British Regional Heart Study: cardiovascular risk factors in middle-aged men in 24 towns

High density lipoprotein cholesterol is not a major risk factor for ischaemic heart disease in British men

The concentration of high density lipoprotein cholesterol (HDL cholesterol) in serum was measured at initial examination in a large prospective study of men aged 40-59 drawn from general practices in 24 British towns. After an average follow up of 4.2 years 193 cases of major ischaemic heart disease had been registered in 7415 men in whom both HDL cholesterol and total cholesterol values had been measured. The mean HDL cholesterol concentration was lower in the men with ischaemic heart disease ("cases") compared with other men, but the difference became small and non-significant after adjustment for age, body mass index, blood pressure, cigarette smoking, and concentration of non-HDL cholesterol. The higher mean concentration of non-HDL cholesterol in "cases" remained highly significant after adjustment for other factors. Men in the highest fifth of non-HDL cholesterol values had over three times the risk of major ischaemic heart disease compared with men in the lowest fifth. Multivariate analysis showed that non-HDL cholesterol was a more powerful predictor of risk than the HDL to total cholesterol ratio. These British findings were compared with six other prospective studies. All the larger studies showed similar results, suggesting that HDL cholesterol is not a major risk factor in the aetiology of ischaemic heart disease.

The patterning of health by social position in contemporary Britain: directions for sociological research

Associations are described between health (variously measured) and occupational class, gender, marital status, age, ethnicity and area of residence, using British data. It is argued that when exploring the social patterning of health, illness and death, it would be profitable for sociologists to consider several or all of these social positions, and to develop models of general vulnerability to ill-health rather than of specific etiology. Three main types of explanation, artefact, health selection and social causation, are reviewed, and six general points are made about how sociological research on social patterning in health should proceed.

Analysing geographic variations in mortality using Poisson regression: the example of ischaemic heart disease in England and Wales 1969-1973

This paper describes how Poisson regression techniques can be used to examine the relationship between mortality and possible explanatory variables over a series of areas in cases where the number of deaths involved is relatively low. As an example an analysis is carried out on deaths from ischaemic heart disease among young adults in the county boroughs of England and Wales during 1969-1973. The results of the study indicate that the number of deaths was higher for males than females and was positively related to age, the size of the 'at risk' population and crowding, but negatively associated with water hardness and the size of the New Commonwealth population. A comparison of the Poisson and log-normal regression models clearly shows that the latter provides an inferior goodness of fit and unreliable results. It is therefore concluded that when the number of deaths is small there are both theoretical and practical advantages in using Poisson regression to analyse mortality data.

Variation in serum lipid and lipoprotein levels associated with changes in smoking behaviour in non-obese Caucasian males

A population of healthy male caucasians was analysed with respect to lipid and lipoprotein parameters, according to differences in current and previous smoking patterns. High density lipoprotein (HDL) cholesterol, and the HDL2 subfraction were significantly higher in non-smokers compared to current smokers. In ex-smokers, the levels of these 2 parameters increased with the length of time since giving up the habit, until levels were no longer distinguishable from non-smokers. A similar increase was observed for weight, although both triglyceride and very low density lipoprotein (VLDL) levels decreased. Low density lipoprotein (LDL) levels showed no significant variation in any of the comparisons. Lower alcohol consumption in both the ex-smokers, and in the non-smokers may account partially for the changes in triglyceride and VLDL, although the same observation is contrary to the effects observed in both HDL and HDL2.

Blood pressure in a national birth cohort at the age of 36 related to social and familial factors, smoking, and body mass

Blood pressure was measured in a birth cohort of 5362 subjects at the age of 36. The prevalence of hypertension in men (blood pressure greater than 140/90 mm Hg) was almost twice that in women, although women received treatment more often. Deaths of fathers of subjects from hypertensive and ischaemic heart disease were associated with significantly higher mean systolic and diastolic pressures in both sexes. Cigarette smoking was not strongly associated with blood pressure in men and not associated at all in women. Of the social factors, low social class of family of origin was associated with high blood pressure in both sexes; but the strongest association was with current body mass, and birth weight also contributed. Differences in blood pressures between the sexes may have been related to protective biological factors, such as endogenous sex hormones, in women and also to differences in types of employment, smoking habits, and body mass. Differences in blood pressures related to the social class of family of origin may reflect long term influences of class differences on diet, exercise, and educational achievement. The importance of measuring secular trends in obesity and blood pressures is emphasised.

