[Epidemiology of sarcoidosis].

The Sarcoidosis is a world-wide phenomenon. The history of its epidemiological investigation is very instructive. The expectancy of noted sarcoidosis-researches that epidemiologic studies might also help to find out the cause of sarcoidosis failed. The available epidemiologic data are still confuse--the probable reasons for that has been explained. Socio-economic parameters--hitherto neglected--find increasingly consideration. The incidence is the only parameter which is suitable for reflecting the epidemiologic situation exactly. The principal problem of a reliable epidemiological research in sarcoidosis is world-wide the mode of ascertainment of the diseased persons. There is no evidence for an increase of the disease in the last 30 years.