Risk factors for ischaemic heart disease in men and women. Results of the 19-year follow-up of the Stockholm Prospective Study

Plasma lipids, lipoproteins and apolipoproteins in hirsute women

OBJECTIVE

To determine whether lipid alterations in hirsute women are due to excessive androgen, low estrogen or to a combination of these abnormalities.

DESIGN

Cross sectional study.

PATIENTS

Forty-five hirsute women between 15 and 39 years of age.

MAIN OUTCOME MEASURES

FSH, LH, 17beta-estradiol, PRL, testosterone, androstenedione, triglycerides and apolipoproteins A-I and B.

RESULTS

Testosterone was correlated with triglycerides (r: 0.76, p<0.01), HDL (r: -0.61, P<0.01) and LDL (r: 0.50, p<0.05). Both HDL (r: 0.66, p<0.01) and LDL (r: -0.57, p<0.01) were correlated with estradiol. Total cholesterol was also correlated with estradiol (r: -0.52, p<0.05). Cross adjusted correlations revealed that, after adjusting for estradiol, lipids were associated with testosterone and that estradiol was also correlated with lipids when adjusted for testosterone.

CONCLUSION

The results suggest that altered lipids in women with hyperandrogenism could result from independent effects of androgens and estrogens.

Multivariate analyses of mortality from coronary heart disease due to biological and behavioural factors

Due to affluence and a sedentary life style a great deal of people in the western countries are affected by coronary heart disease (CHD). The relation between CHD and certain risk factors pertaining to life style is evaluated in this study. A primary purpose is to study certain crucial risk factors for women. The main variables are age, smoking, overweight (measured by BMI), blood pressure and exercise. This prospective study is based on self-reported data from the nation-wide Swedish Level of Living Survey and on data from the national Cause of Death Register. The data were analysed separately by sex using a proportional hazards model. The sample was divided into two strata: those with heart disease and/or diabetes initially, and all the rest. A sample of 2546 men and 2760 women between 45 and 74 years of age was followed from 1980 to the end of 1990. During this period 189 men and 75 women died of coronary heart disease (CHD). It was found that high blood pressure raised the relative risk (RR) of death from CHD by almost 60% in both men and women. Male smokers (> 14 cigarettes a day) had about 60% (significant) and female smokers (> 10 cigarettes a day) 150% (significant) excessive mortality from CHD. Different levels of overweight among women were strongly related to excess mortality from CHD, ranging between 100 and 300%. Among men there was no such relation. Lack of physical activity showed only a weak (non-significant) increased risk of death due to CHD. Diabetes was also found to be an important risk factor for mortality from CHD, especially among women, being seven times as high as among non diabetics. A test of sex differences revealed that there were two significant interactions, namely between sex and overweight, and between sex and age. Background variables in relation to mortality from all cardiovascular diseases (CVD) were also studied. There were of course many similarities between the effects of the background variables in both the disease groups, but there were interesting differences too, e.g. overweight turned out to be a significant risk factor also for men and physical inactivity for women.

Smoking, serum lipids, blood pressure, and sex differences in myocardial infarction. A 12-year follow-up of the Finnmark Study

BACKGROUND

Few epidemiological studies have investigated the relative importance of major coronary risk factors in the two sexes within the same study population. In particular, it is not clear whether smoking carries a similar risk of coronary heart disease in men and women.

METHODS AND RESULTS

The associations between smoking, serum lipids, blood pressure, and myocardial infarction were examined in a population-based prospective study of 11,843 men and women aged 35 to 52 years at entry. During 12 years, 495 cases of first myocardial infarction among men and 103 cases among women were identified. Myocardial infarction incidence was 4.6 times higher among men. The incidence was increased sixfold in women and threefold in men who smoked at least 20 cigarettes per day compared with never-smokers, and the rate in female heavy smokers exceeded that of never-smoking men. Multivariate analysis identified current smoking as a stronger risk factor in women (relative risk, 3.3; 95% confidence interval [CI], 2.1 to 5.1) than in men (relative risk, 1.9; 95% CI, 1.6 to 2.3). Among those under 45 years old at entry, the smoking-related sex difference was more pronounced (in women: relative risk, 7.1; 95% CI, 2.6 to 19.1) (in men: relative risk, 2.3; 95% CI, 1.6 to 3.2). Serum total cholesterol, HDL cholesterol, and systolic blood pressure were also highly significant predictors in both sexes.

CONCLUSIONS

Smoking was a stronger risk factor for myocardial infarction in middle-aged women than in men. Relative risks associated with serum lipids and blood pressure were similar despite large sex differences in myocardial infarction incidence rates.

Physical fitness and perceived stress. Relationships with coronary artery disease risk factors

This study evaluated the relationship between two biochemical risk factors for coronary artery disease, serum lipids and dehydroepiandrosterone-sulfate (DHEA-S), and both fitness and perceived stress among a cohort of senior male Army officers (N = 331). The participants underwent a number of assessments gauging their fitness [exercise tolerance as measured by maximum ventilatory oxygen uptake (MVO2)], psychological well-being, and biochemical cardiovascular risk factors. Perceived stress was significantly and inversely related to DHEA-S levels, even after adjusting for age, though no relationship was found between perceived stress and serum lipids. Significant correlations were found between MVO2 and high-density lipoprotein cholesterol and inversely between MVO2 and triglycerides. Overall, the study's findings are generally consistent with the view that psychological stress and physical activity have opposite effects on parameters that affect cardiovascular status.

