D.D. Reid

COLON CANCER AND BLOOD-CHOLESTEROL

Abstract Internationally there is a correlation between the mortality-rates for colon cancer and coronary heart-disease. Dietary fat is suspected as a common aetiological factor, perhaps operating in colon cancer through the transformation of bile-salts into carcinogens by certain intestinal bacteria. This evidence prompts a search for associations between the two diseases within individual populations, and the present report analyses the relation between blood-cholesterol level and the development of colon cancer. Data from six prospective studies of coronary heart-disease in men have been pooled, yielding 90 cases of colon cancer. The initial levels of blood-cholesterol in these men were found surprisingly to be lower than the expected values, the median deviation being -0·26 standard-deviation units (corresponding to a little more than 10 mg. er 100 ml.), p

SMOKING AND OTHER RISK FACTORS FOR CORONARY HEART-DISEASE IN BRITISH CIVIL SERVANTS

A five-year follow-up of 18 403 male British civil servants between the age of 40 and 64, who had been the subject of an earlier clinical survey found 277 deaths from coronary heart-disease (C.H.D.). After adjusting for age, current cigarette smoking, systolic and diastolic blood-pressure, and blood-cholesterol were shown to be related to both the prevalence of one or more indices of cardiac ischaemia and to the risk of cardiac death. Neither blood-glucose two hours after a 50 g load nor weight/height showed any such simple linear association with mortality. Multivariate analysis confirmed that the main risk factors were independently related to cardiac morbidity and mortality. Irrespective of blood-pressure or plasma-cholesterol, current cigarette smokers thus had a higher risk of C.H.D. death than those not smoking cigarettes.

Smoking, air pollution, and bronchitis in Britain.

Abstract A postal survey of the prevalence of respiratory symptoms has been carried out in a large sample of the British population. Analysis of the 9975 replies from men and women aged between 35 and 69 (74% of those presumed able to reply) showed satisfactory agreement with Census and other data. Increasing prevalence with ageing and cigarette consumption has been confirmed. A male excess is seen among non-smokers as well as smokers. Urban/rural gradients are not explained by smoking differences alone. Prevalence-rates for symptoms rise with increasing levels of air pollution independently of cigarette consumption. Without cigarette smoking, local pollution seems to have little effect. In smokers, however, high levels of pollution are associated with more frequent respiratory symptoms. The frequency of more serious bronchitis increases most steeply with age among smokers in the more polluted districts.

An Anglo-American cardiovascular comparison.

Abstract Surveys of groups of over 600 middle-aged men similarly employed in England and in the eastern United States show that the prevalence of chest pain and electrocardiographic evidence of cardiac ischaemia are significantly commoner among the American men, particularly those over 50 years of age. This finding is consistent with the higher U.S. death-rate from arteriosclerotic heart-disease reported in the national vital statistics. The higher blood-pressure observed in Americans is readily explained by their greater bodyweight and skinfold thickness. Although there are differences in smoking habits, it is suggested that factors associated with the excessive adiposity of the Americans are the more likely explanations of their adverse experience in cardiovascular disease.