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Biomedical subjects

A G Shaper

Publications and source records attributed to A G Shaper.

At least 181 records · Page 10Linked to original sources

Overweight and obesity in middle-aged British men.

Overweight and obesity have been examined in 7735 middle-aged men in 24 British towns. Half the men exceeded the body mass index (BMI) range associated with minimum mortality (20-25 kg/m2). Social class differences in BMI were marked and obesity was more marked in manual workers. The association of reduced BMI with cigarette smoking and of increased BMI with stopping smoking was most clearly seen in manual workers. With increasing alcohol intake, BMI increased progressively, but the effect in the heaviest drinkers was probably diminished by concurrent heavy smoking. Mean BMI decreased with increasing levels of physical activity. There was considerable variation in the rate of obesity between the towns, from 11 to 28 per cent, determined to some extent by social class. Positive associations were observed between BMI and the presence of ischaemic heart disease, high blood pressure, gout, arthritis and gallbladder disease but not with diabetes mellitus. Peptic ulcer was inversely related to BMI and bronchitis showed a curvilinear relationship. For these men, overweight or obesity is virtually 'normal', and a considerable health education effort will be needed to produce a leaner, healthier society.

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Blood pressure and hypertension in middle-aged British men.

Blood pressure measurements in 7735 middle-aged men from general practices in 24 towns in England, Wales and Scotland provide information on the prevalence of hypertension and its management in Great Britain. Despite a substantial correlation (r = 0.70) between systolic and diastolic blood pressures, individuals can show considerable discrepancies between these two measurements; they are not interchangeable. This observation has important implications for the choice of criteria used to define hypertension. However defined, the prevalence of hypertension increases markedly with age, increasing body mass index and with heavy alcohol consumption. It is not related to smoking and only to a small extent to social class. Diastolic hypertension (greater than or equal to 90 mmHg) was present in 26% and systolic hypertension (greater than or equal to 160 mmHg) in 22% of these men. In both systolic and diastolic hypertension, only one quarter of affected men could recall having been diagnosed as hypertensive by a doctor, and only one third of these were on regular antihypertensive treatment. There is a threefold variation in the prevalence of measured hypertension in the 24 towns with a trend towards higher rates in Northern England and Scotland. No relationship was seen between the prevalence rates of measured hypertension in the towns and the rates of doctor diagnosis of hypertension. Cardiovascular mortality rates in the towns were correlated with the measured prevalence rates for systolic and diastolic hypertension (r = 0.70 and r = 0.57, respectively). The geographic variations in blood pressure and hypertension in Great Britain provide a major opportunity for research into the causes of 'essential' hypertension.

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Observer bias in blood pressure studies.

Observer variation in blood pressure measurement following training with standard techniques has been investigated in a study of 7735 middle-aged men. The initial training produced consistent results between observers, but there were progressive deteriorations in the ensuing months. Subsequent re-training led to marked though inconsistent reductions in variation, but within 1 or 2 months, observers reverted back to an individual level of bias. The magnitude of observer variation is in line with the few other published accounts, and is sufficient to have important implications for group comparisons, clinical trials, and the clinical care of individual patients. Four methods of reducing observer variation are considered: regular re-training, self-measurement and ambulatory monitoring, automatic sphygmomanometers, and adjustment in the analysis. The adjustment procedure used in the British Regional Heart Study is described. Regular and frequent re-training with monitoring of performance, or the use of automatic machines are presently considered the two most practical methods of reducing observer variation.

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Social class differences in ischaemic heart disease in British men.

