Wednesday, April 23, 2014
How Does Exposure To Pesticides Cause Sarcoidosis?
My dad is a farm worker and has been told that he has sarcoidosis from being exposed to pesticides. How do you get exposed?
The correlation between pesticide exposure and sarcoidosis remains speculative. The most robust study of this sort, "A Case Control Etiologic Study of Sarcoidosis" (ACCESS), showed an association between exposure to agricultural dusts and pesticides. That is, there was a higher rate of sarcoidosis in those involved in agriculture or industry who were exposed to insecticides (e.g., spraying of crops or trees) within 3 years of their diagnosis.
That does not necessarily mean that insecticides cause sarcoidosis. As the authors of the ACCESS trial stated: "It is possible that the occupational use of insecticides is a surrogate for exposures to one or more antigens in the workplace not directly assessed in our questionnaire." That is to say that people who work around pesticides also tend to be exposed to other types of dusts, fumes and organisms, and the latter may be the actual cause of sarcoidosis.
In support of a possible causal relationship between pesticides and sarcoidosis, there have been cases of "hypersensitivity pneumonitis", a disease of the lungs that has some features (granulomas) that are similar to sarcoidosis, reported after exposure to "pyrethrins", which is a class of insecticide.
Obviously, we need to know more about what causes sarcoidosis!
Elliott D Crouser, MD
Associate Professor of Pulmonary, Allergy, Critical Care & Sleep Medicine
College of Medicine
The Ohio State University