D G Cook

Loss of employment and mortality

Abstract Objective: To assess effect of unemployment and early retirement on mortality in a group of middle aged British men. Design: Prospective cohort study (British Regional Heart Study). Five years after initial screening, information on employment experience was obtained with a postal questionnaire. Setting: One general practice in each of 24 towns in Britain. Subjects: 6191 men aged 40-59 who had been continuously employed for at least five years before initial screening in 1978-80: 1779 experienced some unemployment or retired during the five years after screening, and 4412 remained continuously employed. Main outcome measure: Mortality during 5.5 years after postal questionnaire. Results: Men who experienced unemployment in the five years after initial screening were twice as likely to die during the following 5.5 years as men who remained continuously employed (relative risk 2.13 (95% confidence interval 1.71 to 2.65). After adjustment for socioeconomic variables (town and social class), health related behaviour (smoking, alcohol consumption, and body weight), and health indicators (recall of doctor diagnoses) that had been assessed at initial screening the relative risk was slightly reduced, to 1.95 (1.57 to 2.43). Even men who retired early for reasons other than illness and who appeared to be relatively advantaged and healthy had a significantly increased risk of mortality compared with men who remained continuously employed (relative risk 1.87 (1.35 to 2.60)). The increased risk of mortality from cancer was similar to that of mortality from cardiovascular disease (adjusted relative risk 2.07 and 2.13 respectively). Conclusions: In this group of stably employed middle aged men loss of employment was associated with an increased risk of mortality even after adjustment for background variables, suggesting a causal effect. The effect was non-specific, however, with the increased mortality involving both cancer and cardiovascular disease.

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.

CYTOMEGALOVIRUS INFECTION AND PROGRESSION TOWARDS AIDS IN HAEMOPHILIACS WITH HUMAN IMMUNODEFICIENCY VIRUS INFECTION

To examine whether cytomegalovirus (CMV) infection could accelerate progression of human immunodeficiency virus (HIV) infection to AIDS, serological studies were done on 108 HIV-infected haemophiliacs. In the 1.3-9 years from time of first recognised HIV seroconversion, the age-adjusted risk of CDC group IV disease in CMV-seropositive patients was 2.5 times that in CMV-seronegative patients. CMV-seropositive patients were also more likely to have detectable p24 antigenaemia. Survival analysis showed that CMV-seropositive patients were at greater risk of HIV disease than CMV-seronegative patients from about 2 years after HIV seroconversion. Thus CMV infection is associated with a more rapid progression to HIV disease.

Early influences on blood pressure: a study of children aged 5-7 years.

OBJECTIVE--To examine factors that influence blood pressure in children. DESIGN--Cross sectional study of children aged 5.0-7.0 years who had blood pressure measurements and for whom parental questionnaires were completed. SETTING--School based survey. SUBJECTS--3591 Children aged 5.0-7.5 years selected by stratified random sampling of primary schools in nine British towns (response rate 72%); 3591 were examined and their parental questionnaires were completed. Data were complete for birth rank in 3559, maternal age in 3542, maternal history of hypertension in 3524, and paternal history in 2633. RESULTS--Birth weight was inversely related to mean systolic blood pressure but only when standardised for current weight (weight standardised regression coefficient -1.83 mm Hg/kg (95% confidence interval -1.31 to -2.35). Mean diastolic pressure was similarly related to birth weight. Maternal age, birth rank, and a parental history of hypertension were all related to blood pressure. After standardisation for current weight a 10 year increase in maternal age was associated with a 1.0 mm Hg (0.4 to 1.6) rise in systolic pressure; first born children had systolic blood pressure on average 2.53 mm Hg (0.81 to 4.25) higher than those whose birth rank was greater than or equal to 4; and a maternal history of hypertension was associated with a systolic pressure on average 0.96 mm Hg (0.41 to 1.51) higher than in those with no such history. The effects described were largely independent of one another and of age and social class. The relation for birth rank was, however, closely related to that for family size. CONCLUSIONS--Influences acting in early life may be important determinants of blood pressure in the first decade. The relation between birth weight and blood pressure may reflect the rate of weight gain in infancy. The reasons for the relation with birth rank and maternal age are unknown; if confirmed they imply that delayed motherhood and smaller family size may be associated with higher blood pressure in offspring.

Non-employment and changes in smoking, drinking, and body weight.

