Pilot survey of haemoglobin and plasma urea concentration in a random sample of adults in Wales 1965-66.

Abstract

In epidemiology it is essential that a definite physiological or pathological condition should be studied in a defined community. These requirements are sometimes difficult to meet because, although the population to be studied should be representa tive of a large community, the measurements involved usually require elaborate apparatus and clinical examination rooms which are not easily mobile. Hitherto it has been the policy of the Epidemio logical Research Unit (ERU) to study intensively a specific disease in selected but limited communities (Miall and Cochrane, 1956) as in the Rhondda Fach, Vale of Glamorgan, Staveley, Annandale, or Wensleydale, with the belief that although these communities are certain to experience unique genetic, cultural, economic, and climatic conditions yet a pattern will emerge of meaningful associations between pathological conditions and the environ ment. This policy has been a success in the past, but it has always been open to the criticism that the associations that were found were also unique to the selected population and could not be safely applied to the general population. One way of confirming such epidemiological results is to repeat the investigations in a different community with a different environment, as was done for the surveys of blood pressure (Miall, 1960), bronchitis (Higgins, 1960), rheumatoid arthritis (Miall, Ball, and Kellgren, 1958), and anaemia (Kilpatrick, 1961), in which the studies in the mining valley of the Rhondda Fach were repeated in the agricultural community of the Vale of Glamorgan or elsewhere. A second method is to investigate a condition in large communities of over 100,000 persons where a wider range of modern conditions of class, of industry and commerce, and of age and sex can be seen than in a small defined community; this method is being used in the Rhondda Borough and in Cardiff City.