Geographic Variation in Sarcoidosis in South Carolina: Its Relation to Socioeconomic Status and Health Care Indicators

Abstract

Geographic patterns of sarcoidosis have been detected and studied on a global scale. However, the associations between these disease patterns and population characteristics have not been determined. The authors studied the geographic pattern of sarcoidosis in South Carolina and its relation to socioeconomic status (SES) and health status indicators. Hospitalization rates for the period 1985–1995 were used as geographic indicators of sarcoidosis. Rates were assessed for the 46 counties in South Carolina, adjusting for differences in SES, availability/accessibility of health care, diagnostic practices, and hospital utilization. Patterns in geographic variation were assessed based on physiographic characteristics and proximity to the Atlantic coastline. Significant variation was identified with an increase in sarcoidosis rates proximal to the Atlantic coastline. Population characteristics were identified that appeared to explain regional variation in sarcoidosis in Caucasians; however, regression analysis was unable to explain the regional differences in disease distribution by variation in SES, diagnostic practices, accessibility/availability, or hospital utilization in African Americans. These results suggest that the development of sarcoidosis is associated with a geographically linked risk factor in African Americans. This work supports the need for additional studies that will identify this risk factor(s). Am J Epidemiol 1999; 150: 271–8.