Ascertainment Bias in the Association Between Elevated Lipoprotein(a) and Familial Hypercholesterolemia.

BACKGROUND: Lipoprotein(a) is an atherogenic low-density lipoprotein-like particle and circulating levels are largely determined by genetics. Patients with familial hypercholesterolemia (FH) have elevated lipoprotein(a); however, it remains unclear why. OBJECTIVES: This study compared the levels of lipoprotein(a) and associated genetic factors between individuals that were ascertained for FH clinically versus genetically. METHODS: We investigated causes of elevated lipoprotein(a) in individuals with clinically diagnosed FH (FH cohort, n = 391) and in individuals with genetically diagnosed FH from the general population (UK Biobank; n = 37,486). RESULTS: Patients in the FH cohort had significantly greater lipoprotein(a) levels than either the general population or non-FH dyslipidemic patients. This was accounted for by increased frequency of the rs10455872-G LPA risk allele (15.1% vs. 8.8%; p < 0.05). However, within the FH cohort, lipoprotein(a) levels did not differ based on the presence or absence of an FH-causing variant (means = 1.43 log mg/dl vs. 1.42 log mg/dl; p = 0.97). Lipoprotein(a) levels were also not statistically different between individuals with and without an FH-causing variant in the UK Biobank cohort, which represents a population sample not biased to cardiovascular ascertainment (n = 221 vs. 37,486). We performed a phenome-wide association study between LPA genotypes and 19,202 phenotypes to demonstrate that elevated lipoprotein(a) is associated with increased low-density lipoprotein cholesterol, a family history of cardiovascular disease, premature coronary artery disease, and a diagnosis of FH. CONCLUSIONS: These results suggest that FH does not cause elevated lipoprotein(a), but that elevated lipoprotein(a) increases the likelihood that an individual with genetic FH will be clinically recognized.

Lipoprotein(a) the Insurgent: A New Insight into the Structure, Function, Metabolism, Pathogenicity, and Medications Affecting Lipoprotein(a) Molecule.

Lipoprotein(a) [Lp(a)], aka "Lp little a", was discovered in the 1960s in the lab of the Norwegian physician Kåre Berg. Since then, we have greatly improved our knowledge of lipids and cardiovascular disease (CVD). Lp(a) is an enigmatic class of lipoprotein that is exclusively formed in the liver and comprises two main components, a single copy of apolipoprotein (apo) B-100 (apo-B100) tethered to a single copy of a protein denoted as apolipoprotein(a) apo(a). Plasma levels of Lp(a) increase soon after birth to a steady concentration within a few months of life. In adults, Lp(a) levels range widely from <2 to 2500 mg/L. Evidence that elevated Lp(a) levels >300 mg/L contribute to CVD is significant. The improvement of isoform-independent assays, together with the insight from epidemiologic studies, meta-analyses, genome-wide association studies, and Mendelian randomization studies, has established Lp(a) as the single most common independent genetically inherited causal risk factor for CVD. This breakthrough elevated Lp(a) from a biomarker of atherosclerotic risk to a target of therapy. With the emergence of promising second-generation antisense therapy, we hope that we can answer the question of whether Lp(a) is ready for prime-time clinic use. In this review, we present an update on the metabolism, pathophysiology, and current/future medical interventions for high levels of Lp(a).

Risk of Premature Atherosclerotic Disease in Patients With Monogenic Versus Polygenic Familial Hypercholesterolemia.

