Epidemiological studies of migration and environmental risk factors in the inflammatory bowel diseases

Table 1 Summary of incidence rates for Crohn’s disease and ulcerative colitis in the Middle East stratified by geographical region

Country	Region	Crohn’s disease incidence rate (/105)	Ulcerative colitis incidence rate (/105)	Method	Study period	Ref.
Israel	Upper Galilee		2.33	Survey based study which included all cases in region	1967-1986	Niv et al[51], 1990
	Tel Aviv Yafo	1.55		Prospective multicentre study including all hospitals and gastroenterology departments in region	1970-1980	Fireman et al[31], 1989
	Tel Aviv Yafo		3.86	Population-based study	1970-1980	Grossman et al[32], 1989
	Tel Aviv Yafo		3.66	Survey based multicenter study with well defined catchment area	1961-1970	Gilat et al[50], 1974
	Tel Aviv Yafo	1.28		Survey based	1970-1976	Rozen et al[33], 1979
	Southern Israel	4.2		Hospital and out-patient based, with complete case ascertainment	1968-1992	Odes et al[47], 1994
	Southern Israel		2.98	Retrospective study, hospital and community clinic based	1961-1985	Odes et al[34], 1987
	Kinneret Subdistrict		3.5	Population based study	1965-1994	Shapira et al[52], 1998
	Kinneret Subdistrict	1.96		Hospital serving a well-defined catchment area covering all IBD cases in district	1960-1990	Shapira et al[53], 1994
	Beer Sheva		2.87	Retrospective study, hospital based	1961-1985	Odes et al[34], 1987
	Beer Sheva	1.1		Population-based study	1961-1980	Krawiec et al[36], 1984
	Beer Sheva	2.1	5.4	Retrospective and prospective cohort study, hospital and community clinic based	1979-1987	Odes et al[38], 1989
	Jerusalem		6.3	Survey based	1973-1978	Jacobsohn et al[37], 1986
	Kibbutz settlements	5.0		Community-based survey of physicians	1987-1997	Niv et al[54], 1999
Lebanon	Kibbutz settlements		5.04	Community-based survey of physicians	1987-1997	Niv et al[55], 2000
	National	1.4	4.1	Population based study using a health-maintenance organisation based with large catchment area	2000-2004	Abdul-Baki et al[56], 2007
Turkey	National	2.2	4.4	Questionnaire-based multicentre study	2000-2003	Tozun et al[57], 2009
Oman	Trakya		0.77	Cross-sectional study, hospital based	1998-2001	Tezel et al[58], 2003
	National		1.35	Prospective cohort study, tertiary referral centre based with large catchment area	1987-1994	Radhakrishnan et al[59], 1997
Kuwait	National		2.8	Retrospective cohort study, tertiary referral centre based with large catchment area	1985-1999	Al-Shamali et al[60], 2003
	National	0.45	2.27	Population-based study	1977-1982	Al-Nakib et al[61], 1984

IBD: Inflammatory bowel diseases