Salt Lake City,
The purposes of this study are to estimate the burden of disease due to chronic
gastrointestinal illness in PG veterans, to evaluate whether SBBO is associated with chronic
diarrhea in PG veterans, and to determine whether eradication of SBBO reduces symptoms of
chronic diarrhea, abdominal pain and bloating in PG veterans.
Approximately 700,000 United States military personnel were deployed in the first Persian
Gulf (PG) War. Several months after their return, up to 25% of Veterans had persistent
symptoms which they suspected were related to their military service in the Gulf. Among the
most frequent were gastrointestinal symptoms such as loose stools, excessive gas and
abdominal pain. These symptoms are typical of diarrhea-predominant irritable bowel syndrome
The cause of IBS is not known; speculated mechanisms include altered GI motility, bacterial
overgrowth, visceral hypersensitivity and psychological stress. Another proposed mechanism
relates to the fact that up to one third of patients with IBS describe the onset of their
symptoms following acute gastroenteritis. This is called post-infective IBS (PI-IBS). How
acute gastroenteritis leads to persistent GI symptoms of IBS is not known. A limited amount
of data suggests that patients with IBS may have an imbalance in their gastrointestinal
microflora. Several studies indicate that small bowel bacterial overgrowth is more common in
individuals with IBS. Symptoms of SBBO are similar to diarrhea-predominant IBS and include
chronic diarrhea, bloating and abdominal pain.
More than 50 percent of military personnel developed acute gastroenteritis while on duty in
the Gulf. Most of them who reported symptoms of IBS had an acute onset which occurred in
association with an episode of acute gastroenteritis during their tour of duty. Other
travelers are known to be colonized by new micro-organisms during travel to foreign
countries. This acquisition is thought to be related to a change in diet. The natural
history of this change in bowel flora, in part, depends on host factors and can persist for
months after travel abroad. It seems likely, that PG veterans with persistent diarrhea and a
negative work-up for known GI diseases have PI-IBS. No study in the past has evaluated the
role of SBBO in causing chronic GI symptoms in PG Veterans. Furthermore, soldiers involved
in combat are exposed to a highly stressful environment, perhaps making them more
susceptible to persistent symptoms.
We hypothesize that PG veterans with chronic GI symptoms have symptoms of diarrhea
predominant IBS and this is caused by SBBO due to a change in microflora during deployment
in the Persian Gulf and that it is predisposed to by the stress of combat. Intestinal
microflora, once altered, is known to be relatively stable; once mucosal damage occurs it
may become permanent.
Objectives Objective # 1: Estimate the burden of disease due to chronic gastrointestinal
illness in PG veterans.
i. The prevalence of GI symptoms is high in PG veterans. ii. The prevalence of IBS is
higher in veterans who report acute gastroenteritis during the period of deployment.
iii. PG Veterans with IBS have a lower IBS related QOL
Objective # 2: Evaluate whether SBBO is associated with chronic diarrhea in PG veterans.
Hypothesis i. SBBO is more common in PG veterans than non deployed veterans. ii. SBBO is
more common in PG veterans with diarrhea-predominant IBS vs. those without.
Objective: # 3: Determine whether eradication of SBBO reduces symptoms of chronic diarrhea,
abdominal pain and bloating in PG Veterans.
i. Treatment with rifaximin, a non-absorbable antibiotic, will improve symptoms and QOL in
Veterans with SBBO.
- Men and women age 32-75 years
- Rome III criteria for diarrhea-predominant IBS
- Symptom onset after an apparent episode of acute gastroenteritis
- Symptoms of > 3 months duration
- Normal endoscopic appearance of the colonic mucosa
- Negative markers for celiac disease and inflammatory bowel disease.
- Normal thyroid function and serum calcium levels.
- Must have served in the military or reserves during the time of Operation Desert
Storm (August 1990 to May 1991)
- Clinically significant cardiac, pulmonary, hepatic or renal dysfunction
- History of/or presence of systemic malignancy
- Current evidence of any gastrointestinal disorder such as celiac disease or
inflammatory bowel disease (i.e. Crohns disease or ulcerative colitis)
- Current effects of drug or alcohol abuse
- Investigator perception of patients inability to comply with study protocol
- Unstable psychiatric disease
- Recent change in gastrointestinal medications
- Subjects with a positive pregnancy test
- Subject is currently participating in another research protocol that could interfere
or influence the outcome measures of the present study