Risk factors for ischaemic heart disease: the prospective phase of the British Regional Heart Study

Risk factors for major ischaemic heart disease (acute myocardial infarction or sudden death) have been investigated in a prospective study of 7735 men aged 40-59 years drawn from general practices in 24 British towns. After a mean follow-up of 4.2 years, there have been 202 cases of major ischaemic heart disease. Univariate estimates of the risk of ischaemic heart disease show that serum total cholesterol, HDL-cholesterol and triglyceride concentrations, systolic and diastolic blood pressures, cigarette smoking, and body mass index are all associated with increased risk of ischaemic heart disease. Evidence of ischaemic heart disease at initial examination is also strongly associated with increased risk of subsequent ischaemic heart disease. All these factors were then considered simultaneously using multiple logistic models. Definite myocardial infarction on electrocardiogram and recall of a doctor diagnosis of ischaemic heart disease remained predictive of subsequent major ischaemic heart disease, after allowance for all other risk factors. Serum total cholesterol, blood pressure, and cigarette smoking each remained as highly significant independent risk factors whereas overweight, above average levels of HDL-cholesterol and serum triglyceride were not predictive of risk after allowance for the above factors. Men with and without pre-existing ischaemic heart disease were examined separately in the same way (using multiple logistic models). The strength of association between the principal risk factors and subsequent major ischaemic heart disease was reduced in the men with pre-existing ischaemic heart disease, only age and serum total cholesterol remaining highly significant. Overall the levels of the major risk factors commonly encountered in British men have a marked effect on the risk of ischaemic heart disease. Modification of these risk factors in the general population constitutes an important national priority.

Biochemical and haematological response to alcohol intake

In a clinical survey of 7735 middle-aged men, alcohol consumption has been related to 25 biochemical and haematological measurements obtained from a single blood sample. Most measurements showed some association with alcohol consumption, gamma-glutamyl transferase (GGT) being the most strongly associated. Lead, mean corpuscular haemoglobin (MCH), mean corpuscular volume, high-density lipoprotein-cholesterol (HDL-C), urate and aspartate transaminase also showed substantial associations with alcohol intake. Using a discriminant analysis technique, a simple score based on five variables (GGT, HDL-C, urate, MCH and lead) provided the best discrimination between heavy drinkers (e.g. more than three pints of beer daily) and occasional drinkers, but still failed to identify more than half of the heavy drinkers. This combined score may prove a useful measure of an individual's biochemical/haematological response to alcohol consumption for use in epidemiological and clinical studies of alcohol related disorders. The use of such indices should complement but not replace measures of alcohol intake derived from questionnaires.

Blood lead concentration, blood pressure, and renal function

Blood lead concentrations were related to blood pressure and indicators of renal function in a clinical survey of 7735 middle aged men from 24 British towns. There was no overall evidence that blood lead concentrations were associated with systolic or diastolic blood pressure (r = +0.03 and +0.01, respectively). In the 74 men with a blood lead concentration of 1.8 mumol/l (37.3 micrograms/100 ml) or more there was some suggestion of increased hypertension, but this did not reach significance. Blood lead concentration did not have any relation with serum creatinine concentration. Moderate increases in blood lead concentration were associated with small increases in mean serum urate concentration and small decreases in mean serum urea concentration; these associations were both reduced when alcohol consumption was taken into account. There is no indication that exposure to lead at concentrations commonly encountered in British men is responsible for impaired renal function or increased blood pressure.

Follow-up of subjects in prospective studies based in general practice

In prospective studies of ischaemic heart disease, data on the incidence of morbidity as well as mortality are critical to the understanding of the natural history of disease. In the Regional Heart Study, 7,735 middle-aged men recruited from general practices in 24 towns in England, Wales and Scotland have been examined, and are being followed for morbidity and mortality for at least five years. This paper explains the methods used and the difficulties encountered in maintaining the flow of information on these subjects and, in particular, discusses the problems of removal and tracing. A network of enquiries, using Family Practitioner Committees, the NHS Central Register and the additional 500 doctors (to date) to whom subjects have transferred, has enabled contact to be maintained. In the first seven towns reviewed at five years from the initial examination, replies have been received from 98 per cent of the original sample still alive and living in Great Britain.

