Clinical Research
Copyright ©2007 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Sep 14, 2007; 13(34): 4574-4578
Published online Sep 14, 2007. doi: 10.3748/wjg.v13.i34.4574
Infectious causation of chronic disease: Examining the relationship between Giardia lamblia infection and irritable bowel syndrome
Alice S Penrose, Eden V Wells, Allison E Aiello
Alice S Penrose, Preventive Medicine, University of Michigan, Ann Arbor, MI 48109-2029, United States
Eden V Wells, Michigan Department of Community Health, Lansing, MI, United States
Allison E Aiello, Department of Epidemiology, University of Michigan, Ann Arbor, MI 48109-2029, United States
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Alice S Penrose, MD, MPH, University of Michigan Preventive Medicine Residency, 109 South Observatory Street, Ann Arbor, Michigan 48109-2029, United States. apenrose@umich.edu
Telephone: +1-734-9731908
Received: March 19, 2007
Revised: March 30, 2007
Accepted: March 31, 2007
Published online: September 14, 2007
Abstract

AIM: To evaluate whether a higher prevalence of Giardia lamblia infection is associated with an increase in irritable bowel syndrome (IBS) prescriptions at the county level in Michigan.

METHODS: The Michigan Disease Surveillance System (MDSS) was used to ascertain both the numbers of Giardia lamblia infections as well as the total number of foodborne illnesses per population by county in Michigan during 2005. This was compared with Blue Cross Blue Shield (BCBS) of Michigan numbers of drug prescriptions for IBS per one thousand members per county in 2005. These data were also analyzed for associations with per capita income by county and the number of refugees entering each county in 2005.

RESULTS: There were a total of 786 confirmed cases of Giardia lamblia reported to MDSS in 2005. During the same time period, the number of prescriptions for IBS varied from 0.5 per 1000 members up to 6.0 per 1000 members per month. There was no trend towards higher numbers of IBS prescriptions in the counties with more Giardia lamblia infections. Per capita income was not associated with either IBS prescriptions or Giardiasis. There was a significant linear association between the number of refugees entering each county, and the number of Giardia lamblia cases per 100 000 population.

CONCLUSION: In this ecological study, there was no association found between BCBS prescriptions for IBS and Giardia lamblia infections in Michigan counties. Our findings may have been influenced by the disparate number of refugees admitted per county.

Keywords: Foodborne, Gastrointestinal, Giardia lamblia, Irritable bowel syndrome, Parasite, Prescription, Refugees