A survey of 246 suggested coronary risk factors

Family history as an independent risk factor for incident coronary artery disease in a high-risk cohort in Utah

To test independence of family history of coronary artery disease (CAD) as a risk factor for the development of new clinical CAD, data collected at 2 clinic visits on 1,196 men and women, ages greater than 20 years, were analyzed using Cox proportional hazard method. During a mean follow-up of 2.5 years, 16 new CAD cases were observed. After adjustment for age, sex, total cholesterol, high density lipoprotein cholesterol, hypertension, diabetes, cigarette smoking and body mass index, family history remained a highly significant predictor of future CAD (p = 0.0017). Only age was a more significant covariate (p = 0.0001) than family history. Sex (p = 0.00074) and serum total cholesterol (p = 0.015) also contributed significantly to CAD incidence while high density lipoprotein cholesterol, hypertension, diabetes, body mass index and several interaction terms did not improve the prediction in this population. These results provide evidence for the existence of other heritable risk factors which appear to contribute strongly to the occurrence of early CAD in many high-risk families.

Reduced HDL2 levels in myocardial infarction patients without risk factors for atherosclerosis

Out of a total of 170 patients with a first myocardial infarction, aged below 65 years, consecutively admitted to the Coronary Care Unit of a large urban hospital, only 14 did not present with any risk factor(s) for atherosclerosis (smoking, hypertension, diabetes and obesity). None of these 14 patients showed significant hyperlipidemia. Compared to a control series of normal individuals of the same age (50.0 +/- 5.8 years for males and 61.6 +/- 3.0 years for females), they showed a significant reduction of high-density lipoprotein (HDL)-cholesterol and of apolipoprotein A-I (respectively -18.2 and -9.5%). However, the most striking abnormality was a 30% decrease of the HDL2 mass and of HDL2 cholesterol; both HDL2 and HDL3 had a reduced cholesteryl ester content in the patients. Reduced HDL2 mass and cholesterol levels in plasma, accompanied by significant alterations in HDL subfraction composition, are consistent with a defective cholesterol esterification in HDL. HDL2 deficiency may be a primary alteration in myocardial infarction patients without other significant risk factors.

A stochastic process approach to the development of atheroma

This study aims at formulating a dynamic model of particle sedimentation as applied to lipoprotein deposition during atheroma progression. The basic assumption is that all particles are identical and that the number of sedimented particles is relatively great. It is hypothised that sedimentation of a given particle is random; according to the theory of stochastic processes, the probability of a certain number of particles to sediment or deposit changes with time. The stochastic approach may explain some aspects of atherosclerosis development, i.e. its progression or regression.

Representativeness of the Framingham risk model for coronary heart disease mortality: a comparison with a national cohort study

The Framingham Heart Study has been the foundation upon which several national policies regarding risk factors for coronary heart disease mortality are based. The NHANES I Epidemiologic Followup Study is the first national cohort study based upon a comprehensive medical examination of a probability sample of United States adults. The average follow-up time was 10 years. This study afforded an opportunity to evaluate the generalizability of the Framingham risk model, using systolic blood pressure, total cholesterol, and cigarette smoking, to the U.S. population with respect to predicting death from coronary heart disease. The Framingham model predicts remarkably well for this national sample. The major risk factors for coronary heart disease mortality described in previous Framingham analyses are applicable to the United States white adult population.

Cholesterol oxygenated derivatives induce erythrocyte accumulation and endothelium alterations in the aorta of rats. Turnover of endothelial cells in the apparently intact areas remains unchanged

In this work we have studied the effect of cholesterol autooxidation derivatives on the aortic endothelium of rat. Endothelial alterations were evident after 24 h treatment. Areas showing many spindle shaped nuclei and focal accumulation of erythrocytes were observed. Moreover, in some preparations areas with destroyed and missing endothelium were observed. Autoradiography using 3H-thymidine does not show differences in the mitotic activity between control and treated animals in those areas showing apparently intact endothelium. Therefore, we conclude that cholesterol derivatives present ability to produce important lesions in aortic endothelium and that this effect is similar to that described when cholesterol is used.