Prevalence of ischaemic heart disease in middle aged British men

The prevalence of ischaemic heart disease was determined by an administered questionnaire and electrocardiography in 7735 men aged 40-59 years drawn at random from general practices in 24 British towns. Overall, one quarter of these men had some evidence of ischaemic heart disease on questionnaire or electrocardiogram or both. On questionnaire, 14% of men had possible myocardial infarction or angina, with considerable overlap of the two syndromes. The prevalence of possible myocardial infarction combined with angina and of definite angina only showed a fourfold increase over the age range studied. Electrocardiographic evidence of ischaemic heart disease (definite or possible) was present in 15% of men, there being myocardial infarction in 4.2% and myocardial ischaemia in 10.3%. Electrocardiographic evidence of myocardial infarction increased fourfold over the age range studied. There was considerable overlap of questionnaire and electrocardiographic evidence of ischaemic heart disease. Nevertheless, more than half of those with possible myocardial infarction combined with angina had no resting electrocardiographic evidence of ischaemic heart disease, and half of those with definite myocardial infarction on electrocardiogram had no history of chest pain at any time. This national population based study strongly suggests that the prevalence of ischaemic heart disease in middle aged British men is greater than has been indicated by previous studies based on occupational groups.

Recall of diagnosis by men with ischaemic heart disease

In a study of the prevalence of ischaemic heart disease in middle aged men in 24 British towns, the subjects were asked whether a doctor had ever told them that they had any form of cardiovascular disease. Their recall of various diagnoses was related to evidence of ischaemic heart disease obtained by an administered questionnaire on chest pain and electrocardiography. Twenty one per cent of men recalled a diagnosis of cardiovascular disease, in one quarter of whom it was ischaemic heart disease. There was a sixfold increase in the prevalence of recall of a diagnosis of ischaemic heart disease over the age range studied. Only one third of the men with possible myocardial infarction on questionnaire recalled such a diagnosis having been made by a doctor. Only half of those with a definite myocardial infarction on an electrocardiogram could recall a diagnosis of ischaemic heart disease. Even in severe (grade 2) angina 40% could not recall being told that they had heart disease. Overall, only one in five of those regarded as having ischaemic heart disease was able to recall such a diagnosis having been made by a doctor, and these were likely to be those most severely affected. Ischaemic heart disease is common in middle aged British men, but most of those affected are apparently not aware of their condition. This low level of awareness among patients and doctors may contribute to a lack of public concern regarding the need for action to reduce the incidence of ischaemic heart disease in Great Britain.

Hypertension and the prevention of coronary heart death in general practice

A major attack on the main risk factors of coronary heart disease is essential in order to control it. In general practice, there is a real opportunity to control high blood pressure and smoking; unfortunately coronary risk factors are closely related to social class and unemployment. Major new strategies will be needed both by government and the medical profession in order to achieve a reduction in the commonest single cause of death in the U.K.

Effects of tap water lead, water hardness, alcohol, and cigarettes on blood lead concentrations

A survey of middle-aged men in 24 British towns has found pronounced geographical variation in blood lead concentrations. Towns with the highest mean blood lead concentrations have soft water supplies and have the highest water lead concentrations. Individual blood lead can be considerably increased by raised household tap water lead concentrations. Mean blood lead is estimated to be 43% higher for men when the concentration of lead in first-draw domestic tap water is 100 micrograms/l compared with a zero concentration. Individual blood lead is also affected by alcohol consumption and cigarette smoking, such that on average these two life-style habits together contribute an estimated 17% to the blood concentration of lead in middle-aged men. Lead in water should be given greater priority in any national campaign to reduce lead exposure.

Blood lipids in middle-aged British men

The concentrations of serum total cholesterol, high density lipoprotein-cholesterol, and triglycerides have been measured in 7735 men aged 40 to 59 years who were drawn from general practices in 24 towns in England, Wales, and Scotland. The distribution of these blood lipids, their interrelations and their association with age, social class, body mass index, cigarette smoking, alcohol intake, and physical activity at work have been examined. Body mass index emerges as the factor most strongly associated with these three blood lipids. Serum total cholesterol increased with increasing body mass index until about 28 kg/m2 but thereafter showed no further rise. The relation between body mass index and high density lipoprotein-cholesterol was negative and linear; that between body mass index and triglycerides was positive and linear. The inverse relation between high density lipoprotein-cholesterol and triglycerides was independent of the fact that both were related to body mass index. Alcohol intake was associated with increased high density lipoprotein-cholesterol concentrations and cigarette smoking with lowered high density lipoprotein concentrations; the association with alcohol appeared to be dominant. No significant trends with age were observed for the three blood lipids. In this population, body mass index is closely associated with the concentration of blood lipids but its effects are probably indirect and mediated by a complex of dietary and other factors.

