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Objective: To examine the optimal intensity of leisure time physical activity (LTPA) to decrease the risk of all cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in a population sample of middle aged British men. Design: Prospective study of middle aged men with an 11 year follow up. Setting: A whole population sample of men from Caerphilly, South Wales, UK. Subjects: 1975 men aged 49–64 years without historical or clinical evidence of CHD at baseline examination. Main outcome measures: All cause, CVD, and CHD mortality. Results: Total (cumulative) LTPA had a graded, significant relation with all cause, CVD, and CHD mortality but no trend with cancer deaths. When different intensities of activity were considered, light and moderate intensity LTPA had inconsistent and non-significant relations with all cause, CVD, or CHD mortality whether adjusted only for age or for other cardiovascular risk factors. In contrast a significant dose–response relation was found for heavy intensity LTPA for all cause, CVD, and CHD mortality fully adjusted for other risk factors. Conclusions: These data suggest that, in a population of men without evidence of CHD at baseline, only leisure exercise classified as heavy or vigorous was independently associated with reduced risk of premature death from CVD.

Objectives: To investigate the effect of Chlamydia pneumoniae infection on future development of ischaemic heart disease and mortality. Design: Prospective longitudinal study. Setting: Caerphilly, South Wales. Subjects: Plasma specimens were collected during 1979-83 from 1773 men aged 45-59 years. These were tested for IgG and IgA antibodies to C pneumoniae (TW183) by microimmunofluorescence. Outcome measures: 13 year mortality and incident ischaemic heart disease events were ascertained from death certificates, hospital records, and electrocardiographic changes at follow up every 4 to 5 years. Results: 642 men (36.2%) had IgG antibodies at a titre of Conclusion: This is the first prospective demonstration of an association between IgA antibodies to C pneumoniae, a putative marker of chronic infection, and subsequent risk of death from ischaemic heart disease. In contrast to earlier case-control studies, IgG antibodies were not associated with either prevalent or incident ischaemic heart disease.

Only two studies have specifi-cally tackled the issue of whether large bloodpressure reactions to brief hand immersion incold water are associated with increased risk forcoronary heart disease. In one, the magnitudeof diastolic reactions to the cold pressor testwas reported to be the most significant singlepredictor of 20 year incident coronary heartdisease in a sample of 279 middle aged men.

The 1916 painters and the 1948 electricians who resided in the Canton of Geneva at the time of the 1970 census were identified and followed up to 1984. During the study period 121 disability pensions were awarded to painters and 59 to electricians. Age standardised incidence of disability per 1000 man-years at risk was higher among painters than among electricians for all neuropsychiatric causes (1.23/1000 and 0.68/1000, respectively) and for all other causes (5.50/1000 and 3.41/1000, respectively). No case of presenile dementia was diagnosed among painters. There was inadequate evidence to indicate that the higher risk of neuropsychiatric disability for painters might have been due to their occupational exposure to organic solvents. A possible toxic effect of these substances on the central nervous system was confounded with alcoholism which was associated with disability from neuropsychiatric disease in 12 of 20 painters and in only one of 10 electricians. Mortality and incidence of cancer were assessed among both cohorts and compared with the expected figures calculated from Geneva rates. Among painters there was a significant increase in overall mortality (O = 254, E = 218.5), in mortality from all cancers (O = 96, E = 75.4), and in incidence from all cancers (O = 159, E = 132.0). For the specific cancer sites, there was a significant excess risk for lung cancer (mortality: O = 40, E = 23.0), which was possibly related to occupational exposure to asbestos and to zinc chromate, although cigarette smoking was not controlled. The significant excesses of biliary tract cancer and of bladder cancer were in accordance with previous observations among painters from other countries. There was also a significant increase in incidence from testicular cancer (O=5, E=1.6), which has not been reported before. For causes of death other than cancer the excesses for alcoholism (O=5, E=0.8). for liver cirrhosis (O=14, E=8.8), for motor vehicle accidents (O=12, E=5.9), and for cerebrovascular disease when allowing for ten years of latency (O=8, E=4.0), were consistent with a probable increased risk of alcohol abuse. Among electricians overall mortality was similar to that expected (O=137, E=139.0). No significant excess risk was found for all cancers or for any specific cancer site. Because of the small number of expected deaths the statistical power was low for the assessment of a possible risk for leukaemia or for brain tumour.

