The joint effects of apolipoprotein B, apolipoprotein A1, LDL cholesterol, and HDL cholesterol on risk: 3510 cases of acute myocardial infarction and 9805 controls

Effects of ezetimibe/simvastatin 10/20 mg vs. atorvastatin 20 mg on apolipoprotein B/apolipoprotein A1 in Korean patients with type 2 diabetes mellitus: results of a randomized controlled trial

BACKGROUND

Although the efficacy of ezetimibe/simvastatin and atorvastatin on traditional lipid parameters has been studied extensively, the apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) ratio, which has a better predictive value for cardiovascular events, has not previously been used as a primary endpoint in these two treatment groups.

OBJECTIVE

Our objective was to compare the efficacy and safety of ezetimibe/simvastatin 10/20 mg versus atorvastatin 20 mg once daily in Korean patients with type 2 diabetes mellitus.

STUDY DESIGN

This study was an open-label, randomized, controlled study. Type 2 diabetes patients with high levels of low-density lipoprotein (LDL) cholesterol (>100 mg/dL) were randomized to receive ezetimibe/simvastatin or atorvastatin.

MAIN OUTCOME MEASURE

The primary endpoint was the difference in the percent change of ApoB/ApoA1 at 12 weeks, and secondary endpoints were changes in lipid profiles, glycosylated hemoglobin (HbA1c), homeostatic model assessment (HOMA) index, and C-reactive protein.

RESULTS

In total, 132 patients (66 for each group) were enrolled and randomized. After 12 weeks of treatment, the ApoB/ApoA1 ratio was significantly reduced in both groups; however, the difference of changes between the two groups was not statistically significant (ezetimibe/simvastatin -38.6 ± 18.0 % vs. atorvastatin -34.4 ± 15.5 %; p = 0.059). There were no significant differences in changes to total cholesterol, LDL cholesterol, high-density lipoprotein cholesterol, triglycerides, ApoB, and ApoB48 between the two groups. However, the increments of ApoA1 were significantly greater in the ezetimibe/simvastatin group than in the atorvastatin group (2.8 ± 10.0 vs. -1.8 ± 9.8 %; p = 0.002). In the per-protocol analysis, improvement in ApoB/ApoA1 was significantly greater in the ezetimibe/simvastatin group (-42.8 ± 11.8 vs. -36.7 ± 13.2 %; p = 0.019). The changes in HbA1c, HOMA index, and C-reactive protein were comparable between the two groups. The adverse reaction rate was similar between the two groups (24.2 vs. 34.9 %; p = 0.180).

CONCLUSION

Ezetimibe/simvastatin 10/20 mg is comparable to atorvastatin 20 mg for the management of dyslipidemia, and may have more favorable effects on apolipoprotein profiles than atorvastatin 20 mg in Korean patients with type 2 diabetes mellitus.

Non-HDL cholesterol vs. apo B for risk of coronary heart disease in healthy individuals: the EPIC-Norfolk prospective population study

BACKGROUND

There is an ongoing debate about the performance of non-high-density lipoprotein cholesterol (non-HDL-C) compared with apolipoprotein B (apo B) in the prediction of coronary heart disease (CHD) risk. Therefore, we compared the associations between non-HDL-C and apo B in regard to CHD among apparently healthy Western European individuals.

DESIGN

In the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk prospective population study, 25,639 men and women aged 45-79 years were followed for 11·4 ± 2·8 years. Those with diabetes or prevalent CHD at baseline were excluded. A total of 2066 (12·1%) participants developed CHD during 195 692 person-years follow-up.

RESULTS

The multivariable-adjusted hazard ratio [HR] of future CHD per one standard deviation increase was 1·22 [95% confidence interval (CI): 1·17-1·27] for LDL-C, 1·26 (95% CI 1·20-1·31) for non-HDL-C and 1·19 (95% CI 1·14-1·24) for apo B, respectively. The multivariable-adjusted HR of future CHD in the highest quartile LDL-C was 1·67 (95% CI: 1·47-1·91). For non-HDL-C and apo B, these respective HRs were 1·87 (95% CI: 1·62-2·15) and 1·56 (95% CI: 1·36-1·78). Kaplan-Meier survival analyses showed that there was incremental and comparable increase in risk of CHD with increasing quartiles of both non-HDL-C and apo B.

CONCLUSIONS

In this prospective study, non-HDL-C and apo B were comparable in their ability to predict risk of future CHD.

Associations between smoking, components of metabolic syndrome and lipoprotein particle size

BACKGROUND

The clustering of metabolic and cardiovascular risk factors is known as metabolic syndrome (MetS). The risk of having MetS is strongly associated with increased adiposity and can be further modified by smoking behavior. Apolipoproteins (apo) associated with low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) may be altered in MetS. This study aimed to examine the association between smoking and the following parameters: MetS and its components, levels of apolipoproteins and estimated lipoprotein particle size, separately for men and women, and in different body mass index (BMI) classes.

METHODS

We included 24,389 men and 35,078 women aged between 18 and 80 years who participated in the LifeLines Cohort Study between December 2006 and January 2012; 5,685 men and 6,989 women were current smokers. Participants were categorized into three different body mass index (BMI) classes (BMI <25; BMI 25 to 30; BMI ≥30 kg/m²). MetS was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (NCEP:ATPIII) criteria. Blood pressure, anthropometric and lipid measurements were rigorously standardized, and the large sample size enabled a powerful estimate of quantitative changes. The association between smoking and the individual MetS components, and apoA1 and apoB, was tested with linear regression. Logistic regression was used to examine the effect of smoking and daily tobacco smoked on risk of having MetS. All models were age adjusted and stratified by sex and BMI class.

