Epidemiological Studies of Coronary Disease.

In a previous paper (Thomas, Cochrane, and Higgins, 1958) we considered some of the problems and difficulties that arise in measuring the prevalence of coronary disease in the general community. We illustrated these with two surveys of men aged 55 to 64 years, the first consisting of miners and ex-miners from the Rhondda Fach, a mining valley in South Wales, and the second of men who had never worked in dusty occupations from the rural and predominantly agricultural Vale of Glamorgan. We stressed the difficulties involved both in establishing the population at risk and in identifying those with coronary disease. The experience of two further surveys has indicated that the former problem, though practically tedious, is soluble, but that the latter still waits an entirely satisfactory solution. The purpose of this paper is to consider the problems of diagnosis of coronary disease for epidemiological purposes and to point the way to a possible solution.