Serum triglycerides as an independent risk factor for death from coronary heart disease in middle-aged Norwegian men

Prevalence and predictive role of hypertriglyceridemia in statin-treated patients at very high risk: Insights from the START study

BACKGROUND AND AIM

Elevated triglyceride (TG) levels seem to identify subjects at increased cardiovascular risk, independent of LDL-C levels. We sought to evaluate the predictive role of hypertriglyceridemia, defined as TG levels ≥150 mg/dl, in very high risk (VHR) patients with chronic coronary syndromes (CCS) treated with statins.

METHODS AND RESULTS

Using the data from the STable Coronary Artery Diseases RegisTry (START) study, an Italian nationwide registry, we assessed the association between the TG levels and baseline clinical characteristics, pharmacological treatment and major adverse cardio-cerebrovascular events (MACCE) at 1 year in a large cohort of statin-treated patients at VHR. Of the 4751 consecutive patients with CCS enrolled in the registry and classified as VHR, 2652 (55.8%) had TG values available (mean 120.6 ± 54.9) and were treated with at least a statin at baseline: 2019 (76.1%) with TG < 150 and 633 (23.9%) with TG ≥ 150 mg/dl. At 1 year from enrolment, MACCE occurred in 168 (6.3%) patients, without differences between the two groups of TG (5.9 vs 7.6%; p = 0.14). At multivariable analysis, hypertriglyceridemia did not result as independent predictor of the MACCE (hazard ratio: 1.16; 95% confidence intervals: 0.82-1.64; p = 0.42).

CONCLUSIONS

In the present large, nationwide cohort of consecutive CCS patients at VHR with statin-controlled LDL-C levels, hypertriglyceridemia was present in around 24% of cases and did not result as predictor of MACCE at 1 year. Further studies with a longer follow-up and larger sample size are needed to better define the prognostic role of TG levels when intensive LDL lowering therapies are used.

Predictive Value of the Atherogenic Index of Plasma (AIP) for the Risk of Incident Ischemic Heart Disease among Non-Diabetic Koreans

The atherogenic index of plasma (AIP), composed of triglycerides and high-density lipoprotein cholesterol, is a novel critical marker for assessing the risk of atherogenicity and cardiometabolic health. We aimed to prospectively study the association between AIP and incident ischemic heart disease (IHD) risk in a large cohort of non-diabetic Korean adults. Data were assessed from 17,944 participants without diabetes from the Health Risk Assessment Study (HERAS) and Korea Health Insurance Review and Assessment (HIRA) data. The participants were divided into four groups according to AIP quartiles, calculated as log (triglyceride/high-density lipoprotein cholesterol). We prospectively assessed hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD using multivariate Cox proportional-hazard regression models over a 50-month period that followed the baseline survey. During the follow-up period, 332 participants (1.9%) developed IHD. HRs of IHD for AIP quartiles 2-4 were 1.58 (95% CI, 1.03-2.43), 1.82 (95% CI, 1.20-2.78), and 2.11 (95% CI, 1.37-3.24) after adjusting for age, sex, body mass index, smoking status, alcohol intake, physical activity, mean arterial blood pressure, fasting plasma glucose, high-sensitivity C-reactive protein level, and hypertension medication. Higher AIP levels may precede and predict the development of IHD in non-diabetic Korean adults.

Fasting-Evoked En Route Hypoglycemia in Diabetes (FEEHD): From Guidelines to Clinical Practice

BACKGROUND

Lipid profiles have been used for the purposes of health screening and monitoring of the effects of lipid-lowering medications, especially in patients with diabetes who are prone to hyperlipidemia. Fasting for lipid profiles has been the norm for the past decades. This long-lasting tradition poses a risk of hypoglycemia, especially in patients with diabetes.

OBJECTIVE

Our aim is to review the overlooked occurrence of hypoglycemia in patients who fast for laboratory tests, especially lipid profile tests, and commute to the laboratory facility while fasting; a condition we titled "Fasting-Evoked En route Hypoglycemia in Diabetes patients" or "FEEHD". We also review its prevalence and clinical impact on patients with diabetes.

METHODS

We undertook an extensive literature search using search engines such as PubMed and Google Scholar. We used the following keywords for the search: Fasting, Non-fasting; Hypoglycemia; Hypoglycemic Agents; Laboratory Tests; Glucose, Hypoglycemia, Lipid Profiles, FEEHD.

RESULTS

Our literature review has shown that the prevalence of FEEHD is alarmingly high (17-21% of patients at risk). This form of hypoglycemia is under recognized in the clinical practice despite its frequent occurrence. Recent changes in various international guidelines have uniformly endorsed the utilization of non-fasting lipid profiles as the new standard for obtaining lipid profiles with the exception of certain conditions. Multiple studies showed the efficacy of non-fasting lipid tests in comparison to fasting lipid tests, in routine clinical practice.

CONCLUSION

We hope to increase awareness among clinicians about this overlooked and potentially harmful form of hypoglycemia in patients with diabetes, which can be easily avoided. We also hope to call upon clinicians to consider changing the habit of ordering lipid profiles in the fasting state, which has been recently shown to be largely unnecessary in routine clinical settings, with few exceptions in selected cases.

Individuals with obesity but no other metabolic risk factors are not at significantly elevated all-cause mortality risk in men and women

Studies have examined mortality risk for metabolically healthy obesity, defined as zero or one metabolic risk factors but not as zero risk factors. Thus, we sought to determine the independent mortality risk associated with obesity or elevated glucose, blood pressure or lipids in isolation or clustered together. The sample included 54 089 men and women from five cohort studies (follow-up = 12.8 ± 7.2 years and 4864 [9.0%] deaths). Individuals were categorized as having obesity or elevated glucose, blood pressure or lipids alone or clustered with obesity or another metabolic factor. In our study sample, 6% of individuals presented with obesity but no other metabolic abnormalities. General obesity (hazard ratios [HR], 95% CI = 1.10, 0.8-1.6) and abdominal obesity (HR = 1.24, 0.9-1.7) in the absence of metabolic risk factors were not associated with mortality risk compared to lean individuals. Conversely, diabetes, hypertension and dyslipidaemia in isolation were significantly associated with mortality risk (HR range = 1.17-1.94, P < 0.05). However, when using traditional approaches, obesity (HR = 1.12, 1.02-1.23) is independently associated with mortality risk after statistical adjustment for the other metabolic risk factors. Similarly, metabolically healthy obesity, when defined as zero or one risk factor, is also associated with increased mortality risk (HR = 1.15, 1.01-1.32) as compared to lean healthy individuals. Obesity in the absence of metabolic abnormalities may not be associated with higher risk for all-cause mortality compared to lean healthy individuals. Conversely, elevation of even a single metabolic risk factor is associated with increased mortality risk.

Triglyceride-Rich Lipoproteins and Novel Targets for Anti-atherosclerotic Therapy

Although elevated serum low-density lipoprotein-cholesterol (LDL-C) is without any doubts accepted as an important risk factor for cardiovascular disease (CVD), the role of elevated triglycerides (TGs)-rich lipoproteins as an independent risk factor has until recently been quite controversial. Recent data strongly suggest that elevated TG-rich lipoproteins are an independent risk factor for CVD and that therapeutic targeting of them could possibly provide further benefit in reducing CVD morbidity, events and mortality, apart from LDL-C lowering. Today elevated TGs are treated with lifestyle interventions, and with fibrates which could be combined with omega-3 fatty acids. There are also some new drugs. Volanesorsen, is an antisense oligonucleotid that inhibits the production of the Apo C-III which is crucial in regulating TGs metabolism because it inhibits lipoprotein lipase (LPL) and hepatic lipase activity but also hepatic uptake of TGs-rich particles. Evinacumab is a monoclonal antibody against angiopoietin-like protein 3 (ANGPTL3) and it seems that it can substantially lower elevated TGs levels because ANGPTL3 also regulates TGs metabolism. Pemafibrate is a selective peroxisome proliferator-activated receptor alpha modulator which also decreases TGs, and improves other lipid parameters. It seems that it also has some other possible antiatherogenic effects. Alipogene tiparvovec is a nonreplicating adeno-associated viral vector that delivers copies of the LPL gene to muscle tissue which accelerates the clearance of TG-rich lipoproteins thus decreasing extremely high TGs levels. Pradigastat is a novel diacylglycerol acyltransferase 1 inhibitor which substantially reduces extremely high TGs levels and appears to be promising in treatment of the rare familial chylomicronemia syndrome.