RESULTS

Prevalence of MetS increased with higher BMI levels. A total of 64% of obese men and 42% of obese women had MetS. Current smoking was associated with a higher risk of MetS in both sexes and all BMI classes (odds ratio 1.7 to 2.4 for men, 1.8 to 2.3 for women, all P values <0.001). Current smokers had lower levels of HDL cholesterol and apoA1, higher levels of triglycerides and apoB, and higher waist circumference than non-smokers (all P <0.001). Smoking had no consistent association with blood pressure or fasting blood glucose. In all BMI classes, we found a dose-dependent association of daily tobacco consumption with MetS prevalence as well as with lower levels of HDL cholesterol, higher triglyceride levels and lower ratios of HDL cholesterol/apoA1 and, only in those with BMI <30, LDL cholesterol/apoB (all P <0.001).

CONCLUSIONS

Smoking is associated with an increased prevalence of MetS, independent of sex and BMI class. This increased risk is mainly related to lower HDL cholesterol, and higher triglycerides and waist circumference. In addition, smoking was associated with unfavorable changes in apoA1 and apoB, and in lipoprotein particle size. Please see related commentary: http://www.biomedcentral.com/1741-7015/11/196.

ApoB/apoA1 is an effective predictor of coronary heart disease risk in overweight and obesity

We investigated the relationship of apoB/apoA1 ratio and coronary heart disease (CHD) in persons who were overweight or obese. The subjects were divided by the body mass indexes (BMI) into the normal weight group (n=397, BMI<24 kg/m(2)) and the overweight group (n=400, BMI>24 kg/m(2)). Our results showed that the over-weight group had higher blood pressure [(130.15±19.01) mmHg vs (123.66±18.70) mmHg] and higher levels of blood sugar [(7.09±2.89) mmol/L vs (6.21±2.59) mmol/L], triglyceride [(1.93±1.19) mmol/L vs (1.44±0.85) mmol/L], total cholesterol [(4.26±1.06) mmol/L vs (4.09±0.99) mmol/L], low-density lipoprotein cholesterol (LDL-C) [(2.56±0.75) mmol/L vs (2.39±0.72) mmol/L], and apoB [(0.83±0.27) mg/L vs (0.78±0.23) mg/L], and a higher apoB/apoA1 ratio (0.83±0.27 vs 0.75±0.25) and lower levels high-density lipoprotein cholesterol [(1.10±0.26) mmol/L vs (1.21±0.31) mmol/L] and apoA1 [(1.04±0.20) mg/L vs (1.08±0.22) mg/L] than those of the normal weight group (all P < 0.05). The prevalence of CHD in the over-weight group in the lowest LDL quartile was almost twice greater than that of the highest apoB/apoA1 quartile, compared with the subjects in the lowest apoB/apoA1 quartile. The higher apoB/apoA1 quartile was in agreement with the higher prevalence of CHD. In the overweight and obesity group, the area under ROC curve (AUC) was the highest for apoB/apoA1 (0.655). The cut-off point of apoB/apoA1 for optimal sensitivity and specificity was at 0.80, with a sensitivity of 57.19% and a specificity of 71.72%. In conclusion, apoB and apoA1 were simple clinical indicators, and the apoB/apoA1 ratio was closely related with CHD in overweight and obese patients. The apoB/apoA1 ratio may provide some useful information in the differential diagnosis.

Coronary heart disease incidence in women by waist circumference within categories of body mass index

High body mass index (BMI) and large waist circumference are separately associated with increased coronary heart disease (CHD) risk but these measures are highly correlated. Their separate associations with incident CHD, cross-classifying one variable by the other, are less investigated in large-scale studies. We examined these associations in a large UK cohort (the Million Women Study), which is a prospective population-based study. We followed 496,225 women (mean age 60 years) with both waist circumference and BMI measurements who had no vascular disease or cancer. Adjusted relative risk and 20-year cumulative CHD incidence (first coronary hospitalization or death) from age 55 to 74 years were calculated using Cox regression. Plasma apolipoproteins were assayed in 6295 randomly selected participants. There were 10,998 incident coronary events after mean follow up of 5.1 years. Within each BMI category (<25, 25-29.9, ≥30 kg/m(2)), CHD risk increased with increasing waist circumference; within each waist circumference category (<70, 70-79.9, ≥79 cm), CHD risk increased with increasing BMI. The cumulative CHD incidence was lowest in women with BMI <25 kg/m(2) and waist circumference <70 cm, with 1 in 14 (95% confidence interval 1 in 12 to 16) women developing CHD in the 20 years from age 55 to 74 years, and highest in women with BMI ≥30 kg/m(2) and waist circumference ≥80 cm, with 1 in 8 (95% confidence interval 1 in 7 to 9) women developing CHD over the same period. Similar associations for apolipoprotein B to A1 ratio across adiposity categories were observed, particularly in non-obese women. Our conclusions were that both waist circumference and BMI are independently associated with incident CHD.

Establishing cut-off values for apolipoprotein B and non-HDL-C according to LDL-C values in a South European population

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) remains the primary target of therapy in most strategies of dyslipidaemia management focused on cardiovascular disease prevention. Different guidelines have identified specific LDL-C cut-off points as targets for therapeutic intervention. Many clinical situations characterised by dyslipidaemia and elevated triglycerides are common in our environment and in overall industrialised countries. Thus, lipid goals based only on LDL-C could misclassify an important percentage of subjects. The objective of the present study was to establish cut-off point values for apoB and non-HDL-C in relation to the identified LDL-C cut-off points for cardiovascular risk in a South European population.

METHODS

We performed a cross-sectional study including 1501 subjects (770 women and 731 men) between 18 and 80 years of age. Samples were collected after 12-14 h of fasting. Cholesterol, HDL-C, triglycerides and apoB levels were measured using direct methods. LDL-C was calculated by the Friedewald formula. Non-HDL-C was calculated as total cholesterol minus HDL-C.

RESULTS

The Spearman's rank correlations between apoB and LDL-C (r 0.86, p < 0.0001), and between apoB and non-HDL-C (r 0.91, p < 0.0001) were both significant. The proposed cut-off points for apoB, according to LDL-C goals (70, 100, 130 and 160 mg/dl) in our population are 70, 80, 100 and 115 mg/dl respectively. The proposed cut-off values for non-HDL-C are 100, 120, 150 and 190 mg/dl respectively.

