Decisive factors in designing the Sudbury study of chronic disease.

A SSESSING the prevalence of chronic disease by means of epidemiologic techniques can appear deceptively simple. The obvious difficulties of such studies are in the selection of the study population and its careful enumeration, the adequacy and validity of sampling, and the accurate assessment of nonresponse. Many of these factors have been discussed in relation to the experience gained by the Oxford diabetes study (1). Initiated in 1946, the Oxford study (2) was an attempt to use an entire community to gain information about a chronic disease. In this paper, however, we shall focus on the added, problems encountered in studying chronic disease with measurements presurned to be.. objective., The design of the Sudbury, Mass., study (3) of diabetes mellitus, gout, and rheumatoid arthritis will be used to demonstrate possible ways of handling such problems.