Appropriate public health responses to clusters: the art of being responsibly responsive.

Between 1981 and 1988, the Minnesota Department of Health actively responded to over 400 reports from persons concerned about disease occurrence in their community, school, or workplace. Almost all of these reports involved perceived excesses of cases of cancer. Although there is little potential for identifying unsuspected public health problems or developing new etiologic insights, the Minnesota Department of Health has found that responding to reported clusters is a legitimate and necessary public health activity. To be responsibly responsive to these concerns, the Department has developed four steps to prioritize investigation of reported disease clusters, as well as six criteria for determination of the feasibility of environmental epidemiologic investigations. Approximately 95% of all concerns have been handled within the first two steps of this approach, generally requiring only education, or sometimes examination of readily-available data. Less than 5% of the concerns have required additional data collection and evaluation, and only about 1% have resulted in full-scale epidemiologic studies. Successful conclusions at all levels of this process require that public health officials develop effective communication, maintain objectivity, and provide leadership for controversial and difficult issues.

Prevalence of hypertension and associated risk factors among diabetic individuals. The Three-City Study.

A cross-sectional study was conducted from 1979 through 1982 in three rural Minnesota cities to describe the natural history of diabetes mellitus. Detailed abstracts of the medical records of physician-defined diabetic individuals were used to construct medical profiles. As part of the effort, the date of physician-defined hypertension was identified and used to calculate hypertension prevalence. The crude hypertension prevalence was 56.8% for women and 33.99% for men, with an overall crude prevalence of 47.2%. No hypertensive patients were identified among diabetic patients less than 15 yr old, and most hypertensive diabetic patients were greater than 70 yr old. Hypertension prevalence in diabetic individuals demonstrated a highly significant trend with age (P less than .01). Compared with the general population, diabetic individuals had a significantly higher prevalence of hypertension (P less than .01), largely explained by the higher prevalence in women. Variables known to be associated with hypertension risk in the general population were also significantly associated with hypertension among diabetic individuals. Older age, being female, and increased body mass index were strongly associated with hypertension in this study population. Diabetic individuals with hypertension were six times more likely to have renal disease than those without hypertension. The level of blood glucose control, diabetes treatment (i.e., insulin or oral hypoglycemics versus diet), and diabetes duration were not associated with hypertension.

Feasibility study of a statewide pathology-based cancer surveillance system in Minnesota. I. Information characteristics.

The Minnesota Department of Health has completed a 2-year feasibility study comparing the completeness and accuracy of information from pathology-based cancer ascertainment with that of the traditional surveillance method based on hospital discharge records. Overall, for incident cancers, the primary site designation of the pathology-based system was correct for 94.5% of the cancers, and the histologic designation was correct for 97.0% of the cancers. For prevalent cancers the accuracy of both site and histology designation was inadequate at 81.0 and 76.8% respectively. Pathology-based ascertainment was more complete than discharge-based surveillance (98.4% vs. 96.6%), which reflected the growing number of cancers diagnosed in hospital outpatient departments and medical clinics. The major limitation of the pathology-based system was the inability to determine from written pathology reports whether the cancer was newly diagnosed. However, when asked, pathologists correctly determined the incidence status for approximately 75% of the cancers. In light of the results of the feasibility study, Minnesota is implementing a pathology-based system as a cost-effective, scientifically valid method to meet the state's current and future needs for cancer surveillance.

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.