CONCLUSION

The established LDL-C cut-off values could not be accurate to estimate cardiovascular risk in subjects with mild hypertriglyceridaemia, as frequently occurs in our Mediterranean population. To take into consideration the burden of atherogenic particles and better classify patients at risk we propose cut-off values for apoB or the equivalent for non-HDL-C. Prospective trials including cardiovascular variables are needed to validate our assumption.

Identification of the HDL-ApoCIII to VLDL-ApoCIII ratio as a predictor of coronary artery disease in the general population: the Chin-Shan Community Cardiovascular Cohort (CCCC) study in Taiwan

Background

Apolipoprotein (Apo) levels are considered more reliable than plasma lipoprotein levels for predicting coronary artery disease (CAD). However, a unanimous Apo marker for CAD has not been identified. In the Chin-Shan Community Cardiovascular Cohort (CCCC), we sought to identify a common Apo marker for predicting CAD in the general population.

Methods

We examined the cross-sectional association between Apo markers and CAD in the CCCC from 1990 to 2001. Among 3,602 subjects, 90 had angiographically proven CAD (>50% stenosis in ≥1 vessel), and 200 did not have CAD. These subjects were divided into the following 4 groups for analysis: normolipidemic (total cholesterol [TC] <200 mg/dL, triglyceride [TG] <150 mg/dL), hypertriglyceridemic (TC <200 mg/dL, TG ≥150 mg/dL), hypercholesterolemic (TC ≥200 mg/dL, TG <150 mg/dL), and hyperlipidemic (TC ≥200 mg/dL, TG ≥150 mg/dL).

Results

Compatible with findings in other populations, our results showed that CAD patients in the CCCC had higher ApoB and lower high-density lipoprotein (HDL) cholesterol and ApoAI concentrations than non-CAD subjects, but the differences were not significant in all groups. Plasma concentrations of ApoE and lipoprotein (a) were not consistently correlated with CAD. In contrast, the ratio of HDL-ApoCIII to very-low-density lipoprotein (VLDL)-ApoCIII was the only universal determinant for CAD in the normolipidemic group (P=0.0018), the hypertriglyceridemic group (P=0.0001), the hypercholesterolemic group (P=0.0001), and the hyperlipidemic group (P=0.0001). Overall, a high HDL-ApoCIII/VLDL-ApoCIII ratio was observed in all CAD patients, including those with a normal lipid profile. In multivariate analyses, the HDL-ApoCIII/VLDL-ApoCIII ratio was the strongest predictor for CAD among all lipid factors investigated (odds ratio, 2.04; 95% confidence interval, 1.46–2.84; P<0.0001).

Conclusions

A high HDL-ApoCIII to VLDL-ApoCIII ratio is a better marker for predicting CAD than are the conventional lipid markers or ApoAI and ApoB. High HDL-ApoCIII and low VLDL-ApoCIII values in CAD, irrespective of lipid variations, suggest that ApoCIII is markedly transported from VLDL to HDL in this disease. Measurement of plasma ApoCIII may improve CAD prediction in the general population.

Lipid-related markers and cardiovascular disease prediction

CONTEXT

The value of assessing various emerging lipid-related markers for prediction of first cardiovascular events is debated.

OBJECTIVE

To determine whether adding information on apolipoprotein B and apolipoprotein A-I, lipoprotein(a), or lipoprotein-associated phospholipase A2 to total cholesterol and high-density lipoprotein cholesterol (HDL-C) improves cardiovascular disease (CVD) risk prediction.

DESIGN, SETTING, AND PARTICIPANTS

Individual records were available for 165,544 participants without baseline CVD in 37 prospective cohorts (calendar years of recruitment: 1968-2007) with up to 15,126 incident fatal or nonfatal CVD outcomes (10,132 CHD and 4994 stroke outcomes) during a median follow-up of 10.4 years (interquartile range, 7.6-14 years).

MAIN OUTCOME MEASURES

Discrimination of CVD outcomes and reclassification of participants across predicted 10-year risk categories of low (<10%), intermediate (10%-<20%), and high (≥20%) risk.

RESULTS

The addition of information on various lipid-related markers to total cholesterol, HDL-C, and other conventional risk factors yielded improvement in the model's discrimination: C-index change, 0.0006 (95% CI, 0.0002-0.0009) for the combination of apolipoprotein B and A-I; 0.0016 (95% CI, 0.0009-0.0023) for lipoprotein(a); and 0.0018 (95% CI, 0.0010-0.0026) for lipoprotein-associated phospholipase A2 mass. Net reclassification improvements were less than 1% with the addition of each of these markers to risk scores containing conventional risk factors. We estimated that for 100,000 adults aged 40 years or older, 15,436 would be initially classified at intermediate risk using conventional risk factors alone. Additional testing with a combination of apolipoprotein B and A-I would reclassify 1.1%; lipoprotein(a), 4.1%; and lipoprotein-associated phospholipase A2 mass, 2.7% of people to a 20% or higher predicted CVD risk category and, therefore, in need of statin treatment under Adult Treatment Panel III guidelines.

CONCLUSION

In a study of individuals without known CVD, the addition of information on the combination of apolipoprotein B and A-I, lipoprotein(a), or lipoprotein-associated phospholipase A2 mass to risk scores containing total cholesterol and HDL-C led to slight improvement in CVD prediction.

Lipids and lipoproteins and risk of different vascular events in the MRC/BHF Heart Protection Study

BACKGROUND

Low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol are established risk factors for vascular disease, but lipoprotein particle concentrations may be stronger determinants of risk.

