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Inflammatory bowel disease and childhood environment

 

Clinical bottom line

Improved living conditions may be associated with increased risk of Crohn's disease. The childhood environment is an important determinant of of the risk of inflammatory bowel disease in later life, with distinct factors for Crohn's disease and ulcerative colitis.


Reference

MA Feeney et al. A case-control study of childhood environmental risk factors for the development of inflammatory bowel disease. European Journal of Gastroenterology and Hepatology 2002 14: 529-534.

Study

The study cases were attendees at gastroenterology clinics, aged over 15 years and less than 45 years, with conventional diagnoses of Crohn's disease or ulcerative colitis. Controls were matched by age and sex to an individual froma control group pool of patients with functional bowel disorder drawn from hospital outpatient clinics.

Patients undertook a medical history, tests for Helicobacter hepatitis A, and completed a questionnaire on family characteristics (number of siblkings, parental smoking, for instance) and childhood circumstances (number of indoor toilets, house moves, urban/rural, for instance), which could be completed with family help.

Results

Crohn's disease was negatively associated with Helicobacter pylori infection, but positively associated with both having eczema before the age of 10 years and frequent use of a swimming pool (Table 1).

Ulcerative colitis was negatively associated with having an appendectomy before the age of 17 (Table 1).

Table 1: Childhood factors associated with developing Crohn's disease or ulcerative colitis

Factor

Odds ratio (95% CI)

Crohn's disease

Helicobactor pyloir serology

0.18 (0.16 to 0.52)

Eczema before 10 years

2.8 (1.2 to 6.4)

Frequent swimming pool use

2.9 (1.2 to 6.9)

Ulcerative colitis

Appendectomy before 17 years

0.05 (0.01 to 0.51)

Comment

This is a useful report because it has a brief review of previous studies, for instance linking Crohn's disease to childhood eczema and appendectomy with a reduced risk of ulcerative colitis. The reduced association between helicobacter infection and Crohn's disease was taken to mean that increased childhood hygeine may give rise to later development of Crohn's disease. This may be correct, and is a useful working hypothesis, especially when put alongside other information, but the link is not yet proved. Much depends on parental attitudes to childrens' play.