A randomised controlled study was carried out of the effect on growth of the provision of free milk supplements to schoolchildren aged 7 and 8. In selecting children for this study, the aim was to identify those whose socioeconomic circumstances might place them at a disadvantage for growth. Five hundred and eighty-one-children were selected from schools where a high proportion of the pupils received free school meals, and from families with four or more children. The subjects were randomly allocated to receive a third of a pint (190 ml) of free milk daily for six school terms or to a control group. The mean difference in height gain at the end of twenty-one-and-a-half months was 3% or 2.93 mm (P less than 0.05) in favour of the children provided with free milk. The mean difference in weight gain was 130 g (P greater than 0.05) in their favour. The height and weight gain associated with the provision of free mild was very small in the study population, and it is therefore likely that the benefit to growth of providing free milk for the whole unselected population of schoolchildren of these ages would be even smaller.

There is a large excess in prescribing costs by GPs in Wales compared with England. This excess amounts to about 30%, equivalent at present to over pounds 11 m a year. The pattern of drug prescribing by GPs and of patient consultation was studied in random samples of electors in Cardiff and Bristol. Overall, more subjects in Cardiff had received prescriptions, and the average number of scripts for each person was higher than in England in the same period. The pattern for consultations was similar. For both prescriptions and consultations the rates were higher in Wales and the difference from those in England seemed to be greater for women than for men. There was no consistent difference between the two cities in the proportions of those who had consulted who received a script, nor was there any evidence that subjects in Cardiff received more prescriptions without a consultation. In both cities similar proportions of subjects bought drugs from chemists without a prescription.

Data from two community studies on men from South Wales and the west of England suggest that the effects of smoking on the haemostatic system remain for many years after giving up. Long term correlations between several variables, including plasma fibrinogen and white cell count, and the length of time after giving up were seen in ex-smokers. Dose response relations were apparent in current smokers in terms of the white cell count and two haematological variables, the packed and mean cell volumes. These long term correlations probably reflect the toxicity of other agents in tobacco smoke besides nicotine and carbon monoxide, which act only in the short term. Identification of these agents may further our understanding of the mechanism by which cigarette smoking is associated with atherosclerotic disease.

Data for 387 men who had completed seven-day weighed dietary records as part of the Caerphilly Heart Study were examined for relations of alcohol, diet, body mass index (BMI), and other variables to blood pressure. These included age, smoking, exercise, and social class. For men not on antihypertensive treatment (n = 356) regression analysis showed that age (p less than 0.001), BMI (p less than 0.05), and alcohol intake (p less than 0.01) were significantly related to systolic blood pressure, and BMI (p less than 0.001) and alcohol intake (p less than 0.01) to diastolic blood pressure. In addition, protein intake (p less than 0.05) was significantly and inversely related to the risk of being hypertensive, but other dietary variables were not related to blood pressure. For men on antihypertensive treatment (n = 31) significant inverse correlations were observed between diastolic blood pressure and the intakes of potassium (p less than 0.01), fibre (p less than 0.001), polyunsaturated fat (p less than 0.01), and a number of other dietary variables. Reasons for these differences are discussed.

In the Speedwell study set up to examine primarily the relation of plasma lipids and ischaemic heart disease in men aged 45 to 64 years drawn randomly from the practices of 16 general practitioners, various haemostatic factors which may contribute both to thrombogenesis and atherogenesis were measured. Fibrinogen measured nephelometrically and plasma viscosity were positively associated with the prevalence of ischaemic heart disease. Antithrombin III was negatively associated with the prevalence of ischaemic heart disease. These associations were statistically significant at the 1% level of probability. Fibrinogen measured by a clotting method and the heparin neutralising activity of platelet poor plasma had negative and positive associations with ischaemic heart disease, respectively, but neither association achieved statistical significance. Because of the interrelation of these variables and also age, a multiple logistic regression analysis was undertaken separately for the two measures of fibrinogen. The negative association of "clottable' fibrinogen and the positive association of plasma viscosity with the prevalence of ischaemic heart disease were confirmed and both were statistically significant at the 5% level of probability. Apart from age the independent association of the other variables with ischaemic heart disease did not achieve statistical significance. Fibrinogen measured by both methods had positive and statistically significant associations with serum total cholesterol, but no associations with serum total triglycerides, smoking, or alcohol consumption. "Clottable' fibrinogen had an inverse and statistically insignificant association with serum high density lipoprotein cholesterol. The observed associations support the concept of the involvement of some haemostatic factors in the aetiology of ischaemic heart disease, and these associations are now being examined more critically in a longitudinal study.