[Serum magnesium concentration in myocardial infarct]

Serum magnesium concentrations were followed during the course of coronary infarction and were correlated to the event on the basis of the creatinine kinase activity E.C. no. 2.7.3.2. Those patients admitted to the hospital at a very early stage of the infarction showed initial high serum magnesium concentrations which fell during the event to subnormal values and then normalized later. In the case of severe coronary infarction (maximum CK activity greater than 700 U/1) the subsequent decrease in serum magnesium concentration was more pronounced than in subjects with lower CK activity. Patients suffering from angina pectoris had normal serum magnesium values which did not show any concentration change during a clinical follow-up. The previously postulated correlation between low serum magnesium and high risk for myocardial infarction may be questioned in the light of our observations.

Prevention of atherosclerosis in childhood

Atherosclerosis begins in infancy, with fatty streaks appearing at the age of 3 years and fibrous plaques appearing during adolescence. Fatty streaks and fibrous plaques are related to serum total cholesterol, LDL-C, and systolic blood pressure levels. Children with elevated levels of cholesterol and blood pressure track (i.e., maintain elevated levels over time) and are candidates for premature coronary artery and cerebrovascular disease, especially if there is a positive family history of premature CVD. Screening for CVD risk factors in children is rapid, simple, inexpensive, and effective, with tremendous potential to prevent future adult CVD. At their annual physical examinations, children 5 years of age or older should have careful blood pressure measurements by two observers, and determinations of serum total cholesterol levels. Levels should be plotted on standard percentile grids (Figs. 5-7) in the child's permanent medical record. Those with persistently elevated levels of blood pressure and/or serum LDL-C require nonpharmacologic intervention initially, but may require antihypertensive or antilipid medication if unresponsive to behavioral modification for diet, physical activity, and cigarette smoking. Pediatric health professionals can play vital roles in primary prevention and reduction of adult CVD.

The significance of myocardial bridge upon atherosclerosis in the left anterior descending coronary artery

The relation between myocardial bridges (MB) and atherosclerosis in the left anterior descending coronary artery (LAD) was explored using morphometric methods in 642 hearts. The location of myocardial bridges in the LAD was classified according to distribution as proximal, middle and distal. Myocardial bridges were found in 48 per cent of males and 36 per cent of females. When proximal myocardial bridging was present intimal thickening and macroscopic raised lesion were increased just before the bridge as compared with the corresponding site in the other two categories. Underneath bridges eccentric plaques and raised lesions are absent although there is often concentric intimal thickening. The overall frequency of myocardial infarction was the same in patients with and without myocardial bridges. However, when infarction occurred in the patients having bridges, it was almost confined to those in the proximal group despite this being infrequent in the general distribution of myocardial bridges in the left anterior descending artery. It is postulated that hypertension may enhance infarction in the case of myocardial bridges in the very proximal left anterior descending artery. It is concluded that the location of myocardial bridges greatly alters the distribution of physical force against the arterial wall and influences the extent of atherosclerosis.

Hypertension among urban and rural Tongans

A cross-sectional study of urban and rural Tongans showed the prevalence of hypertension to be 8.4%. Hypertension occurred more often in urban men than in women. Systolic blood pressure (BP) showed a significant increase with age in all groups, except among rural men. Multivariant discriminant analysis identified the characteristics that were associated with a raised BP. The independent variables were selected for entry into the analysis on the basis of their power to separate BP categories, using Rao's V as the generalized measure of distance between groups. Age and body build (BMI or Fatsum) accounted for most differences between normotensive and hypertensive persons, especially in women. The fasting plasma glucose level was a significant discriminating characteristic for both men and women. The packed red cell volume was the most powerful single discriminating characteristic in men and the serum triglyceride level in women. The use of each characteristic to classify individuals by BP category may help clinicians to use cross-sectional data when deciding on the treatment of raised BP.

A chronobiologic study on some cardiovascular parameters

We studied the chronobiologic pattern of heart rate, R and T wave voltage, QT interval, and ST segment displacement. Premature atrial and ventricular beats obtained by dynamic electrocardiography, as well as arterial blood pressure measurements obtained by autometry, have also been studied in 131 untreated subjects (25 with hypertension, 28 with major risk factors for coronary artery disease, 9 with coronary artery disease, 37 presumably healthy and 11 shift workers). Our results show the existence of circadian rhythms in heart rate, in the duration of the QT interval and also in the voltage of R and T waves. Our data for R and T wave voltages do not completely agree with those from other authors. We demonstrated also that smoking may influence the circadian acrophase of the rhythm in R wave voltage while sleeping does not show any relationship with R and T wave voltages although it seems related to the displacement of the ST segment. We could point out only small differences in the chronobiologic behavior of patients with coronary disease and that of normal subjects, unlike the results previously reported by other authors. Our study demonstrated the existence of circadian and ultradian rhythms in premature atrial and ventricular beats as well as circadian and circaseptan rhythms in arterial blood pressure. Further studies are needed to improve our chronobiologic knowledge in order to optimize dosage and time of administration of the drugs used in the long term management of arrhythmias and hypertension.