Severe hypertriglyceridemia in Norway: prevalence, clinical and genetic characteristics

BACKGROUND

There is a lack of comprehensive patient-datasets regarding prevalence of severe hypertriglyceridemia (sHTG; triglycerides ≥10 mmol/L), frequency of co-morbidities, gene mutations, and gene characterization in sHTG. Using large surveys combined with detailed analysis of sub-cohorts of sHTG patients, we here sought to address these issues.

METHODS

We used data from several large Norwegian surveys that included 681,990 subjects, to estimate the prevalence. Sixty-five sHTG patients were investigated to obtain clinical profiles and candidate disease genes. We obtained peripheral blood mononuclear cells (PBMC) from six male patients and nine healthy controls and examined expression of mRNAs involved in lipid metabolism.

RESULTS

The prevalence of sHTG was 0.13 (95% CI 0.12-0.14)%, and highest in men aged 40-49 years and in women 60-69 years. Among the 65 sHTG patients, a possible genetic cause was found in four and 11 had experienced acute pancreatitis. The mRNA expression levels of carnitine palmitoyltransferase (CPT)-1A, CPT2, and hormone-sensitive lipase, were significantly higher in patients compared to controls, whereas those of ATP-binding cassette, sub-family G, member 1 were significantly lower.

CONCLUSIONS

In Norway, sHTG is present in 0.1%, carries considerable co-morbidity and is associated with an imbalance of genes involved in lipid metabolism, all potentially contributing to increased cardiovascular morbidity in sHTG.

Hypertriglyceridaemia and risk of coronary artery disease

An elevated serum level of LDL cholesterol is a well-known risk factor for cardiovascular disease (CVD), but the role of elevated triglyceride levels is debated. Controversies regarding hypertriglyceridaemia as an independent risk factor for CVD have occurred partly because elevated triglyceride levels are often a component of atherogenic dyslipidaemia - they are associated with decreased levels of HDL cholesterol and increased levels of small dense LDL particles, which are highly atherogenic. Findings from several large studies indicate that elevated levels of triglycerides (either fasting or nonfasting) or, more specifically, triglyceride-rich lipoproteins and their remnants, are independently associated with increased risk of CVD. Possible mechanisms for this association include excessive free fatty acid release, production of proinflammatory cytokines, coagulation factors, and impairment of fibrinolysis. Therapeutic targeting of hypertriglyceridaemia could, therefore, reduce CVD and cardiovascular events, beyond the reduction achieved by LDL-cholesterol lowering. Elevated triglyceride levels are reduced with lifestyle interventions and fibrates, which can be combined with omega-3 fatty acids. Some new drugs are on the horizon, such as volanesorsen (which targets apolipoprotein C-III), pemafibrate, and others. However, CVD outcome studies with triglyceride-lowering agents have produced inconsistent results, meaning that no convincing evidence is available that lowering triglycerides by any approach can reduce mortality.

A 16-week study to compare the effect of vildagliptin versus gliclazide on postprandial lipoprotein concentrations and oxidative stress in patients with type 2 diabetes inadequately controlled with metformin monotherapy

BACKGROUND

Diabetes is closely linked with coronary artery disease, either by means of direct effects of hyperglycemia, or indirectly by its frequent association with dyslipidemia. Any treatment for diabetes that has beyond the capacity of reduce glycated hemoglobin, the propensity to improve lipid profile and reduce weight will bring many benefits to patients.

METHOD

We compare the effects of vildagliptin with the gliclazide on lipid profile before and after a standardized meal test, on glycemic control and oxidative stress in diabetic patients using metformin without adequate glycemic control. This is a prospective study of 16 weeks with diabetic patients using metformin without adequate glycemic control. Patients were randomized to receive gliclazide 30-120 mg/day or vildagliptin 100 mg/day.

RESULTS

36 patients were randomized, with no loss of follow up. Regarding the lipid profile the difference observed at the end of the study was a higher HDL level in the vildagliptin group compared with gliclazide fasting (62.3 vs. 51.3 mg/dL, p = 0.021) and postprandial (62.9 vs. 51.1 mg/dL, p = 0.015). We also observed a variation of negative weight (decrease the end compared to the beginning) of the vildagliptin and a positive (increase) in the gliclazide (-0.3 vs. +1.4 Kg, p = 0.048). The decrease in A1c was lower in the vildagliptin group compared to gliclazide (-1.7 vs.-2.3 %, P = 0.031), however there was no difference in the number of patients reaching target glycated hemoglobin <7 % (50 vs. 61.1 %, p = 0.738). Only the group of vildagliptin presented at the end of the study compared to the beginning, decreased insulin values (599.6 vs.705, 59 pg/ml, p = 0.021), glucagon (46.6 vs.65, 2 pg/ml, p = 0.004) and the marker of oxidative stress TBARS (8.0 vs. 9.0 nmol MDA/ml, p = 0.035).

CONCLUSION

Vildagliptin showed some advantages in addition to metformin in relation to addition of gliclazide. Patients treated with vildagliptin had a higher HDL at the end of the study, less variance in weight, reduced insulin and glucagon as well as reduction of oxidative stress.

The traditions and risks of fasting for lipid profiles in patients with diabetes

Fasting overnight has been traditionally recommended by clinicians when ordering laboratory tests for lipid profiles for the purposes of health screening or monitoring of the effects of lipid-lowering medications. Patients with diabetes are tested for lipid profiles at least annually. This deeply rooted tradition of fasting for lipid testing has recently been challenged. Several studies have shown little benefit obtained by testing lipids in fasting compared with postprandial states. Furthermore, recent studies have shown the importance of postprandial lipid spikes in the pathogenesis of cardiovascular disease. At the same time, recent reports have alerted the medical community to the risk of hypoglycemia in patients with diabetes on antidiabetic medications (particularly insulin and sulfonylureas) who are asked to fast for lab tests. This article reviews the literature on these emerging issues in lipid testing in patients with diabetes, and offers recommendations for lipid testing in these patients in view of these emerging discussions.

Cigarette smoking and colorectal cancer mortality among 602,242 Norwegian males and females

BACKGROUND

Colorectal cancer (CRC) is one of the main cancer types, with high incidence and mortality in Norway. We examined the association between different measures of smoking exposure and CRC mortality overall and by subsite in a large Norwegian cohort.

METHODS

We followed 602,242 participants from four Norwegian health surveys, aged 19-67 years at enrollment between 1972 and 2003 by linkage to the national registries through December 2007. We used Cox proportional hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) by smoking categories for different CRC endpoints.

RESULTS

During a mean follow-up of 14 years, 2,333 Norwegian males and females died of CRC (60% men). Male and female ever smokers had a 20% (HR 1.23, CI 1.08-1.40 and HR 1.22, 95% CI 1.06-1.40, respectively) increased risk of death from CRC compared with sex-specific never smokers. For proximal colon cancer mortality, female ever smokers had a 50% (HR 1.49, 95% CI 1.20-1.87) increased risk compared with female never smokers. The increased risk of rectal cancer mortality was about 40% higher for male ever smokers (HR 1.43, 95% CI 1.14-1.81) compared with male never smokers. A test for heterogeneity by sex showed an increased risk of rectal cancer mortality among men which was significant for former smokers (Wald χ(2) =0.02) and an increased risk of proximal colon cancer mortality among women which was significant for ever and former smokers (Wald χ(2) =0.02 and χ(2) =0.04, respectively).