BACKGROUND: A pathogenic variant in LDLR, APOB, or PCSK9 can be identified in 30% to 80% of patients with clinically-diagnosed familial hypercholesterolemia (FH). Alternatively, ∼20% of clinical FH is thought to have a polygenic cause. The cardiovascular disease (CVD) risk associated with polygenic versus monogenic FH is unclear. OBJECTIVES: This study evaluated the effect of monogenic and polygenic causes of FH on premature (age <55 years) CVD events in patients with clinically diagnosed FH. METHODS: Targeted sequencing of genes known to cause FH as well as common genetic variants was performed to calculate polygenic scores in patients with "possible," "probable," or "definite" FH, according to Dutch Lipid Clinic Network Criteria (n = 626). Patients with a polygenic score ≥80th percentile were considered to have polygenic FH. We examined the risk of unstable angina, myocardial infarction, coronary revascularization, or stoke. RESULTS: A monogenic cause of FH was associated with significantly greater risk of CVD (adjusted hazard ratio: 1.96; 95% confidence interval: 1.24 to 3.12; p = 0.004), whereas the risk of CVD in patients with polygenic FH was not significantly different compared with patients in whom no genetic cause of FH was identified. However, the presence of an elevated low-density lipoprotein cholesterol (LDL-C) polygenic risk score further increased CVD risk in patients with monogenic FH (adjusted hazard ratio: 3.06; 95% confidence interval: 1.56 to 5.99; p = 0.001). CONCLUSIONS: Patients with monogenic FH and superimposed elevated LDL-C polygenic risk scores have the greatest risk of premature CVD. Genetic testing for FH provides important prognostic information that is independent of LDL-C levels.

Simplified Canadian Definition for Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal codominant lipoprotein disorder characterized by elevated low-density lipoprotein cholesterol (LDL-C) and high risk of premature atherosclerotic cardiovascular disease. Definitions for FH rely on complex algorithms that are on the basis of levels of total or LDL-C, clinical features, family history, and DNA analysis that are often difficult to obtain. We propose a novel simplified definition for FH. Definite FH includes: (1) elevated LDL-C (≥ 8.50 mmol/L); or (2) LDL-C ≥ 5.0 mmol/L (for age 40 years or older; ≥ 4.0 mmol/L if age younger than 18 years; and ≥ 4.5 mmol/L if age is between 18 and 39 years) when associated with at least 1 of: (1) tendon xanthomas; or (2) causal DNA mutation in the LDLR, APOB, or PCSK9 genes in the proband or first-degree relative. Probable FH is defined as subjects with an elevated LDL-C (≥ 5.0 mmol/L) and the presence of premature atherosclerotic cardiovascular disease in the patient or a first-degree relative or an elevated LDL-C in a first-degree relative. LDL-C cut points were determined from a large database comprising > 3.3 million subjects. To compare the proposed definition with currently used algorithms (ie, the Simon Broome Register and Dutch Lipid Clinic Network), we performed concordance analyses in 5987 individuals from Canada. The new FH definition showed very good agreement compared with the Simon Broome Register and Dutch Lipid Clinic Network criteria (κ = 0.969 and 0.966, respectively). In conclusion, the proposed FH definition has diagnostic performance comparable to existing criteria, but adapted to the Canadian population, and will facilitate the diagnosis of FH patients.

Attainment of Recommended Lipid Targets in Patients With Familial Hypercholesterolemia: Real-World Experience With PCSK9 Inhibitors.

BACKGROUND: Familial hypercholesterolemia (FH) is the most common inherited dyslipidemia and is characterized by elevated low-density lipoprotein cholesterol (LDL-C) and markedly increased risk for atherosclerotic cardiovascular disease. Lipid-lowering therapy is the mainstay of treatment, but few patients with FH are able to achieve commonly recommended lipid targets. METHODS: We examined changes in LDL-C levels in patients in the British Columbia FH Registry from 2015 to 2017, corresponding to the period immediately before, and the first 2 years after, availability of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in Canada. RESULTS: Among 275 patients with a clinical diagnosis of FH in whom a lipid profile was available between January 1, 2016 and December 31, 2017, 48 had started using a PCSK9 inhibitor. LDL-C decreased in the cohort overall from 2015 to 2017. When patients were stratified according to PCSK9 inhibitor use, the reduction in LDL-C was significantly greater in patients receiving a PCSK9 inhibitor compared with those who did not receive one. Among patients receiving a PCSK9 inhibitor, 85.4% achieved a ≥ 50% reduction in LDL-C or LDL-C < 2 mmol/L, compared with 50.2% of patients not receiving a PCSK9 inhibitor (P < 0.001). CONCLUSIONS: Our results suggest that control of lipid levels in patients with FH has improved and that the achievement of guideline-directed goals has been facilitated by access to PCSK9 inhibitors. These observations provide insight into the real-world effectiveness of PCSK9 inhibitor therapy in patients with FH.