METHODS AND RESULTS

Associations between vascular events and baseline concentrations of cholesterol fractions, apolipoproteins B and A(1), and lipoprotein particles assessed by nuclear magnetic resonance were considered in the Heart Protection Study randomized trial of simvastatin versus placebo (>5000 vascular events during 5.3 years of follow-up among 20 000 participants). Major occlusive coronary events were equally strongly associated with the cholesterol- and particle-based total LDL measures; adjusted hazard ratios per 1-SD-higher level were 1.25 (95% confidence interval [CI], 1.16-1.34) for LDL cholesterol, 1.22 (95% CI, 1.14-1.32) for non-HDL cholesterol, 1.23 (95% CI, 1.15-1.33) for apolipoprotein B, and 1.25 (95% CI, 1.16-1.35) for LDL particle number. Given the total LDL particle number, the distribution between small and large particles did not add predictive value. Associations of these different LDL-related measures were similar with arterial revascularization procedures but much weaker or nonexistent with ischemic stroke and other cardiac events (mainly heart failure). After adjustment for LDL particle number, the hazard ratios for major occlusive coronary event per 1-SD-higher level were 0.91 (95% CI, 0.86-0.96) for HDL cholesterol and 0.89 (95% CI, 0.85-0.93) for HDL particle number. Other cardiac events were inversely associated with total (hazard ratio, 0.84; 95% CI, 0.79-0.90) and small (0.82; 95% CI, 0.76-0.89) HDL particle number but only very weakly associated with HDL cholesterol (0.94; 95% CI, 0.88-1.00).

CONCLUSIONS

In a population at 2% average coronary event risk per year, cholesterol, apolipoprotein, and particle measures of LDL were strongly correlated and had similar predictive values for incident major occlusive vascular events. It is unclear whether the associations between HDL particle numbers and other cardiac events represent a causal or reverse-causal effect.

Clinical utility of inflammatory markers and advanced lipoprotein testing: advice from an expert panel of lipid specialists

The National Cholesterol Education Program Adult Treatment Panel guidelines have established low-density lipoprotein cholesterol (LDL-C) treatment goals, and secondary non-high-density lipoprotein (HDL)-C treatment goals for persons with hypertriglyceridemia. The use of lipid-lowering therapies, particularly statins, to achieve these goals has reduced cardiovascular disease (CVD) morbidity and mortality; however, significant residual risk for events remains. This, combined with the rising prevalence of obesity, which has shifted the risk profile of the population toward patients in whom LDL-C is less predictive of CVD events (metabolic syndrome, low HDL-C, elevated triglycerides), has increased interest in the clinical use of inflammatory and lipid biomarker assessments. Furthermore, the cost effectiveness of pharmacological intervention for both the initiation of therapy and the intensification of therapy has been enhanced by the availability of a variety of generic statins. This report describes the consensus view of an expert panel convened by the National Lipid Association to evaluate the use of selected biomarkers [C-reactive protein, lipoprotein-associated phospholipase A(2), apolipoprotein B, LDL particle concentration, lipoprotein(a), and LDL and HDL subfractions] to improve risk assessment, or to adjust therapy. These panel recommendations are intended to provide practical advice to clinicians who wrestle with the challenges of identifying the patients who are most likely to benefit from therapy, or intensification of therapy, to provide the optimum protection from CV risk.

Opening a new lipid "apo-thecary": incorporating apolipoproteins as potential risk factors and treatment targets to reduce cardiovascular risk

Statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) represent the cornerstone of drug therapy to reduce low-density lipoprotein (LDL) cholesterol and cardiovascular risk. However, even optimal statin management of LDL cholesterol leaves many patients with residual cardiovascular risk, in part because statins are more effective in reducing LDL cholesterol than apolipoprotein B (Apo B). Apo B may be a better marker of atherogenic risk than LDL cholesterol because Apo B measures the total number of all atherogenic particles (total atherosclerotic burden), including LDL, very low-density lipoprotein, intermediate-density lipoprotein, remnant lipoproteins, and lipoprotein(a). To determine whether Apo B is a better indicator of baseline cardiovascular risk and residual risk after lipid therapy compared with LDL cholesterol, a MEDLINE search of the literature published in English from January 1, 1975, through December 1, 2010, was conducted. On the basis of data from most population studies, elevated Apo B was more strongly associated with incident coronary heart disease than similarly elevated LDL cholesterol. Apo B was also a superior benchmark (vs LDL cholesterol) of statins' cardioprotective efficacy in both primary-prevention and secondary-prevention trials. To minimize cardiovascular risk among persons with hypercholesterolemia or dyslipidemia, the best available evidence suggests that intensive therapy with statins should be initiated to achieve the lowest possible Apo B level (with adequate drug toleration) and then other therapies (eg, niacin, bile acid resins, ezetimibe) added to potentiate these Apo B-lowering effects. In future consensus lipid-lowering treatment guidelines, Apo B should be considered as an index of residual risk, a potential parameter of treatment efficacy, and a treatment target to minimize risk of coronary heart disease.

How Do Apolipoproteins ApoB and ApoA-I Perform in Patients with Acute Coronary Syndromes

Acute coronary syndromes are the leading cause of hospitalization and death. Results from recent studies suggest that apolipoprotein measurement and apoB:apoA-I are superior to traditional lipids in the estimation of coronary risk. We compared apolipoprotein concentrations and apoB:apoA-I with traditional lipid measures and atherogenic indices in patients diagnosed with acute coronary syndromes (ACS) within 6 hrs from the onset of chest pain. A study group consisted of 227 patients diagnosed with ACS (STEMI=60, NSTEMI=66 and UA=105). Clinically healthy volunteers (n=85) served as controls. Measurements of cardiac TnI, lipid profile, hsCRP, apolipoprotein A-I and apoB100 were performed and apoB:apoA-I, TC-HDL-C, LDL-C:HDL-C ratios were calculated. Patients had increased LDL-C (>3.0 mmol/L) and non-HDL-C (>3.4 mmol/L). Triglycerides were below the cut-off value, but patients had significantly higher TG concentrations and lower HDL-C compared to controls (p<0.001). Apo B and apoA-I concentration in patients remained within the accepted range. Atherogenic indices TC:HDL-C, LDL-C:HDL-C and apoB:apoA-I were significantly increased in patients. ApoB:apoA-I ratio in ACS males was within low risk whereas in females corresponded to medium risk. ApoB:apoA-I and LDL-C:HDL-C ratios were of good diagnostic utility for discrimination between patients and controls (AUC 0.71 and 0.79; respectively). ApoB:apoA-I and LDL-C:HDL-C were of very good diagnostic utility for discrimination between STEMI patients and controls (AUC 0.80 and 0.84). We could not show the superiority of apoB:apoA-I over LDL-C:HDL-C as the discrimination power of both was almost identical. Determination of apolipoproteins should not be recommended for routine clinical use, however, incorporating apoB and apoB:apoA-I into risk assessment could provide additional important information on cardiovascular risk.

