Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

Clinical implications of the BARI 2D and COURAGE trials of coronary artery disease

The results of the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) and Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) clinical trials raise important questions about the prevention and treatment of coronary heart disease among type 2 diabetics and nondiabetics. The BARI 2D and COURAGE trials showed that pharmacological therapy is as effective as surgery or angioplasty, because of the incidence of total mortality and cardiovascular disease events. The results are consistent with the clinical trials of lipid-lowering, antihypertensive therapy. The efficacy of lowering glycohemoglobin below 7% or benefits of specific glucose-lowering drugs is still unresolved. The BARI 2D trial focused on more advanced atherosclerotic disease. An important question is whether newly incident diabetics should be screened for subclinical atherosclerosis and treated aggressively with pharmacological therapy as in the BARI 2D trial. We are still uncertain whether raising high-density lipoprotein cholesterol will provide further benefit in reducing coronary heart disease. Better measurement of plaque morphology, determinants of hypercoagulable status, and drugs to reduce thrombosis and plaque are of high priority. Longer follow-up of the BARI 2D and COURAGE trials will provide important information about the risks of cardiovascular disease events and disability. It will be important but difficult to translate the results of the trials to community practice under the current health care system.

Diagnosis and treatment of apolipoprotein B dyslipoproteinemias

Conventionally, atherogenic dyslipidemias have been defined by elevated levels of triglyceride and/or LDL cholesterol. However, cholesterol and triglycerides are not metabolically and physically independent entities. Rather, they are constituents of the atherogenic apolipoprotein B (apoB) particles, which differ in their origin and their metabolic function. Moreover, the risk of vascular disease is not related to the plasma concentration of cholesterol or triglyceride per se, but to the number, composition and size of the apoB particles, within which the cholesterol and triglycerides are contained. After all, the entire apoB particle--rather than individual cholesterol or triglyceride molecules--enters and is trapped within the arterial wall, and this particle initiates and sustains the process that results in atherosclerosis. Accordingly, we suggest a change of name and focus from dyslipidemias to dyslipoproteinemias. Virtually all the atherogenic apoB dyslipoproteinemias can be specifically identified on the basis of plasma levels of cholesterol, triglyceride and apoB. Not only does this enable an accurate diagnosis in the individual, but the major familial dyslipoproteinemias can be identified as well. Here, we review the diagnostic algorithm for apoB dyslipoproteinemias and provide, for the first time, a treatment plan on the basis of a reduction of atherogenic lipoprotein particles rather than plasma lipids.

Effect of mipomersen, an apolipoprotein B synthesis inhibitor, on low-density lipoprotein cholesterol in patients with familial hypercholesterolemia

A randomized, double-blind, placebo-controlled, dose-escalation study was conducted to examine the efficacy and safety of mipomersen (ISIS 301012), an antisense inhibitor of apolipoprotein B, when added to conventional lipid-lowering therapy for patients with heterozygous familial hypercholesterolemia. A total of 44 patients were enrolled and were separated into 4 cohorts, with doses ranging from 50 to 300 mg (4:1 active treatment/placebo ratio). Patients received 8 doses subcutaneously during a 6-week treatment period. Patients assigned to the 300-mg dose continued for an additional 7 weeks with once-per-week dosing. The primary efficacy end point was the percentage of change from baseline to week 7 in low-density lipoprotein (LDL) cholesterol. Safety was assessed using the laboratory test results and according to the incidence, severity, and relation of adverse events to drug dose. Mipomersen produced significant reductions in LDL cholesterol and other atherogenic apolipoprotein B-containing lipoproteins. After 6 weeks of treatment, the LDL cholesterol level was reduced by 21% from baseline in the 200-mg/week dose group (p <0.05) and 34% from baseline in the 300-mg/week dose group (p <0.01), with a concomitant reduction in apolipoprotein B of 23% (p <0.05) and 33% (p <0.01), respectively. Injection site reactions were the most common adverse event. Elevations in liver transaminase levels (> or =3 times the upper limit of normal) occurred in 4 (11%) of 36 patients assigned to active treatment; 3 of these patients were in the highest dose group. In conclusion, mipomersen has an incremental LDL cholesterol lowering effect when added to conventional lipid-lowering therapy.

Targeting residual risk: the rationale for the use of non-HDL cholesterol

There is a wealth of epidemiological and clinical data linking low-density lipoprotein cholesterol (LDLc) with atherosclerotic cardiovascular disease. Numerous primary and secondary prevention trials have demonstrated that reduction in LDLc leads to significant decrease in cardiovascular event rates. However, patients continue to be at significant risk for recurrent events despite aggressive LDLc lowering, reflecting a substantial residual risk. Numerous parameters like apolipoprotein B, LDL particle size, number and non-high density lipoprotein cholesterol (non-HDLc) measurement have been used to assess and address this high residual risk. Herein, we discuss the rationale and the evidence supporting the use of non-HDLc. We also discuss therapeutic options and provide a practical approach to residual risk reduction from a primary care perspective.

Serum n-6 fatty acids and lipoprotein subclasses in middle-aged men: the population-based cross-sectional ERA-JUMP study

BACKGROUND

The associations of serum omega-6 (n-6) fatty acids with lipoprotein subclasses at the population level are uncertain.

OBJECTIVE

We aimed to examine associations between major n-6 fatty acids [ie, linoleic acid (LA, 18:2n-6) and arachidonic acid (AA, 20:4n-6)] and the lipoprotein subclasses VLDL, LDL, and HDL.

DESIGN

We conducted a cross-sectional study in 1098 participants using population-based data from US white, Japanese American, Japanese, and Korean men aged 40-49 y. Serum fatty acids were analyzed by capillary gas-liquid chromatography. Lipoprotein subclasses were measured by nuclear magnetic resonance spectroscopy. Multiple linear regression models as a function of each fatty acid were used after adjustment for age, population, body mass index, pack-years of smoking, alcohol consumption, diabetes, hypertension, and omega-3 (n-3) and trans fatty acids.

RESULTS

Serum LA was inversely associated with large VLDL (beta = -0.62, P < 0.001), total LDL (beta = -22.08, P < 0.001), and small LDL (beta = -31.89, P < 0.001) particle concentrations and VLDL size (beta = -0.72, P < 0.001). Serum LA was positively associated with large HDL particle concentration (beta = 0.21, P < 0.001) and HDL size (beta = 0.03, P < 0.001). The patterns of association of AA with large VLDL and large HDL particle concentrations were comparable with those of LA.

