 percentage point in HbA(1c) and final HbA(1c) </= 8%). Improvement in glycemic control (HbA(1c) 7.01% +/- 0.63%, P <.0005 v baseline) after a follow-up of 3.5 (range, 1 to 13) months resulted in a significant reduction in LDLc (3.34 +/- 1.02 v 3.62 +/- 1.15 mmol/L, P <.05) and apoB (1.07 +/- 0.25 v 1.17 +/- 0.29 g/L, P <.01) and an increase in HDLc (1.21 +/- 0.32 v 1.13 +/- 0.34 mmol/L, P <.05) and apoAI (1.36 +/- 0.24 v 1.27 +/- 0.24 mmol/L, P < 0.01) in the whole group, and an increase in LDL particle size (25.61 +/- 0.53 v 25.10 +/- 0.31 nm, P <.005) in the 14 patients showing LDL phenotype B at baseline. No significant changes were seen in body weight or BMI. We conclude that improvement of glycemic control in type 2 diabetes improves most of the components of diabetic dyslipidemia, including a shift towards larger LDL particles in subjects with phenotype B.

Postprandial lipidemia is normal in non-obese type 2 diabetic patients with relatively preserved insulin secretion

To assess postprandial lipidemia in normotriglyceridaemic type 2 diabetic patients treated with diet only, 12 non-obese patients (8 males, hemoglobin A(1c) [HbA(1c)] 6.80 +/- 0.67%) and 14 controls of similar age, body mass index (BMI), and fasting triglyceride (Tg) were given a test meal (58 g fat, 100,000 IU vitamin A). Fasting low-density lipoprotein (LDL) cholesterol (LDLc), high-density lipoprotein (HDL) cholesterol (HDLc), free fatty acids, and apolipoprotein B (apoB), and fasting and postprandial Tg, retinylpalmitate (RP), LDL size, glucose, and insulin were measured. The homeostasis assessment model (HOMA) index and lipoprotein (Lpl) and hepatic (HL) lipase activities were estimated. Patients showed lower fasting HDLc (1.12 +/- 0.26 v 1.40 +/- 0.28 mmol/L, P =.02) and a trend towards smaller LDL particles, which was significant 4 hours postprandially (25.86 +/- 0.40 v 26.16 +/- 0.30 nm, P =.04). The area under the curve of Tg (AUC-Tg) and RP, and Lpl were similar, but HL was higher in patients (156.63 +/- 23.89 v 118 +/- 43.27 U/L, P =.011). HL correlated inversely with LDL size and directly with the HOMA index. In conclusion, normotriglyceridemic type 2 diabetic patients with insulin resistance but relatively preserved insulin secretion show low fasting HDLc and increased HL, but normal postprandial lipidemia.

Non-HDL cholesterol and apolipoprotein B in the dyslipidemic classification of type 2 diabetic patients

OBJECTIVE

To compare non-HDL cholesterol (HDLc) and apolipoprotein B (apoB) in the identification of nonconventional high-risk dyslipidemic phenotypes in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Total cholesterol and triglycerides, HDLc, LDL cholesterol, non-HDLc, apolipoprotein B (apoB), and LDL size were determined in 122 type 2 diabetic patients (68% male, aged 59.6 +/- 9.7 years, and HbA(1c) 7.5% [range 5.2-16.0]). They were then classified as normo- and hypertriglyceridemic if their triglyceride concentrations were below/above 2.25 mmol/l, as normo/hyper-non-HDLc if non-HDLc concentrations were below/above 4.13 mmol/l, and as normo- and hyperapoB if apoB concentrations were below/above 0.97 g/l. Both classifications were compared (concordance assessed with the kappa index), and low HDLc and LDL phenotype B were identified in each category.

RESULTS

A total of 26 patients were hypertriglyceridemic and 96 were normotriglyceridemic. All hypertriglyceridemic subjects had increased non-HDLc, whereas 24 had increased apoB (kappa= 0.95). In the normotriglyceridemic group, 44 had increased non-HDLc, 68 had increased apoB, and 25 of the 52 patients with normal non-HDLc had increased apoB (kappa= 0.587). Low HDLc and LDL phenotype B were similarly distributed into the equivalent categories.

CONCLUSIONS

Non-HDLc and apoB are equivalent risk markers in hypertriglyceridemic patients, but apoB identifies additional patients with high-risk dyslipidemic phenotypes in normotriglyceridemic type 2 diabetic patients.