Background: Temporal trends in the incidence of inflammatory bowel disease (IBD) in the Arab and Jewish populations in Israel have been poorly described.

Objectives: To compare the annual incidence and prevalence rates of Crohn's disease (CD) and ulcerative colitis (UC) in the Arab and Jewish populations in Israel between the years 2003 and 2008.

Methods: We applied a common case identification algorithm to the Clalit Health Services database to both determine trends in age-adjusted incidence and prevalence rates for IBD in both populations during this period and estimate the burden of IBD in Israel.

Results: The incidence of CD in the Arab population increased from 3.1/100,000 in 2003 to 10.6/100,000 person-years in 2008, compared with a decrease in the Jewish population from 14.3/100,000 to 11.7/100,000 person-years for the same period. The incidence of UC in the Arab population increased from 4.1/100,000 in 2003 to 5.0/100,000 person-years in 2008, a low but stable rate, compared with a decrease from 16.4/100,000 to 9.5/100,000 person-years for the same time period in the Jewish population. The prevalence of both diseases increased due to the accumulation of incident cases but remained much lower among Arabs.

Conclusions: Understanding the factors underlying the differences in incidence and prevalence of IBD in the Jewish and Arab populations may shed light on the genetic and environmental factors associated with these diseases.