Risk factors for ischaemic heart-disease in normal men aged 40. Edinburgh-Stockholm Study

107 healthy men in Edinburgh and 82 in Stockholm, all aged 40 and selected at random, took part in a study aimed at identifying factors which might explain why, in men of this age, the mortality-rates from ischaemic heart disease are three times greater in Edinburgh men. Clinical measurements and electrocardiographic procedures were standardised, and steps taken to eliminate interlaboratory differences. Edinburgh men were shorter and fatter; had higher systolic and diastolic blood-pressures; smoked more cigarettes (but the number of cigarette smokers in the two groups was similar); drank more alcohol; had more E.C.G. abnormalities and lower exercise tolerance. They had higher levels of total serum-triglycerides and triglycerides in very low (V.L.D.L.), low (L.D.L.), and high (H.D.L.) density lipoproteins. Triglyceride clearance (assessed by an intravenous fat-tolerance test) was similar. Serum-cholesterol and L.D.L.-cholesterol concentrations were similar in both cities but cholesterol in V.L.D.L. was higher, and cholesterol in H.D.L. was lower, in Edinburgh men. The relative linoleic-acid content of plasma-triglycerides and of plasma-cholesterol esters were lower in Edinburgh men, and their subcutaneous adipose tissue glycerides had a lower polyunsaturated/ saturated fatty-acid ratio and a strikingly lower relative linoleic acid content. Edinburgh men had a greater total plasma-insulin response to a standardised glucose-tolerance test. The glucose response was the same in both cities. Plasma free fatty-acids and free glycerol were reduced by a lesser extent in Edinburgh men in response to a glucose load. Although the high incidence of ischaemic heart-disease in Scotland may be due to many factors, some of which are well established, this study points out metabolic factors which may provide new information on the pathogenesis of ischaemic heart-disease.