Comparisons of apolipoprotein B levels estimated by immunoassay, nuclear magnetic resonance, vertical auto profile, and non-high-density lipoprotein cholesterol in subjects with hypertriglyceridemia (SAFARI Trial)

Low-density lipoprotein (LDL) cholesterol and triglyceride-rich lipoproteins constitute non-high-density lipoprotein (non-HDL) cholesterol. These are atherogenic lipoproteins and non-HDL cholesterol is a secondary target of treatment beyond LDL cholesterol in patients with hypertriglyceridemia. Some investigators favor total apolipoprotein B over non-HDL cholesterol as the secondary target of treatment. This is based on publications suggesting that total apolipoprotein B is more predictive of cardiovascular events than non-HDL cholesterol. Several methods are available for estimating total apolipoprotein B. This study compared total apolipoprotein estimated by immunonephelometric assay (INA), vertical auto profile (VAP), nuclear magnetic resonance (NMR), and non-HDL cholesterol levels in patients with hypertriglyceridemia from the previously reported Simvastatin plus Fenofibrate for Combined Hyperlipidemia (SAFARI) trial. Total apolipoprotein B levels were found to be highest by INA, intermediate by NMR and non-HDL cholesterol, and lowest by VAP. Concordance for non-HDL cholesterol levels among the INA, VAP, and NMR methods was better than that for total apolipoprotein B levels; the correlation between non-HDL cholesterol and apolipoprotein B by INA was strongest (0.929). In patients with a low triglyceride/HDL cholesterol ratio (<3.5), total apolipoprotein B determined by INA was higher than that estimated from non-HDL cholesterol levels, whereas in patients with a high triglyceride/HDL C ratio (≥3.5), apolipoprotein B predicted using non-HDL cholesterol was in better agreement with INA-determined apolipoprotein B levels. Similar trends were observed with VAP using equations specific for LDL particle size. In conclusion, more work is needed to improve agreement of apolipoprotein B measurements among methods employed clinically. Non-HDL cholesterol is also useful to predict total apolipoprotein B and some improvement may be attained by taking into account the ratio of triglyceride/HDL cholesterol as a measurement of LDL particle size.

Primary prevention of coronary heart disease: integration of new data, evolving views, revised goals, and role of rosuvastatin in management. A comprehensive survey

A recent explosion in the amount of cardiovascular risk and incipient, undetected subclinical cardiovascular pathology has swept across the globe. Nearly 70% of adult Americans are overweight or obese; the prevalence of visceral obesity stands at 53% and continues to rise. At any one time, 55% of the population is on a weight-loss diet, and almost all fail. Fewer than 15% of adults or children exercise sufficiently, and over 60% engage in no vigorous activity. Among adults, 11%-13% have diabetes, 34% have hypertension, 36% have prehypertension, 36% have prediabetes, 12% have both prediabetes and prehypertension, and 15% of the population with either diabetes, hypertension, or dyslipidemia are undiagnosed. About one-third of the adult population, and 80% of the obese, have fatty livers. With 34% of children overweight or obese, prevalence having doubled in just a few years, type 2 diabetes, hypertension, dyslipidemia, and fatty livers in children are at their highest levels ever. Half of adults have at least one cardiovascular risk factor. Not even 1% of the population attains ideal cardiovascular health. Despite falling coronary death rates for decades, coronary heart disease (CHD) death rates in US women 35 to 54 years of age may now be increasing because of the obesity epidemic. Up to 65% of patients do not have their conventional risk biomarkers under control. Only 30% of high risk patients with CHD achieve aggressive low density lipoprotein (LDL) targets. Of those patients with multiple risk factors, fewer than 10% have all of them adequately controlled. Even when patients are titrated to evidence-based targets, about 70% of cardiac events remain unaddressed. Undertreatment is also common. About two-thirds of high risk primary care patients are not taking needed medications for dyslipidemia. Poor patient adherence, typically below 50%, adds further difficulty. Hence, after all such fractional reductions are multiplied, only a modest portion of total cardiovascular risk burden is actually being eliminated, and the full potential of risk reduction remains unrealized. Worldwide the situation is similar, with the prevalence of metabolic syndrome approaching 50%. Primordial prevention, resulting from healthful lifestyle habits that do not permit the appearance of risk factors, is the preferred method to lower cardiovascular risk. Lowering the prevalence of obesity is the most urgent matter, and is pleiotropic since it affects blood pressure, lipid profiles, glucose metabolism, inflammation, and atherothrombotic disease progression. Physical activity also improves several risk factors, with the additional potential to lower heart rate. Given the current obstacles, success of primordial prevention remains uncertain. At the same time, the consequences of delay and inaction will inevitably be disastrous, and the sense of urgency mounts. Since most CHD events arise in a large subpopulation of low- to moderate-risk individuals, identifying a high proportion of those who will go on to develop events with accuracy remains unlikely. Without a refinement in risk prediction, the current model of targeting high-risk individuals for aggressive therapy may not succeed alone, especially given the rising burden of risk. Estimating cardiovascular risk over a period of 10 years, using scoring systems such as Framingham or SCORE, continues to enjoy widespread use and is recommended for all adults. Limitations in the former have been of concern, including the under- or over-estimation of risk in specific populations, a relatively short 10-year risk horizon, focus on myocardial infarction and CHD death, and exclusion of family history. Classification errors may occur in up to 37% of individuals, particularly women and the young. Several different scoring systems are discussed in this review. The use of lifetime risk is an important conceptual advance, since ≥90% of young adults with a low 10-year risk have a lifetime risk of ≥39%; over half of all American adults have a low 10-year risk but a high lifetime risk. At age 50 the absence of traditional risk factors is associated with extremely low lifetime risk and significantly greater longevity. Pathological and epidemiological data confirm that atherosclerosis begins in early childhood, and advances seamlessly and inexorably throughout life. Risk factors in childhood are similar to those in adults, and track between stages of life. When indicated, aggressive treatment should begin at the earliest indication, and be continued for years. For those patients at intermediate risk according to global risk scores, C-reactive protein (CRP), coronary artery calcium (CAC), and carotid intima-media thickness (CIMT) are available for further stratification. Using statins for primary prevention is recommended by guidelines, is prevalent, but remains underprescribed. Statin drugs are unrivaled, evidence-based, major weapons to lower cardiovascular risk. Even when low density lipoprotein cholesterol (LDL-C) targets are attained, over half of patients continue to have disease progression and clinical events. This residual risk is of great concern, and multiple sources of remaining risk exist. Though clinical evidence is incomplete, altering or raising the blood high density lipoprotein cholesterol (HDL-C) level continues to be pursued. Of all agents available, rosuvastatin produces the greatest reduction in LDL-C, LDL-P, and improvement in apoA-I/apoB, together with a favorable safety profile. Several recent proposals and methods to lower cardiovascular risk are reviewed. A combination of approaches, such as the addition of lifetime risk, refinement of risk prediction, guideline compliance, novel treatments, improvement in adherence, and primordial prevention, including environmental and social intervention, will be necessary to lower the present high risk burden.