CONCLUSIONS

At the population level, higher serum concentrations of LA were significantly associated with lower concentrations of total LDL particles. Higher serum concentrations of LA and AA were significantly associated with a lower concentration of large VLDL particles and a higher concentration of large HDL particles. These associations were consistent across the population groups. This trial was registered at clinicaltrials.gov as NCT00069797.

Work and diet-related risk factors of cardiovascular diseases: comparison of two occupational groups

BACKGROUND

Although work related risk factors associated with Cardiovascular Diseases (CD) have been well researched, there is no detailed knowledge regarding disparate occupational groups each with a different risk exposition. Therefore, two occupational groups (chefs and office workers) were compared with a focus on nutritional and psychosocial factors.

METHODS

Two groups of subjects were tested for work and diet-related risks of CD (45 chefs and 48 office workers). The groups matched both for gender (male) and age (30 to 45 years). The study included a medical check-up, bioelectrical impedance analysis as well as an evaluation of questionnaires on health, nutritional behaviour and coping capacity. In addition, volunteers were required to compile a 7-day-dietary-record and collect their urine 24 h prior to their check-up. Blood samples drawn were analysed for glucose and lipid metabolism, homocysteine, vitamin B12, folic acid; C-reactive protein, uric acid, red blood cell fatty acids, plant sterols, antioxidative capacity and oxidative stress.

RESULTS

On average, the chefs showed one risk factor more compared to the office workers. The most frequent risk factors in both groups included overweight/obesity (chef group [CG]: 62.2%; office group [OG]: 58.3%) and elevated TC (CG: 62.2%; OG: 43.8%]. Moreover, although the chefs often had higher CRP-concentrations (40.0%), more office workers suffered from hypertension (37.5%).Chefs showed significant higher concentrations of saturated fatty acids and oleic acid, whereas docosahexaenoic acid, Omega-6- and trans fatty acids were found more frequently in the red blood cell membranes of office workers. While there were no significant differences in analysed plant sterols between the two occupational groups, 7,8-dihydro-8-oxo-2'-deoxyguanosine was significantly increased in office workers.Concerning the work-related psychosocial factors, the chefs were characterised by a stronger subjective importance of work, a greater degree of professional aspiration and enhanced efforts at perfectionism at their workplace.

CONCLUSIONS

The chefs in the study bear a higher risk of CD compared to the office-workers. Although, CD is not exclusively a result of workplace-conditions, study results show that work-related influences can not be ignored. Thus, prevention of CD may be an important task attributable to occupational physicians.

Association of apolipoprotein B with incident type 2 diabetes in an aboriginal Canadian population

BACKGROUND

Expanding evidence indicates that apolipoprotein B (apo B) is superior to LDL cholesterol as a marker of vascular disease. Although traditional lipid measures are known to predict type 2 diabetes, limited data are available regarding apo B. We assessed the association of apo B with incident type 2 diabetes and compared it with traditional lipid variables as a risk predictor in aboriginal Canadians.

METHODS

Of an initial cohort of 606 individuals without diabetes in 1993-1995, 540 were contacted for the 10-year follow-up evaluation in 2003-2005. Fasting and 2-h postload glucose concentrations were obtained at baseline and follow-up to determine incident type 2 diabetes. Baseline fasting serum lipids were measured with standard laboratory procedures.

RESULTS

The cumulative 10-year incidence of type 2 diabetes was 17.5%. High concentrations of apo B, triglycerides, and LDL cholesterol, and low concentrations of HDL cholesterol were individually associated with incident type 2 diabetes in univariate analyses. Comparing C statistics of univariate models showed apo B to be a superior determinant of incident diabetes compared with LDL (P = 0.026) or HDL (P = 0.004) cholesterol. With multivariate adjustment including waist circumference, apo B (odds ratio, 1.50; 95% CI, 1.11-2.02) and triglycerides (odds ratio, 1.49; 95% CI, 1.12-1.98) remained associated with incident diabetes, whereas LDL and HDL cholesterol became nonsignificant.

CONCLUSIONS

The association of plasma apo B with incident type 2 diabetes and its better prediction of risk compared with LDL or HDL cholesterol suggest the potential for the use of apo B in type 2 diabetes risk communication and prevention.

Identification of two common variants contributing to serum apolipoprotein B levels in Mexicans

BACKGROUND AND PURPOSE

Although the Mexican population has a high predisposition to dyslipidemias and premature coronary artery disease, this population is underinvestigated for the genetic factors conferring the high susceptibility. This study attempted to determine these genetic factors.

METHODS AND RESULTS

First, we investigated apolipoprotein B (apoB) levels in Mexican extended families with familial combined hyperlipidemia using a two-step testing strategy. In the screening step, we screened 5721 single-nucleotide polymorphisms (SNPs) for linkage signals with apoB. In the test step, we analyzed the 130 SNPs residing in regions of suggestive linkage signals for association with apoB. We identified significant associations with two SNPs (ie, rs1424032 [P=6.07x10(-6)] and rs1349411 [P=2.72x10(-4)]) that surpassed the significance level for the number of tests performed in the test step (P<3.84x10(-4)). Second, these SNPs were tested for replication in Mexican hyperlipidemic case-control samples. The same risk alleles as in the families with familial combined hyperlipidemia were significantly associated (P<0.05) with apoB in the case-control samples. The rs1349411 resides near the apoB messenger RNA editing enzyme (APOBEC1) involved in the processing of APOB messenger RNA in the small intestine. The rs1424032 resides in a highly conserved noncoding region predicted to function as a regulatory element.

CONCLUSIONS

We identified two novel variants, rs1349411 and rs1424032, for serum apoB levels in Mexicans.

What's the deal with niacin development: is laropiprant add-on therapy a winning strategy to beat a straight flush?

PURPOSE OF REVIEW

Niacin is a B-complex vitamin used as a lipid-altering drug since the 1950s. Niacin improves multiple lipid parameters. Atherosclerotic coronary heart disease outcome studies support niacin's efficacy in reducing coronary heart disease events, either as monotherapy or when used in combination with other lipid-altering drugs. The most commonly reported reason for the lack of its more widespread clinical use is niacin-induced flushing.