To examine why ischaemic heart disease (IHD) mortality rates in Britain are higher in manual than in non-manual workers 7735 middle-aged men in the British Regional Heart Study were followed up for 6 years, during which time 336 men experienced a major IHD event (fatal or non-fatal myocardial infarction or sudden cardiac death). The prevalence rates of IHD at screening, were higher in manual workers. Also, the attack rate of major IHD events during follow-up was 44% higher in manual workers. Marked differences in cigarette smoking contributed substantially to the increased risk of IHD in manual workers, who also had higher levels of blood pressure, were more obese, and took much less physical activity in leisure time. Adjustment for differences in these risk factors narrowed the gap between manual and non-manual workers in attack rates of IHD. Since the risk of IHD in Great Britain is high in all social classes, there would seem to be little justification for any overall policy for prevention of IHD to focus on social class. However, anti-smoking strategies might well take into account the social class differences described.

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Type A behaviour and ischaemic heart disease in middle aged British men.

The Bortner questionnaire, which measures aspects of type A (coronary prone) behaviour was completed by 5936 men aged 40-59 selected at random from one general practice in each of 19 British towns. The presence of ischaemic heart disease was determined at initial examination and the men were followed up for an average of 6.2 years for morbidity and mortality from myocardial infarction and for sudden cardiac death. Non-manual workers had significantly higher scores (more type A) than manual workers and the score decreased (less type A) with increasing age. After adjustment for social class and age men with higher scores had higher prevalences of ischaemic heart disease less marked for electrocardiographic evidence and more marked for response to a chest pain questionnaire (angina or possible myocardial infarction). A man's recall of a doctor's diagnosis of ischaemic heart disease, however, did not relate to his Bortner score. There was no significant relation between the Bortner score and the attack rate or incidence of major ischaemic heart disease events. In this study type A behaviour, as measured by the Bortner questionnaire, did not predict major ischaemic heart disease events in British middle aged men.

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Alcohol and ischaemic heart disease in middle aged British men.

The relation between alcohol intake and ischaemic heart disease was examined in a large scale prospective study of middle aged men drawn from general practices in 24 British towns. After an average follow up of 6.2 years 335 of the 7729 men had experienced a myocardial infarction (fatal or non-fatal) or sudden cardiac death. No significant relation was found between reported alcohol intake and the incidence of such events. Though the group of light daily drinkers had the lowest incidence of ischaemic heart disease events, it also contained the lowest proportion of current smokers, had the lowest mean blood pressure, had the lowest mean body mass index, and contained the lowest proportion of manual workers. These characteristics are more likely to account for the apparent protective effect of alcohol against ischaemic heart disease than a direct effect of alcohol. Compared with the effects of established risk factors alcohol seems to be quite unimportant in the development of ischaemic heart disease.

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Environmental factors in coronary heart disease: diet.

The customary diet of a population is the essential factor determining susceptibility to atherosclerosis and coronary heart disease (CHD), and it does so through its effects on lipoproteins, blood pressure and the coagulation system. The simplest and possibly strongest measure of this dietary effect is the serum total cholesterol concentration in the population. Within populations on high-risk diets [high saturated fat intakes and low ratio of polyunsaturated to saturated fatty acids (P/S ratio)], hypertension and cigarette smoking are potent secondary factors. Adipose tissue fatty acid studies support this concept of a dietary basis to CHD; low levels of linoleic acid and high P/S ratios are associated with a higher risk of CHD. Marine long-chain polyunsaturated fats may play a protective role in the CHD story. Monounsaturated fats are as effective in lowering serum total cholesterol as low fat-high carbohydrate diets. Coagulation factors of possible importance to CHD risks can be affected by dietary fat intake. Dietary fats affect blood pressure levels and may initiate hypertension. Coffee and alcohol consumption do not appear to effect the risk of CHD, although coffee may raise the blood cholesterol and alcohol raise the blood pressure. Diet is probably the central environmental factor in the development of CHD.

Coronary Disease↗

Non-participation and mortality in a prospective study of cardiovascular disease.