Studies in hypertriglyceridaemia, III: Glucose tolerance, insulin sensitivity and indices of adipose tissue lipolysis in randomly selected non-diabetic hypertriglyceridaemic Swedish men

Hypertriglyceridaemia, insulin resistance and glucose intolerance are conditions associated with an increased risk of coronary heart disease. In this study we have examined randomly selected nondiabetic hypertriglyceridaemic (HTG) males, 40-50 years (n = 65) and age-matched normotriglyceridaemic (NTG) controls (n = 61). The (mean +/- SD) insulin sensitivity index, as assessed by the Minimal Model method, was significantly lower in the HTG compared with the NTG group (3.69 +/- 2.96 vs. 6.29 +/- 3.38 x 10(-4) min-1 per mUL-1; P < 0.001). Thirty-eight per cent of the HTG group was glucose intolerant, compared with 8% in the NTG group (X2 = 13.16; P < 0.001). The glucose intolerant HTG sub-group had, when compared with the glucose tolerant one, significantly higher serum concentrations of apoB (1318 +/- 284 vs. 1094 +/- 312 mg L-1; P < 0.01) and glycerol (84 +/- 26 vs. 65 +/- 22 nmol L-1; P < 0.01). Serum FFA concentrations were, irrespective of glucose tolerance/intolerance, higher in the HTG than in the NTG group. By logistic regression analysis with the HTG/NTG state as the dichotomous variable, it was found that neither a low insulin sensitivity, nor glucose intolerance were independently linked with the HTG state. Instead, the lower insulin sensitivity of the HTG group was related to their higher body mass index. The higher frequency of glucose intolerance in the HTG group was explained by their higher mean serum apoB concentration, when compared with the NTG group. In conclusion, this study of a randomly selected of HTG group has confirmed the frequent coexistance of HTG, insulin resistance and glucose intolerance. The new important finding was that neither of these two latter conditions appear to be of direct pathogenetic importance for HTG.

Human triacylglycerol-rich lipoprotein subfractions as substrates for lipoprotein lipase

In order to test the hypothesis that lipoprotein lipase (LPL) acts preferentially on larger lipoprotein particles, we determined the susceptibility of triacylglycerol-rich lipoprotein (TRL) subfractions to hydrolysis by LPL in vitro. Chylomicrons (Sf > 400), very low density lipoproteins (VLDL)1 (Sf 60-400) and VLDL2 (Sf 20-60) were isolated from six subjects with a range of plasma-triacylglycerol (TAG) concentrations following an overnight fast and for up to 6 h after the consumption of a mixed meal (41% fat). The percent of TRL-TAG hydrolysed by LPL in subfractions isolated following overnight fast was VLDL1 > VLDL2 (46.8 +/- 10.2 vs. 25.9 +/- 7.4%, P = 0.006) and 3 h after the meal it was chylomicrons > VLDL1 > VLDL2 (81.0 +/- 12.6 vs. 52.8 +/- 10.2 vs. 27.7 +/- 6.2%, chylomicrons vs. VLDL1 and VLDL1 vs. VLDL2, both P < or = 0.005). The percent of VLDL1-TAG hydrolysed increased both within and between subjects as VLDL1-TAG concentrations increased. This relationship could be explained by the positive correlation observed between VLDL1-TAG and VLDL1-TAG:apolipoprotein B. In conclusion, increasing the size and TAG content of a lipoprotein particle increases its susceptibility to hydrolysis by LPL.

Evaluation of cultured hamster hepatocytes as an experimental model for the study of very low density lipoprotein secretion

The secretion of triacylglycerol, cholesterol and cholesteryl ester in very low density lipoprotein (VLDL) by cultured hamster hepatocytes was studied, and the results compared with those obtained previously using cultured rat hepatocytes and the human hepatoma cell line HepG2. The hamster cells secreted apolipoprotein B and VLDL triacylglycerol, cholesterol and cholesteryl ester linearly during 24 h in culture, and this time period was used in all experiments. Addition of oleate (1 mM) to the culture medium resulted in increased secretion of triacylglycerol, but cholesterol ester output were unchanged. Triacylglycerol secretion was also increased in the presence of lipogenic substrates (10 mM lactate + 1 mM pyruvate) plus dexamethasone (1 microM), but not with either of these agents alone. Inhibition of cholesterol synthesis in the hamster cells by incubation with mevinolin (2 micrograms/ml) did not change VLDL lipid secretion, but stimulation using mevalonate lactone resulted in decreased triacylglycerol output. Manipulation of the rate of cholesterol esterification in the hepatocytes by inhibiting or stimulating the activity of acyl coenzyme A cholesterol:acyl transferase using the inhibitor Dup128 (25 microM) and 25-hydroxycholesterol (50 microM), respectively, had no effect on the secretion of VLDL lipid. In the presence of 1 mM oleate plus 25-hydroxycholesterol, however, a rise in the output of triacylglycerol and cholesteryl ester was observed. Hepatocytes prepared from hamsters fed 2% cholestyramine secreted significantly less triacylglycerol than those from animals given the control diet, but cholesterol and cholesteryl ester output were unchanged, despite a decrease of about 40% in the total cholesterol content of the cells. These results show that the secretion of lipid in VLDL in hamster hepatocytes differs from that in rat and human liver in its response to dietary cholestyramine, and from rat hepatocytes and HepG2 cells in its response to changes in the rate of lipogenesis and cholesterol synthesis and esterification. Overall, hamster hepatocytes appear to be less susceptible to modification the rate of hepatic VLDL secretion, and should provide a useful additional tool for the investigation of this process.

Lecithin-cholesterol acryltransferase activity in patients with coronary artery disease examined by coronary angiography

This study grew out of observations of certain lecithin:cholesterol acyltransferase (LCAT) abnormalities in patients with atherosclerosis. We studied the interrelationships among LCAT, and total cholesterol, free and esterified cholesterol, cholesterol in individual lipoprotein fractions, triglycerides, phospholipids, free fatty acids, L-lactates in 90 angiographically examined patients with coronary artery disease and 30 control subjects without clinical manifestations of coronary artery disease. Results of the study showed LCAT activity to be significantly decreased (P < 0.05) in patients with single-, double-, or triple-vessel disease than in disease-free subjects. LCAT was also found to follow the stage of coronary artery disease in angiographically examined patients. Decreased LCAT activity was accompanied by lower high-density lipoprotein cholesterol, elevated ratio of unesterified to esterified cholesterol, and increased levels of L-lactates, free fatty acids, and low-density lipoprotein cholesterol. Total cholesterol and triglycerides were within or slightly above the normal limits. The results show LCAT to be a significantly better indicator of the risk of coronary artery disease than either total cholesterol or triglycerides.