RECENT FINDINGS

Laropiprant is a highly selective prostaglandin D2 receptor 1 antagonist that mitigates niacin-induced flushing.

SUMMARY

This review examines the history and provides a perspective regarding the extended-release niacin/laropiprant development program, which was designed to better allow patients to achieve a more therapeutic niacin dose of 2 g/day, without the need for titration. Ongoing coronary heart disease outcome studies will provide better insight as to the benefits of niacin in general, and the safety and efficacy of extended-release niacin/laropiprant specifically.

Analysis of recently identified dyslipidemia alleles reveals two loci that contribute to risk for carotid artery disease

Background

Genome-wide association studies have identified numerous single nucleotide polymorphisms (SNPs) affecting high density lipoprotein (HDL) or low density lipoprotein (LDL) cholesterol levels; these SNPs may contribute to the genetic basis of vascular diseases.

Results

We assessed the impact of 34 SNPs at 23 loci on dyslipidemia, key lipid sub-phenotypes, and severe carotid artery disease (CAAD) in a case-control cohort. The effects of these SNPs on HDL and LDL were consistent with those previously reported, and we provide unbiased estimates of the percent variance in HDL (3.9%) and LDL (3.3%) explained by genetic risk scores. We assessed the effects of these SNPs on HDL subfractions, apolipoprotein A-1, LDL buoyancy, apolipoprotein B, and lipoprotein (a) and found that rs646776 predicts apolipoprotein B level while rs2075650 predicts LDL buoyancy. Finally, we tested the role of these SNPs in conferring risk for ultrasonographically documented CAAD stenosis status. We found that two loci, chromosome 1p13.3 near CELSR2 and PSRC1 which contains rs646776, and 19q13.2 near TOMM40 and APOE which contains rs2075650, harbor risk alleles for CAAD.

Conclusion

Our analysis of 34 SNPs contributing to dyslipidemia at 23 loci suggests that genetic variation in the 1p13.3 region may increase risk of CAAD by increasing LDL particle number, whereas variation in the 19q13.2 region may increase CAAD risk by promoting formation of smaller, denser LDL particles.

Apolipoprotein measurements: is more widespread use clinically indicated?

Apolipoprotein (apo) B may be a more sensitive measure of atherogenicity than low-density lipoprotein cholesterol (LDL-C) and a better index for assessing cardiovascular risk. The refined risk assessment provided by apo B may be important in patients at high cardiometabolic risk such as those with diabetes mellitus or metabolic syndrome, as these conditions are often associated with normal LDL-C values but increased numbers of small, dense low-density lipoprotein (LDL) particles (indicating increased levels of apo B). Although apo B is not currently a treatment target in the United States cholesterol-lowering guidelines, a consensus conference endorsed by the American Diabetes Association and the American College of Cardiology recently recommended that apo B be added as a therapeutic target in patients at high cardiometabolic risk and in patients with clinical cardiovascular disease or diabetes. Suggested target goals are < 90 for high risk and < 80 mg/dL for highest risk patients. Current clinical data indicate that intensive statin therapy can lower apo B to meet this aggressive goal. While the proatherogenic/antiatherogenic ratio of apo B/apo A-I is a better risk discriminator than the single proatherogenic measurement (apo B), clinical trial data are lacking regarding the impact of increasing apo A-I and high-density lipoprotein on outcomes.

2009 Canadian Cardiovascular Society/Canadian guidelines for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease in the adult - 2009 recommendations

The present article represents the 2009 update of the Canadian Cardiovascular Society guidelines for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease in the adult.

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

AIMS

Plasma levels of apolipoprotein B (apoB), the main surface protein on LDL particles, and LDL-C, the amount of cholesterol in those particles, are closely correlated and, considered separately, are positive risk factors. Plasma levels of apolipoprotein A(1), the main surface protein on HDL particles, and HDL-C, the amount of cholesterol in those particles, are also closely correlated with each other and, considered separately, are negative risk factors. The interdependence of these four risk factors is unclear.

METHODS AND RESULTS

Case-control study among 3510 acute myocardial infarction patients (without prior vascular disease, diabetes, or statin use) in UK hospitals and 9805 controls. Relative risks (age, sex, smoking, and obesity-adjusted) were more strongly related to apoB than to LDL-C and, given apoB, more strongly negatively related to apoA(1) than to HDL-C. The ratio apoB/apoA(1) was uncorrelated with time since symptom onset in cases, was reproducible in samples collected a few years apart in controls (correlation 0.81), and encapsulated almost all the predictive power of these four measurements. Its effect was continuous, substantial throughout the UK normal range [relative risk, top vs. bottom decile of this ratio, 7.3 (95% CI 5.8-9.2)] and varied little with age. The ratio apoB/apoA(1) was substantially more informative about risk (chi(1)(2) = 550) than were commonly used measures such as LDL-C/HDL-C, total/HDL cholesterol, non-HDL cholesterol, and total cholesterol (chi(1)(2) = 407, 334, 204, and 105, respectively). Given apoB and apoA(1), the relationship with risk of LDL-C was reversed, and this reversal was strengthened by appropriate allowance for random measurement errors in two correlated variables. Given usual apoB, lower LDL-C (consistent with smaller LDL particles) was associated with higher risk (P < 0.0001). During the first 8 h after symptom onset HDL-C increased by about 10%, precluding reliable assessment of the joint relationship of apoA(1) and pre-onset HDL-C with risk in such retrospective case-control studies.

CONCLUSION

Apolipoprotein ratios are more informative about risk than lipid fractions are. This suggests that, among lipoprotein particles of a particular type (LDL or HDL), some smaller and larger subtypes differ in their effects on risk. Direct measurements of even more specific subtypes of lipoprotein particles may be even more informative about risk.

