Coronary artery disease in Wales.

Recent investigations have shown that the population of the Principality ofWales is heterogeneous and is composed of two moieties, the indigenous Welsh and immigrants, mostly from the English side of the border. Genetic differences in the major blood group systems and cultural differences in the use of the Welsh language and the practice of religious observances have been found to be related to the possession of a Welsh surname (Ashley and Davies, 1966a). The surname in turn has been used as a marker to indicate the genetic nature of the higher mortality from gastric cancer in Wales and the higher morbidity from prostatic hyperplasia (Ashley and Davies, 1966b; Ashley, 1966). The present investigation is directed to a study of coronary artery disease in Wales with reference to the possibility that genetic factors may be responsible for the difference in mortality from this cause in Wales as compared with England. The Registrar General (1965, 1966) reported Standardized Mortality Ratios (S.M.R.) for deaths classified as Arteriosclerotic Heart Disease, including Coronary Artery Disease, for the area of the Welsh Hospital Board, which is coterminous with the Principality. The S.M.Rs. were for males and females, respectively, 112 and 105 in 1963, and 112 and 112 in 1964; all four of these ratios are significantly different from 100. These high S.M.Rs. are particularly striking when it is remembered that coronary thrombosis tends to be an urban disease while Wales is a largely rural country.