Cardiomegaly in Northern Zambia: clinico-pathological observations

Massive cardiomegaly (heart weight above 400 g in females and 450 g in males) was studied in 26 Zambians examined post mortem. The aetiologies found were: hypertensive heart disease alone in six cases; hypertensive and alcoholic heart disease in two cases; alcoholic heart disease alone in five; alcoholic and pulmonary heart disease in one; alcohol with possible hypertensive heart disease in one. Eleven cases were classified as being idiopathic mainly due to lack of data and in five of these hypertension was suspected as being the cause. The series qualitatively represented the spectrum of non-rheumatic heart disease seen in patients admitted to the Central Hospital, Ndola, Zambia. Hypertension had a central role in the causation of massive cardiomegaly. Follow-up of several patients enabled observations on the cardiac effects of hypertension and alcoholism operating simultaneously and on the relationship between hypertension and congestive cardiomyopathy.

Tranquillizer use in middle-aged British men

We have examined the use of tranquillizers by 7,735 middle-aged men currently enrolled in the British Regional Heart Study, a prospective study of cardiovascular disease in 24 towns throughout Great Britain. Tranquillizer use was reported by 620 men (8 per cent). There was a slightly greater prevalence of tranquillizer use in the older men and the non-manual workers. Men with physical disease diagnosed by their doctor or by objective measurements during the study were more likely to be using tranquillizers than men with no physical disease. This was most evident for ischaemic heart disease, however diagnosed, and for hypertension diagnosed by their doctors. There was an inverse relationship between drinking and tranquillizer usage: heavy drinkers had lower rates of usage. There was no association between tranquillizer use and smoking habits.This study indicates that tranquillizer use in these middle-aged men is little influenced by age, social class or smoking, but that there is a strong, positive association between tranquillizer use and the presence of doctor-diagnosed physical disease. While our data provide support for the suggestion that alcohol and tranquillizers may be used interchangeably by some individuals, this finding could also be an outcome of doctors' and patients' awareness of the undesirable effects of combining alcohol and tranquillizers.

Health of unemployed middle-aged men in Great Britain

The frequencies of several factors, including major physical disease, in employed and unemployed men enrolled in the British Regional Heart Study (BRHS) have been compared. The BRHS is a prospective study of cardiovascular disease in middle-aged men selected at random from general practices in twenty-four towns. The unemployed group was subdivided into those who said they were unemployed because of ill-health and those who regarded their unemployment as not due to illness. The ill unemployed reported a much higher rate of doctor-diagnosed illnesses than the not-ill unemployed or the employed. The frequencies of bronchitis, obstructive lung disease, and ischaemic heart disease were higher in the unemployed than the employed, with the highest rates in the ill unemployed. The frequency of hypertension was the same in employed and unemployed men. Cigarette smoking and heavy drinking were apparently more common among the unemployed, but after adjustment for social class and town of residence only smoking was slightly higher among the unemployed. Use of tranquillisers was three to four times more common in the ill unemployed than in the not-ill unemployed or the employed. In this study, the unemployed had far more chronic physical illnesses than the employed, whether or not the employed men regarded themselves as ill. Studies of the health consequences of unemployment must allow for the pre-existing state of health, and evidence on the state of health cannot rely solely on self-reporting of illness.

Effects of alcohol and smoking on blood lead in middle-aged British men

A survey of middle-aged men in 24 British towns showed a strong association between blood lead concentrations, alcohol consumption, and cigarette smoking. The association with alcohol persisted after age, social class, body mass index, cigarette smoking, water lead concentrations, and the town of residence had been taken into account. There was an independent but less pronounced association between cigarette smoking and blood lead concentrations after adjustment for the other factors. The possible mechanisms include a decreased excretion of lead due to alcohol-induced hepatic dysfunction and an increased lead intake from cigarette smoking. These findings have implications for widespread measurement of blood lead concentrations in adults in the community and for all studies attempting to relate blood lead concentrations to environmental exposure.

Smoking and drinking by middle-aged British men: effects of social class and town of residence

In 7735 men aged 40-59, selected at random from general practices in 24 towns throughout Britain, pronounced differences were noted in the prevalences of smoking and drinking between the social classes. Social class differences also existed for frequency and quantity of drinking, type of beverage, and several aspects of smoking behaviour. Increasing amounts of smoking were associated with higher prevalences of moderate to heavy drinking, particularly in daily rather than weekend drinkers. Between drinking groups, however, the relation with smoking was more U-shaped, with light and heavy drinkers smoking more than moderate drinkers. The lowest rates of moderate to heavy smoking were observed in frequent light drinkers, particularly in the nonmanual workers. The proportion of moderate to heavy drinkers was no higher among ex-cigarette smokers than among current smokers. When the data were examined by town of residence social class differences persisted. Controlling for social class still showed pronounced differences between towns in both smoking and drinking behaviour. These data confirm that town of residence and social class have independent effects on smoking and drinking. The established regional and social class differences in cardiovascular disease may be due in part to the independent influences of town and social class on smoking and drinking behaviour.