The epidemiology of coronary heart disease. A review

Multivariate prediction of coronary heart disease during 8.5 year follow-up in the Western Collaborative Group Study

The Western Collaborative Group Study is a prospective study of 3,154 employed men aged 39 to 59 years. Ischemic heart disease occurred in 257 subjects during 8.5 years of follow-up. Risk of coronary heart disease was studied with use of the multiple logistic risk model. The incidence of coronary heart disease had a highly significant association with serum cholesterol level, behavior pattern, cigarette smoking and systolic blood pressure in younger (39 to 49 years) and older (50 to 59 years) men and also with age and corneal arcus in the younger group. Type A behavior pattern was strongly related to the incidence of coronary disease in both age groups, independent of interrelations of behavior patterns with any other risk factor.

Behavioral science applied to cardiovascular health: progress and research needs in the modification of risk-taking habits in adult populations

Epidemiological and experimental studies provide evidence that a complex of behavioral, biological and environmental factors interact in the etiology of many cardiovascular diseases. A survey of research and theory concerning training and counseling programs for adult populations is provided. Six basic behavioral recommendations are made for the maintenance of cardiovascular health. Problems in the design of mass media and interpersonal campaigns to alter the health habits of large populations are considered.

Alcohol consumption in relation to factors associated with ischemic heart disease: a cotwin control study

Moderately alcohol-discordant male twin pairs, aged 45-65 years, have been examined with respect to ischemic heart disease (IHD) and associated factors. No conclusion can yet be drawn with regard to manifest or subclinical IHD, while significant disparities were found with regard to systolic and diastolic blood pressures, high cigarette consumption, hyperglycemia, and serum cholesterol; the greater number of findings of pathological values were found in the high alcohol-consumption as compared to the low alcohol-consumption cotwins. These findings offer a possible explanation for the increased number of reports showing a connection between high consumption of alcohol and occurrence heart disease.

Age-related interrelationships of blood pressure and arterial sterol accumulation in spontaneously atherosclerosis-susceptible and atherosclerosis-resistant pigeons

Interrelationships of arterial sterol accumulation and blood pressures were examined in age-matched White Carneau and Show Racer pigeons. It was found that the systolic blood pressure of White Carneaux changed from 155.0 mm Hg at nine months of age to 168.8 mm Hg at 17 months of age (P less than 0.005) while that of the Show Racers did not show any age-related increases. In White Carneaux, the total sterol content in the aorta increased by 43.6% from 9 months to 17 months of age (P less than 0.001) with major changes in the steryl ester fraction while no such changes were evident in the Show Racers. This indicates interrelationships of the arterial sterol content and blood pressure in the White Carneau pigeon.

Heart disease mortality among black migrants: a study of Ohio residents (1960-1967)

In a demographic study, the black Ohio residents were characterized by those born in Ohio and those born in other regions of the United States, and comparisons were made of rates for all deaths (1960-1967) for coronary heart disease (420), endocarditis and myocardial degeneration (421-422), hypertensive cardiovascular diseases (440-447), cerebrovascular diseases (300-334), cardiovascular diseases (400-468), and total diseases of the cardiovascular system (300-334) (400-468). The division of the total United States-born Ohio residents by region of birth provided marked differences in the age-adjusted rates in the relative comparisons. The black males and females born in the South had a markedly higher age-adjusted death rate (ages 45 to 64) than those born in Ohio in each of the categories of cardiovascular diseases studied. For coronary heart disease, the age-adjusted death rate for the black males showed a marked excess over the black females, for each region of birth, whereas for hypertensive cardiovascular diseases the black males and females had similar age-adjusted rates for each region of birth. The findings indicate a carry-over among the black of a higher cardiovascular risk among those born in the South and lend support to the concept of the influence of the endemic factors in the early years of life. In the prospective study of black steelworkers, it was observed that migrant and nonmigrant workers had approximately the same mortality for cardiovascular disease overall, and when specific work areas were considered. Selective factors of employment, of medical screening, and capability of continued employment in strenuous environments, were considered the most likely basis for the similar mortality experience.

Incidence of ischaemic heart disease in two cohorts of Belgian clerks

A study during a five-year period has been conducted on the incidence of ischaemic heart disease (IHD) among two cohorts of Belgian employees who were free of IHD at entry. As regards the final outcome these incidences differ significantly. The chief difference between the two cohorts is their systolic blood pressure. These pressure differences may be attributed to differences in the level of work pressure. The increased work pressure in Cohort I might account, through stress, for the greater incidence of sudden death or myocardial infarction.