Increased prevalence of clinical and subclinical atherosclerosis in patients with damaging mutations in ABCA1 or APOA1.

BACKGROUND: A low level of high-density lipoprotein cholesterol (HDL-C) is a common clinical scenario and poses challenges for management. Many patients with low HDL-C harbor a damaging mutation in ABCA1 or APOA1, but the clinical implications of genetic testing for these mutations are unclear. OBJECTIVE: The purpose of this study was to investigate the prevalence of clinical or subclinical atherosclerosis among patients with low HDL-C due to a mutation in ABCA1 or APOA1, compared with patients with low HDL-C without such a mutation. METHODS: We performed targeted next-generation sequencing to identify mutations in ABCA1 and APOA1 in 72 patients with HDL-C levels below the 10th percentile. We examined the prevalence of clinical atherosclerosis and subclinical atherosclerosis in these patients. We also measured cholesterol efflux capacity (CEC) in plasma. RESULTS: We identified a known disease-causing or likely pathogenic variant in the ABCA1 or APOA1 genes in 22% of patients with low HDL-C. Eighty-three percent of patients with a damaging mutation in ABCA1 or APOA1 had evidence of atherosclerosis compared with 38.6% with low HDL-C without such a mutation (P = .04). Patients with damaging mutations in ABCA1 or APOA1 had lower CEC compared with patients without a mutation (25.9% vs 30.1%). CONCLUSION: The presence of a damaging mutation in ABCA1 or APOA1 confers an increased risk of atherosclerosis relative to patients without such a mutation at a comparable level of HDL cholesterol, possibly because of a reduction in CEC.

Contemporary Trends in the Management and Outcomes of Patients With Familial Hypercholesterolemia in Canada: A Prospective Observational Study.

BACKGROUND: Heterozygous familial hypercholesterolemia (HeFH) is one of the most common genetic diseases in the world and an important cause of premature cardiovascular (CV) disease. The purpose of this study was to characterize the clinical features, current treatment patterns, and CV outcomes of patients with HeFH in British Columbia, Canada. METHODS: We conducted a longitudinal observational study of patients with HeFH attending a specialized lipid clinic. We collected data on lipid levels, medication use, and CV events at baseline and last follow-up. RESULTS: We recruited 339 patients with clinically diagnosed HeFH, with a total of 3700 person-years of follow-up. The mean low-density lipoprotein cholesterol (LDL-C) level was 5.9 mmol/L at baseline and 3.7 mmol/L at last follow-up. Use of lipid-lowering therapy (LLT) increased from 35.7% at baseline to 84.7% at last follow-up. A ≥ 50% reduction in LDL-C level was achieved in 34.5% of patients, and an LDL-C level ≤ 2 mmol/L was seen in 8.3%. The overall CV event rate in this cohort was 33.5/1000 person-years. Among patients who had a CV event during follow-up, 59% experienced a recurrent event within 5 years. CONCLUSIONS: These data contribute to our understanding of contemporary trends in the management of patients with HeFH in Canada. Despite a majority of patients receiving LLT, few patients reached high-risk lipid targets. These data highlight important opportunities to improve the care of patients with HeFH.

Statin-Associated Muscle Adverse Events: Update for clinicians.

Statins are potent medications which reduce low-density lipoprotein cholesterol (LDL-C) levels. Their efficacy in cardiovascular risk reduction is well established and indications for their use are expanding. While statins are generally well tolerated and safe, adverse events are relatively common, particularly statin-associated muscle adverse events (SaMAEs), which are the most frequently encountered type of adverse event. Recent guidelines and guideline updates on SaMAEs and statin intolerance have included revised definitions of SaMAEs, incorporating new evidence on their pathogenesis and management. As SaMAEs emerge as a therapeutic challenge, it is important for physicians to be aware of updates on management strategies to ensure better patient outcomes. The majority of patients who are considered statin-intolerant can nevertheless tolerate some forms of statin therapy and successfully achieve optimal LDL-C levels. This review article discusses the recent classification of SaMAEs with emphasis on pathogenesis and management strategies.