Dyslipidemia and coronary artery disease

Genetically determined and metabolically induced disturbances in lipid metabolism, as manifested in several types of dyslipidemia, have been shown to be causally related to the development of coronary artery disease (CAD). A diversity of clinical and angiographic studies has been made to evaluate the linkage between plasma lipid-control therapy in the development of initial and recurrent cardiovascular events. The plan of treatment invariably begins with a low-fat, low-cholesterol diet before initiation of drug therapy. However, many patients have difficulty in adhering to the low-fat diet. Fortunately, metabolic studies show that foods which contain fats rich in stearic (saturated) and oleic (monounsaturated) fatty acids may be given in limited amounts to boost patients' compliance to a low-fat diet and to prevent their blood lipids from rising to abnormal levels. A bile acid sequestrant (cholestyramine or colestipol) is the first-line drug for control of hypercholesterolemia. Either gemfibrozil or gemfibrozil plus niacin is prescribed to raise high-density lipoprotein (HDL) levels of CAD patients. Approval of two HMG CoA reductase inhibitors, pravastatin and simvastatin, by the FDA gives physicians the additional flexibility of employing a single or a combination drug therapy for optimal control of dyslipidemia. The association of low serum cholesterol level (< 160 mg/dl) with increase in noncardiac mortality has prompted health professionals to consider modifying the universal screening and treatment of serum cholesterol in children and young women and to use hypolipidemic drugs in patients judiciously.

Development of new coronary atherosclerotic lesions during a 4-year multifactor risk reduction program: the Stanford Coronary Risk Intervention Project (SCRIP)

OBJECTIVES

This study attempted to determine whether an intensive multifactor risk reduction program conducted over 4 years would reduce the rate of development of new coronary artery lesions.

BACKGROUND

Recent angiographic trials have generally demonstrated that normalization of plasma lipoprotein profiles reduces the rate of progression of established coronary lesions, but limited data exist on how these treatments influence the development of new lesions.

METHODS

Three hundred men and women with coronary artery disease were randomized to multifactor risk reduction or usual care. Highly significant improvements in risk factors were achieved by the risk reduction group compared with minimal changes by the usual care group. Quantitative coronary angiography was performed on entry and after 4 years under identical conditions. A decrement in the minimal diameter of visually normal segments > 0.2 mm was considered to indicate new lesion formation.

RESULTS

A total of 1,605 segments, representing 257 patients, were considered normal at baseline, with 804 and 801 disease-free segments in the usual care and risk reduction groups, respectively. Ninety-nine segments (6.1%) were identified by follow-up quantitative angiography and two angiographic observers as having new lesion formation (usual care 7.6%, risk reduction 4.7%, p = 0.05). New lesion formation was observed in 41 (31%) of 131 patients in the usual care group and in 29 (23%) of 126 patients in the risk reduction group (p = 0.16), with a mean number of new lesions/patient of 0.47 in the usual care group and 0.30 in the risk reduction group (p = 0.06). Multiple regression analysis identified on-study dietary fat intake as the best correlate with new lesion formation.

CONCLUSIONS

These data indicate that intensive multifactor risk reduction tends to diminish the frequency of new coronary lesion formation.

Coronary artery disease regression. Convincing evidence for the benefit of aggressive lipoprotein management

BACKGROUND

Numerous reports suggest that coronary artery disease can regress with lipoprotein manipulation. Many of these reports lack control groups and contain relatively small numbers.

METHODS AND RESULTS

Ten randomized controlled clinical trials using coronary arteriography to assess the effect of lipoprotein manipulation on the rate of progression and regression of atherosclerosis have been either published or reported as an abstract at a national meeting. These studies were critically reviewed for individual differences and combined clinically applicable lessons. These trials involved a total of 2095 subjects and have consistently reported reduction in the percentage of patients arteriographically defined as progressing (mean, 23.6%) and an increase in the percentage regressing (mean, 20.0%) compared with control groups. Compared with large clinical trials using clinical end points, lipoprotein change was greater, achieving on average a 28% reduction in low-density lipoprotein cholesterol, 11% reduction in triglycerides, and 11% increase in high-density lipoprotein cholesterol compared with control groups. Four investigations used a nonpharmacological approach, and seven used single and multiple drug therapy combined with diet. Despite the relatively brief treatment time of often 2 to 4 years, clinical events were fewer in the treatment groups; within some studies, this reached statistical significance. Side effects from the different therapies were tolerated by most patients, and severe adverse clinical events were few.

CONCLUSIONS

These trials present convincing evidence that aggressive lipoprotein manipulation can result in improved arteriographic measurements and fewer cardiovascular events in a relatively short period of time of 2 to 4 years. Extrapolation of this information to the larger population with known coronary artery disease suggests that directed lipoprotein manipulation can reduce clinical events in a cost-effective manner.

Studies in hypertriglyceridaemia. 1. Serum triglyceride distribution and its correlates in randomly selected Swedish middle-aged men

OBJECTIVES

To obtain a randomly selected hypertriglyceridaemic population for detailed further characterization.

DESIGN

Study of randomly selected males.

SETTING

Subjects examined and blood sampled at Sollentuna Primary Health Care Centre.

SUBJECTS

Men aged 40-50 years (n = 1564), living in the Stockholm area, who were screened for hypertriglyceridaemia, January 1990-June 1992.

MAIN OUTCOME MEASURES

Fasting concentrations of serum triglycerides.

RESULTS

The serum triglyceride concentration distribution showed the expected skew distribution with the 90th and the 95th percentile at 2.51 and 3.05 mmol L-1, respectively. The mean serum triglyceride level compared well with several population values reported from this laboratory over the last 30 years, indicating stable triglyceride levels over time. There was no significant age-trend for the triglyceride concentration. Lower mean values for triglyceride, insulin and waist-to-hip (W/H) ratio were observed during the summer, whilst apolipoprotein A-I levels were higher. There was a linear relation between the number of cigarettes smoked and the serum triglyceride concentration. In stepwise multiple linear regression analysis with the triglyceride concentration as the dependent variable the following variables appeared as significant (P < 0.01) contributors: insulin, cholesterol, glucose, apolipoprotein A-I, number of cigarettes smoked, BMI, W/H ratio and diastolic blood pressure. The regression coefficient for apolipoprotein A-I was negative; all the others were positive. The multiple regression (R) was 0.68, suggesting that up to 47% of the variation of the serum triglyceride concentration could be predicted by these factors.

CONCLUSIONS

A group of randomly selected hypertriglyceridaemic men has been recruited for further clinical, metabolic and genetic studies. Basic characteristics of the population for their recruitment are described.

Determinants of femoral and carotid artery atherosclerosis

OBJECTIVES

The aim of the study was to find the most important determinants of early atherosclerosis in the carotid and femoral arteries.

DESIGN

Carotid and femoral maximal intima media thickness (IMT) was measured 19 months after the first of 4 risk factor measurements.

SETTING

Department of Community Health and General Practice, University of Kuopio, and Occupational Health Care in Pyhäsalmi Mine, Finland.