Correlation of non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol with apolipoprotein B during simvastatin + fenofibrate therapy in patients with combined hyperlipidemia (a subanalysis of the SAFARI trial)

Guidelines have recommended non-high-density lipoprotein (non-HDL) cholesterol as a secondary target for therapy after the low-density lipoprotein (LDL) cholesterol goals have been met in patients with hypertriglyceridemia; non-HDL cholesterol is viewed as a surrogate for apolipoprotein (Apo)B, an alternate end point of treatment. The present analysis of the previously reported Simvastatin plus Fenofibrate for Combined Hyperlipidemia (SAFARI) trial assessed the associations of non-HDL cholesterol and LDL cholesterol with ApoB levels in patients with combined hyperlipidemia treated with combination simvastatin (20 mg) and fenofibrate (160 mg) or simvastatin monotherapy (20 mg). The correlations of these factors were analyzed in the overall modified intent-to-treat population (n = 594) and in patient subgroups stratified by triglyceride (TG) tertiles. Simvastatin plus fenofibrate and simvastatin alone significantly reduced LDL cholesterol, TG, non-HDL cholesterol and ApoB levels and non-HDL cholesterol/ApoB ratio (p < or =0.0004), regardless of the TG level. The greatest reductions occurred with combination treatment. The baseline levels of non-HDL cholesterol and LDL cholesterol correlated highly with ApoB and were stronger in the lower TG tertiles than in the higher TG tertiles. After 12 weeks, the correlations had changed little with simvastatin monotherapy but had increased substantially with combination therapy and were most improved at high TG levels. In conclusion, these results suggest that both non-HDL cholesterol and ApoB provide similar information in relation to treatment response in patients with combined hyperlipidemia and hypertriglyceridemia, and that non-HDL cholesterol is a good indicator of ApoB-containing lipoproteins, supporting its recommended use as a secondary therapeutic target in these patients.

Obesity and cardiometabolic risk factors in a representative population of Iranian adolescents and adults in comparison to a Western population: the Isfahan Healthy Heart Programme

Objective

The aim of the present study was to develop reference data for the Iranian population for anthropometric values and cardiometabolic data in comparison with those in Americans, as representative of a Western population.

Design

The present cross-sectional survey, conducted as part of the baseline survey of a community-based interventional study (the Isfahan Healthy Heart Programme), used a two-stage clustering design and was conducted in 12 600 randomly selected adults (≥19 years of age) and 2000 adolescents (aged 11–18 years) living in three cities in the central part of Iran. For comparison with a Western population, comparable data for Americans were derived from the data sets of the Second and Third National Health and Nutrition Examination Surveys (NHANES II and NHANES III).

Results

Iranian women had significantly higher mean BMI, waist circumference (WC), hip circumference (HC) and waist:hip ratio (WHR) than Iranian men and American women; but the mean BMI of Iranian men was lower than that of American men. The mean serum TAG level of Iranian men was significantly higher than that of Iranian women, whereas the mean serum total cholesterol (TC), LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) levels were significantly higher in Iranian women than in men. The Iranian population had lower mean TC, LDL-C and TAG levels than the Americans, but such difference was not documented for HDL-C. Iranian adolescents had significantly lower mean BMI and higher mean TAG than did American adolescents.

Conclusions

Our findings provide serious evidence for health professionals and policy makers about the very high prevalence of generalized and abdominal obesity in Iran. Controlling this emerging health problem, notably in women, should become a national priority in Iran and necessitates comprehensive public health programmes.

Apolipoprotein B but not LDL cholesterol is associated with coronary artery calcification in type 2 diabetic whites

OBJECTIVE

Evidence favors apolipoprotein B (apoB) over LDL cholesterol as a predictor of cardiovascular events, but data are lacking on coronary artery calcification (CAC), especially in type 2 diabetes, where LDL cholesterol may underestimate atherosclerotic burden. We investigated the hypothesis that apoB is a superior marker of CAC relative to LDL cholesterol.

RESEARCH DESIGN AND METHODS

We performed cross-sectional analyses of white subjects in two community-based studies: the Penn Diabetes Heart Study (N = 611 type 2 diabetic subjects, 71.4% men) and the Study of Inherited Risk of Coronary Atherosclerosis (N = 803 nondiabetic subjects, 52.8% men) using multivariate analysis of apoB and LDL cholesterol stratified by diabetes status.

RESULTS

In type 2 diabetes, apoB was associated with CAC after adjusting for age, sex, and medications [Tobit regression ratio of increased CAC for 1-SD increase in apoB; 1.36 (95% CI 1.06-1.75), P = 0.016] whereas LDL cholesterol was not [1.09 (0.85-1.41)]. In nondiabetic subjects, both were associated with CAC [apoB 1.65 (1.38-1.96), P < 0.001; LDL cholesterol 1.56 (1.30-1.86), P < 0.001]. In combined analysis of diabetic and nondiabetic subjects, apoB provided value in predicting CAC scores beyond LDL cholesterol, total cholesterol, the total cholesterol/HDL cholesterol and triglyceride/HDL cholesterol ratios, and marginally beyond non-HDL cholesterol.

CONCLUSIONS

Plasma apoB, but not LDL cholesterol, levels were associated with CAC scores in type 2 diabetic whites. ApoB levels may be particularly useful in assessing atherosclerotic burden and cardiovascular risk in type 2 diabetes.

The common apolipoprotein A-1 polymorphism -75A>G is associated with ethnic differences in recurrent coronary events after recovery from an acute myocardial infarction

Since data regarding the relationship between a common polymorphism (SNP) of the apoA1 gene with apoA1 levels and risk of coronary artery disease are inconsistent, we hypothesized that its association with recurrent coronary events differs for White and Black individuals with diagnosed coronary heart disease. The apoA1 -75G>A SNP was genotyped in a cohort of 834 Black (n=129) and White (n=705) post-myocardial infarction patients. Recurrent coronary events (coronary-related death, non-fatal myocardial infarction, or unstable angina) were documented during an average follow-up of 28 months. Thirty percent of White and 21% of Black patients carried the SNP. Cox proportional-hazards regression analysis, adjusting for clinical and laboratory covariates, demonstrated that the SNP was not associated with recurrent events in the total cohort (HR=1.37, 95% CI 0.95-1.97; p= 0.09) but was the only variable associated with an increased risk of recurrent cardiac events in Blacks (HR=2.40, 95% CI 1.07-5.40; p= 0.034). Conversely in Whites, the SNP was not associated with recurrent events (HR=1.12, 95% CI 0.75-1.67; p= 0.59) whereas apoB (HR=1.78, 95% CI 1.20 -2.65; p= 0.0042) and calcium channel blocker use (HR=2.53, 95% CI 1.72-3.72; p<0.001) were associated; p= 0.0024 for interaction between ethnicity and the SNP. A common apoA1 SNP is associated with a significantly increased risk of recurrent cardiac events among Black, but not White, postmyocardial infarction patients. Relationships with lipoproteins may help explain this finding.

