Environmental factors are likely to be involved in the pathogenesis of inflammatory bowel disease.
The incidence of both Crohn's disease and ulcerative colitis increased with improved living standards in Europe after World War 2.
|For parasitic infections, the odds ratio was 1.2 for ulcerative colitis|
|European Journal of Gastroenterology & Hepatology|
Earlier reports suggest that hygienic standards may also play a role in the pathogenesis of inflammatory bowel disease.
Dr Stefan Hafner and colleagues investigated the influence of Hepatitis A seroprevalence as an indicator for poorer hygienic conditions and worm infestations in inflammatory bowel disease.
The team examined Hepatitis A seroprevalence in patients with ulcerative colitis and Crohn's disease.
Patients with minor endocrinological disorders served as controls.
All patients were questioned about immunizations, parasitic infections, contact with animals, living on a farm, and ever traveling abroad.
The team excluded patients for active Hepatitis A immunization or recent passive immunization.
Results are presented as Mantel-Haenszel odds ratios with 95% confidence interval, adjusted for age group.
The researchers evaluated 307 patients, of which 73 had Crohn's disease, 48 had ulcerative colitis, and 186 controls.
Hepatitis A seroprevalence was strongly associated with age older than 50 years.
The team found age adjusted Mantel-Haenszel odds ratios were 0.3 for ulcerative colitis, and 0.8 for Crohn's disease versus controls.
For parasitic infections, the odds ratios were 1.2 for ulcerative colitis and 0.3 for Crohn's disease.
Dr Hafner‘s team concluded, "Our team were able to demonstrate a negative association of Hepatitis A infection with ulcerative colitis only."
"In contrast, a novel finding was a strong protective effect of worm infestations for the occurrence of Crohn's disease, but not ulcerative colitis."