Search

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.

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.

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.

Two random samples of women aged 55-64 living in the Vale of Glamorgan and the Rhondda Fach were followed up for 20 years. In each sample heights, weights, serum cholesterol concentrations, and specific causes of death were noted and the Quetelet index (weight/height2) calculated. The two samples were combined for analysis of total mortality. In the combined sample there was a strong positive association between Quetlet index and both total mortality and mortality from ischaemic heart disease. Multiple logistic regression analysis showed that both of these associations were significant, as was the strong positive association between Quetelet index and mortailty from ischaemic heart disease in the samples considered separately. There was no significant association between cholesterol concentration and mortality from ischaemic heart disease in each sample. There was a small negative association between cholesterol concentration and both total mortaility in the combined sample and ischaemic heart disease in the Rhondda Fach sample. These results suggest that the Quetelet index is important for prognosis, whereas the serum cholesterol concentration is not.

Twenty-four subjects received three oral glucose tolerance tests, in the morning, afternoon, and evening of separate days. The mean blood sugar levels in the afternoon and evening tests were similar, and they were both significantly higher than those in the morning test. Plasma immunoreactive insulin levels, however, were highest in the morning test. The pattern of insulin levels during the afternoon and evening tests resembled that described as typical of maturity-onset diabetes.