Temporal discrepancies in the association between the apoB/apoA-I ratio and mortality in incident dialysis patients

BACKGROUND

In the general population, a high apoB/apoA-I ratio is a strong risk factor for cardiovascular disease and mortality. However, whether this is the case in chronic kidney disease (CKD) patients is currently unknown.

STUDY DESIGN

The apoB/apoA-I ratio was evaluated in 391 incident CKD stage 5 patients examined close to dialysis initiation, and again after 1 year of dialysis in a subgroup of 182 patients, subsequently followed for up to 3 years.

RESULTS

Baseline values of the apoB/apoA-I ratio as well as changes in the ratio during the first year of dialysis correlated with body mass index (BMI) and fat mass. The baseline apoB/apoA-I ratio showed no association with 4-year mortality. However, after adjustment for confounders, a high apoB/apoA-I ratio (>0.9) predicted short-term (first year) survival [hazard ratio (HR): 0.35; 95% confidence interval (CI): 0.13-0.85)] and long-term (next 3 years) mortality (HR: 1.72; 95% CI: 1.01-2.96). An increase in the apoB/apoA-I ratio during the first year of dialysis was linked to a survival advantage thereafter (HR: 0.48; 95% CI: 0.22-0.98). However, this association lost its significance (HR: 0.62; 95% CI: 0.26-1.36) after adjustment for indices of protein-energy wasting.

CONCLUSIONS

A high apoB/apoA-I ratio and an increase in this ratio during the first year on dialysis were associated with short-term survival advantage in CKD patients. This paradoxical relationship represents an example of the so-called reverse epidemiology phenomenon in CKD patients and suggests that the apoB/apoA-I ratio should always be interpreted with caution in this patient population.

Effects of rosuvastatin and atorvastatin on LDL and HDL particle concentrations in patients with metabolic syndrome: a randomized, double-blind, controlled study

OBJECTIVE

The purpose of this study was to examine the effects of statin therapy on lipoprotein particle concentrations in patients with the metabolic syndrome. Changes in lipoprotein particle concentration may predict the risk of coronary heart disease more accurately than lipoprotein cholesterol levels.

RESEARCH DESIGN AND METHODS

Patients with dyslipidemia and the metabolic syndrome (n = 318) were randomly assigned in a double-blind study comparing 10 mg rosuvastatin (RSV), 10 mg atorvastatin, or placebo daily for 6 weeks. From weeks 6 to 12, patients in the RSV and placebo groups received 20 mg RSV, whereas the ATV group increased their dose to 20 mg daily. Lipoprotein particle concentrations were measured by nuclear magnetic resonance spectroscopy, LDL cholesterol was measured by beta-quantification, and other lipoproteins were measured by standard methods at baseline, 6 weeks, and 12 weeks. Lipoprotein levels were compared by analysis of covariance.

RESULTS

Statins reduced LDL particle concentration less than LDL cholesterol (-30 to -38 vs. -38 to -51%). Reductions were greater with RSV than with ATV (P < 0.05 for LDL particle concentration and P < 0.001 for LDL cholesterol). Most patients attained LDL cholesterol <2.59 mmol/l (100 mg/dl) at 12 weeks (80% with RSV and 59% with ATV; P = 0.003), but only 27% of patients receiving RSV and 19% receiving ATV attained the goal of LDL particle concentration <1,000 nmol/l (P = 0.07).

CONCLUSIONS

In patients with the metabolic syndrome, statin-induced changes in LDL cholesterol do not accurately reflect changes in LDL particle concentration. Consequently, despite attainment of LDL cholesterol goals, these patients may retain considerable residual coronary heart disease risk.

Potential effect of an apoprotein B-based algorithm on management of new patients with hypertriglyceridemia referred to a specialty lipid clinic

BACKGROUND

In patients with hypertriglyceridemia, non-high density lipoprotein cholesterol (nonHDL-C) is a targeted goal. However, apoprotein B100 (apoB) may be superior in predicting cardiovascular risk so we assessed the utility of an apoB-based.

METHODS

New patients (n = 125) who had both apoB and standard lipids measured on the same day were included and we determined the concordances of having achieved goal lipid levels based upon proposed apoB versus nonHDL-C (ATP III) targets in patients with elevated TG (>or=150 mg*dl(-1)) levels.

RESULTS

Although apoB was correlated with nonHDL-C (r = 0.47, p <or= 0.001), the tests had only a fair level of agreement when categorizing the percentage of patients achieving lipid goals for their degree of cardiovascular risk (kappa = 0.22). Among patients with an elevation in nonHDL-C above ATP III goals, between 12-42% had achieved target apoB. On the contrary, between 44-50% of patients were found to be at nonHDL-C but not apoB target. The results were not substantively altered if the analyses were confined to patients with TG values between 200-499 mg*dl(-1), rather than all patients with TG levels >or= 150 mg*dl(-1), as specifically outlined in ATP III guidelines. In total, > 50% of all subjects would have been treated either more or less aggressively following an apoB-based therapeutic algorithm.

CONCLUSIONS

Our findings confirm that the majority of patients referred with hypertriglyceridemia would be managed differently by following an apoB-based treatment algorithm compared to ATP III guidelines. Although many patients would be candidates for more intense therapy, many would be treated less aggressively.

Apolipoprotein B versus LDL-cholesterol: Association with other risk factors for atherosclerosis

OBJECTIVE

To characterize the differences in various risk factors for atherosclerosis between individuals with apoB higher (H) and lower (L) than predicted from regression equation apoB vs LDL-C.

METHODS

We evaluated 391 dyslipidemic subjects not treated with hypolipidemic drugs. The measured parameters included lipid profile, apolipoproteins A-1 and B, markers of insulin resistance and inflammation/hemostasis.

RESULTS

Correlation coefficient between apoB and LDL-C was 0.9 (p<0.0001). Individuals with H apoB compared to L apoB had significantly higher sex and age adjusted BMI, waist circumference, insulin, HOMA (fasting insulinglucose/22.5), C-peptide, proinsulin, PAI-1, sICAM-1, sVCAM-1, t-PA, vWF, frequency of metabolic syndrome and lower values of TC, LDL-C and HDL-C (p<0.05 to <0.001 for all parameters).