A meta-analysis of low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B as markers of cardiovascular risk

BACKGROUND

Whether apolipoprotein B (apoB) or non-high-density lipoprotein cholesterol (HDL-C) adds to the predictive power of low-density lipoprotein cholesterol (LDL-C) for cardiovascular risk remains controversial.

METHODS AND RESULTS

This meta-analysis is based on all the published epidemiological studies that contained estimates of the relative risks of non-HDL-C and apoB of fatal or nonfatal ischemic cardiovascular events. Twelve independent reports, including 233 455 subjects and 22 950 events, were analyzed. All published risk estimates were converted to standardized relative risk ratios (RRRs) and analyzed by quantitative meta-analysis using a random-effects model. Whether analyzed individually or in head-to-head comparisons, apoB was the most potent marker of cardiovascular risk (RRR, 1.43; 95% CI, 1.35 to 1.51), LDL-C was the least (RRR, 1.25; 95% CI, 1.18 to 1.33), and non-HDL-C was intermediate (RRR, 1.34; 95% CI, 1.24 to 1.44). The overall comparisons of the within-study differences showed that apoB RRR was 5.7%>non-HDL-C (P<0.001) and 12.0%>LDL-C (P<0.0001) and that non-HDL-C RRR was 5.0%>LDL-C (P=0.017). Only HDL-C accounted for any substantial portion of the variance of the results among the studies. We calculated the number of clinical events prevented by a high-risk treatment regimen of all those >70th percentile of the US adult population using each of the 3 markers. Over a 10-year period, a non-HDL-C strategy would prevent 300 000 more events than an LDL-C strategy, whereas an apoB strategy would prevent 500 000 more events than a non-HDL-C strategy.

CONCLUSIONS

These results further validate the value of apoB in clinical care.

Apolipoprotein B/A-I and total cholesterol/high-density lipoprotein cholesterol ratios both predict cardiovascular events in the general population independently of nonlipid risk factors, albuminuria and C-reactive protein

BACKGROUND

the total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) and apolipoprotein (apo) B/A-I ratios predict major adverse cardiovascular events (MACEs). The extent to which these associations are modified by high-sensitivity C-reactive protein (hs-CRP) and albuminuria is largely unknown. We compared the strength of these ratios with first MACE in the general population and determined whether these associations remain when taking account of these risk markers.

SUBJECTS AND METHODS

a prospective case-cohort study was performed among 6948 subjects (PREVEND cohort) without previous cardiovascular disease and who did not use lipid-lowering drugs initially. Fasting serum TC, low-density lipoprotein cholesterol (LDL-C), HDL-C, non-HDL-C, apoB, apoA-I, triglycerides, hs-CRP and albuminuria were measured at baseline. The composite endpoint was incident MACE.

RESULTS

a total of 362 first cardiovascular events occurred during 7.9 years of follow-up. All pro- and anti-atherogenic measures of lipoproteins and apos predicted MACEs in age- and sex-adjusted Cox proportional hazard analyses (P = 0.018 to P < 0.001). The age- and sex-adjusted hazard ratio (HR) was 1.37 [95% confidence interval (CI), 1.26-1.48] for the apoB/apoA-I ratio and 1.24 (95% CI, 1.18-1.29) for the TC/HDL-C ratio (both P < 0.001). These relationships were essentially unaltered after additional adjustment for triglyceride levels. Pair-wise comparison revealed that these ratios were of similar importance in age- and sex-adjusted analysis (P = 0.397). The HRs of apoB/apoA-I (P < 0.001) and TC/HDL-C (P < 0.001) for risk of MACEs were only marginally attenuated by additional controlling for traditional risk factors (hypertension, diabetes, obesity and smoking), hs-CRP and albuminuria.

CONCLUSIONS

first MACE is associated with both the fasting serum apoB/apoA-I ratio and the TC/HDL-C ratio in the general population, independently of triglycerides, hs-CRP and albuminuria.

Comparison of Apolipoprotein Concentrations and Values of APOB:APOAI with Traditional Lipid Measures in Women Diagnosed with Acute Cornonary Syndromes - A Preliminary Report

BACKGROUND

Acute coronary syndromes (ACS) are the leading cause of hospitalization and death in the modern world. Reliable indicators of risk assessment could be useful in clinical investigation. Results from recent studies suggest that apolipoprotein measurement and apoB:apoI ratio are superior to traditional lipids in the estimation of coronary risk. We compared apolipoprotein concentrations and apoB:apoAI index with traditional lipid measures in ACS patients.