Evidence that lysolecithin is an important causal agent of atherosclerosis

We examine the hypothesis of Portman et al. (1970) that lysolecithin is a causal agent of atherosclerosis. Four lines of argument support this hypothesis. (1) Lysolecithin is present, taken up and can act. Large amounts of lysolecithin are formed in plasma concomitant with triglyceride transport and it is readily taken up by arteries and retained for some time. Lysolecithin in aortic intima increases several-fold early in the induction of atherosclerosis in animals. From model system studies it is plausible that physiological doses of lysolecithin have physiologically significant effects. (2) At least one plausible mechanism of action can be formulated: stimulation of smooth muscle cell division due to lysolecithin-increased Ca2+ uptake. (3) The hypothesis is consistent with, and rationalizes, many literature observations in that inferred lysolecithin levels or production rates are appropriately correlated with a variety of positive and negative risk factors to a degree highly unlikely by chance. We found no data contradicting the hypothesis and only one piece weakening it. (4) A mechanism is outlined showing that low density lipoprotein receptor deficiency, the severest known risk factor, should cause the delivery of very high lysolecithin doses to artery walls. We conclude that the evidence, although indirect, is strong enough to give direct tests a high priority.

Plasma pyridoxal-5-phosphate level as risk index for coronary artery disease

Preliminary evidence is presented that plasma pyridoxal-5-phosphate levels are considerably and significantly reduced (P less than 0.0001) in patients suffering from myocardial infarction when compared to a healthy control group.

Atherosclerosis precursors in Finnish children and adolescents. I. General description of the cross-sectional study of 1980, and an account of the children's and families' state of health

The paper describes the general outline of a multicentre study on the risk factors of coronary heart disease (CHD) and their determinants in children of various ages in different parts of Finland. The study was a cross-sectional one, and was carried out in 1980 in five university cities of Finland with medical schools and in 12 rural communities in their vicinity. The randomized sample included an equal number of boys and girls, aged 3, 6, 9, 12, 15, and 18 years, and an equal number of urban and rural population in each area. The total sample size was 4,320 subjects, and of these 3,596 participated (83.1%). The families received before the medical examination of the child, questionnaires on the socioeconomic background the child's general health and development, the parents' and grandparents' health status, and the child's food and exercise habits. At the physical examination also a fasting blood sample (lipids, insulin, trace elements) was taken, a bundle of hair was cut for trace element analysis, and a 48-hour recall on food intake was obtained from every second subject. 19.5% of the children had in their history some long-term disease, allergic diseases being the most common. CHD and other cardiovascular diseases were significantly more frequent among the grandparents and parents in eastern than in western Finland. The study is meant to be a basis for a longitudinal study.

Atherosclerosis precursors in Finnish children and adolescents. VIII. Food consumption and nutrient intakes

A dietary survey was conducted in 1980 in connection with the Multicentre Study on Atherosclerosis Precursors in Finnish Children in five urban and 12 rural communes in various parts of Finland. 1,768 children aged 3, 6, 9, 12, 15 and 18 years were interviewed using the 48 hour recall method. Food consumption, and the intakes of energy and 49 nutrients were calculated. The intakes of energy and most nutrients increased in the successive age groups until the age of 15 years. There were only small differences in the diet of children belonging to different social classes. Protein accounted for 14% of total energy intake, fat for 38%, total carbohydrate for 48%, and sucrose for 10%. The ratio of polyunsaturated and saturated fatty acids in the diet (P/S) was 0.24 for the whole material, which is higher than found in previous studies in Finland. The P/S ratio was higher in urban areas and West Finland than in rural areas and in East Finland. The share of fat of energy intake exceeded the recommendation given by the Ministry of Health and the P/S ratio was lower than recommended. The mean daily intakes of energy and vitamins met the recommendations. Of the mineral elements, the intakes of calcium, phosphorus, potassium, magnesium and manganese were abundant. The intakes of iron, copper, zinc, molybdenum and chromium were lower than recommended in most age groups and the intakes of selenium and fluorine in all age groups. The large share of refined foods in the children's diet was the main reason for the low nutrient densities.

