It is estimated that the prevalence of auto-immune disease is 3.2% in the general population [1]. Autoimmune diseases are multi-factorial in nature, with genetics, environmental, and other as yet undetermined determinants playing a role. In order to assess the role of environment, a retrospective study was done on US Veterans at the VA Medical Center in Wilkes Barre. The rationale was that US servicemen and women have had exposure to diverse socio-economic environments across the globe, ranging from well developed countries to developing ones. They also have exposure to diverse ecosystems, ranging from deserts to mountains to tropical jungles. Thus, they are a good group to analyze the effect of the environment on the prevalence of autoimmune diseases and compare it to US population as a whole.

A retrospective chart analysis was done in patients at the VA Medical Center at Wilkes Barre, Pennsylvania. The prevalence of autoimmune diseases in Veterans who fought in WWII (Europe and Asia Pacific), Korean War, Vietnam Conflict, and the Persian Gulf War was compared to the prevalence of these diseases in the US population. The prevalence was also compared by gender and, for the WWII Vets, between those who served in Europe versus those who served in Asia Pacific. The diseases studied included psoriasis, psoriatic arthritis, inflammatory bowel disease, rheumatoid arthritis, lupus, myositis, auto-immune thyroiditis, vasculitis, ankylosing spondylitis, pemphigus, bullous dermatitis, systemic sclerosis, autoimmune hepatitis, Sjogren’s Syndrome, reactive arthritis, polymyalgia rheumatic, and sarcoidosis.

There were 37,373 patients in the database, of whom 441 had autoimmune diseases, a prevalence of 1.177%, which is about half that seen in the general population. The most common auto-immune disease was rheumatoid arthritis. The highest prevalence was in female veterans who fought in the Korean War, at 1.3%. The lowest was in the Persian Gulf War, at 0.03% in males and 0.06% in females, perhaps reflecting the demographic age group of these patients. It ranged from 0.2% - 0.6% in the other groups. This prevalence is less than that seen in the civilian population where the prevalence is around 0.5 - 1% [2]. The prevalence of all other auto-immune diseases was similarly lower than in the US population as a whole. Females had a higher prevalence than males. There was no difference in prevalence of any auto-immune disease between veterans of different wars except for auto-immune thyroiditis, which was higher in those who served in the Persian Gulf War. While no cases were found in any other war, the prevalence was 0.4% in men and 0.6% in women who served in the Persian Gulf War (Table 1).

Table 1: Number of patients with auto-immune diseases stratified by period and disease.

In this brief retrospective study, no clear environmental influence was seen in veterans with auto-immune diseases. This encompassed various theatres of war, including different climate, topography and socio-economic exposures. Unfortunately, there was not enough detail in patient charts to ascertain and analyze dietary habits or religious affiliation. Nevertheless, in this study, the prevalence of auto-immune diseases in this veteran population was found to be lower than that seen in the US population suggesting that if anything, the military environment is protective against auto-immune diseases. A larger study would be needed to explore this observation further.

1. Cooper GS, Bynum MLK, Somers EC (2009)Recent insights in the epidemiology of autoimmune diseases: improved prevalence estimates and understanding of clustering of diseases. J. Autoimmun 33: 197-207.
2. Helmick CG, Felson DT, Lawrence RC, Gabriel S, Hirsch R, et al. (2008) Estimates of the prevalence of arthritis and other rheumatic conditions in the United States- Part I. Arthritis Rheum 58: 15-25.