CONCLUSION

Smoking is associated with increased CRC mortality in both sexes. The risk of rectal and proximal colon cancer mortality was most pronounced among male and female smokers respectively.

The increased risk of colon cancer due to cigarette smoking may be greater in women than men

BACKGROUND

Smoking is a recently established risk factor for colon cancer. We wanted to explore the hypothesis that women may be more susceptible to smoking-attributed colon cancer than men as one of the possible explanations for the high colon cancer risk of Norwegian women.

METHODS

We followed 602,242 participants aged 19 to 67 years at enrollment in 1972-2003, by linkage to national registries through December 2007. We used Cox proportional hazard models to estimate HRs and 95% confidence intervals (CI).

RESULTS

During a mean follow-up of 14 years, altogether 3,998 (46% women) subjects developed colon cancer. Female ever-smokers had a 19% (HR = 1.19, 95% CI = 1.09-1.32) and male ever-smokers an 8% (HR = 1.08, CI = 0.97-1.19) increased risk of colon cancer compared with never smokers. For all the four dose-response variables examined, female ever-smokers in the most exposed category of smoking initiation, (HR = 1.48, 95% CI = 1.21-1.81), of daily cigarette consumption (HR = 1.28, 95% CI = 1.06-1.55), of smoking duration (HR = 1.47, 95% CI = 1.11-1.95), and of pack-years of smoking (HR = 1.33, 95% CI = 1.11-1.57) had a significantly increased risk of more than 20% for colon cancer overall and of more than 40% for proximal colon cancer, compared with never smokers. A test for heterogeneity by gender was statistically significant only for ever smoking and risk of proximal colon cancer (Wald χ(2), P = 0.02).

CONCLUSIONS

Female smokers may be more susceptible to colon cancer and especially to proximal colon cancer than male smokers.

IMPACT

Women who smoke are more vulnerable to colon cancer than men.

Postprandial dysmetabolism and the heart

Epidemiologic evidence indicates that abnormal elevations in glycemia and lipidemia after a meal, termed postprandial dysmetabolism, are linked with increased risk of morbidity and mortality due to cardiovascular disease in individuals with or without type 2 diabetes. Both postprandial hyperglycemia and postprandial hyperlipidemia are independently associated with deteriorating endothelial function and vascular damage, which are likely mediated by increased oxidative stress and are more pronounced when both derangements coexist. Pharmacotherapies that target postprandial hyperglycemia and/or postprandial dyslipidemia are likely to improve endothelial function, which may have positive implications for cardiovascular outcomes.

Postprandial hyperlipidemia, endothelial dysfunction and cardiovascular risk: focus on incretins

Cardiovascular disease (CVD) risk in type 2 diabetes (T2DM) is only partially reduced by intensive glycemic control. Diabetic dyslipidemia is suggested to be an additional important contributor to CVD risk in T2DM. Multiple lipid lowering medications effectively reduce fasting LDL cholesterol and triglycerides concentrations and several of them routinely reduce CVD risk. However, in contemporary Western societies the vasculature is commonly exposed to prolonged postprandial hyperlipidemia. Metabolism of these postprandial carbohydrates and lipids yields multiple proatherogenic products. Even a transient increase in these factors may worsen vascular function and induces impaired endothelial dependent vasodilatation, a predictor of atherosclerosis and future cardiovascular events. There is a recent increased appreciation for the role of gut-derived incretin hormones in controlling the postprandial metabolic milieu. Incretin-based medications have been developed and are now used to control postprandial hyperglycemia in T2DM. Recent data indicate that these medications may also have profound effects on postprandial lipid metabolism and may favorably influence several cardiovascular functions. This review discusses (1) the postprandial state with special emphasis on postprandial lipid metabolism and its role in endothelial dysfunction and cardiovascular risk, (2) the ability of incretins to modulate postprandial hyperlipidemia and (3) the potential of incretin-based therapeutic strategies to improve vascular function and reduce CVD risk.

Nonfasting triglycerides and risk of cardiovascular death in men and women from the Norwegian Counties Study

The association between nonfasting triglycerides and cardiovascular disease (CVD) has recently been actualized. The aim of the present study was to investigate nonfasting triglycerides as a predictor of CVD mortality in men and women. A total of 86,261 participants in the Norwegian Counties Study 1974–2007, initially aged 20–50 years and free of CVD were included. We estimated hazard ratios (HRs) for deaths from CVD, ischemic heart disease (IHD), stroke and all causes by level of nonfasting triglycerides. Mean follow-up was 27.0 years. A total of 9,528 men died (3,620 from CVD, 2,408 IHD, 543 stroke), and totally 5,267 women died (1,296 CVD, 626 IHD, 360 stroke). After adjustment for CVD risk factors other than HDL-cholesterol, the HRs (95% CI) per 1 mmol/l increase in nonfasting triglycerides were 1.16 (1.13–1.20), 1.20 (1.14–1.27), 1.26 (1.19–1.34) and 1.09 (0.96–1.23) for all cause mortality, CVD, IHD, and stroke mortality in women. Corresponding figures in men were 1.03 (1.01–1.04), 1.03 (1.00–1.05), 1.03 (1.00–1.06) and 0.99 (0.92–1.07). In a subsample where HDL-cholesterol was measured (n = 40,144), the association between CVD mortality and triglycerides observed in women disappeared after adjustment for HDL-cholesterol. In a model including the Framingham CHD risk score the effect of triglycerides disappeared in both men and women. In conclusion, nonfasting triglycerides were associated with increased risk of CVD death for both women and men. Adjustment for major cardiovascular risk factors, however, attenuated the effect. Nonfasting triglycerides added no predictive information on CVD mortality beyond the Framingham CHD risk score in men and women.

Blood glucose and risk of incident and fatal cancer in the metabolic syndrome and cancer project (me-can): analysis of six prospective cohorts

BACKGROUND

Prospective studies have indicated that elevated blood glucose levels may be linked with increased cancer risk, but the strength of the association is unclear. We examined the association between blood glucose and cancer risk in a prospective study of six European cohorts.

METHODS AND FINDINGS

The Metabolic syndrome and Cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included 274,126 men and 275,818 women. Mean age at baseline was 44.8 years and mean follow-up time was 10.4 years. Excluding the first year of follow-up, 18,621 men and 11,664 women were diagnosed with cancer, and 6,973 men and 3,088 women died of cancer. We used Cox regression models to calculate relative risk (RR) for glucose levels, and included adjustment for body mass index (BMI) and smoking status in the analyses. RRs were corrected for regression dilution ratio of glucose. RR (95% confidence interval) per 1 mmol/l increment of glucose for overall incident cancer was 1.05 (1.01-1.10) in men and 1.11 (1.05-1.16) in women, and corresponding RRs for fatal cancer were 1.15 (1.07-1.22) and 1.21 (1.11-1.33), respectively. Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri, and stomach.

CONCLUSIONS

Data from our study indicate that abnormal glucose metabolism, independent of BMI, is associated with an increased risk of cancer overall and at several cancer sites. Our data showed stronger associations among women than among men, and for fatal cancer compared to incident cancer. Please see later in the article for the Editors' Summary.

High-density lipoprotein-cholesterol and ischemic heart disease risk in Korean men with cardiac risk

BACKGROUND

Although many epidemiological studies have suggested that a decreased level of high-density lipoprotein-cholesterol (HDL-C) is a risk factor for heart disease; this relationship remains uncertain in relation to triglycerides (TG). This study examined the effects of serum TG and HDL-C on the incidence of ischemic heart disease (IHD) in Korean men.