Mortality from ischaemic heart disease remains high in the United Kingdom, and the present report describes the prevalence of the various epidemiological manifestations of the disease in two recent community studies with a common core protocol, each containing samples of over 2000 men, carried out in South Wales (Caerphilly) and the West of England (Speedwell, Bristol). The prevalence of electrocardiographic evidence of ischaemia was similar in the two communities--8.7% of men aged 45-49 years rising to 18.6% in men aged 55-59 years in the samples from South Wales, and 8.0% and 17.2% respectively in the Bristol population. The overall prevalence of angina was 7.7% in Caerphilly and 7.8% in Speedwell in men aged 45-59 years, but symptoms of severe chest pain were more commonly reported in South Wales than in Speedwell (10.1% compared with 6.3%). The data, however, suggested that the overall prevalence of ischaemic heart disease was very similar in the two areas. The prevalence of ischaemic heart disease was compared with that found in other population studies carried out in the United Kingdom and was higher than that found when employed men only were studied. There were substantial differences in mortality between the two areas; possible reasons for this are differences in community or medical services, smoking habit, or unemployment rates.

In epidemiological studies the diagnosis of a past history of myocardial infarction is made from the answer to a single question: "Have you ever had a severe pain across the front of your chest lasting for half an hour or more?" Two additional questions, which form an optional part of the London School of Hygiene and Tropical Medicine chest pain questionnaire, were used in two large community studies, with other information to determine the likely accuracy of the diagnosis ("Did you see a doctor about this pain?" If so, "What did he say it was?") The prevalence of possible myocardial infarction from the use of the single question was significantly higher among men from South Wales than among men from Speedwell, Bristol (10.1% and 6.9% respectively); in contrast, positive responses to the additional questions reduced the prevalence in the two populations to 5.8% and 4.9% respectively. These latter figures are very similar to those of self-reported coronary thrombosis in the two populations. Among subjects with positive responses to the additional questions the prevalence of ECG ischaemia was about 50%; in contrast, the prevalence of ECG ischaemia among those positive only to the severe chest pain question was very similar to that among those with no history of chest pain (12%). Preliminary mortality data show a similar classification of level of risk. These findings indicate that the false positive error rate for possible myocardial infarction could be significantly reduced by the use of two additional questions which form an optional part of the London School of Hygiene chest pain questionnaire but are rarely used. However, the present findings relate to populations with uniform levels of adequately accessible medical care; comparisons between populations with different levels of medical care will require cautious interpretation.

Acute respiratory effects occur in a high proportion of subjects exposed to textile dusts. The extent to which these lead to permanent respiratory symptoms and loss of lung function is unknown. A survey of random population samples was therefore conducted in ten towns in Northern Ireland in which flax processing had been a major source of employment. The MRC questionnaire on respiratory symptoms was administered and Vitalograph tracings recorded on subjects aged 40 to 74 inclusive. An occupational history was taken at the end of each interview. Lung function in ex-flax workers was slightly lower than in control subjects never exposed to flax dust, but the presence of a positive interaction with age meant that differences were apparent only in the younger subjects. Over about the age of 65 the lung function in the ex-flax workers was comparable with that of the controls and overall the loss was at most about half that due to light smoking (1-14 cigarettes a day). The association between a "dust exposure score" and lung function was inconsistent in the two sexes. In men there was a small decrement with increasing dust exposure. In women there was also a small decrement, but a positive interaction with age meant that the women with the highest dust exposure scores had a lower loss with increasing age than the women with the least dust exposure. There was an excess in symptoms in the ex-flax workers but the size of the excess was greater than would be expected from the lung function results. It is possible that, although the survey was conducted without explicit reference to the flax industry, knowledge throughout Northern Ireland that many flax workers have been awarded compensation on the grounds of respiratory disablement may have led to an increased reporting of symptoms in the ex-flax workers.

Possible aetiological factors for urinary incontinence were examined in a prevalence study among a random sample of 1000 women aged 18 and over. Infective factors were not markedly associated with incontinence but mechanical factors such as parity and obesity were. No association was found, however, between a history of perineal damage at childbirth and incontinence. Women with incontinence had on average a higher score for a 'neuroticism' trait elicited by questionnaire than women without the disorder.

A further follow-up traced 1970 workers employed at an asbestos cement factory for at least six months between 1936 and 1977. At the beginning of this period some crocidolite was used in the factory but by the end of 1936 chrysotile had become the only type of asbestos in use. Only 378 women were employed during the period concerned, and of the 30 who had died, none had a cause of death that is generally associated with exposure to asbestos. The mortality experience of the men was examined separately for all workers, all workers alive after 15 or more years after first exposure, and a smaller group of workers who were employed in 1935-6 and may have been exposed to crocidolite. In none of the three groups was there an appreciably raised standardised mortality ratio (SMR) for the causes of death investigated. These were: all causes, all neoplasms, cancers of the lung and pleura, and cancers of the gastrointestinal tract. An excess of lung cancers noted in the first follow-up study in 1964 was not found in this study. Two pleural mesotheliomas were identified but in both cases the men had worked at the factory before 1936 and therefore had been exposed to crocidolite. No cancers of the larynx were found.