Diagnosis, Prevention, and Management of Statin Adverse Effects and Intolerance: Canadian Consensus Working Group Update (2016).

The Canadian Consensus Working Group has updated its evaluation of the literature pertaining to statin intolerance and adverse effects. This overview introduces a pragmatic definition of statin intolerance (goal-inhibiting statin intolerance) that emphasizes the effects of symptoms on achieving nationally vetted goals in patients fulfilling indications for lipid-lowering therapy and cardiovascular risk reduction. The Canadian Consensus Working Group provides a structured framework for avoiding, evaluating and managing goal-inhibiting statin intolerance. Particularly difficult practice situations are reviewed, including management in young and elderly individuals, and in athletes and labourers. Finally, targeted at specialty practitioners, more detailed analyses of specific but more unusual adverse effects ascribed to statins are updated including evidence regarding new-onset diabetes, cognitive dysfunction, cataracts, and the rare but important immune-mediated necrotizing myopathy.

Coronary artery calcification score as tool for risk assessment among families with premature coronary artery disease.

INTRODUCTION: There is discussion about incorporating a family history (FamHis) of premature coronary artery disease (CAD) in risk score algorithms. However, FamHis provides information on individual risk. Coronary artery calcification score (CACS) is a metric of atherosclerosis that may determine the individual risk within families at high risk of premature CAD. METHODS: In asymptomatic individuals (n = 704), we assessed the association between FamHis of CAD and elevated CACS. To assess the predictive value of CACS in individuals with a FamHis of CAD, we performed a post-hoc analysis on the St. Francis Heart Study (n = 834). We assessed, in a case control design, the risk of future CAD in individuals with a FamHis of CAD and either CACS >80th percentile or no CACS at all. RESULTS: Individuals with a FamHis for CAD had an increased risk for elevated CACS (adjusted odds ratio (OR) 2.23 (95% CI 1.48-3.36); p < 0.05), compared to those without a FamHis. In the prospective study (3.5 years follow-up), the event rate equally low in those with a positive FamHis and a negative FamHis (0% vs. 1%), if they had a CAC of 0. However, in those with CACS >80(th) percentile, a FamHis of CAD doubled the CAD event rate (positive FamHis 12.5% vs. negative FamHis 6.8%; adjusted HR 2.08 (95% CI 1.09-3.87; p < 0.05). CONCLUSION: CAC scoring leads to risk discrimination among those with a positive FamHis for premature CAD. These results support testing CAC score in asymptomatic individuals with a positive FamHis to identify a high risk population.

Lipoprotein (a), an independent cardiovascular risk marker.

Epidemiological and genetic studies have identified elevated levels of lipoprotein (a) ((Lp(a)) as a causal and independent risk factor for cardiovascular diseases (CVD). The Lp(a)-induced increased risk of CVD may be mediated by both its proatherogenic and prothrombotic mechanisms. Several guidelines recommend screening of Lp(a) level; however, there are few treatment options for the management of patients with elevated Lp(a). Several new medications for Lp(a) are under development. PCSK9 inhibitors, apolipoprotein (a)-antisense, and apolipoprotein(B-100)-antisense mipomersen have shown promising results. Lp(a) reduction will continue to be an active area of investigation.

Targeted next-generation sequencing to diagnose disorders of HDL cholesterol.

A low level of HDL cholesterol (HDL-C) is a common clinical scenario and an important marker for increased cardiovascular risk. Many patients with very low or very high HDL-C have a rare mutation in one of several genes, but identification of the molecular abnormality in patients with extreme HDL-C is rarely performed in clinical practice. We investigated the accuracy and diagnostic yield of a targeted next-generation sequencing (NGS) assay for extreme levels of HDL-C. We developed a targeted NGS panel to capture the exons, intron/exon boundaries, and untranslated regions of 26 genes with highly penetrant effects on plasma lipid levels. We sequenced 141 patients with extreme HDL-C levels and prioritized variants in accordance with medical genetics guidelines. We identified 35 pathogenic and probably pathogenic variants in HDL genes, including 21 novel variants, and performed functional validation on a subset of these. Overall, a molecular diagnosis was established in 35.9% of patients with low HDL-C and 5.2% with high HDL-C, and all prioritized variants identified by NGS were confirmed by Sanger sequencing. Our results suggest that a molecular diagnosis can be identified in a substantial proportion of patients with low HDL-C using targeted NGS.