METHODS AND RESULTS

A 14-year prospective cohort study was carried out with 29,171 Korean men who received insurance from the National Health Insurance Corporation and underwent a second screening for their cardiovascular risks. The main outcome measures were incidence of IHD. During 379,539 person-years of follow-up, 1,634 IHD (227 fatal IHD) events occurred. In the age-adjusted models, men in the lowest level of HDL-C (<30 mg/dl) showed a higher risk [hazard ratio (HR) 1.57; 95% confidence interval (CI) 1.26-1.95] when compared with men with the highest concentration (HDL-C > or =60 g/dl), defined as the reference group. When TG were included in the multivariate adjusted Cox model, the relationship of HDL-C with IHD was weakened but remained (HR 1.38; 95%CI 1.10-1.73). The results were similar for TG in the multivariate model including HDL-C.

CONCLUSIONS

These findings indicate that elevated TG and reduced HDL-C are independent risk factors for IHD risk in Korean men with cardiovascular risks.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Triglycerides and the risk of coronary heart disease: 10,158 incident cases among 262,525 participants in 29 Western prospective studies

BACKGROUND

Many epidemiological studies have reported on associations between serum triglyceride concentrations and the risk of coronary heart disease, but this association has not been reliably quantified. In the present study, we report 2 separate nested case-control comparisons in 2 different prospective, population-based cohorts, plus an updated meta-analysis of 27 additional prospective studies in general Western populations.

METHODS AND RESULTS

Measurements were made in a total of 3582 incident cases of fatal and nonfatal coronary heart disease and 6175 controls selected from among the 44,237 men and women screened in the Reykjavik and the European Prospective Investigation of Cancer (EPIC)-Norfolk studies. Repeat measurements were obtained an average of 4 years apart in 1933 participants in the EPIC-Norfolk Study and an average of 12 years apart in 379 participants in the Reykjavik study. The long-term stability of log-triglyceride values (within-person correlation coefficients of 0.64 [95% CI, 0.60 to 0.68] over 4 years and 0.63 [95% CI, 0.57 to 0.70] over 12 years) was similar to those of blood pressure and total serum cholesterol. After adjustment for baseline values of several established risk factors, the strength of the association was substantially attenuated, and the adjusted odds ratio for coronary heart disease was 1.76 (95% CI, 1.39 to 2.21) in the Reykjavik study and 1.57 (95% CI, 1.10 to 2.24) in the EPIC-Norfolk study in a comparison of individuals in the top third with those in the bottom third of usual log-triglyceride values. Similar overall findings (adjusted odds ratio, 1.72; 95% CI, 1.56 to 1.90) were observed in an updated meta-analysis involving a total of 10,158 incident coronary heart disease cases from 262,525 participants in 29 studies.

CONCLUSIONS

Available prospective studies in Western populations consistently indicate moderate and highly significant associations between triglyceride values and coronary heart disease risk. Because these associations depend considerably on levels of established risk factors, however, further studies are needed to help assess the nature of any independent associations.

Increased triglyceride levels in a Japanese population living in southern Brazil

BACKGROUND

In the present study we investigated 96 individuals of Japanese descent living in southern Brazil (Cascavel-PR) in terms of triglyceride (TG) levels (> or < or = 200 mg/dL) and compared them to non-Japanese control individuals.

METHODS

We analyzed TG and total cholesterol (TC) levels by an enzymatic method and apolipoprotein A-I and B (apo A-I and apo B) by a turbidimetric method. We also determined the lipoproteins HDL and LDL by a direct method and by electrophoresis. All these determinations were performed in plasma.

RESULTS

TG levels were above 200 mg/dL in 18.7% of the individuals of Japanese descent and in 8.4% of the controls. Mean TC levels were 259 mg/dL for Japanese descendants and 225 mg/dL for the control group. We observed that individuals of Japanese descent with TG levels above 200 mg/dL had the highest TC, LDL-c, and VLDL-c levels and the lowest HDL-c and apo A-I levels. Body mass index (BMI) was also higher in individuals of Japanese descent with TG above 200 mg/dL.

CONCLUSIONS

This Japanese population has high TG levels compared to control individuals, and diet did not influence these levels.

Role of fibric acid derivatives in the management of risk factors for coronary heart disease

Although elevated low-density lipoprotein (LDL)-cholesterol is a well established coronary heart disease (CHD) risk factor, the ability to adequately discriminate high-risk individuals by this risk factor alone is limited and other metabolic risk variables are known to modulate CHD risk. For instance, it has been reported that the cluster of metabolic disturbances observed among individuals with abdominal obesity, the so-called metabolic syndrome, is associated with a substantially increased risk of CHD. Among the features of the dyslipidaemic profile observed in these individuals, the high triglyceride-low high-density lipoprotein (HDL)-cholesterol dyslipidaemia is predictive of an elevated risk of CHD. Fibric acid derivatives (fibrates) have been used in clinical practice for more than 2 decades as a class of agents known to decrease triglyceride levels while substantially increasing HDL-cholesterol levels, with a limited but significant additional lowering effect on LDL-cholesterol levels. Although the clinical benefits of HMG-CoA reductase inhibitors (statins) have been well documented by primary and secondary prevention trials that justify their widespread use, it was not until the publication of the VA-HIT (Veterans Affairs High-Density Lipoprotein Intervention Trial) that the relevance of identifying HDL-cholesterol as a therapeutic target to reduce the risk of recurrent CHD events was finally confirmed. The clinical benefits of fibrate therapy are especially important in the subpopulation of patients with low HDL-cholesterol levels with the metabolic syndrome, particularly in patients with type 2 diabetes mellitus or in abdominally obese, hyperinsulinaemic patients. Evidence also suggests that there is a 'fibrate effect' that mediates the reduction in CHD risk beyond the favourable impact of these agents on HDL-cholesterol levels. This last notion is consistent with the pleiotropic effects of fibrates which are known to be related to their mechanisms of action. Through peroxisome proliferator-activated alpha-receptors, fibrates have a significant impact on the synthesis of several apolipoproteins (apo) and enzymes of lipoprotein metabolism as well as on the expression of several genes involved in fibrinolysis and inflammation. Fibrate therapy has been reported to decrease apo CIII levels (a powerful inhibitor of lipoprotein lipase) and increase apo AI levels, as well as to increase lipoprotein lipase activity. Such changes contribute to improve the catabolism of triglyceride-rich lipoproteins, leading to a substantial increase in HDL-cholesterol levels accompanied by a shift in the size and density of LDL particles (from small, dense LDL particles to larger, more buoyant cholesteryl ester-rich LDL). It is proposed that some of these pleiotropic effects could explain some of the clinical benefits of fibrate therapy beyond its HDL-raising properties, particularly among patients with abdominal obesity, hyperinsulinaemia or type 2 diabetes with both low HDL- and low/normal LDL-cholesterol levels.