SUBJECTS

The subjects comprised 60 male volunteers aged from 32 to 65 years from amongst 277 workers at the Pyhäsalmi Mine, Finland. Subjects were invited for an ultrasound examination, in order of serum total cholesterol content, until the required figure of 60 cases was achieved.

MAIN OUTCOME MEASURES

Carotid and femoral maximal intima media thickness.

RESULTS

Systolic blood pressure (P < 0.01), serum total cholesterol (P < 0.01), age (P = 0.01) and pack-years smoked (P = 0.02) were independent determinants of maximal carotid artery IMT, and total cholesterol (P = 0.01), age (P = 0.03) and pack-years smoked (P = 0.01) for maximal femoral artery IMT. For the latter, plasma fibrinogen concentration (P = 0.10) was the next factor to enter the multiple regression model. Body mass index, heart rate, serum HDL cholesterol, triglycerides, urate, apolipoprotein A1, antithrombin III, lipid peroxides, vitamin E and plasma vitamin C had no significant association with either maximal carotid or femoral IMT or the mean of the carotid and femoral IMT.

CONCLUSIONS

Systolic blood pressure, serum total cholesterol, age and pack-years smoked are the most important determinants of early atherosclerosis in the carotid artery and total cholesterol, age and pack-years smoked in the femoral artery. Prevention should take into consideration these findings. The role of plasma fibrinogen and oxidized low density lipoprotein would require re-evaluation in larger populations studied longitudinally.

Reference intervals and decision limits for plasma lipids and lipoproteins: a practical evaluation of current recommendations

As part of a longitudinal study--the Kristianstad Survey--we measured plasma cholesterol, HDL- and LDL-cholesterol, triglycerides and lipoprotein (a) in a reference group consisting of 203 men and women aged 20-80, randomly sampled from a well-defined area in the southernmost part of Sweden. The selection of reference individuals and the collection of specimens for assay of the constituents were performed in accordance with current recommendations. The results were subjected to statistical analyses both with and without application of exclusion criteria. Application of the theoretical exclusion criteria resulted in the exclusion of 22% of the participants; however, this procedure had a remarkably weak impact on the results: the mean values and the standard deviations were almost unaltered. The mean (standard deviation) for cholesterol was 5.9 (1.3) mmol l-1, for HDL-C 1.1 (0.3) mmol l-1, and for LDL-C 4.3 (1.2) mmol l-1. Women had higher values than men. Plasma triglycerides were positively skewed; their median and Q3-Q1-values were 1.0 and 0.5 mmol l-1 respectively, men higher than women. There was an increase with age for cholesterol and LDL-C in both sexes and for triglycerides in women. The steepest increase of cholesterol values with age in women coincided with menopause, which have a more clear-cut separation between high and low cholesterol values than did any age limit.

The relationship of serum total sialic acid with serum acute phase proteins and lipoprotein (a) in patients with severe hypertriglyceridaemia

Total serum sialic acid (TSA), recently shown to be a cardiovascular risk factor, was measured in 15 patients with severe hypertriglyceridaemia (fasting triglyceride > 2.3 mmol l-1) and 15 age and sex matched normal control subjects. To test the hypothesis that serum TSA is related in some way to serum acute phase proteins we also measured five acute phase proteins, namely alpha-1-antichymotrypsin (ACT), alpha-1-acid-glycoprotein (AGP), alpha-2-macroglobulin (AMG), C-reactive protein (CRP) and haptoglobin (HAP) in both groups. Of note was the significantly elevated serum TSA in the severely hypertriglyceridaemic group as compared to normal subjects. Serum TSA being 71.9 +/- 11.7 mg dl-1 and 59.6 +/- 10.2 mg dl-1 respectively (P < 0.01 Mann-Whitney test). Serum CRP was significantly elevated in the type IV patients as compared to controls (6.4 +/- 4.5 mg l-1 vs. 3.3 +/- 1.9 mg l-1 P < 0.05 Mann Whitney test) as was serum AMG (2.1 +/- 0.89 g l-1 vs. 1.5 +/- 0.53 g l-1 P < 0.05 Mann Whitney test). There was no correlation between serum TSA and lipoprotein (a) in either the normal or severely hypertriglyceridaemic subjects. We suggest that serum TSA could in part be related to hypertriglyceridaemia and serum acute phase proteins but that its property as a cardiovascular risk factor is not related to serum lipoprotein (a) concentrations.

The role of diabetes mellitus and hypertriglyceridaemia as coronary risk factors in treated hypertension: 15 years of follow-up of antihypertensive treatment in middle-aged men in the Primary Prevention Trial in Göteborg, Sweden

OBJECTIVE

To analyse the importance of diabetes mellitus and hypertriglyceridaemia as potential risk factors for coronary heart disease (CHD) in middle-aged, treated hypertensive men.

DESIGN

A prospective, long-term observational study.

SUBJECTS

Derived from a random population sample--686 hypertensive men aged 47-54 years at entry--followed for 15 years at a special out-patient hypertension clinic.

INTERVENTION AND OUTCOME MEASURES

The patients were mainly treated with beta-adrenoceptor blockers and/or thiazide diuretics. Cardiovascular morbidity was closely monitored during follow-up.

RESULTS

In all, 133 subjects suffered a CHD event during follow-up. The presence of diabetes mellitus at entry more than doubled the CHD risk and a 1 mmol l-1 increment of the serum triglyceride level at entry increased the CHD risk by 21%. In multivariate analyses, smoking, the presence of diabetes mellitus at entry, serum cholesterol and signs or symptoms of hypertensive end organ damage were found to be independent risk factors for CHD. In absolute terms the existence of cardiovascular damage was of much greater prognostic importance than were the presence of various metabolic abnormalities. Of the mean in-study variables, both the average serum cholesterol level and the achieved diastolic blood pressure were significantly associated with CHD. However, new diabetes mellitus which developed during follow-up as well as mean serum triglyceride levels were not associated with CHD.

CONCLUSIONS

Diabetes mellitus and hypertriglyceridaemia present at the start of treatment have a prognostic impact in treated hypertensive men, whereas when such metabolic disorders develop during drug treatment they seem to be of much less importance. Smoking and already existing evidence of hypertensive end organ damage are of utmost importance for the prognosis in this type of patient.