CONCLUSION

Individuals with apoB higher than predicted by their LDL-C levels are more insulin resistant and have more atherogenic risk profile. Thus, at least for dyslipidemic patients with high cardiometabolic risk, apoB is a more appropriate marker of risk than LDL-C.

Dyslipidemia and Risk of Coronary Heart Disease: Role of Lifestyle Approaches for Its Management

Multiple risk factors have a causative relationship to the etiology of coronary heart disease (CHD). However, it is clear that dyslipidemia plays a central role. The chain of evidence is strongest for elevated levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). An inverse association has also been demonstrated between levels of high-density lipoprotein cholesterol (HDL-C) and its principal apolipoprotein, A-1, and risk of CHD. Elevated levels of fasting triglyceride (TG) also are a predictor of CHD, but the independent contribution of TG is difficult to prove because of its usual association with reduced levels of HDL-C; elevated levels of small, dense, highly-atherogenic LDL particles; and the metabolic syndrome. Elevated fasting levels of non—HDL-C (TC — LDL-C) and apolipoprotein B also are strongly predictive of the risk of CHD. Therapeutic lifestyle changes are important adjuncts to pharmacologic management of dyslipidemia. The purpose of this article is to review these contributions with an emphasis on dietary habits (particularly lipid intake), weight management, and aerobic exercise.

Apo-B/AI ratio identifies cardiovascular risk in childhood: the Australian Aboriginal Birth Cohort study

We describe the lipoprotein and apolipoprotein profiles and their relationship to cardiovascular risk factors in Australian Aboriginal children. This cross-sectional study within a longitudinal birth cohort study involved Australian Aboriginal children born between 1987 and 1990 and re-examined between 1998 and 2001. Height, weight, blood pressure, waist circumference, body fat percentage, cholesterol, triglycerides, HDL-c, LDL-c, apolipoprotein B and A1 were measured. Mean age was 11.4 years (52% male). Mean cholesterol, triglyceride, HDL-c and LDL-c did not differ from reference data. Measures of obesity, blood pressure and prevalence of the metabolic syndrome did not differ in those children with lipoproteins in the upper quartile of the cohort (lower quartile for HDL-c). Boys with an Apo-B/A1 ratio in the upper quartile of the cohort had higher BMI z-score, waist z-score, % body fat, diastolic blood pressure and frequency of the metabolic syndrome (p<0.05). In girls, waist circumference, % body fat and the prevalence of the metabolic syndrome was higher in those with an Apo-B/A1 ratio in the upper quartile (p<0.05).The Apo-B/A1 ratio may be useful to identify cardiovascular risk in Australian Aboriginal children and is suited to clinical practice as the assays are standardised, accurate, automated and a fasting sample is not required.

Carotid intima-media thickness and apolipoprotein B/apolipoprotein A-I ratio in middle-aged patients with Type 2 diabetes

AIMS

To explore the association between carotid intima-media thickness (IMT) and the apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio compared with conventional lipids in middle-aged patients with Type 2 diabetes.

METHODS

We analysed data from 247 patients with Type 2 diabetes, aged 55-66 years, in the Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care (CARDIPP-1) study. Primary care nurses measured blood pressure and anthropometric characteristics. Blood samples were taken for laboratory analyses. The carotid IMT was determined by ultrasonography at the University Hospital in Linköping and at the County Hospital Ryhov, Jönköping, Sweden.

RESULTS

The ApoB/apoA-I ratio (r = 0.207, P = 0.001), apoB (r = 0.166, P = 0.009) and non-high-density lipoprotein cholesterol (non-HDL-c) (r = 0.129, P = 0.046) correlated with IMT. Conventional lipids, high-sensitivity C-reactive protein (hsCRP), glycated haemoglobin (HbA(1c)) and systolic blood pressure were not significantly correlated to IMT. A stepwise logistic regression analysis was conducted with IMT as the dependent variable and the apoB/apoA-I ratio, HbA(1c), hsCRP, low-density lipoprotein cholesterol (LDL-c), total cholesterol, non-HDL-c and treatment with statins as independent variables. Following adjustment for age and gender, only the apoB/apoA-I ratio remained significantly associated with IMT (odds ratio 4.3, 95% confidence intervals 1.7-10.8, P = 0.002).

CONCLUSIONS

We conclude that there was a significant association between the apoB/apoA-I ratio and IMT in middle-aged patients with Type 2 diabetes. The association was independent of conventional lipids, hsCRP, glycaemic control and use of statins.

Lack of pharmacokinetic interaction of mipomersen sodium (ISIS 301012), a 2'-O-methoxyethyl modified antisense oligonucleotide targeting apolipoprotein B-100 messenger RNA, with simvastatin and ezetimibe

BACKGROUND AND OBJECTIVES

Mipomersen sodium (ISIS 301012) is a 20-mer phosphorothioate antisense oligonucleotide that is complementary to human apolipoprotein B-100 (apoB-100) messenger RNA and subsequently reduces translation of ApoB-100 protein, the major apolipoprotein of very low-density lipoprotein, intermediate-density lipoprotein and low-density lipoprotein (LDL). Mipomersen sodium is currently being studied in phase II/III clinical studies to determine its clinical utility as add-on therapy to HMG-CoA reductase inhibitors or other lipid-lowering agents in subjects with hypercholesterolaemia. The aim of this study was to characterize the pharmacokinetic interactions of mipomersen sodium with simvastatin and ezetimibe. Another aim was to evaluate the ability of mipomersen sodium to inhibit major cytochrome P450 (CYP) isoenzymes in vitro.