METHODS

A study group consisted of 94 women diagnosed with ACS (STEMI=21, NSTEMI=25 and UA=48). Clinically healthy volunteers (n=30) served as controls. Measurements of serum cardiac TnI, lipid profile, high sensitivity C-reactive protein, apolipoprotein AI and apoB100 concentrations were performed and apoB:apoAI ratio was calculated.

RESULTS

ACS patients had significantly decreased median HDL-cholesterol, increased atherogenic indexes TC:HDL-C, apoB:apoAI and abnormally high CRP compared to controls. Median LDL-cholesterol and apoAI concentrations, although significantly higher in ACS patients, remained within the normal range. Comparison of atherogenic indexes in ACS patients has shown increased TC:HDL-C (>4) and apoB:apoAI (>0,3) in 60,4% and 96,8% of which 55,4% had moderate and high risk (>0,6). ApoB:apoAI ratio was of good diagnostic utility for discrimination between ACS cases and non-ACS controls (AUC=0,715), and little better than TC:HDL-C. In both groups similar percentage of increased LDL-C and triglycerides was observed whereas increased apoB concentration was three times more likely in ACS cases. The highest apoB:apoAI was observed predominantly in STEMI cases (49%) whereas the lowest in UA and NSTEMI (30%).

CONCLUSIONS

Determination of apolipoproteins and assessment of apoB:apoAI ratio seems to be useful and better tool than traditional lipid measures in assessing risk of acute coronary syndromes in women.

Lipid assessment, metabolic syndrome and coronary heart disease risk

BACKGROUND

Although the total to high-density lipoprotein cholesterol ratio (TC/HDL-C) has been used for decades to identify individuals at risk for coronary heart disease (CHD), apolipoprotein-based (apolipoprotein B/apolipoprotein A-I [apoB/apoA-I]) and nuclear magnetic resonance spectroscopy (NMR)-based lipoprotein concentrations (low-density lipoprotein(NMR) /high-density lipoprotein(NMR) [LDL(NMR) /HDL(NMR)]) may also be useful for CHD risk stratification.

MATERIALS AND METHODS

In a case-control study conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study population, 870 individuals who developed CHD during a 6-year follow-up were matched to 1659 controls on the basis of gender, age and enrollment time. LDL(NMR) and HDL(NMR) were measured by proton NMR spectroscopy.

RESULTS

After adjusting for traditional CHD risk factors, men in the top quintile of the various lipoprotein ratios proved to be at increased CHD risk (OR = 2·59 [95% IC, 1·76-3·83] for TC/HDL-C ratio, 2·59 [1·75-3·83] for apoB/apoA-I ratio and 2·78 [1·86-4·17] for LDL(NMR) /HDL(NMR) ratio) compared with men in the bottom quintile. Similar associations were observed in women (OR = 2·86 [1·71-4·80] for TC/HDL-C ratio, 2·94 [1·74-4·97] for apoB/apoA-I ratio and 2·03 [1·21-3·43] for LDL(NMR)/HDL(NMR) ratio). Compared with participants with only one component of the metabolic syndrome, those who had five had an increased TC/HDL-C ratio (73·0% and 80·4% in men and women respectively), apoB/apoA-I ratio (58·0% and 62·9% in men and women respectively) and for LDL(NMR)/HDL(NMR) ratio (52·6% and 54·1% in men and women respectively).

CONCLUSION

In this European study population, the TC/HDL-C, apoB/apoA-I and LDL(NMR) /HDL(NMR) ratios were similarly associated with components of the metabolic syndrome and CHD risk.

A novel model of cholesterol efflux from lipid-loaded cells

Cholesterol efflux from lipid-loaded cells is a key athero-protective event that counteracts cholesterol uptake. The imbalance between cholesterol efflux and uptake determines the prevention or development of atherosclerosis. Many proteins and factors participate in the cholesterol efflux event. However, there are currently no systematic models of reverse cholesterol transport (RCT) that include most RCT-related factors and events. On the basis of recent research findings from other and our laboratories, we propose a novel model of one center and four systems with coupling transportation and networking regulation. This model represents a common way of cholesterol efflux; however, the systems in the model consist of different proteins/factors in different cells. In this review, we evaluate the novel model in vascular smooth muscle cells (VSMCs) and macrophages, which are the most important original cells of foam cells. This novel model consists of 1) a caveolae transport center, 2) an intracellular trafficking system of the caveolin-1 complex, 3) a transmembrane transport system of the ABC-A1 complex, 4) a transmembrane transport system of the SR-B1 complex, and 5) an extracelluar trafficking system of HDL/Apo-A1. In brief, the caveolin-1 system transports cholesterol from intracellular compartments to caveolae. Subsequently, both ABC-A1 and SR-B1 complex systems transfer cholesterol from caveolae to extracellular HDL/Apo-A1. The four systems are linked by a regulatory network. This model provides a simple and concise way to understand the dynamic process of atherosclerosis.

The Framingham Heart Study: impact on the prevention and control of cardiovascular diseases in India

India is in the middle of the epidemiological transition, with the burden of disease shifting towards chronic conditions, of which cardiovascular diseases (CVDs) form a major part. Findings from the Framingham Heart Study (FHS) have tremendous potential to circumvent the projected increase in CVD burden in India, as they highlight the importance of measuring risk in individuals and populations, and preventing future onset of disease. The findings of the FHS have stimulated several cross-sectional studies in India documenting a high and increasing burden of CVD risk factors. These have led to policy level changes in the country, in the form of Framework Convention on Tobacco Control ratification, and the National Program on Diabetes, CVD, and Stroke. There is now need for an Indian cohort study on the lines of the FHS, which can more closely evaluate the use of the FHS risk score among Indians and translate FHS findings into the Indian context.

Cystatin C and risk of vascular and nonvascular mortality: a prospective cohort study of older men

OBJECTIVE

To assess the relevance of cystatin C, as a marker of mild-to-moderate renal impairment, for vascular and nonvascular mortality in older people.

DESIGN

Prospective cohort study.

SETTING

Re-survey in 1997 to 1998 of survivors in the 1970 Whitehall study of London civil servants.

