Familial aggregation of inflammatory bowel disease: a population-based study in South Limburg, The Netherlands. The South Limburg IBD Study Group.

BACKGROUND

The aim of our study was to investigate the prevalence of Crohn's disease (CD) and ulcerative colitis (UC) in first-degree relatives of IBD patients living in a well-defined area.

METHODS

IBD patients known at the IBD Registration South Limburg as well as population controls were asked about the occurrence of IBD in their first-degree relatives.

RESULTS

IBD was reported and confirmed in 16 (out of 1554) relatives by 11 (out of 245) patients. Prevalence of IBD was highest for siblings (1.5%) and children (1.3%), while only 0.2% of the parents were affected with IBD. Among relatives of the control subjects, IBD was observed in 0.8% (versus 4.5% in IBD patients), resulting in an odds ratio of 5.7 (95% CI: 2.0-16.7).

CONCLUSIONS

The observed risk of IBD for first-degree relatives of IBD patients was higher than in controls. However, the risk in our population is lower than has been reported by other centres, possibly because of the population-based character of our study.