Risk factors for small bowel bacterial overgrowth in cystic fibrosis.
OBJECTIVE
The purpose of this study was to determine the prevalence of small bowel bacterial overgrowth in patients with pancreatic-insufficient cystic fibrosis (CF) compared with age-matched controls and to identify potential risk factors for small bowel bacterial overgrowth.


METHODS
Fifty patients, 25 pancreatic-insufficient CF study patients (mean age, 17 y) and 25 gastrointestinal clinic control patients (mean age, 15 y), completed a glucose-hydrogen breath test after an overnight fast. Study patients completed a quality-of-life questionnaire modified from the Cystic Fibrosis Questionnaire. The medical history of each patient was compared with breath test results. A positive breath test was defined as a fasting hydrogen > or =15 ppm or a rise of > or =10 ppm hydrogen over baseline during the test.


RESULTS
The prevalence of positive breath tests was higher in the CF study group (56%) than in the control group (20%) (P = 0.02). The mean fasting hydrogen levels of patients in the study and control groups were 22 and 5 ppm (P = 0.0001). The mean questionnaire scores were not significantly different between breath test-positive and -negative study patients. The use of azithromycin was associated with an increased risk of a positive breath test. Use of laxatives and inhaled ipratropium was associated with a decreased risk of a positive breath test.


CONCLUSIONS
Patients with CF were more likely to have elevated fasting hydrogen levels compared with controls. This suggests a high prevalence of small bowel bacterial overgrowth in CF patients. Medications commonly used by CF patients may influence intestinal health.
Fridge
Jacqueline L
JL
Division of Gastroenterology, Children's Hospital and Research Center Oakland, Oakland, CA 94609-1809, USA. Jfridge@mail.cho.org
Conrad
Carol
C
Gerson
Lauren
L
Castillo
Ricardo O
RO
Cox
Kenneth
K
D000293:Adolescent; D000328:Adult; D001424:Bacterial Infections / Q000175:diagnosis / Q000382:microbiology*; D001944:Breath Tests; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D007410:Intestinal Diseases / Q000175:diagnosis / Q000382:microbiology*; D007421:Intestine, Small / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011788:Quality of Life; D012307:Risk Factors
D006859:Hydrogen