Lipid lowering efficacy and safety of Ezetimibe combined with rosuvastatin compared with titrating rosuvastatin monotherapy in HIV-positive patients.

BACKGROUND: HIV-infected patients on antiretroviral therapy frequently develop dyslipidemias and, despite therapy with potent lipid-lowering agents, a high percentage does not achieve guideline recommended lipid targets. In this study, we examined the efficacy of combination treatment with a statin and the cholesterol transport blocker, ezetimibe, vs. monotherapy with a statin in HIV-infected patients not achieving lipid goals. METHODS: This was a 12-week, prospective, randomized, open-label clinical trial. Patients were eligible if they had an apolipoprotein B (apoB) >0.80 g/L despite therapy with rosuvastatin 10 mg daily for a minimum of 12 weeks. Patients were randomized to take ezetimibe 10 mg/rosuvastatin 10 mg or rosuvastatin 20 mg for 12 weeks. Percentage and absolute change in apoB (primary outcome), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, apoliporpotein A1 (apoA1), apoB/apoA1, TC/HDL-C, atherogenic index of plasma (API), and high-sensitivity C-reactive protein (hsCRP) were compared. Changes in safety parameters (such as AST, ALT, CK) and clinical symptoms were also assessed. RESULTS: Forty-three patients (23 on ezetimibe 10 mg/rosuvastatin 10 mg and 20 on rosuvastatin 20 mg) completed the trial. Baseline characteristics did not differ between the groups. Significant improvements in apoB were seen with both ezetimibe plus rosuvastatin (mean of -0.17 g/L, p < 0.001) and rosuvastatin 20 mg (mean of -0.13 g/L, p = 0.03) treatment groups, but did not differ between groups (p = 0.53). Significant between-group differences were observed for mean TC (-1.01 mmol/L vs. -0.50 mmol/L, p = 0.03), TG (-0.62 mmol/L vs -0.17 mmol/L, p = 0.03), and non-HDL-C (-0.97 mmol/L vs. -0.53 mmol/L, p = 0.03) all in favour of the ezetimibe plus rosuvastatin group. Two patients, both in the rosuvastatin 20 mg group, experienced mild myalgias; neither discontinued the study. CONCLUSIONS: The addition of ezetimibe to rosuvastatin appears to be safe in patients with HIV. Furthermore, the combination of ezetimibe and rosuvastatin improved TG, AIP and non-HDL cholesterol levels more than a dose increase in rosuvastatin in patients with HIV-associated dyslipidemia.

Clinical, Biochemical, and Molecular Characterization of Novel Mutations in ABCA1 in Families with Tangier Disease.

Tangier disease is a rare, autosomal recessive disorder caused by mutations in the ABCA1 gene and is characterized by near absence of plasma high-density lipoprotein cholesterol, accumulation of cholesterol in multiple tissues, peripheral neuropathy, and accelerated atherosclerosis. Here we report three new kindreds with Tangier disease harboring both known and novel mutations in ABCA1. One patient was identified to be homozygous for a nonsense mutation, p.Gln1038*. In a remarkably large Tangier disease pedigree with four affected siblings, we identified compound heterozygosity for previously reported missense variants, p.Arg937Val and p.Thr940Met, and show that both of these mutations result in significantly impaired cholesterol efflux in transfected cells. In a third pedigree, the proband was identified to be compound heterozygous for two novel mutations, a frameshift (p.Ile1200Hisfs*4) and an intronic variant (c.4176-11T>G), that lead to the creation of a cryptic splice site acceptor and premature truncation, p.Ser1392Argfs*6. We demonstrate that this mutation arose de novo, the first demonstration of a pathogenic de novo mutation in ABCA1 associated with Tangier disease. We also report results of glucose tolerance testing in a Tangier disease kindred for the first time, showing a gene-dose relationship between ABCA1 activity and glucose tolerance and suggesting that Tangier disease patients may have substantially impaired islet function. Our findings provide insight into the diverse phenotypic manifestations of this rare disorder, expand the list of pathogenic mutations in ABCA1, and increase our understanding of how specific mutations in this gene lead to abnormal cellular and physiological phenotypes.