Influence of triglyceride concentration on the relationship between lipoprotein cholesterol and apolipoprotein B and A-I levels

A sample of 2,103 men aged 47 to 76 years from the Québec Cardiovascular Study cohort was examined to quantify the influence of plasma triglyceride (TG) levels on the relationship between plasma lipoprotein cholesterol and either apolipoprotein A-I (apo A-I) or apo B concentrations. Regression analyses between high-density lipoprotein cholesterol (HDL-C) and apo A-I through TG tertiles showed highly significant correlations (.62 < or = r < or = .75, P < .0001) in all TG tertiles between these 2 variables. The associations for plasma apo B versus low-density lipoprotein cholesterol (LDL-C) and non-HDL-C levels were also studied on the basis of TG concentrations, and correlation coefficients between either LDL-C or non-HDL-C and apo B were essentially similar among TG tertiles (.78 < or = r < or = .85 and .83 < or = r < or = .86 for LDL-C and non-HDL-C, respectively, P < .0001). Regression analyses also showed that lower HDL-C levels were found for any given apo A-I concentration among men in the 2 upper TG tertiles, whereas lower LDL-C concentrations were observed at any given apo B level among subjects in the upper TG tertile. We further investigated whether there were synergistic alterations in the HDL-C/apo A-I and LDL-C/apo B ratios as a function of increasing plasma TG. A significant association was noted between these 2 ratios (r = .37; P < .0001). Mean HDL-C/apo A-I and LDL-C/apo B ratios were then calculated across quintiles of plasma TG concentrations. Increased TG concentrations were first associated with a reduced HDL-C/apo A-I ratio, followed by a decreased LDL-C/apo B ratio. These results suggest that a relatively modest increase in TG may rapidly alter the relative cholesterol content of HDL particles. Finally, the cholesterol content of the non-HDL fraction appears to be influenced less by TG levels than HDL-C and LDL-C fractions. Thus, the plasma apo B-containing lipoprotein cholesterol level may provide a better index of number of atherogenic particles than the LDL-C concentration, particularly in the presence of hypertriglyceridemia (HTG).

Long-term Treatment With Pravastatin Alone and in Combination With Gemfibrozil in Familial Type IIB Hyperlipoproteinemia or Combined Hyperlipidemia

BACKGROUND: Pravastatin inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase. It prevents mevalonate synthesis, reducing endogenous cholesterol production, and reduces cholesterol content in the liver, thus resulting in a down-regulation of low-density lipoprotein receptor production. Gemfibrozil reduces very low-density lipoprotein production and low-density lipoprotein-cholesterol level and increases very low-density lipoprotein catabolism. Therefore, it was suggested that combination therapy with both drugs could effect greater reduction of cholesterol levels as compared to pravastatin alone. The present study was carried out to evaluate the efficacy and safety of pravastatin as a monotherapy or in combination with gemfibrozil in the treatment of patients with familial type IIb hyperlipoproteinemia or familial combined hyperlipidemia. METHODS AND RESULTS: Forty-one patients were included in the study. All patients initially followed 6 weeks of hypolipidemic diet; subsequently they were randomized and received either 20 mg once daily of pravastatin alone (n = 13) or 20 mg of pravastatin together with 600 mg of gemfibrozil twice daily (n = 14). As a control, 14 patients were treated with diet only. The treatment lasted 24 months and clinical evaluation and laboratory tests were done at given time points. Both groups of treated patients showed an early reduction (3 months) of total (about 30% P <.01 vs controls), low-density lipoprotein (about 35%, P <.01 vs controls) and very low-density lipoprotein cholesterol levels (about 18%, P = NS). In contrast, high-density lipoprotein cholesterol levels increased significantly in patients treated with pravastatin and gemfibrozil (about 20%, P <.05 vs controls). Pravastatin treatment alone reduced the level of serum triglycerides as efficiently as in combination with gemfibrozil. Data showed a sustained normalization of lipid profile until 24 months. However, this effect was achieved in patients that had rather low levels of triglycerides. During the treatment we did not observe any difference in the incidence of possible drug-related side effects. Severe myopathy or rhabdomyolysis was not observed at the doses of the drugs used in our study. CONCLUSIONS: Therapy with pravastatin and in combination with gemfibrozil resulted in significant and sustained normalization of lipid profile in high-risk patients with familial type IIb hyperlipoproteinemia or familial combined hyperlipidemia.

Triglycerides and HDL-cholesterol as risk factors for ischemic heart disease. Results from the Québec cardiovascular study

The relative importance of reduced plasma high density lipoprotein-cholesterol (HDL-C) levels and elevated plasma triglyceride (TG) concentrations as risk factors for ischemic heart disease (IHD) was examined in a sample of 2177 men from the Québec City suburbs. The sample included 202 men with known IHD. The relationship between HDL-C and TG levels, although significant (r = -0.49, P < 0.0001), was not linear, as most of the variation in HDL-C levels was observed within TG levels below 2.5 mmol/l. Reduced HDL-C (< 0.9 mmol/l) was a prevalent condition in men with IHD (50%) compared to those without IHD (30%). On the other hand 26% and 20% of men with and without IHD, respectively, had elevated TG levels (TG > 2.3 mmol/l). A 2-fold increase in prevalence odds ratio (OR) was observed in men with TG levels > 2.3 mmol/l (95% confidence intervals (CI) [1.2;3.3]). No residual association between elevated TG levels and IHD was found, however, after adjustment for HDL-C concentrations (OR 1.2, 95% CI 0.7;2.1). On the other hand, HDL-C remained a significant predictor of IHD after adjustment for other risk factors (OR 0.3, 95%, CI 0.2;0.6). Men with reduced HDL-C levels were also characterized by a cluster of risk factors such as obesity, diabetes mellitus and hypertension, which may contribute to increase the risk of IHD. Finally, the independent interpretation of cholesterol, TG or LDL-C levels may lead to an inadequate prediction of risk, as a large number of IHD patients showed a cluster of risk factors which included low HDL-C concentrations.

Plasma HDL cholesterol, triglycerides, and adiposity. A quantitative genetic test of the conjoint trait hypothesis in the San Antonio Family Heart Study

BACKGROUND

The conjoint trait hypothesis proposes that combined low HDL cholesterol (HDL-C) and high triglyceride (TG) levels represent a single, inherited phenotype that adiposity may influence in an unspecified manner. We conducted formal statistical genetic tests of the conjoint trait hypothesis and the relation of the conjoint trait to adiposity using data for 569 subjects in 25 pedigrees from the San Antonio Family Heart Study.

METHODS AND RESULTS

We conducted multivariate genetic analyses to detect the effects of genes and environmental factors on variation in plasma concentrations of HDL-C and TG, fat mass (as percent body weight [FM%], determined by bioelectric impedance), and body mass index (BMI). We used maximum-likelihood methods to simultaneously estimate the phenotypic means and SDs, heritabilities (h2), effects of sex, age-by-sex, eight dietary and medical covariates, and genetic and environmental correlations. Likelihood ratio tests disclosed significant heritabilities (P < .001) for all traits (h2HDL-C = 0.55, h2TG = 0.53, h2FM% = 0.37, h2BMI = 0.44) but significant genetic correlations (P < .001), indicating pleiotropy, between two trait pairs only: HDL-C and TG (PG = -0.52) and fat mass and BMI (PG = 0.86). We obtained significant environmental correlations between all trait pairs except HDL-C and BMI (P > .05).

CONCLUSIONS

Both shared genes (pleiotropy) and shared environmental factors contribute to the commonly observed inverse phenotypic association between plasma levels of HDL-C and TG. Rather than low HDL-C and high TG being a single, genetically transmissible entity, it is the inverse relation between these two phenotypes throughout their normal ranges of variation as well as at the extremes that is influenced by shared genes and shared environments. However, common environmental factors, not shared genes, account for reported associations of plasma HDL-C and TG levels with measures of adiposity.

Identification of patients at high risk for adverse coronary events while awaiting routine coronary angioplasty

BACKGROUND

Identification of patients at risk for progression of coronary stenosis and adverse clinical events while awaiting coronary angioplasty is desirable.

OBJECTIVE

To determine the standard clinical or angiographic variables, or both, present at initial angiography associated with the development of adverse coronary events (unstable angina, myocardial infarction, and angiographic total coronary occlusion) in patients awaiting routine percutaneous transluminal coronary angioplasty (PTCA).

PATIENTS AND METHODS

Consecutive male patients on a waiting list for routine PTCA. Routine clinical details were obtained at initial angiography. Stenosis severity was measured using computerised angiography.

OUTCOME MEASURES

Development of one or more of myocardial infarction, unstable angina, or angiographic total coronary occlusion while awaiting PTCA were recorded as an adverse event.

