Prevalence of sarcoidosis in Switzerland is associated with environmental factors.

The current study aimed to investigate incidence, prevalence and regional distribution of sarcoidosis in Switzerland with respect to environmental exposures. All sarcoidosis patients hospitalised between 2002 and 2005 were identified from the Swiss hospital statistics from the Swiss Federal Office for Statistics (Neuchâtel, Switzerland). Regional exposure characteristics included the regional distribution of different industrial sectors, agriculture and air quality. Co-inertia analysis, as well as a generalised linear model, was applied. The prevalence of "ever-in-life" diagnosed sarcoidosis, currently active sarcoidosis and sarcoidosis requiring hospitalisation was 121 (95% CI 93-149), 44 (95% CI 34-54) and 16 (95% CI 10-22) per 100,000 inhabitants, respectively. The mean annual incidence of sarcoidosis was 7 (95% CI 5-11) per 100,000 inhabitants. The regional workforce in the metal industry, water supply, air transport factories and the area of potato production, artificial meadows (grassland) and bread grains were positively associated with the frequency of sarcoidosis. The prevalence of sarcoidosis was higher than assumed based on former international estimates. Higher frequency was found in regions with metal industry and intense agriculture, especially production of potatoes, bread grains and artificial meadows.