THE PREVALENCE OF DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) IN 2 LARGE AMERICAN MIDWEST METROPOLITAN HOSPITAL POPULATIONS

Objective. There are no published large-scale studies of the overall p revalence of diffuse idiopathic skeletal hyperostosis (DISH) and it ha s been proposed that the prevalence is greater than previously reporte d. We thus decided to review chest radiographs in a population of pati ents over 50 years of age seen at two large bur differing metropolitan hospitals in a major American Midwest city. Design and patients. The posterior-anterior and lateral chest radiographs of 1363 patients were reviewed for evidence of DISH at the University of Minnesota Hospital and Clinic. There were 500 consecutive inpatient admissions, 540 cons ecutive patients who attended the outpatient clinics and 326 patients collected from our film archive. A population of 1001 patients seen at Hennepin County Medical Center was also studied. It was possible to s ubclassify this latter group with respect to race. Results and conclus ion. Using strict criteria, i.e., four or more levels involved, the ov erall prevalence of DISH in the male population over age 50 years was 25% and in the female population over age 50 years was 15%. This preva lence climbed to 28% in males over 80 years and to over 35% in males o ver age 70 years. In females over 80 years, the prevalence was found t o be 26%. Although our population base was small, DISH was found to be less common in the black, Native-American and Asian populations. The prevalence of DISH was also found to be far lower in a similar white p opulation with osteoporosis. The overall prevalence of DISH was higher than expected in a predominantly white population over age 50 years w ith a lesser incidence in the black. Native-American and Asian populat ions, suggesting a genetic origin of the condition.