RESULTS

Some 214 of 219 patients underwent a second angiogram. One had a fatal myocardial infarction and four (2%) were lost to follow up. Fifty patients (23%) developed one or more adverse events (myocardial infarction five, unstable angina 35, total coronary occlusion 23) at a median (range) interval of 8 (3-25) months. Twenty (57%) of the 35 patients with unstable angina developed adverse events compared with 30 (17%) of the 180 with stable angina (P = 0.0001). Plasma triglyceride concentration was 2.6 (1.2) mmol/l in patients with adverse coronary events compared with 2.2 (1.1) mmol/l in those without such events (P < 0.05). Patients with adverse events were younger than those without (54 (9) years v 58 (9) years, P < 0.01). The relative risk of an adverse event in patients with unstable angina and increased plasma triglyceride concentrations was 6.9 compared with those presenting with stable angina and a normal triglyceride concentration (P < 0.02).

CONCLUSIONS

The study shows that adverse events are not uncommon in patients awaiting PTCA. Patients at high risk for adverse events may be predicted by the presence of acute coronary syndrome, increased concentration of plasma triglyceride, and younger age at the time of the first angiogram.

Comparative study of risk factors in patients undergoing coronary or femoropopliteal artery bypass grafting

OBJECTIVE

To compare risk factors in two populations of patients with advanced atheroma requiring coronary or femoropopliteal artery bypass grafting to try to account for the different localisations of vascular disease.

DESIGN

Cross sectional epidemiological study.

SETTING

Cardiovascular surgery department of a university hospital.

SUBJECTS

464 men (mean age 59.25 (SD 8.57) years) undergoing coronary artery bypass grafting; 74 men (mean age 56.28 (13.3) years) undergoing femoropopliteal artery bypass grafting; and 204 control men (mean age 45.07 (6.59) years) who had been recruited in a preventive medicine department.

INTERVENTIONS

Blood samples were drawn 24 hours before surgery.

METHODS

Lipid and lipoprotein concentrations were measured for each patient and with adjustment for age were compared by analysis of covariance. The main risk factors (smoking, arterial hypertension, obesity, and diabetes) were determined by a standardised history, and the chi 2 test was used to compare the results in the two patient groups. Pairwise comparisons between the three populations were performed by logistic discriminant analysis.

RESULTS

Both patient groups showed a significant rise in triglyceride concentration and in the ratio of total cholesterol to high density lipoprotein cholesterol (R1) and a drop in apolipoprotein AI and high density lipoprotein cholesterol concentrations. Disturbances were greater in patients undergoing coronary artery bypass grafting than in those undergoing femoropopliteal artery bypass grafting for the R1 ratio, apolipoprotein B concentration, and the ratio of apolipoprotein AI to apolipoprotein B (R2). A higher proportion of smokers was found in the femoropopliteal bypass group than in the coronary bypass group, whereas were often obese. Logistic discriminant analysis with adjustment for age and with the coronary bypass as the reference group selected three factors: smoking, the R2 ratio, and obesity.

CONCLUSION

Disturbances in lipid and apoprotein concentrations varied with respect to bypass site. Other risk factors played a part in accelerating the atherogenic process, especially smoking in patients undergoing femoropopliteal artery bypass grafting and, to a lesser degree, obesity in patients undergoing coronary artery bypass grafting.

Serum triglycerides in the prediction of coronary artery disease (an Italian experience)

An occupational group living in Rome and composed of 3,007 men aged 46 to 65 years who were free from previous major coronary events was screened for a number of coronary risk factors and then followed up for 10 years. In all, 107 coronary deaths occurred in 10 years. There was a positive relation between coronary death rate and increasing levels of triglycerides, but the difference between the extreme quintile classes was not any more significant after adjustment for cholesterol levels. A cross-classification involving low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglyceride levels showed a higher coronary artery disease (CAD) mortality in subjects with a higher LDL cholesterol/HDL cholesterol ratio and higher triglycerides. However, the excess risk in this subgroup was largely explained by the mean levels of total cholesterol. The multivariate proportional-hazards Cox model with coronary deaths as the end point, and age and triglycerides as predictors, produced a significant coefficient for triglycerides that became nonsignificant when other lipids alone or in combination (total, HDL and LDL cholesterol and some of their ratio) were fed into the model as further covariates. It is concluded that there is no evidence of an independent role of triglycerides in the prediction of coronary deaths.

Non-fasting serum triglyceride concentration and mortality from coronary heart disease and any cause in middle aged Norwegian women

OBJECTIVE

To study the association between non-fasting serum triglyceride concentrations and mortality in women from coronary and cardiovascular disease and all causes.

DESIGN

Follow up by ambulatory teams of men and women who underwent cardiovascular screening for a mean of 14.6 years.

SETTING

National health screening service in Norway.

SUBJECTS

25,058 men and 24,535 women aged 35-49 years.

MAIN OUTCOME MEASURE

Predictive value of non-fasting serum triglyceride concentrations.

RESULTS

At initial screening total serum cholesterol concentration, serum triglyceride concentration, blood pressure, height, and weight were measured, and self reported information about smoking habits, physical activity, and time since last meal were recorded. During subsequent follow up 108 women died from coronary heart disease, 238 from cardiovascular diseases, and 931 from all causes. In women mortality increased steadily with increasing triglyceride concentration for all three causes of death. With the proportional hazards model and adjustment for age, systolic blood pressure, total cholesterol concentration, time since last meal, and number of cigarettes a day the relative risk between triglyceride concentration > or = 3.5 mmol/l and < 1.5 mmol/l was 4.7 (95% confidence interval 2.5 to 8.9) for deaths from coronary heart disease, 3.0 (1.9 to 4.8) for deaths from cardiovascular disease, 2.3 (1.8 to 2.9) for total deaths in all women.

CONCLUSIONS

A raised non-fasting concentration of triglycerides is an independent risk factor for mortality from coronary heart disease, cardiovascular disease, and any cause mortality among middle aged Norwegian women in contrast to what is seen in men.

The predictability of risk factors with respect to incidence and mortality of myocardial infarction and total mortality. A 12-year follow-up of the Oslo Study, Norway

OBJECTIVES

To study the prognostic value of several risk factors on incidence and mortality of myocardial infarction (MI) and total mortality in men.

DESIGN

Prospective cohort study of 12 years' follow-up.

SETTING

All men in Oslo aged 40-49 and a 7% sample of men aged 20-39 were invited for screening.

SUBJECTS

Of all 30,025 invited men, of whom 25,015 were aged 40-49, a total of 16,209 men aged 40-49 attended the screening and risk factors were recorded for these men.

MAIN OUTCOME MEASURES

Incidence of first MI (non-fatal and fatal), mortality of MI, total mortality.

RESULTS

When examining the rate ratio of the fifth to the first quintile of risk factors we found that systolic and diastolic blood pressures were stronger predictors for mortality than incidence of MI. The rate ratios (95% confidence interval) of systolic blood pressure were 3.73 (2.56, 5.44) and 2.56 (2.01, 3.25) respectively. For diastolic blood pressure the corresponding rate ratios were 4.14 (2.84, 6.04) and 2.78 (2.18, 3.54). Small differences in the rate ratios for these end-points were found for total serum cholesterol and triglycerides. Daily cigarette smoking versus non-cigarette smoking was a stronger predictor for MI mortality than incidence, with rate ratios of 3.16 (2.45, 4.24) and 2.34 (2.00, 2.79) respectively. The Cox proportional hazards regression analysis confirmed the above results.

CONCLUSIONS

Total serum cholesterol and triglycerides predicted incidence and mortality of MI equally well. Whereas blood pressure and daily cigarette smoking predicted mortality of MI more strongly.

