A Case Controlled Etiologic Study of Sarcoidosis (ACCESS)

BACKGROUND: Sarcoidosis is a systemic granulomatous disorder of unknown etiology. While recognized as a distinct clinical entity for over a century, information on incidence, prevalence, risk factors, and natural history in the United States remains quite limited. Data available on the occurrence in the United States indicate that the incidence ranges from about 1 to 10 per 100,000 and prevalence from about 5 to 50 per 100,000. Incidence appears highest for young adults, ages 25 to 40, higher in females than males, and much greater in African Americans than other ethnic groups. Morbidity from this chronic disease is not well estimated by mortality data. In 1981, there were over 10,000 discharges from United States hospitals for sarcoidosis. Like mortality data, the hospital discharge information probably substantially underestimates the morbidity associated with sarcoidosis which is typically managed on an outpatient basis. The Requests for Proposals were issued in September, 1994. Awards were made in June, 1995. DESIGN NARRATIVE: Each of ten clinical centers enrolled patients with sarcoidosis. Because population-based case-finding mechanisms have not been widely implemented for sarcoidosis, an institution-based rather than a population-based design was used. Participating institutions were located in geographic regions where the disease was known and ethnic and gender factors could be addressed. Several investigator-initiated studies were carried out. In addition to etiology, ACCESS examined the socioeconomic status and clinical course of patients with sarcoidosis. Newly diagnosed cases of sarcoidosis were compared to age, sex, and race matched controls. Leads to the etiology of sarcoidosis have come from diverse sources: in clinical laboratory investigations, alveolitis has been found to precede granulomatous inflammation; in case control studies, familial aggregation has been identified; and in case reports, recurrence of granulomatous inflammation has been observed after lung transplantation.