Differences in the serum lipid constituents of hyperlipidemic men and women

A thousand cases of hyperlipidemia were studied and significant differences were found in the levels of cholesterol and triglycerides between the two sexes. Hyperlipidemic men had higher triglycerides levels and hyperlipidemic women higher cholesterol levels. When divided into different hyperlipidemia groups, women were equally distributed among them, while the men were grouped essentially in the group characterised by normal cholesterol level and elevated triglycerides level. Within this same group men had more accentuated triglycerides values than women. From the fact that most hyperlipidemic men belong to Type IV, hyperlipidemia may constitute a strong "risk" factor in the development of coronary disease in men.

Myocardial infarction in young men. Study of risk factors in nine countries

In order to determine whether the development of myocardial infarction in different countries is associated with different risk factors, 240 male survivors, aged 40 or less, were studied in nine countries. In the seven centres in developed countries (Auckland, Melbourne, Los Angles/Atlanta, Cape Town, Tel Avic, Heidelberg, and Edinburgh) there was a high procedure of risk factors, particularly of hyperlipidaemia and cigarette smoking. The prevalence of hypertension, obesity, hyperglycaemia, and hyperuricaemia varied from centre to centre. Risk factors were less prevalent in Bombay and Singapore: the most common risks operating in Bombay seemed to be cigarette smoking and hyperglycaemia, while in Singpore cigarette smoking was the commonest. The mean age of the whole group was 35.4 years. Serum cholesterol levels of 7.25 mmol/l (280 mg/dl) or more were present in 25 per cent of all patients, serum triglyceride levels of 2.26 mmol/l )l200 mg/dl) or more in 35 per cent. 80 per cent of the patients were smokers, and 15 per cent were either for hypertension before myocardial infarction or had a raised blood pressure after myocardial infarction. Obesity was found in 19 per cent of all patients and serum uric acid levels over 0.5 mmol/l (8.5 mg/dl) in 17 per cent. 10 per cent of all patients were either treated for diabetes mellitus before myocardial infarction or showed an abnormal glucose tolerance after myocardial infarction. This collaborative study may help, by showing differences in the prevalence of risk factors, to indicate to each centre and to national and to international organizations, the direction for their future studies into the causation and prevention of myocardial infarction in young men.

The posthospital phase of myocardial infarction: identification of patients with increased mortality risk

A prospective follow-up study was carried out on 100 patients recovering from acute myocardial infarction in order to develop a method for identifying those patients who are at high risk of late cardiac death. Variables, which were recorded just prior to the patient's hospital discharge after the acute attack, included six rhythm parameters from a six-hour tape ECG recording, three indices of severity of the acute coronary event, and seven nonspecific variables. Seventy-nine of the 100 patients survived a two-year follow-up, and 17 of 21 patients who died succumbed from cardiac-related problems. A stepwise discriminant analysis program was used to derive a formula which would predict the likelihood of surviving two years after a myocardial infarction. The population was divided into two groups on the basis of the presence (Group A, N = 67) or absence (Group B, N = 29) of ventricular premature beats on the initial ECG tape recording. In Group A, 91% of both the survivors and nonsurvivors were correctly identified by a discriminant combination of three arrhythmia parameters and age. In Group B, 75% of the survivors and 100% of the nonsurvivors were properly classified simply from age and one index of severity.

Coronary heart disease epidemiology revisited. Clinical and community aspects

Epidemiological research relating coronary heart disease risk to risk factors has been reviewed and condensed into simple, diagrammatic form. The predictive power of risk factors for detecting susceptibles in the population is presented. While much is now known about long-term prediction, there is an urgent need for tests to signal impending heart attacks. Against this background, the potential for preventive action is discussed in the light of current knowledge. The "clinical-individual" and "community" approaches to prevention are contrasted. To what extent is prevention on the community level warranted, pending the results of controlled prophylactic trials? The view is presented that advice on preventive measures to the population at large is justified at this time, based on education and planned change but short of an all-out campaign which must await conclusive data from intervention studies.

Immediate and remote prognostic significance of fascicular block during acute myocardial infarction

The electrocardiograms of 538 patients with acute myocardial infarction were searched to identify all instances of atrioventricular (A-V) and intraventricular (I-V) conduction disturbances. Data concerning mode of therapy and clinical complications were obtained by review of the record. These variables were then analyzed for significance in relation to the development of type II A-V block acutely and syncope or sudden death during the first year of follow-up.

The most accurate predictor for both these events was the status of A-V conduction in combination with the status of I-V conduction. At highest risk (50%) for type II progression were patients with acute adjacent fascicular block plus P-R prolongation, i.e., left anterior hemiblock plus right bundle-branch block (RBBB), or left bundle-branch block (LBBB), or patients with acute nonadjacent fascicular block, i.e., RBBB plus left posterior hemiblock or alternating bundle-branch block. The nonpaced survivors from this same group, plus any other patients with transient type II progression, were also at high risk (45%) for syncope or sudden death in follow-up. No syncope or sudden death has occurred in seven patients with type II progression discharged with a pacemaker. All other patients were at lower risk for these acute and chronic complications.