Health-based reference values of the Mini-Finland Health Survey: 3. Triglycerides in total serum and in different lipoprotein fractions

The reference values for triglyceride concentrations in total serum and in its VLDL, LDL and HDL fractions have been produced based on the data obtained in the Mini-Finland Health Survey. The lipoprotein fractions were separated with ultracentrifugation. Efforts were made to obtain reference values for the healthy ambulatory population. Two health-derived selection criteria were used for inclusion of persons into the reference population: those based on the literature available and those based on the recommendations published by the Committee on Reference Values of the Scandinavian Society for Clinical Chemistry and Clinical Physiology, with minor modifications. The frequency distributions of triglycerides especially in total serum and in VLDL fraction were very skewed. Because of that the data were transformed before the calculation of the reference ranges according to the method of Box and Cox [1]. This transformation method appeared to be the best one of many tested methods in obtaining the distributions closer to the normal ones. The 95% inner reference intervals of total serum triglycerides in all subjects and in the two selection groups were 0.5-4.0, 0.5-2.8, and 0.5-3.2 mmol l-1 for men and 0.5-3.4, 0.5-2.3, and 0.5-2.4 mmol l-1 for women, respectively. The age dependence of triglyceride level was prominent in women after the early middle age. The distribution and age dependence of VLDL triglycerides resembled those of total triglycerides. In LDL and HDL fractions the skewness was not as clear as in the whole serum or in VLDL fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol and cardiovascular disease: basic science

Cholesterol is a normal constituent of blood plasma and of cell membranes in every tissue of the body. It is transported in plasma as a component of lipoproteins. Increased concentrations of specific lipoprotein fractions, namely low density lipoproteins (LDL) and intermediate density lipoproteins (IDL), have been implicated both in vitro and in vivo as causes of atherosclerosis. The mechanism by which these lipoproteins initiate atherosclerosis is unknown, although there is growing evidence that it involves interactions between lipoproteins and cells within the artery wall, setting in train complex, reactions which lead ultimately to the fully developed lesions.

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.

Relation of plasma levels and composition of apolipoprotein B-containing lipoproteins to angiographically defined coronary artery disease in young patients with myocardial infarction

BACKGROUND

Hypertriglyceridemia is a common metabolic disturbance in men < 45 years old with myocardial infarction. To further investigate the relation between triglyceride-rich lipoproteins and severity of coronary atherosclerosis in this subset of postinfarction patients, apolipoprotein B-containing lipoproteins of 64 consecutive patients were subfractionated in connection with coronary angiography.

METHODS AND RESULTS

Density-gradient ultracentrifugation of plasma and coronary angiography were performed 4 to 6 months after the myocardial infarction. Global coronary atherosclerosis and the number and severity of distinct stenoses were evaluated by semiquantitative analysis of 15 proximal coronary segments. The majority of the patients (60%) were hypertriglyceridemic and had higher coronary scores than normotriglyceridemic patients. Of the major plasma lipoproteins, triglycerides and cholesterol in the low-density lipoprotein (LDL) fraction were associated with global coronary atherosclerosis, whereas LDL triglycerides and high-density lipoprotein (HDL) cholesterol correlated directly and inversely, respectively, with the coronary stenosis score. Plasma apolipoprotein B correlated with both coronary scores. The plasma concentrations of lipid and protein in the very-low-density lipoprotein (VLDL) subfractions (VLDL1 through VLDL3) and intermediate-density lipoprotein (IDL) did not correlate with either of the coronary scores, whereas the concentration of triglycerides in dense LDL (density > 1.040 kg/L) was strongly associated with both coronary scores. Compositional analysis of the smallest VLDL particles (VLDL3) and IDL revealed a correlation between the number of cholesteryl ester molecules in small VLDL and global coronary atherosclerosis in hypertriglyceridemic patients.

CONCLUSIONS

Global coronary atherosclerosis and distinct stenoses in young postinfarction patients are associated with the number of apolipoprotein B-containing particles in plasma and the concentration of LDL triglyceride. Specifically, dense triglyceride-rich LDL particles and, in hypertriglyceridemic patients, small cholesteryl ester-rich VLDL particles relate to coronary artery disease severity.

Postmenopausal hormone replacement therapy with Tibolone decreases serum lipoprotein(a)

Lipoprotein(a) is a cholesterol-rich plasma lipoprotein consisting of LDL and apolipoprotein(a). Apolipoprotein(a) shows structural similarity with plasminogen and thus may interfere with thrombogenesis. Lipoprotein(a) has been shown to be a strong independent risk factor for coronary heart disease. So far no drug or diet is known to have prominent effects on the serum levels of lipoprotein(a). In the present study we found a highly significant decrease (in the order of 26%) of lipoprotein(a) in 28 women treated for 6 months with Tibolone, compared with an age-matched healthy control group. Tibolone is a synthetic steroid with gestagenic and weak androgenic and oestrogenic properties, which shows no stimulation of the endometrium. Tibolone also produced a decrease in HDL-cholesterol of 23% (p < 0.001), a decrease in apolipoprotein A-I of 14% (p < 0.001) and an increase in apolipoprotein B of 17% (p < 0.001), whereas the control group showed no significant changes in these quantities. Tibolone in a daily dose of 2.5 mg is at present the only complete postmenopausal hormone replacement therapy that shows a significant inhibiting influence on serum levels of lipoprotein(a). Its effect on lipoprotein(a) might counterbalance, at least to some extent, the theoretical adverse effect on the other lipoprotein risk factors.

Triglyceride-rich lipoproteins and atherosclerosis, from fast to feast

There is increasing evidence that fasting hypertriglyceridaemia identifies individuals who are at increased risk for coronary artery disease. It is probable that this reflects the effects of the smaller triglyceride-bearing lipoproteins. It may also reflect increased levels of postprandial lipoproteins. There is considerable theoretical and experimental evidence to support an atherogenic role for the smaller, triglyceride-rich postprandial lipoproteins. Cross-sectional studies in humans also indicate that those with coronary disease have increased levels of postprandial lipids, probably in the remnants of chylomicrons. Recently we have completed a study examining the progression of coronary atherosclerosis angiographically. The study showed that the progression was linearly related to the numbers of chylomicron remnant particles, as reflected by the quantity of apoB48 in Sf20-60 lipoproteins, in the postprandial circulation. This paper reviews these studies, the physiology of postprandial lipoprotein metabolism and the therapeutic implications of this information.

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.