OBJECTIVE--To assess the effect of unemployment and early retirement on cigarette smoking, alcohol consumption, and body weight in middle aged British men. DESIGN--Prospective cohort study (British regional heart study). SETTING--One general practice in 24 towns in Britain. SUBJECTS--6057 men aged 40-59 who had been continuously employed for five years before the initial screening. Five years after screening 4412 men had been continuously employed and 1645 had experienced some unemployment or retired. MAIN OUTCOME MEASURES--Numbers of cigarettes smoked and units of alcohol consumed per week and body mass index (kg/m2). RESULTS--An initial screening significantly higher percentages of men who subsequently experienced non-employment smoked or had high alcohol consumption than of men who remained continuously employed: 43.0% versus 37.0% continuously employed for cigarette smoking (95% confidence interval for difference 3.2% to 9.0%) and 12.1% versus 9.0% for heavy drinking (1.3% to 5.1%). There was no evidence that men increased their smoking or drinking on becoming non-employed. Men non-employed through illness were significantly more likely to reduce their smoking and drinking than men who remained continuously employed. Men who experienced non-employment were significantly more likely to gain over 10% in weight than men who remained continuously employed: 7.5% versus 5.0% continuously employed (0.9% to 4.0%). CONCLUSIONS--Loss of employment was not associated with increased smoking or drinking but was associated with an increased likelihood of gaining weight. The long term effects of the higher levels of smoking and alcohol consumption before nonemployment should be taken into account when comparing mortality and morbidity in groups of unemployed and employed people.

British Regional Heart Study: geographic variations in cardiovascular mortality, and the role of water quality

In a study of regional variations in cardiovascular mortality in Great Britain during 1969-73 based on 253 towns the possible contributions of drinking water quality, climate, air pollution, blood groups, and socioeconomic factors were evaluated. A twofold range in mortality from stroke and ischaemic heart disease was apparent, the highest mortality being in the west of Scotland and the lowest in south-east England. A multifactorial approach identified five principal factors that substantially explained this geographic variation in cardiovascular mortality—namely, water hardness, rainfall, temperature, and two social factors (percentage of manual workers and car ownership). After adjustment for other factors cardiovascular mortality in areas with very soft water, around 0·25 mmol/l (calcium carbonate equivalent 25 mg/l), was estimated to be 10-15% higher than that in areas with medium-hard water, around 1·7 mmol/l (170 mg/l), while any further increase in hardness beyond 1·7 mmol/l did not additionally lower cardiovascular mortality. Thus a negative relation existed between water hardness and cardiovascular mortality, although climate and socioeconomic conditions also appeared to be important influences. Cross-sectional and prospective surveys of 7500 middle-aged men from 24 towns are in progress and will permit further exploration of these geographic differences, especially with regard to personal risk factors such as blood pressure, blood lipid concentrations, and cigarette smoking.

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.

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.

D-PENICILLAMINE TREATMENT IMPROVES SURVIVAL IN PRIMARY BILIARY CIRRHOSIS

The copper-chelating, immunological, and antifibrotic effects of D-penicillamine indicated that it might be suitable for the treatment of primary biliary cirrhosis (PBC). In a randomised clinical trail, 55 PBC patients received penicillamine (600 mg daily), and 32 received a placebo. Drug reactions developed in 16 patients on penicillamine. All deaths occurred in patients with stage 3 or 4 (late stage) liver histology on entry to the study. 5 (14%) of 37 penicillamine-treated patients and 10 (43%) of 23 placebo patients have died (p less than 0.01). Improvement in survival only became evident after 18 months. Survivors in the penicillamine group demonstrated a significant fall in serum aspartate transaminase, serum immunoglobulins, and liver copper concentrations. On follow-up liver biopsy 12-72 months (median 33) after joining the study, 21% of penicillamine-treated patients had less pronounced inflammation and piecemeal necrosis, whereas there had been no improvement in patients on placebo (p less than 0.02). Penicillamine did not retard the histological evolution of the liver disease from the early prefibrotic stages to the late fibrotic or cirrhotic stages. Both the copper-chelating and immunological effects of penicillamine are probably important in improving survival. The excellent prognosis of patients with PBC in its early histological stages, and the failure of penicillamine to prevent histological progression from early to late stages, suggests that penicillamine treatment should not be given to patients with PBC in the early (stage 1 or 2) histological phase of the disease. Penicillamine treatment is recommended in patients once liver biopsy has demonstrated histological results typical of late stage 3 or 4 PBC.

ABO blood group and ischaemic heart disease in British men.

OBJECTIVE--To establish whether ABO blood group is related to ischaemic heart disease on an individual and geographic basis in Britain. DESIGN--Prospective study of 7662 men with known ABO blood group selected from age-sex registers in general practices in 24 British towns. MEASUREMENTS--ABO blood group, standard cardiovascular risk factors, social class, and presence or absence of ischaemic heart disease determined at entry to study. END POINTS--Eight year follow up of fatal and nonfatal ischaemic heart disease events achieved for 99% of study population. RESULTS--Towns with a higher prevalence of blood group O had higher incidences of ischaemic heart disease. In individual subjects, however, the incidence of ischaemic heart disease was higher in those with group A than in those with other blood groups (relative risk 1.21, 95% confidence limits 1.01 to 1.46). Total serum cholesterol concentration was slightly higher in subjects of blood group A. No other cardiovascular risk factor (including social class) was related to blood group. CONCLUSIONS--Blood group A is related to the incidence of ischaemic heart disease in individual subjects. Geographic differences in the distribution of ABO blood groups do not explain geographic variation in rates of ischaemic heart disease in Britain. The findings do not support the view that ABO blood group and social class are related.