A new study finds marked differences in the onset of chronic fatigue syndrome between Gulf War veterans and the general population.
It has been established that there is a high incidence of chronic fatigue syndrome (CFS) amongst Gulf War veterans. Studies conducted around the turn of the millennium found that around 6% of veterans returning from the first Gulf War complained of fatigue and other vague symptoms and that 2.2% of these met the diagnostic criteria for CFS as laid out by the US Centers for Disease Control and Prevention (CDC).
These figures compare with an incidence of CFS in the general US population of only 0.4% as established by community surveys.
This discrepency has led researchers to theorize that there are differences in the way CFS develops in veterans and civilians and that since CFS is diagnosed based purely on symptom presentation that it may actually not be a single illness.
This has been a major issue in CFS research for a long time with many studies finding certain abnormalities in some patients and not others. This suggests that although the illness experienced by patients may be the same there could be any number of causes.
With these things in mind a study funded by the National Institues of Health and the New Jersey War Related Illness and Injury Study Center sought to compare Gulf War veterans with CFS to civilians with CFS to look for any differences in their illnesses.
Researchers compared 45 male veterans with CFS to 84 male civilians who satisfied identical CFS criteria. All study participants were given a physical examination, had blood taken to rule out identifiable causes of fatigue, and were asked to complete questionnaries. Special attention was paid to whether the patients illnesses had an acute onset or developed gradually. Participants were also evaluated for fibromyalgia (FM), multiple chemical sensitivity (MCS) and psychiatric comorbidity.
Participants were excluded if they had a psychiatric illness which rules out a diagnosis of CFS according to the CDC diagnostic criteria i.e. schizophrenia, bipolar or eating disorders, or substance/alcohol abuse within the past two years.
The questionnaires asked participants to record the number of days they spent in bed, the number of days with reduced activity in the past month, and their disability status. In addition, veterans were asked to complete a standard checklist of nine toxic exposures that might have occurred in the Gulf. These included smoke from burning oil wells, pesticides, and debris from SCUD missiles.
Significant findings in the study were that a significantly higher number of white civilians became ill after a sudden viral infection than did white veterans. Roughly half of civilians had a gradual onset of CFS compared to 90% of veterans. There were also differences in comorbid conditions with 22% of civilians also having fibromyalgia where as none of the veterans did. As would be expected more veterans suffered from post-traumatic stress disorder (PTSD).
Perhaps surprisingly was the finding that there was no difference between the number of civilians and verterans suffering from multiple chemical sensitivity. This despite 64% of veterans reporting exposure to at least six potentially toxic chemicals and a recent study confirming that pyridostigmine bromide (an anti-chemical warfare drug given to troops) is a cause of illness in many veterans.
Finally, differences in levels of disability between civilians and veterans was noted with 43% of civilians being registered as disabled and only 13% of veterans being so. The researchers suggest however that this difference may be due to more civilians also suffering from fibromyalgia and not because of innate differences between severity of CFS between the groups.
In conclusion the researchers state that the significant differences found between male civilians and male veterans with CFS, particularly in rate of onset and comorbid illnesses, suggests that CFS seen in the two groups may have different causes and may in fact not be the same disease. They add the caveat that the results cannot be used to confer that the same findings would hold true for women or different racial groups.
The study was carried out by Donald S. Ciccone PhD, an Associate Professor of Psychiatry and Benjamin H. Natelson MD, Professor of Neurosciences at New Jersey Medical School.
Source: Journal of Health Psychology