Plasma triglyceride level and mortality from coronary heart disease

BACKGROUND

Whether the plasma triglyceride level is a risk factor for coronary heart disease has been controversial, and evaluation of the triglyceride level as a risk factor is fraught with methodologic difficulties.

METHODS

We studied the association between plasma triglyceride levels and the 12-year incidence of death from coronary heart disease in 10 North American populations participating in the Lipid Research Clinics Follow-up Study, while adjusting for the potential confounding effects of other risk factors for cardiovascular disease, including the level of high-density lipoprotein (HDL) cholesterol. All analyses were sex-specific, and separate analyses were performed in high and low strata of HDL cholesterol, low-density lipoprotein (LDL) cholesterol, fasting plasma glucose, and age.

RESULTS

The rates of coronary death in both men and women increased with the triglyceride level. In Cox proportional-hazards models adjusted for age, in which the natural log of the triglyceride levels was used to give a normal distribution, the relative risk per natural-log unit of triglyceride (e.g., a triglyceride level of 150 mg per deciliter vs. a level of 55 mg per deciliter) was 1.54 (95 percent confidence interval, 1.19 to 1.98; P < 0.001) in men and 1.88 (95 percent confidence interval, 1.19 to 2.98; P < 0.007) in women. After an adjustment for potential covariates, however, these relative risks were not statistically significant. Analyses based on lipoprotein cholesterol levels revealed a positive association between the triglyceride level and coronary mortality in the lower stratum of both HDL and LDL cholesterol, but not in the higher stratum. Conversely, the HDL cholesterol level was unrelated to coronary mortality in the lower stratum of LDL cholesterol, but was strongly inversely associated with coronary death in the higher stratum of LDL cholesterol. The relative risk of coronary death associated with triglyceride level was higher at younger ages. The associations between the triglyceride level and coronary mortality in the lower HDL cholesterol, LDL cholesterol, and age strata were small and were further reduced by an adjustment for the fasting plasma glucose level.

CONCLUSIONS

Overall, the plasma triglyceride level showed no independent association with coronary mortality. However, in subgroups of subjects with lower HDL and LDL cholesterol levels and in younger subjects, defined a priori, an association between the triglyceride level and coronary mortality was observed, although this association was small and was not statistically significant after an adjustment for the plasma glucose level.

Metabolic heterogeneity associated with high plasma triglyceride or low HDL cholesterol levels in men

To further understand the factors involved in the regulation of high plasma triglyceride (TG) or low plasma high density lipoprotein cholesterol (HDL-C) levels, three groups of male subjects (normal TG with low HDL-C levels, high TG with normal HDL-C levels, and high TG with low HDL-C levels) were compared with a sample of normolipemic men with normal TG and HDL-C plasma levels. Mean age was 34 years (range, 20-42 years), and none of the subjects had plasma TG levels > 4.0 mmol/l or familial hypercholesterolemia. Both groups of subjects with high TG levels had a higher body mass index, waist circumference, waist-to-hip circumferences ratio, and a higher ratio of abdominal to femoral adipose tissue areas as measured by computed tomography when compared with normolipemic control subjects. However, during an oral glucose tolerance test only high TG-low HDL-C men had fasting hyperinsulinemia and higher plasma insulin levels compared with normolipemic subjects. In addition, the high TG-low HDL-C group showed reduced HDL apoprotein (apo) A-I levels and a low HDL2-C/HDL3-C ratio. These changes were observed along with a nonsignificant trend for a lower plasma postheparin lipoprotein lipase activity. However, among subjects with high TG and normal HDL-C levels, no evidence of insulin resistance or of a reduction in postheparin lipoprotein lipase activity was observed, suggesting that the high plasma TG levels could be attributed to an increased production of apo B-containing lipoproteins, as high plasma apo B and low density lipoprotein (LDL)-apo B levels were observed in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular risk factors: interactive effects of lipids, coagulation and fibrinolysis

In western societies cardiovascular disease accounts for approximately one of every three deaths, and is a major contributor to chronic debiliation. During the last years our knowledge of factors that contribute to the development and progression of this disease has increased markedly. Elevated serum total cholesterol, hypertension and cigarette smoking are "traditional", well-known risk factors. In addition, low serum levels of high density lipoprotein (HDL) cholesterol predispose to development of disease, whereas in epidemiological studies the role of increased triglycerides is more controversial. During the last years derangements in several haemostatic components in persons who develop cardiovascular disease have been observed. Such alterations include increased plasma concentrations of fibrinogen, Factor VII coagulant activity and plasminogen activator inhibitor-1 (PAI-1). Furthermore, interactions between lipoproteins and haemostatic factors are gradually being disclosed. Serum triglycerides have been shown to correlate both to PAI-1 and to Factor VII. The lipoprotein (a), first described by Berg in 1963, also appears to be a link between lipoprotein metabolism and fibrinolytic function. In addition, linkages are observed between high triglycerides, low HDL cholesterol, reduced glucose tolerance, hyperinsulinemia, obesity, low physical activity, reduced fibrinolytic capacity and increased Factor VII. This clustering of risk factors has been suggested to be a coronary risk syndrome and has been called Reavens syndrome, syndrome X and insulin-resistance syndrome. A more descriptive name, athero-thrombogenic syndrome (ATS), has recently been suggested, thereby indicating that both atherosclerosis and thrombosis contribute to its development.(ABSTRACT TRUNCATED AT 250 WORDS)

Docosahexaenoic and eicosapentaenoic acids in plasma phospholipids are divergently associated with high density lipoprotein in humans

The effect of fish oil rich in eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on serum lipoprotein concentrations is not clear, and it is not known whether EPA and DHA are similarly related to serum lipid or lipoprotein levels. We conducted a randomized, 10-week, dietary supplementation trial in which the effects of 6 g per day of 85% EPA and DHA were compared with 6 g per day of corn oil in 156 men and women. Multivariate analyses were used to assess independent relations between plasma phospholipid EPA and DHA and serum lipoprotein levels. In the fish oil group triglycerides fell 21% (p less than 0.001) and high density lipoprotein cholesterol (HDL-C) rose 3.8% (p less than 0.05). In the corn oil group triglycerides did not change, but HDL-C rose 6.1% (p less than 0.01). Compared with fish oil, apolipoprotein A-I (apo A-I) rose 5.1% after corn oil intake (p less than 0.05). Plasma EPA and DHA levels rose after fish oil intake and fell after corn oil intake (all p less than 0.001). The change (delta) in EPA was inversely correlated with delta triglycerides (p = 0.035) and positively correlated with delta HDL-C and delta apo A-I (both p less than 0.001) in the multivariate analyses. In contrast, delta DHA was not correlated with delta triglycerides but was inversely correlated with delta HDL-C and delta apo A-I (both p less than 0.001). Standardizing for DHA removed the difference in apo A-I levels between groups. This study suggests that EPA and DHA are divergently associated with HDL, possibly through different mechanisms.

The importance of triglycerides: results from the Prospective Cardiovascular Münster (PROCAM) Study

In the PROCAM study hypertriglyceridaemia was much more common among men (18.6%) than women (4.2%). Prevalence increased with age in women, but remained nearly constant at about 20% in men aged 35 years or more. In a multiple regression analysis a strong negative correlation between triglycerides and HDL cholesterol was found. A positive relationship was observed with cholesterol, blood glucose, factor VIIc, and PAI-1 in both sexes. Only in men, triglycerides are positively correlated with Apo A-I, body mass index, cigarette smoking, and alcohol consumption. Postmenopausal women showed higher triglyceride levels than premenopausal women. No independent relationships were observed to age, blood pressure, Lp(a), Apo A-II, Apo B, AT-III, protein C, fibrinogen, and oral contraceptives. A longitudinal analysis of data from 4474 male PROCAM participants aged 40-64 years with a follow-up of 4 years did not identify triglycerides as an independent risk factor, but the data suggest hypertriglyceridaemia is an additional risk factor for CHD, when excessive triglycerides coincide with a high ratio of plasma cholesterol to HDL-cholesterol and with low HDL-cholesterol values.