The phenomenon of a high triglyceride response to an oral lipid load in healthy subjects and its link to the metabolic syndrome

Excessive postprandial triglyceride (TG) responses despite normal fasting TG levels have been described in single cases within small groups of healthy subjects and in patients with obesity or precocious atherosclerosis, known to be associated with high insulin fasting levels. To clarify this association, fasting and postprandial TG and insulin levels were studied in 113 healthy young (25.7 +/- 2.6 years), normal weight (body mass index 20.8 +/- 2.3 kg/m2) male subjects who were selected from among 117 subjects on the basis of TG fasting levels < 200 mg/dl. After a 12-hour fast a standardized liquid lipid load was administered containing 58 g mainly saturated fat and 1,017 kcal energy. Both fasting TG values and postprandial TG peak values showed bimodal frequency distributions. Statistical analysis of fasting TG discriminated two groups: a low fasting TG group with normally distributed values < 150 mg/dl (mean +/- SEM: 79.5 +/- 2.7 mg/dl; n = 104) and a high fasting TG group > 150 mg/dl (194.5 +/- 7.2 mg/dl; n = 13). Likewise, two groups could be differentiated according to their maximal postprandial TG response (TG max) to the lipid load: (1) normal responders with TG max < 260 mg/dl (mean +/- SEM: 123 +/- 4.8 mg/dl; n = 96) and (2) high responders with TG max > 260 mg/dl (272.5 +/- 20.5 mg/dl; n = 17). Fasting TG and TG max were highly correlated (r = 0.745; p < 0.0001). However, 9 of 17 (53%) high responders had fasting TG < 150 mg/dl, which means that the prediction of high response is only 47.0% based on fasting TG values. Fasting insulin levels were significantly higher in high responders than in normal responders, whereas they did not differ between the low and high fasting TG group. In conclusion, the bimodal frequency distribution of TG max after a lipid load permitted the differentiation of two groups, normal responders and high responders, with higher fasting insulin levels, which might indicate a link to the metabolic syndrome.

Lipids, lipoproteins and other coronary risk factors in Chinese male survivors of myocardial infarction

OBJECTIVE

To assess the importance of an abnormal lipid profile as a risk factor in relation to non-biochemical risk factors, and to define the risk levels for lipid, lipoprotein and apolipoprotein in a Chinese population.

PATIENTS AND METHODS

Serum lipids, lipoproteins, apolipoproteins and other cardiovascular risk factors were studied in 89 Chinese men 3 months after acute myocardial infarction and 56 controls.

RESULTS

Cases had higher mean total cholesterol (TC), LDL- and VLDL-cholesterol, triglycerides and apolipoprotein B (Apo B), and lower mean HDL-cholesterol and apolipoprotein AI (Apo AI). Mean BMI was also higher, as was the prevalence of smokers and subjects with a history of hypertension. In univariate analysis, the odds ratios for TG > or = 1.6 mmol/l, LDL-cholesterol > or = 4.1 mmol/l, VLDL-cholesterol > or = 0.73 mmol/l, Apo B > or = 104 mg/dl were of the same order of magnitude as being a current smoker, having a BMI > or = 24.3 kg/m2, and a history of hypertension. High HDL-cholesterol (> or = 1.39 mmol/l) and Apo AI (> or = 139 mg/dl) were protective factors. The odds ratios for successively higher quartile values of cholesterol were not statistically significant. Multiple logistic regression identified smoking habit, history of hypertension, obesity, high Apo B and low Apo AI concentrations as independent risk factors for myocardial infarction.

CONCLUSIONS

In a Chinese population, low serum Apo AI and high Apo B are risk factors for myocardial infarction of a comparable magnitude to smoking, hypertension and obesity.

Prognostic importance of plasma lipoprotein-analyses in patients with unstable coronary artery disease

The lipoprotein (Lp) pattern was analysed in patients with suspected unstable coronary artery disease (UCAD), to compare the pattern as a prognostic instrument regarding subsequent coronary events with smoking, hypertension, diabetes mellitus and with the result of an early exercise test. Included were 295 patients with UCAD. Blood samples for Lp values were obtained in the acute phase and after one year. Apolipoprotein-A1, Apolipoprotein-B (Apo-B), Lipoprotein(a) (Lp[a]) HDL-Cholesterol, Cholesterol (Chol) and Triglycerides (TG). were estimated in serum. During the 1-year follow-up coronary events (myocardial infarction, cardiac death, coronary artery by-pass surgery) occurred in 48 patients. The severity of CAD, overweight, smoking and beta-blockade influenced the Lp-pattern. Chol-, TG- and Apo-B-levels were highest in the group with a coronary event. Apo-B turned out to be the second best predictive variable in multiple regression analysis, in men. In women no such analysis was done because of very few coronary events during follow-up. Nevertheless, the exercise test variables, ST depression and pain were more predictive of coronary events than Apo-B in men.

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.

Lipoprotein lipase activity in muscle tissue influenced by fatness, fat distribution and insulin in obese females

Obesity is associated with dyslipidaemia and increased morbidity and mortality from premature atherosclerosis and diabetes mellitus. Particularly, hypertriglyceridaemia is a characteristic finding in patients with obesity. In addition, the elevated levels of triglycerides may be an important risk factor for development of the obesity-related complications. Lipoprotein lipase activity in skeletal muscle tissue (mLPL) has previously been found to be an important factor regulating the concentration of serum triglycerides. To describe the relationship between mLPL, triglycerides and fatness/fat distribution in more detail we have investigated these parameters under basal conditions and during insulin stimulation in 20 obese females. During hyperinsulinaemia (204 microU ml-1) for 4 h the mLPL activity decreased from 528 +/- 52 nmol FFA g-1 to 412 +/- 44 (P < 0.001). Basal mLPL was negatively correlated with serum triglycerides (r = -0.48, P < 0.05) and positively correlated with HDL-cholesterol (r = 0.58, P < 0.01). Employing multiple variance analysis it was found that both BMI and WHR were negatively correlated to mLPL, however, the impaired lipid profile (high triglyceride, low HDL-cholesterol, high FFA) could only be related to BMI and not to WHR in these obese females. However, reduced insulin-action (insulin resistance) was closely related to abdominal fatness determined by WHR both in relation to the insulin-effect on mLPL as well as for the insulin-effect on whole-body glucose metabolism (clamp-study).(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Reduced lipolysis of large apo E-poor very-low-density lipoprotein subfractions from type IV hypertriglyceridemic subjects in vitro and in vivo