METHODS

In a phase I clinical study, ten healthy subjects per cohort received a single oral dose of simvastatin 40 mg or ezetimibe 10 mg followed by four 2-hour intravenous doses of mipomersen sodium 200 mg over an 8-day period, with simvastatin 40 mg or ezetimibe 10 mg being administered again with the last dose of mipomersen sodium. Mipomersen sodium pharmacokinetic profiles were assessed following the first dose (mipomersen sodium alone) and the last dose (mipomersen sodium in combination with simvastatin or ezetimibe). Plasma samples for measurement of simvastatin, simvastatin acid, and free and total ezetimibe concentrations were collected at various timepoints following their first and last oral dosing. A comparative pharmacokinetic analysis was performed to determine if there were any effects resulting from coadministration of mipomersen sodium with these lipid-lowering drugs. In addition to the clinical pharmacokinetic analysis, the ability of mipomersen sodium to inhibit the major CYP isoform enzymes (namely CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) was evaluated in cryo-preserved human hepatocytes in vitro.

RESULTS

The area under the plasma concentration-time curve (AUC) from 0 to 24 hours (AUC(24)), maximum plasma concentration and apparent elimination half-life values of mipomersen sodium were similar when administered alone and in combination with oral simvastatin or oral ezetimibe. The 90% confidence intervals of the geometric least squares means ratios (%Reference) of the mipomersen sodium AUC(24) values were 93.6, 107 when administered together with simvastatin, and 92.4, 111 when administered with ezetimibe. Therefore, there were no large deviations outside the default no-effect boundaries (80-125%) for total exposure (the AUC) of mipomersen sodium in combination with either simvastatin or ezetimibe. Similarly, large deviations outside the default no-effect boundaries were not observed for simvastatin, simvastatin acid, or free and total ezetimibe exposure in combination with mipomersen sodium. In cryo-preserved human hepatocytes, mipomersen sodium exhibited no cytotoxicity. Significant cell uptake was demonstrated by analysing cell-associated concentrations of mipomersen sodium. All evaluated enzyme activities had <10% inhibition at tested concentrations up to 800 microg/mL (approximately 100 micromol/L) of mipomersen sodium, and dose-dependent inhibition was not observed. Therefore, mipomersen sodium is not considered an inhibitor of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 enzyme activities.

CONCLUSIONS

These data provide evidence that mipomersen sodium exhibits no clinically relevant pharmacokinetic interactions with the disposition and clearance of simvastatin or ezetimibe, and vice versa. Moreover, mipomersen sodium does not inhibit any of the major CYP enzymes that were evaluated. Taken together, the results from this study support the use of mipomersen sodium in combination with oral lipid-lowering agents.

Apolipoprotein B and Cardiovascular Disease Risk: Position Statement from the AACC Lipoproteins and Vascular Diseases Division Working Group on Best Practices

Background: Low-density lipoprotein cholesterol (LDL-C) has been the cornerstone measurement for assessing cardiovascular risk for nearly 20 years.

Content: Recent data demonstrate that apolipoprotein B (apo B) is a better measure of circulating LDL particle number (LDL-P) concentration and is a more reliable indicator of risk than LDL-C, and there is growing support for the idea that addition of apo B measurement to the routine lipid panel for assessing and monitoring patients at risk for cardiovascular disease (CVD) would enhance patient management. In this report, we review the studies of apo B and LDL-P reported to date, discuss potential advantages of their measurement over that of LDL-C, and present information related to standardization.

Conclusions: In line with recently adopted Canadian guidelines, the addition of apo B represents a logical next step to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) and other guidelines in the US. Considering that it has taken years to educate physicians and patients regarding the use of LDL-C, changing perceptions and practices will not be easy. Thus, it appears prudent to consider using apo B along with LDL-C to assess LDL-related risk for an interim period until the superiority of apo B is generally recognized.

Lipoprotein particle profiles by nuclear magnetic resonance compared with standard lipids and apolipoproteins in predicting incident cardiovascular disease in women

BACKGROUND

Nuclear magnetic resonance (NMR) spectroscopy measures the number and size of lipoprotein particles instead of their cholesterol or triglyceride content, but its clinical utility is uncertain.

METHODS AND RESULTS

Baseline lipoproteins were measured by NMR in 27 673 initially healthy women followed up for incident cardiovascular disease (n=1015) over an 11-year period. After adjustment for nonlipid risk factors, hazard ratios and 95% confidence intervals for the top versus the bottom quintile of NMR-measured lipoprotein particle concentration (measured in particles per liter) were 2.51 (1.91 to 3.30) for low-density lipoprotein (LDL(NMR)), 0.91 (0.75 to 1.12) for high-density lipoprotein (HDL(NMR)), 1.71 (1.38 to 2.12) for very low-density lipoprotein (VLDL(NMR)), and 2.25 (1.80 to 2.81) for the LDL(NMR)/HDL(NMR) ratio. Similarly adjusted results for NMR-measured lipoprotein particle size (measured in nanometers) were 0.64 (0.52 to 0.79) for LDL(NMR) size, 0.65 (0.51 to 0.81) for HDL(NMR) size, and 1.37 (1.10 to 1.70) for VLDL(NMR) size. Hazard ratios for NMR measures were comparable but not superior to standard lipids (total cholesterol 2.08 [1.63 to 2.67], LDL cholesterol 1.74 [1.40 to 2.16], HDL cholesterol 0.52 [0.42 to 0.64], triglycerides 2.58 [1.95 to 3.41], non-HDL cholesterol 2.52 [1.95 to 3.25], total/HDL cholesterol ratio 2.82 [2.23 to 3.58]) and apolipoproteins (B(100) 2.57 [1.98 to 3.33], A-1 0.63 [0.52 to 0.77], and B(100)/A-1 ratio 2.79 [2.21 to 3.54]). Essentially no reclassification improvement was found with the addition of the LDL(NMR) particle concentration or apolipoprotein B(100) to a model that already included the total/HDL cholesterol ratio and nonlipid risk factors (net reclassification index 0% and 1.9%, respectively), nor did the addition of either variable result in a statistically significant improvement in the c-index.

CONCLUSIONS

In this prospective study of healthy women, cardiovascular disease risk prediction associated with lipoprotein profiles evaluated by NMR was comparable but not superior to that of standard lipids or apolipoproteins.

Apolipoproteins, cardiovascular risk and statin response in type 2 diabetes: the Collaborative Atorvastatin Diabetes Study (CARDS)

AIMS/HYPOTHESIS

Controversy surrounds whether the ratio of apolipoprotein B (ApoB) to apolipoprotein A-I (ApoA-I) is the best lipoprotein discriminator of CHD risk in non-diabetic populations, but the issue has never been investigated in type 2 diabetes.