Coronary calcification and its relation to extracoronary atherosclerosis in asymptomatic hypercholesterolemic men. The PCV METRA Group

BACKGROUND

The prevalence of coronary calcifications and extracoronary plaques was studied in patients with asymptomatic hypercholesterolemia.

METHODS AND RESULTS

Ultrafast computed tomography for coronary calcification (presence or absence: calcium score) and echographic assessment of carotid, aortic, and femoral plaques were performed in 111 hypercholesterolemic men: 65% had coronary calcification, 72% had extracoronary plaque. The two lesions were associated as: 1) compared with subjects without coronary calcification, those with calcification had a higher prevalence of aortic (p less than 0.05) and femoral (p less than 0.01) plaque and of two diseased sites (p less than 0.05); 2) the prevalence of coronary calcification was higher in the presence than in the absence of aortic (p less than 0.05) or femoral (p less than 0.01) plaque and higher in two (p less than 0.01) and three diseased (p less than 0.05) sites than in no diseased site; 3) the calcium score was higher in the presence than in the absence of carotid (p less than 0.05), aortic (p less than 0.05), or femoral (p less than 0.001) plaque, higher in two (p less than 0.001) and three diseased (p less than 0.05) sites than in no diseased sites, and higher in two (p less than 0.01) than in one diseased site; and 4) the calcium score correlated with femoral plaque (p less than 0.001). Overall, the presence of two or three diseased extracoronary sites versus no or one diseased site showed a power of 78% for predicting coronary calcification. Coronary calcium score correlated with age (p less than 0.01) and triglycerides (p less than 0.05).

CONCLUSIONS

The close relation between coronary calcium and extracoronary plaques suggests that echography of extracoronary vessels could aid in the screening of coronary atherosclerosis in high-risk, asymptomatic individuals.

Effects of a monounsaturated rapeseed oil and a polyunsaturated sunflower oil diet on lipoprotein levels in humans

The effects of high oleic acid rapeseed oil compared with polyunsaturated fats on serum lipoprotein levels are largely unknown. Therefore, we fed 30 women and 29 men a baseline diet rich in saturated fat, which was followed by a diet rich in high oleic and low erucic acid rapeseed oil (total energy content of fat, 38%; saturates, 12.4%; monounsaturates, 16%; n-6 polyunsaturates, 6%; and n-3 polyunsaturates, 2%) and one rich in sunflower oil (total energy content of fat, 38%; saturates, 12.7%; monounsaturates, 10%; n-6 polyunsaturates, 13%; and n-3 polyunsaturates, 0%). The oils were incorporated into mixed natural diets that were dispensed in a random order for 3.5 weeks each in a blinded crossover design. The diet composition was confirmed by analysis of duplicate diets. Both test diets reduced serum total cholesterol (TC) and low density lipoprotein (LDL) cholesterol levels from baseline, the monounsaturated rapeseed oil diet more than the polyunsaturated sunflower oil diet (TC: -15% versus -12%, p less than 0.01; LDL cholesterol: -23% versus -17%, p less than 0.01). Very low density lipoprotein (VLDL) cholesterol and total, VLDL, and LDL triglyceride levels were lower during the sunflower oil diet compared with the rapeseed oil diet. Total high density lipoprotein (HDL) cholesterol levels remained unchanged by both diets. The consumption of rapeseed oil resulted in a more favorable HDL2 to LDL cholesterol ratio (0.43 +/- 0.19 versus 0.39 +/- 0.18, p less than 0.01) and an apolipoprotein A-I to B ratio (3.0 +/- 1.4 versus 2.4 +/- 1.6, p less than 0.001) than did the sunflower oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of triglycerides and HDL cholesterol in hypertriglyceridemia

Hypoalphalipoproteinemia (plasma HDL-cholesterol concentration at or below 35 mg/dl as reported in the National Cholesterol Education Program Guidelines) is a well known risk factor for premature coronary artery disease (CAD). In hypertriglyceridemic patients, hypoalphalipoproteinemia is commonly believed to be linked to the derangement of triglyceride metabolism. In this study the occurrence of primary hypoalphalipoproteinemia has been investigated in a cohort of hypertriglyceridemic patients whose plasma triglyceride concentration had been normalized either through diet or diet plus drug treatment. Following the initial visit, 115 hypertriglyceridemic patients received dietary advice and returned for the second visit four months later. Diet reduced plasma triglycerides in all the patients. HDL-cholesterol increased in 76 patients whereas in the others, it remained unchanged or even decreased. Plasma triglyceride concentration was normalized (less than 200 mg/dl) in 54 patients by diet alone, but among these 11 remained hypoalphalipoproteinemics. Patients in whom, despite dietary restrictions, triglycerides exceeded 200 mg/dl, were considered for pharmacological treatment with Bezafibrate (300 mg t.i.d.) for 4 months. Thirty-nine concluded the study. Treatment significantly decreased plasma triglyceride concentration in all the subjects. Normalization was achieved in 32 patients. Four of them, however, remained hypoalphalipoproteinemic. These results indicate that a subgroup of hypertriglyceridemic patients remained hypoalphalipoproteinemic even after normalization of triglyceride levels. In these patients hypertriglyceridemia and hypoalphalipoproteinemia may occur as expression of two distinct primary metabolic defects.

Plasma triglyceride and coronary heart disease

Although the literature on epidemiological associations between plasma triglyceride and CHD is not completely consistent, trends do emerge from the studies described here. First, the majority of observational studies demonstrate a significant univariate relation, although the results of case-control and cross-sectional studies are more uniform than those from prospective study designs. In many but not all studies, triglyceride remains a significant predictor of CHD in multivariate statistical analyses after controlling for TC or LDL-C. Perhaps the least consistent result is that the triglyceride association does not persist in some analyses controlling for HDL-C, while in other studies, the association remains significant. Although most studies have been conducted in men, the studies providing data on women, normocholesterolemic subjects, and diabetic subjects have generally found triglyceride to be, at the very least, a univariate risk factor. The results of intervention trials differ considerably, but no such study to date has been specifically designed to evaluate triglyceride-lowering effects on primary prevention of CHD. Important statistical properties must be taken into consideration in evaluating triglyceride as a risk factor for CHD. The large variability of triglyceride measurements and the correlation of triglyceride values with other lipid measures appears to result in the underestimation of the association between triglyceride and disease in multivariate analyses. Finally, individual genetic susceptibility may play an important role in the relation between plasma triglyceride levels and CHD. For example, risk of CHD clearly varies among the well-established familial forms of hypertriglyceridemia. A predominance of small, dense, LDL particles (LDL subclass pattern B) also appears to be a genetic trait associated with both increased risk of MI and increases in plasma triglyceride levels.

Lipid effects of antihypertensive drugs

Despite the well-established correlation between coronary heart disease (CHD) and hypertension, conventional antihypertensive therapy with diuretics and beta-adrenergic blockers has failed to provide protection against CHD. A possible explanation for this failure is the unfavourable effect such drugs have on lipid metabolism. To compare the lipid profiles of commonly used antihypertensive drugs, a survey was made of selected studies from the literature. Diuretics and selective and nonselective beta-blockers were found to have adverse effects on blood lipids. Beta-blockers with intrinsic sympathomimetic activity, labetalol, methyldopa, calcium channel blockers and ACE-inhibitors are lipid neutral, whereas alpha-adrenergic blockers seemed to have a favourable effect on lipid metabolism. Controlled clinical trials with drugs that have no adverse effects on lipid metabolism are needed to establish the long-term clinical importance of such agents.