Heparin-Sepharose chromatography was used to separate Sf 60-400 very-low-density lipoproteins (VLDL) from type IV hypertriglyceridemic subjects into apolipoprotein (apo) E-poor and apo E-rich subfractions. Since we have previously demonstrated that the apo E-poor fraction accumulates in plasma of type IV subjects, the aim of the present studies was to determine whether it was resistant to lipolysis in comparison to the apo E-rich fraction. The apo E-rich fraction was found to be 30% more effective than the apo E-poor fraction at competing with a glycerol tri[1-14C]oleate emulsion for in vitro lipolysis by normolipidemic human post-heparin plasma (P < .01), when assayed under conditions in which both lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were active. Similar results were obtained when bovine milk LPL was used as the source of lipolytic activity (P < .025 for apo E-rich relative to apo E-poor VLDL), while neither fraction competed effectively with the synthetic substrate for lipolysis by HTGL only. When equal amounts of triglyceride from VLDL subfractions were incubated with bovine milk LPL, 25% more free fatty acid was released from the apo E-rich fraction than from the apo E-poor fraction (P < .025). The effects of heparin-induced lipolysis in vivo in type IV subjects on the relative amounts and composition of these VLDL subfractions were also assessed. Heparin infusion was associated with a 50% reduction in plasma Sf 60-400 VLDL triglyceride concentration. In addition, heparin-induced lipolysis resulted in a marked decrease in the relative amount of apo E-rich VLDL, while the relative amount of apo E-poor VLDL was increased. These results demonstrate that the apo E-poor VLDL subfraction is resistant to lipolysis by LPL relative to its apo E-rich counterpart, suggesting that reduced lipolytic efficiency may contribute to its observed accumulation in plasma of type IV subjects.

Large intercommunity difference in cardiovascular drug consumption: relation to mortality, risk factors and socioeconomic differences

A comparison of cardiovascular drug sales and cardiovascular mortality was made between two Swedish counties (Värmland and Malmöhus) and between two rural municipalities in those counties (Torsby in Värmland and Hörby in Malmöhus). Cardiovascular drug sales (defined daily doses (DDD) per 1,000 inhabitants per day) during 1986-87 were 25% higher in Värmland than in Malmöhus county, and the age-standardized mortality of coronary heart disease (CHD) was 36% (men) and 54% (women) higher. In Torsby, age-standardized CHD mortality (1986-87) was 71% (both sexes) higher than in Hörby, and the sales of cardiovascular drugs (1978-87) were 58% higher. Statistically, every third inhabitant of Torsby took one DDD of a cardiovascular drug every day, as compared to every fifth inhabitant in Hörby. In Torsby there was a 6% higher serum cholesterol, 71% lower tap water hardness, 33% lower income, a lower educational level, a three-fold higher unemployment rate, and a different ethnic background (20% eastern Finnish ancestry), all factors assumed to promote a high CHD rate. All of these factors may contribute to the higher CHD mortality, which was in turn reflected in higher sales of cardiovascular drugs.

Moderate oxidation of hypertriglyceridemic low-density lipoprotein causes apolipoprotein B epitope change and enhances its uptake by macrophages

We prepared monoclonal antibody (MabB4) that selectively binds to acetylated low-density lipoprotein (LDL). Native hypertriglyceridemic LDL (HT-LDL) obtained from IIb and native normotriglyceridemic LDL (NT-LDL) from type IIa scarcely bound with MabB4. When these LDL were oxidized moderately by incubation with copper ions, the binding of MabB4 to HT-LDL was enhanced compared to that of NT-LDL, although the contents of the hydroperoxide they produced were the same. The incorporation of moderately oxidized HT-LDL into macrophages was enhanced compared to that of NT-LDL, and the rate of incorporation parallel the binding of LDL for MabB4. These results suggested that moderate oxidation of HT-LDL expressed some apolipoprotein B epitope on the surface of acetylated LDL to a much greater degree than NT-LDL, and that this expressed epitope might work as a ligand of moderately oxidized HT-LDL for the recognition by macrophages.

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.

Lipoproteins and their genetic variation in subjects with and without angiographically verified coronary artery disease

To examine the concentration of serum lipoproteins and the association of their genetic variation with the occurrence of coronary artery disease (CAD), composite serum lipoprotein profiles including lipoprotein(a) (Lp[a]), apolipoprotein (apo) E phenotypes, and apo B Xba I genotypes were determined in patients with angiographically verified CAD (CAD+ group, n = 111) and in subjects with no angiographic evidence of CAD (CAD- group, n = 46). In addition, we determined the concentrations of serum lipids, lipoproteins, and apolipoproteins in 96 healthy controls. Both CAD- and CAD+ groups had lower concentrations of apos A-I and A-II but higher concentrations of serum total and very low density lipoprotein triglyceride and very low density lipoprotein cholesterol than did healthy controls. The mean concentrations of serum total and low density lipoprotein cholesterol and the median values of Lp(a) were similar in the CAD+ and CAD- groups, both having higher concentrations of low density lipoprotein cholesterol and apo B than the healthy controls. Irrespective of gender, patients with CAD had significantly lower serum high density lipoprotein cholesterol than did those without CAD (1.48 +/- 0.40 versus 1.16 +/- 0.29 mmol/l, p less than 0.001). In women, the mean serum total and very low density lipoprotein triglyceride concentration was also higher in the CAD+ than in the CAD- group. The frequency of the apo E4 allele (epsilon 4) was significantly higher in the CAD+ group (0.293) than in the CAD- group (0.174; p less than 0.001). The frequencies of the two apo B alleles, X1 (Xba I restriction site absent) and X2 (Xba I restriction site present), were similar in the two groups. Stepwise discriminant analysis revealed that in men, serum high density lipoprotein cholesterol had the highest power to discriminate for CAD. In addition, the concentration of plasma apo B levels and the occurrence of apo E phenotypes were independently associated with CAD in men. In women, the only independent factor associated with CAD after adjustment for beta-blocker and diuretics usage was the concentration of serum triglycerides.

