Incidence, prevalence, and mortality of diabetes mellitus in Wadena, Marshall, and Grand Rapids, Minnesota: the Three-City Study.

The Minnesota Department of Health (MDH) in concert with the Centers for Disease Control (CDC) conducted population-based studies of diabetes mellitus in three Minnesota communities. The use of hospital and clinic records alone for case ascertainment purposes would have missed 16% of study-eligible diabetic individuals. Thus, studies that use only hospital or clinic records may present a biased view of the natural history of diabetes. Physician-defined diabetes without additional diagnostic review yielded a prevalence of 1.6% (age standardized to the 1970 US Caucasian population). Diabetes incidence was 117 per 100,000 (age standardized to the same population). These results compare well with those of a Mayo Clinic population-based study in Rochester, Minnesota, and indicate the utility of physician-defined diabetes as an epidemiologic case definition. Despite differences in population size and structure as well as different medical care systems, diabetes incidence, prevalence, and mortality in these communities was remarkably similar.