More than 8 million Americans suffer from autoimmune diseases, in which the immune system attacks the body's own tissues, and several occupational exposures have been linked to systemic autoimmune diseases, which affect multiple organs. A new study published in the October issue of Arthritis & Rheumatism examined the possible associations between occupation and the risk of dying from systemic autoimmune diseases and found that occupational exposures in farming and industry may be linked to higher death rates from these diseases.
Researchers, led by Laura Gold, a predoctoral research associate in the Public Health Sciences Division, and Dr. Anneclaire De Roos examined death-certificate data from 26 states from 1984 to 1998. Any cases that listed a systemic autoimmune disease (for example, rheumatoid arthritis) as a cause of death were included, as were disease types with a suspected systemic autoimmune disease origin (such as unspecified connective-tissue disorder). The researchers established each person's longest-held occupation from the "usual occupation" listed on the death certificate. In addition, they examined specific exposures based on occupation and industry. These included asbestos, solvents, benzene, pesticides and other substances. They also tracked occupations involving significant exposure to the public or animals.
The results showed that some occupations involving exposure to the public (such as nurses and teachers) were associated with an increased risk of dying from a systemic autoimmune disease, but this was not the case with all jobs involving public exposure (for example, food-service jobs). Farmers showed increased risk of death from systemic autoimmune disease, particularly for those who worked with crops. In addition, several industrial occupations including mining and textile machine operators, timber cutters and loggers had an increased risk of death from this group of diseases.
Further analysis showed that the same occupations and exposures were present in those who were older than the typical retirement age when they died, "implying that the occupational exposures were involved in a chronic pathogenic process leading to either disease incidence or slow progression of existing autoimmunity," the authors wrote. They suggested that the higher risk associated with jobs involving public contact may be due to exposure to multiple infectious agents leading to an autoimmune response.
[Adapted from an Arthritis & Rheumatism news release.]