A review on lecithin:cholesterol acyltransferase deficiency.

Lecithin cholesterol acyl transferase (LCAT) is a plasma enzyme which esterifies cholesterol, and plays a key role in the metabolism of high-density lipoprotein cholesterol (HDL-C). Genetic disorders of LCAT are associated with lipoprotein abnormalities including low levels of HDL-C and presence of lipoprotein X, and clinical features mainly corneal opacities, changes in erythrocyte morphology and renal failure. Recombinant LCAT is being developed for the treatment of patients with LCAT deficiency.

Canadian Cardiovascular Society position statement on familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is the most common genetic disorder causing premature cardiovascular disease and death. Heterozygous FH conservatively affects approximately 1:500 Canadians, and the more serious homozygous form affects approximately 1:1,000,000 Canadians, although these numbers might be underestimated. Of approximately 83,500 Canadians estimated to have FH, most are undiagnosed, which represents a simultaneous public health deficit and opportunity, because early treatment of heterozygous FH can normalize life expectancy. Diagnostic algorithms for FH incorporate increased plasma low-density lipoprotein cholesterol, pathognomonic clinical features, and family history of early cardiovascular disease and hyperlipidemia. DNA-based detection of causative mutations in FH-related genes can help with diagnosis. Maximizing diagnosis and treatment of FH in Canada will involve a multipronged approach, including: (1) increasing awareness of FH among health care providers and patients; (2) creating a national registry for FH individuals; (3) setting standards for screening, including cascade screening in affected families; (4) ensuring availability of standard-of-care therapies, in particular optimization of plasma low-density lipoprotein cholesterol levels and timely access to future validated therapies; (5) promoting patient-based support and advocacy groups; and (6) forming alliances with international colleagues, resources, and initiatives that focus on FH. This document aims to raise awareness of FH nationally, and to mobilize knowledge translation, patient support, and availability of treatment and health care resources for this underrecognized, but important medical condition.

Consumption of a dietary portfolio of cholesterol lowering foods improves blood lipids without affecting concentrations of fat soluble compounds.

BACKGROUND: Consumption of a cholesterol lowering dietary portfolio including plant sterols (PS), viscous fibre, soy proteins and nuts for 6 months improves blood lipid profile. Plant sterols reduce blood cholesterol by inhibiting intestinal cholesterol absorption and concerns have been raised whether PS consumption reduces fat soluble vitamin absorption. OBJECTIVE: The objective was to determine effects of consumption of a cholesterol lowering dietary portfolio on circulating concentrations of PS and fat soluble vitamins. METHODS: Using a parallel design study, 351 hyperlipidemic participants from 4 centres across Canada were randomized to 1 of 3 groups. Participants followed dietary advice with control or portfolio diet. Participants on routine and intensive portfolio involved 2 and 7 clinic visits, respectively, over 6 months. RESULTS: No changes in plasma concentrations of α and γ tocopherol, lutein, lycopene and retinol, but decreased ß-carotene concentrations were observed with intensive (week 12: p = 0.045; week 24: p = 0.039) and routine (week 12: p = 0.031; week 24: p = 0.078) portfolio groups compared to control. However, cholesterol adjusted ß-carotene and fat soluble compound concentrations were not different compared to control. Plasma PS concentrations were increased with intensive (campesterol:p = 0.012; ß-sitosterol:p = 0.035) and routine (campesterol: p = 0.034; ß-sitosterol: p = 0.080) portfolio groups compared to control. Plasma cholesterol-adjusted campesterol and ß-sitosterol concentrations were negatively correlated (p < 0.001) with total and LDL-C levels. CONCLUSION: Results demonstrate that consuming a portfolio diet reduces serum total and LDL-C levels while increasing PS values, without altering fat soluble compounds concentrations. The extent of increments of PS with the current study are not deleterious and also maintaining optimum levels of fat soluble vitamins are of paramount necessity to maintain overall metabolism and health. Results indicate portfolio diet as one of the best options for CVD risk reduction. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00438425.