METHODS

In 2,627 participants without known vascular disease in the Collaborative Atorvastatin Diabetes Study, ApoB, ApoA-I, LDL-cholesterol (LDLC) and HDL-cholesterol (HDLC) were assayed at baseline.

RESULTS

There were 108 CHD and 59 stroke endpoints over 3.9 years. The ApoB:A-I ratio at baseline was the lipoprotein variable most closely predicting CHD risk both by comparison of the hazard ratio for a 1 SD change or tertiles of frequency distribution. The areas under the receiver-operator curve for the ApoB:ApoA-I and the LDLC to HDLC [corrected] ratios, although not significantly different from each other, were greater (p = 0.0005 and p = 0.0125 respectively) than that of non-HDLC:HDLC. The 27% decrease in the ApoB:ApoA-I ratio on atorvastatin predicted a 32% (95% CI 5.4-51.2%) risk reduction in CHD, close to the 36% decrease observed. Neither the ApoB:ApoA-I nor any other lipoprotein concentration or ratio predicted the stroke outcome.

CONCLUSIONS/INTERPRETATION

Overall, the ApoB:ApoA-I ratio improved on the non-HDLC:HDLC ratio in predicting CHD, but, depending on the assessment chosen, its superiority over LDLC:HDLC may be marginal. The statin-induced decrease in stroke risk may not be lipoprotein mediated.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00327418.

FUNDING

The study was supported by unrestricted grants from Diabetes UK, the Department of Health and Pfizer to the University of Manchester and to University College, London.

Targets of statin therapy: LDL cholesterol, non-HDL cholesterol, and apolipoprotein B in type 2 diabetes in the Collaborative Atorvastatin Diabetes Study (CARDS)

BACKGROUND

LDL can vary considerably in its cholesterol content; thus, lowering LDL cholesterol (LDLC) as a goal of statin treatment implies the existence of considerable variation in the extent to which statin treatment removes circulating LDL particles. This consideration is particularly applicable in diabetes mellitus, in which LDL is frequently depleted of cholesterol.

METHODS

Type 2 diabetes patients randomly allocated to 10 mg/day atorvastatin (n = 1154) or to placebo (n = 1196) for 1 year were studied to compare spontaneous and statin-induced apolipoprotein B (apo B) concentrations (a measure of LDL particle concentration) at LDLC and non-HDL cholesterol (non-HDLC) concentrations proposed as statin targets in type 2 diabetes.

RESULTS

Patients treated with atorvastatin produced lower serum apo B concentrations at any given LDLC concentration than patients on placebo. An LDLC concentration of 1.8 mmol/L (70 mg/dL) during atorvastatin treatment was equivalent to a non-HDLC concentration of 2.59 mmol/L (100 mg/dL) or an apo B concentration of 0.8 g/L. At the more conservative LDLC targets of 2.59 mmol/L (100 mg/dL) and 3.37 mmol/L (130 mg/dL) for non-HDLC, however, the apo B concentration exceeded the 0.9-g/L value anticipated in the recent Consensus Statement from the American Diabetes Association and the American College of Cardiology.

CONCLUSIONS

The apo B concentration provides a more consistent goal for statin treatment than the LDLC or non-HDLC concentration.

Estimation of VLDL, IDL, LDL, HDL2, apoA-I, and apoB from the Friedewald inputs--apoB and IDL, but not LDL, are associated with mortality in type 1 diabetes

BACKGROUND

There is an unmet need for a straightforward and cost-effective assessment of multiple lipoprotein risk factors for vascular diseases.

AIMS

1) To study the relation of various lipoprotein lipid and apolipoprotein (apo) measures on the Friedewald inputs, i.e. plasma triglycerides (TG), cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C). 2) To build up regression models for the appropriate measures based solely on the Friedewald inputs.

METHODS

Data were available for 1,775 plasma samples, from which very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and HDL were also isolated by ultracentrifugation. For HDL(2)-C and apolipoproteins, 343 and 247 samples were available, respectively.

RESULTS

Accurate models were obtained for VLDL-TG (cross-validation r=0.98), LDL-C (r=0.91), HDL(2)-C (r=0.92), apoA-I (r=0.92), and apoB (r=0.95). A semi-quantitative model was obtained for IDL-C (r=0.78). Due to the anticipated role of IDL-C in atherosclerosis, it was still kept within the accepted models and pursued further. The associations of the estimates with premature deaths were studied in 4,084 patients with type 1 diabetes. The associations of IDL-C and LDL-C were markedly different, the best predictors of mortality being apoB, apoB to apoA-I ratio, and IDL-C.

CONCLUSIONS

The new models allow identification of clinically relevant lipoprotein profiles with no added cost to the conventional Friedewald formula.

Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.

Diabetes, abdominal adiposity, and atherogenic dyslipoproteinemia in women compared with men

OBJECTIVE

To understand why atherogenic risk differs more between diabetic and nondiabetic women than between diabetic and nondiabetic men.

RESEARCH DESIGN AND METHODS AND RESULTS

Measures of cardiovascular risk, body composition, and serum hormones from the baseline examinations of the Insulin Resistance Atherosclerosis Study on 524 nondiabetic women, 258 diabetic women, 421 nondiabetic men, and 220 diabetic men were compared to detect greater adverse differences in women than in men. Systolic blood pressure; apolipoprotein B (apoB); total cholesterol; apoB-to-apoA-I ratio; non-HDL cholesterol; LDL particle count, small LDL, and intermediate-density lipoprotein by nuclear magnetic resonance; and C-reactive protein exhibited significant diabetes-sex interaction (P < 0.05). ApoB exhibited the most significant interaction (P = 0.0005). Age- and ethnicity-adjusted apoB means were lower in nondiabetic women than nondiabetic men (102.4 vs. 106.8 mg/dl, P < 0.05) but higher in diabetes (115.7 vs. 110.2 mg/dl, P < 0.01). Plotted against BMI, waist circumference was 6% higher and hip circumference 10% lower in diabetic than nondiabetic women (both P < 0.05), whereas the circumference measures did not differ conspicuously between diabetic and nondiabetic men.

CONCLUSIONS

In diabetic women, an elevated level of atherogenic particles, as manifested by apoB and LDL particle count, which may result from abdominal adiposity, represents a major treatable cardiovascular risk factor.