Long-term effect of vasectomy on coronary heart disease

We investigated the association between coronary heart disease (CHD) and vasectomy in a population of 10,632 men who were under surveillance for multiple CHD risk factors during participation in a university-based exercise testing program. We conducted a mail survey with telephone follow-up to determine the vasectomy status of individuals in the population. Responses were obtained from 6,159 individuals. The 4.944 males on whom information was complete enough to be included in the multivariate analysis comprised the study population. Among the 1,383 (28 per cent) vasectomized males in the study populations, the interval from vasectomy to the time of the survey ranged from less than one year to 37 years with a mean duration of 15 years. Although increased relative risks for CHD were found to be associated with family history of CHD, high blood pressure and smoking in this population, the relative risk of CHD associated with vasectomy was not increased in general, nor was it increased when the vasectomized males were classified by time since vasectomy. Likewise, serum antisperm-antibody titers were not predictive of CHD among vasectomized men. These studies support the findings from previous investigations of populations with shorter average post-vasectomy experience in which vasectomy has been shown to be unassociated with altered risk of CHD in humans.

[Xanthine oxidase in homogenized cow's milk and Oster's hypothesis: a review]

Oster has postulated that the enzyme xanthine oxidase in homogenized cow's milk is the cause of myocardial infarction and angina pectoris. This enzyme may be absorbed by ingestion, especially of the small particles of the fat globules, and then carried by lymph streams to the arterial vascular system, where it is deposited into the myocardium. Then it destroys the aldehydes liberated from the cell membrane-based plasmalogens. This results in the intimal damage to the cell membranes of the arterial intima and the myocardium and ultimately in the development of typical atherosclerotic lesions in the arteries. The presented review is a critical approach to this hypothesis. The following factors are discussed: - the influence of conditions prevailing in the intestine and the stomach on the activity of the xanthine oxidase in milk, - the possibility of this enzyme being absorbed in the intestine, - the formation of antibodies against absorbed xanthine oxidase and - the behaviour of xanthine oxidase administered intravenously. Compared with present knowledge, this theory gives little evidence only.

Copper and ischemic heart disease

Absolute or relative deficiency of copper is hypothesized to be of prime importance in the etiology of ischemic heart disease. According to recent estimates, only 25% of the diets in the United States contain the 2 mg of copper thought to be required daily by adults. Some of these diets have ratios of zinc to copper greater than those that have produced hypercholesteremia in animals. There are many epidemiologic associations between the ratio of zinc to copper and dietary characteristics, organ analyses, clinical status, and environmental features that relate the metabolism of these elements to the anatomy, chemistry, pathology, pharmacology, and physiology of ischemic heart disease. Animals deficient in copper or exposed to a high dietary ratio of zinc to copper, which can produce a relative copper deficiency, are hypercholesteremic and hyperuricemic, and have glucose intolerance and abnormalities of the electrocardiogram. Their hearts and arteries have abnormal connective tissue, lipid deposits, and inflammatory changes; they die suddenly, often with ruptured hearts. Hypercholesteremia and glucose intolerance have been found in men depleted of copper and in children with Menkes' disease, an inability to absorb copper.

Effects of fat level, feeding period, and source of fat on lipid fluidity and physical state of rabbit plasma lipoproteins

Elevating fat content from 5 to 20% of diet by weight or extending the feeding period from 6 months to more than 1 year did not substantially alter the fluidity of rabbit plasma lipoprotein lipid domains. Dietary fatty acid saturation was not adequate as a predictor of lipoprotein fluidity. Rabbits fed corn oil, high in polyunsaturated fatty acid content, did not have more fluid lipoproteins than rabbits fed cocoa butter which contains a high level of saturated long chain fatty acids. Order parameters calculated from fluorescence depolarization measurements with diphenylhexatriene (DPH) showed that very low density lipoprotein (VLDL) lipids were in highly fluid or 'liquid' states at or below body temperature. Order parameter data showed transitions from ordered phase to isotropic liquid in low density lipoproteins (LDL) that were heretofore unnoted with DPH fluorescence depolarization measurements. The transition temperature was inversely related to the LDL triglyceride content, indicating probe intercalation between the fatty acyl chains of the core triacylglycerols in VLDL and LDL.