Clinical usefulness of lipid ratios to identify men and women with metabolic syndrome: a cross-sectional study.

BACKGROUND: Waist circumference, a metabolic syndrome (MetSy) criterion, is not routinely measured in clinical practice making early identification of individuals with MetSy challenging. It has been argued that ratios of commonly measured parameters such as lipids and lipoproteins may be an acceptable alternative for identifying individuals with MetSy. The objective of our study was to explore clinical utility of lipid ratios to identify men and women with MetSy; and to explore the association between lipid ratios and the number of MetSy components. METHODS: Men and women (N = 797) of Aboriginal, Chinese, European, and South Asian origin (35-60 years), recruited across ranges of body mass index (BMI), with no diagnosed cardiovascular disease (CVD) or on medications to treat CVD risk factors were assessed for anthropometrics, family history of CVD, MetSy components (waist circumference, blood pressure, glucose, triglycerides (TG), high-density-lipoprotein-cholesterol (HDL-C)), low-density-lipoprotein-cholesterol (LDL-C), nonHDL-C, and health-related behaviours. RESULTS: Mean levels of lipid ratios significantly increased with increasing number of MetSy components in men and women (p < 0.05). After adjustment for age, ethnicity, smoking, alcohol consumption, physical activity, family history of CVD and BMI, (and menopausal status in women), all lipid ratios were associated with the number of MetSy components in men and women (Poisson regression, p < 0.001). Compared to the rest of the lipid ratios (ROC curve analysis), TG/HDL-C was best able to discriminate between individuals with and without MetSy (AUC = 0.869 (95% CI: 0.830, 0.908) men; AUC = 0.872 (95% CI: 0.832, 0.912) women). The discriminatory power of TC/HDL-C and nonHDL-C/HDL-C to identify individuals with MetSY was the same (for both ratios, AUC = 0.793 (95% CI: 0.744, 0.842) men; 0.818 (95% CI: 0.772, 0.864) women). Additionally, LDL-C/HDL-C was a good marker for women (AUC = 0.759 (95% CI: 0.706, 0.812)), but not for men (AUC = 0.689 (95% CI: 0.631, 0.748)). Based on a multiethnic sample, we identified TG/HDL-C cut-off values of 1.62 in men and 1.18 in women that were best able to discriminate between men and women with and without MetSY. CONCLUSIONS: Our results indicate that TG/HDL-C is a superior marker to identify men and women with MetSy compared to TC/HDL-C, LDL-C/HDL-C, and nonHDL-C/HDL-C.

Implementing phytosterols into medical practice as a cholesterol-lowering strategy: overview of efficacy, effectiveness, and safety.

More than 200 clinical trial reports and several meta-analyses have demonstrated that phytosterols (PSs), natural components of plants, induce clinically relevant reductions in blood low-density lipoprotein cholesterol levels. Here we review data regarding the biochemical effects and potential cardiovascular benefit of PSs as part of the dietary management of dyslipidemia. In addition to discussing the efficacy, effectiveness, and safety of PSs as hypocholesterolemic agents, this review provides an overview of PSs as an adjunctive therapy to cholesterol-lowering pharmaceuticals. Given this lack of evidence regarding the benefits of PSs for reducing cardiovascular end points, this review also discusses the present knowledge that exists about the ability for therapeutic dosages of PSs to confer protection from cardiovascular-related mortality and morbidity. Finally, this review summarizes the factors that affect PS efficacy and the Canadian regulations that govern the use of PSs as cholesterol-lowering agents in foods and supplements.