Thus, the electrocardiogram in acute myocardial infarction can identify a high-risk group for acute type II progression in whom prophylactic pacer insertion may be beneficial. Similarly, the electrocardiogram can identify a high-risk group for syncope or sudden death in follow-up and implicates progression to higher degrees of A-V block as an important pathophysiologic mechanism.The possible role of permanent pacemaker therapy in preventing syncope or sudden death in this high-risk group is also suggested.

Approaches to sudden death from coronary heart disease

Sudden cardiac death (SCD) continues unabated. Coronary care units, while effective in lowering hospital mortality, cannot significantly reduce SCD which occurs primarily outside the hospital and accounts for the majority of deaths from coronary heart disease (CHD). In view of the frequent precipitous nature of SCD, only a program which identifies and protects the victim prior to the event can hope to be successful in preventing the majority of SCD. Since it is likely that SCD is due to an arrhythmia, drug prophylaxis might prove effective. In view of the toxicity of currently available agents, it is mandatory to preselect a population at highest risk before embarking on a drug trial. Ventricular premature beats (VPB) may identify subjects susceptible to SCD. Epidemiologic and physiologic information on VPB is reviewed, and proposals are made for studies designed to establish the usefulness of VPB as a risk factor for SCD.

A study of the primary prevention of coronary heart disease

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Effects of hyperlipoproteinemias and their treatment on the peripheral circulation

The purpose of this study was to determine the effect of familial hyperlipoproteinemia (HLP) on peripheral vascular disease (PVD) and the extent to which the vascular disease (PVD) and the extent to which the vascular disease is modified by treatment of the lipoprotein disorder. PVD was detected plethysmographically by observing a diminished peak reactive hyperemia blood (PRHBF) following ischemia. The value for PRHBF in the extremity demonstrating the lowest response in 32 normal subjects (age 19-50 yr) was 39.6+/-1.5 SEM, ml/min per 100 g. Patients with untreated HLP. who had PRHBF below the lower limit of normal, were 2 of 11 type II, 9 of 12 type III, 1 of 10 type IV. As a group, patients with type III HLP showed diminished PRHBF (26.6 +/-3.0 ml/min per 100 g, P <0.01). In view of the high incidence of PVD and the striking reduction in serum lipids and complete resorption of xanthomas observed in type III HLP with therapy, six patients were studied before and after 3-6 months of treatment with a therapeutic diet and clofibrate. PRHBF in the most severely affected extremity increased markedly, from 20.4 +/-1.6 to 31.9 +/-1.8 ml/min per 100 g (P<0.01), indicating a dramatic increase in maximum blood flow to this extremity. In two type III patients with PVD not treated, no change in PRHBF occurred over 5 months. In two other type III patients the PRHBF increased 17% during the first 25 days of therapy concomitant with a 30% reduction in whole blood viscosity. Over the next 120 days, blood viscosity decreased only an additional 4.6% whereas the PRHBF increased 57%, indicating that the observed changes seen in the PRHBF with therapy of type III patients can be only minimally accounted for by changes in the viscosity of the blood. Thus, patients with type III HLP are particularly susceptible to the development of PVD and objective improvement of PVD can occur with medical treatment of this lipid transport disorder.

Systolic hypertension in the elderly. An epidemiologic assessment

Isolated systolic hypertension (systolic blood pressure of 160 mm Hg or greater, diastolic blood pressure less than 90) was investigated in the Leisure World population at Seal Beach, California. The prevalence of this condition was 13.9% if the blood pressure at the initial examination was used but dropped to 2.7% if the subsequent two determinations of blood pressure were also reviewed.

Seventy-two of the subjects with persistent systolic hypertension were compared with 72 matched normotensive control subjects. Cardiovascular morbidity and mortality were generally more frequent among subjects with systolic hypertension. That this association is causal has yet to be proven.

In this elderly population isolated systolic hypertension was a labile, relatively infrequent condition associated with an increased risk of developing cardiovascular complications.

Blood pressure in a Scottish island community

A survey of mean blood pressure levels in age-and-sex-matched samples of the population of the island of Tiree appears to support the local belief that blood pressure is higher on the island than on the mainland. This conclusion may be related to the observation of a greater mean width of the heart, measured radiologically, in the island population compared with the mainland population. The greater mean body weight observed in the island compared with the mainland may be a factor. Blood pressure in men between the ages of 40 and 59 years is higher in Tiree than in selected samples in England and America.