U-73482: a novel ACAT inhibitor that elevates HDL-cholesterol, lowers plasma triglyceride and facilitates hepatic cholesterol mobilization in the rat

U-73482, a novel acylCoA:cholesterol acyltransferase (ACAT) inhibitor with systemic activity, has been evaluated for its effects on a variety of lipid metabolic parameters in the rat. The compound inhibits ACAT in vitro in cultured Fu5AH rat hepatoma cells and demonstrates systemic activity through inhibition of hepatic ACAT in rats receiving the drug orally. U-73482 also lowers plasma triglycerides at 40 mg/kg per day in the rat and elevates high density lipoprotein cholesterol (HDL-chol) in a dose-related fashion over the range of daily intakes of 0-40 mg/kg in the rat. Elevations in HDL-chol are followed by elevations in total plasma cholesterol in normal rats but the compound exerts hypocholesterolemic activity in cholesterol-fed rats and promotes clearance of stored hepatic sterol in rats pretreated with a hypercholesterolemic diet and then changed over to normal chow. The triglyceride-lowering and HDL-chol elevating effects of U-73482 coupled with its ability to promote tissue sterol clearance and block the hypercholesterolemic effects of dietary cholesterol in animals, suggests that the compound has potential as a therapeutic agent for treatment of lipid disorders in man.

Triglycerides and blood glucose are the major coronary risk factors in elderly Swedish men. The study of men born in 1913

In 1980 we examined 707 67-year-old men, 656 of whom had no previous myocardial infarction. During 8 years of follow-up, 70 (10.7%) of the 656 men developed a first myocardial infarction or died from coronary heart disease (CHD). The incidence of CHD increased 1.6-fold from the lowest to the highest quintile of cholesterol levels, 2.7-fold from the lowest to the highest quintile of triglyceride levels, and 2.2-fold among those with diabetes. Blood pressure, smoking habits, and two measurements of obesity (body mass index and waist circumference) were not significantly related to the incidence of CHD. In multivariate analysis, serum triglyceride levels and blood glucose concentration remained as significant risk factors for CHD. This may reflect that disturbances in glucose and triglyceride metabolism (as part of a metabolic syndrome?) are more important CHD risk factors in older than in younger men.

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.

Abnormalities of carbohydrate and lipid metabolism in Dahl rats

Plasma glucose, insulin, and triglyceride concentration, blood pressure, and insulin action on isolated adipocytes were determined in weight-matched Sprague-Dawley, Dahl salt-resistant, and Dahl salt-sensitive rats. Blood pressure and plasma glucose concentrations were not significantly different in the three groups. However, Dahl salt-sensitive rats had significantly higher plasma insulin (39 +/- 2 microunits/ml) and triglyceride (213 +/- 11 mg/dl) concentrations than did Sprague-Dawley rats (27 +/- 2 microunits/ml and 101 +/- 6 mg/dl, respectively). Values for insulin (34 +/- 4 microunits/ml) and triglyceride (159 +/- 11 mg/dl) were intermediate in Dahl salt-resistant rats. In contrast, maximal insulin-stimulated glucose transport was significantly lower in adipocytes isolated from Dahl salt-sensitive as compared with Sprague-Dawley rats (400 +/- 16 versus 523 +/- 14 fl/cell/sec), with Dahl salt-resistant rats again having intermediate values. However, the ability of insulin to maximally inhibit catecholamine-stimulated lipolysis was similar in all three groups, averaging approximately 20% of the activity present in the absence of insulin. All of these differences were seen when the rats were eating conventional chow and did not change in Dahl rats after 2 weeks of an 8% NaCl diet. On the other hand, the predicted rise in blood pressure took place in Dahl salt-sensitive rats, increasing from 147 +/- 4 to 181 +/- 6 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a soy-protein beverage on plasma lipoproteins in children with familial hypercholesterolemia

The effects of soy protein (35% of protein energy) given as a beverage and those of cow-milk proteins were investigated on plasma lipoprotein concentrations in children with familial hypercholesterolemia (FH). Subjects were randomly assigned to either the soy-protein or cow-milk-protein experimental period, with subsequent crossover after a washout period, each period lasting 4 wk. Diets were planned to provide 20% energy as protein, 28% as fat (polyunsaturated:monounsaturated:saturated fatty acids, 1:3:3) and less than 200 mg cholesterol/d. No changes were observed in either plasma cholesterol, low-density-lipoprotein cholesterol, or apolipoprotein concentrations. However, the soy beverage significantly reduced the concentrations of triglyceride and very-low-density-lipoprotein cholesterol (P less than 0.05) and significantly increased the concentrations of high-density-lipoprotein cholesterol (HDL-C) and HDL3-C (P less than 0.04 and P less than 0.03, respectively). These results indicate that the administration of soy protein may induce clinically beneficial effects in children with FH.

Insulin resistance and compensatory hyperinsulinemia: role in hypertension, dyslipidemia, and coronary heart disease

Resistance to insulin-stimulated glucose uptake and hyperinsulinemia may play a central role in the cause and clinical course of patients with non-insulin-dependent diabetes mellitus, high blood pressure, abnormalities of lipoprotein metabolism, and coronary heart disease. This article summarizes the evidence in support of this general hypothesis.

Serum lipids and apolipoproteins in patients with essential hypertension

Fifty hypertensive untreated outpatients (34 women, 16 men), with stage I and II essential hypertension, were studied in comparison to 50 age- and sex-matched controls with similar life-styles. Total cholesterol triglycerides, LDL-cholesterol, VLDL-cholesterol, and HDL-cholesterol were measured by enzymatic methods, and apolipoproteins AI, AII, B, CII, CIII and E by RID. The results showed significant differences between hypertensives and controls respectively in triglycerides (135.2 +/- 73.9 versus 90.2 +/- 33.8, P less than 0.01) and VLDL cholesterol (26.7 +/- 14.8 versus 17.7 +/- 6.6, P less than 0.01) while no significant differences were observed in total, LDL and HDL cholesterol. Significant differences between the two groups were also observed in apolipoproteins, particularly in apo AI (130.0 +/- 28.2 versus 144.9 +/- 27.9, P less than 0.05), apo AII (32.9 +/- 10.2 versus 39.6 +/- 11.4, P less than 0.01), apo CII (4.0 +/- 2.6 versus 5.4 +/- 2.9, P less than 0.05) and apo E (5.0 +/- 1.8 versus 4.3 +/- 1.8, P less than 0.05), while no significant differences were observed in apo B and CIII values. The results suggest that in untreated hypertensive patients alterations in the apolipoproteins profile are present which, in part, may be responsible for the elevated incidence of cardiovascular disease, independently from the blood pressure values.