SUBJECTS

Five thousand three hundred and seventy-one men (mean age at resurvey: 77 years) who took part in the resurvey and had plasma cystatin C concentration measured.

MAIN OUTCOME MEASURES

Cause-specific mortality over subsequent 11 years (1997 to 2008).

METHODS

Cox regression was used to estimate the associations of cystatin C with vascular and nonvascular mortality, before and after adjustment for prior disease and other risk factors (including lifetime blood pressure).

RESULTS

During an 11.0-year follow-up period, there were 1171 deaths from vascular causes [26 per 1000 per year (py)] and 1615 deaths from nonvascular causes (36 per 1000 py). Compared with men with cystatin C in the bottom fifth of the distribution, men in the top 10th had about two-fold higher mortality rates from vascular and nonvascular mortality (fully adjusted P both <0.001) even after adjustment for prior disease and all measured confounders, including lifetime blood pressure. The fully adjusted relative risks per 50% higher cystatin C concentrations were 1.66 [95% CI 1.48 to 1.85] for vascular mortality, 1.92 [95% CI 1.66 to 2.22] for ischaemic heart disease mortality and 1.46 [95% CI 1.31 to 1.61] for nonvascular mortality.

CONCLUSIONS

In older men, plasma concentration of cystatin C, probably as a marker of mild renal disease, is a strong independent predictor of both vascular and nonvascular mortality.

Relationship of serum cholesterol levels to atopy in the US population

BACKGROUND

Cholesterol promotes Th2 immunity and allergic inflammation in rodents; whether this occurs in humans is unclear. Reports of both direct and inverse associations between serum cholesterol and atopy in different populations suggest that race and/or other demographic variables may modify these relationships.

AIMS OF THE STUDY

To determine the relationships between levels of three serum cholesterol measures [total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), and non-HDL-C] and atopy in a sample representative of the US population.

METHODS

Cross-sectional study of 6854 participants aged > or =6 years from the 2005-2006 National Health and Nutrition Examination Survey.

RESULTS

In the overall population, adjusted odds ratios (AORs) per two-standard deviation increase in TC and non-HDL-C for biochemical atopy (defined as > or =1 allergen-specific IgE to 19 allergens) were 1.17 [95% confidence interval (CI), 1.00-1.38] and 1.19 (95% CI, 1.03-1.39), respectively. Interactions by race were noted for the two relationships (interaction P = 0.004 and P = 0.009, respectively) with non-Hispanic Whites (NHWs) having direct relationships [TC: AOR 1.27 (95% CI, 1.03-1.57); non-HDL-C: AOR 1.27 (95% CI, 1.03-1.56)] and non-Hispanic Blacks (NHBs) inverse relationships [TC: AOR 0.77 (95% CI, 0.62-0.95); non-HDL-C: AOR 0.86 (95% CI, 0.69-1.08)]. The adjusted HDL-C-atopy relationship was nonsignificant for NHWs and inverse for NHBs [AOR 0.77 (95% CI, 0.61-0.96)]. Relationships were independent of body mass index and serum C-reactive protein and unmodified by corticosteroid or statin usage. Results were similar using current hay fever/allergy as the atopy outcome.

CONCLUSIONS

There are marked inter-racial differences in the relationship between serum cholesterol and atopy in the US population.

Major lipids, apolipoproteins, and risk of vascular disease

CONTEXT

Associations of major lipids and apolipoproteins with the risk of vascular disease have not been reliably quantified.

OBJECTIVE

To assess major lipids and apolipoproteins in vascular risk.

DESIGN, SETTING, AND PARTICIPANTS

Individual records were supplied on 302,430 people without initial vascular disease from 68 long-term prospective studies, mostly in Europe and North America. During 2.79 million person-years of follow-up, there were 8857 nonfatal myocardial infarctions, 3928 coronary heart disease [CHD] deaths, 2534 ischemic strokes, 513 hemorrhagic strokes, and 2536 unclassified strokes.

MAIN OUTCOME MEASURES

Hazard ratios (HRs), adjusted for several conventional factors, were calculated for 1-SD higher values: 0.52 log(e) triglyceride, 15 mg/dL high-density lipoprotein cholesterol (HDL-C), 43 mg/dL non-HDL-C, 29 mg/dL apolipoprotein AI, 29 mg/dL apolipoprotein B, and 33 mg/dL directly measured low-density lipoprotein cholesterol (LDL-C). Within-study regression analyses were adjusted for within-person variation and combined using meta-analysis.

RESULTS

The rates of CHD per 1000 person-years in the bottom and top thirds of baseline lipid distributions, respectively, were 2.6 and 6.2 with triglyceride, 6.4 and 2.4 with HDL-C, and 2.3 and 6.7 with non-HDL-C. Adjusted HRs for CHD were 0.99 (95% CI, 0.94-1.05) with triglyceride, 0.78 (95% CI, 0.74-0.82) with HDL-C, and 1.50 (95% CI, 1.39-1.61) with non-HDL-C. Hazard ratios were at least as strong in participants who did not fast as in those who did. The HR for CHD was 0.35 (95% CI, 0.30-0.42) with a combination of 80 mg/dL lower non-HDL-C and 15 mg/dL higher HDL-C. For the subset with apolipoproteins or directly measured LDL-C, HRs were 1.50 (95% CI, 1.38-1.62) with the ratio non-HDL-C/HDL-C, 1.49 (95% CI, 1.39-1.60) with the ratio apo B/apo AI, 1.42 (95% CI, 1.06-1.91) with non-HDL-C, and 1.38 (95% CI, 1.09-1.73) with directly measured LDL-C. Hazard ratios for ischemic stroke were 1.02 (95% CI, 0.94-1.11) with triglyceride, 0.93 (95% CI, 0.84-1.02) with HDL-C, and 1.12 (95% CI, 1.04-1.20) with non-HDL-C.

CONCLUSION

Lipid assessment in vascular disease can be simplified by measurement of either total and HDL cholesterol levels or apolipoproteins without the need to fast and without regard to triglyceride.