Men who did not participate in a prospective study of cardiovascular disease (The British Regional Heart Study) were younger than the participants, more likely to be unmarried, and more likely to be less skilled workers. In the first three years of follow-up, their total mortality rate was significantly higher than that of the participants; thereafter it declined to levels not significantly different from those of the participants. This excess of early deaths could not be attributed to age. There was a small but non significant excess mortality in non-participants due to neoplasms and cardiovascular disease and a somewhat greater excess from all other causes combined. The social characteristics of the non-participant population appear to contribute to their significantly higher total mortality rate, and allowance needs to be made for this in interpreting the study findings. However the death rate from cardiovascular disease was similar in participants and non-participants, suggesting that any analysis related to this particular cause of death should not be biased by non-participation.

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A scoring system to identify men at high risk of a heart attack.

A scoring system for identification of men at high risk of a heart attack within 5 years of screening is presented. The full scoring system includes an electrocardiogram and blood cholesterol measurement and the top fifth of the distribution of this full score yields 59% of the major ischaemic heart disease events occurring in the 5 years after screening. An intermediate scoring system, without an electrocardiogram but retaining blood cholesterol, yields 58% of cases from the top fifth of the score distribution. A basic (GP) score, without electrocardiogram or blood cholesterol measurement, yields 54% of cases and is recommended for use in opportunistic screening in general practice. This high risk strategy would increase public awareness of the size of the problem, help to prevent premature death and provide a useful complement to the population strategies of health education and government policy.

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Giving up smoking and the risk of heart attacks. A report from The British Regional Heart Study.

In a prospective study of 7735 middle-aged men, both current and ex-cigarette-smokers had a risk of a major IHD event, within an average 6.2 years of screening, more than twice that in men who had never smoked cigarettes; men who had given up smoking more than 20 years ago still had an increased risk. This excess risk among ex-smokers is only to a small extent explained by their higher blood pressure, serum total cholesterol, and body-mass index. An increased prevalence of IHD in men who had recently given up smoking also made a small contribution to excess risk. In both current and former cigarette smokers, the number of years a man had smoked cigarettes ("smoking-years") was the clearest indicator of IHD risk due to cigarettes. The major benefit of giving up smoking may lie in halting the accumulation of smoking years.

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Identifying men at high risk of heart attacks: strategy for use in general practice.

A strategy was devised for identifying men at high risk of acute myocardial infarction or sudden ischaemic death. A risk score was devised using cigarette smoking, mean blood pressure, recall of ischaemic heart disease or diabetes mellitus diagnosed by a doctor, history of parental death from "heart trouble," and the presence of angina reported on a questionnaire. The top fifth of the score distribution identified 53% of ischaemic heart disease cases--that is, men who subsequently experienced major ischaemic heart disease over the next five years. The addition of serum total cholesterol concentration and electrocardiographic evidence only slightly improved prediction (to 59%) and would have considerably increased the cost and effort of screening. Using this risk score on an opportunistic basis could be particularly valuable in general practice. Management of this high risk group is regarded as appropriate medical care and is complementary to the population approach to preventing ischaemic heart disease. Such a strategy for reducing the incidence of and mortality from ischaemic heart disease in men at high risk would also increase professional and public awareness of the need for preventive action.

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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.

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Serum uric acid, serum glucose and diabetes: relationships in a population study.

The relationships between serum uric acid, serum glucose and diabetes have been examined in a survey of 7735 middle-aged men drawn at random from general practices in 24 British towns. There was a positive relationship between serum glucose and serum uric acid concentrations up to about 8.0 mmol/l; at higher levels of glucose, serum uric acid decreased. Uric acid levels were significantly reduced in insulin-dependent diabetics and in those on oral hypoglycaemics and also in 'non-diabetics' with casual glucose levels greater than 10 mmol/l. Both uric acid and glucose concentrations were positively related to body mass index; only uric acid was positively related to alcohol intake. Men on antihypertensive treatment had raised levels of uric acid (significant) and glucose (non-significant). The positive relationship between serum uric acid and serum glucose could not be explained by associations with body mass index, alcohol intake, age, social class, gout or treatment for hypertension. It probably reflects the biochemical interaction between serum glucose and purine metabolism, with increased excretion of uric acid during hyperglycaemia and glycosuria.

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