Purpose: To identify and quantify the risk of developing sarcoidosis associated with specific rural exposures previously recognized as potential risk factors for this disease.
Methods: A matched case-control design was carried out with a 2-to-1 ratio of controls to cases. Case exposure histories were determine from a detailed questionnaire collecting self-reported information covering the period from birth through disease development and comparing that to exposure histories for the corresponding period in age-, race-, and gender-matched controls identified using Random Digit Dial survey methodology. Conditional logistic regression was used to analyze the matched data while controlling for several baseline variables.
Results: A number of exposures were found to be univariately associated with the development of sarcoidosis including: the use of wood stoves, the use of fireplaces, the use of nonpublic water supplies, and living or working on a farm. A dose-response gradient was detected from exposure to wood stoves and fireplaces continued to be significantly associated with sarcoidosis in multivariable models.
Conclusions: The results of this study provide further support for the hypothesis that behaviors associated with rural living play some role in the development of sarcoidosis. This study further suggests that exposures involving the handling or burning of wood such as using wood stoves or fireplaces for home heating may, in part, explain this rural association.