Table 1: Summary of the main studies on IBD epidemiology that were reviewed for the special issue.

Authors/paper/year [Reference]CountryNumber of IBD patients enrolledPatients ageTime period of the studyIBD incidence

Benchimol et al., Gut 2009 [2]Canada (Ontario)Population-based clinical databasePaediatric
(<15 yrs)
17 yrs (1991–2008)Age- and sex-standardized prevalence 42.1/100,000 (in 1994)
56.3/100,000 (in 2005) incidence
9.5/100,000 (in 1994)
11.4/100,000 (in 2005).

Chouraki et al., Aliment. Pharmacol. Ther. 2011 [3] Northern France
(EPIMAD Registry)
12.084
CD 7428
UC 4656
Paediatric20 yrs
(1988–2007)
CD
In 1988–1990: 5.2/100,000
In 2006-2007:
6.7/100,000

Jussila et al., J. Crohn’s Colitis 2013 [4] FinlandPatients with special reimbursement of medications for IBD in the years 1993 ( = 10,958) and 2008 (31,703)Paediatric and adult14 yrs (1998–2002)Nationwide point prevalence of IBD 216/100,000 in 1993 and 595/100,000 in 2008.

Burisch et al., Gut 2013. [5] Europe (31 centers from 14 Western and 8 Eastern European countries)1515 patients
535 (35%) CD
813 (54%) UC
167 (11%) IBD-U
Adult (≥15 yrs)Overall incidence rate ratios in all Western European centres were 1.9 (95% CI 1.5 to 2.4) for CD and 2.1 (95% CI 1.8 to 2.6) for UC compared with Eastern European centres
Median crude annual incidence rates per 100,000 in 2010:
CD 6.5 (range 0–10.7) in Western European centres
3.1 (range 0.4–11.5) in Eastern European centres
UC 10.8 (range 2.9–31.5) in Western European centres and 4.1 (range 2.4–10.3) in Eastern European centres
IBDU 1.9 (range 0–39.4) in Western European centres and 0 (range 0–1.2) in Eastern European centres

Malmborg et al., J. Pediatr. Gastroenterol. Nutr. 2013 [6] Sweden
(Stockholm county)
133Paediatric (<16 yrs at onset)6 yrs (2002–2007)IBD
12.8/100,000 (95% CI 10.8–15.2)
CD
9.2 (95% CI 7.5–11.2)
UC
2.8 (95% CI 1.9–4.0)

Turunen et al., Inflamm. Bowel Dis. 2006 [7] Finland604
CD 203 (34%)
UC 317 (52%)
IBD-U 83 (14%)
Paediatric (<18 yrs at onset)
12 to <15 yrs: 200 (33%)
<3 yrs: 5.1%
<6 yrs: 14%
17 yrs (1987–2003) IBD 
In 1987: 3.9/100,000 (95% CI 2.5–5.8)
In 2003:
7.0/100,000 (CI 5.0–9.4)
( )

Sawczenko and Sandhu, Arch. Dis Child 2003 [8] Great Britain and Ireland739
CD 431
UC 211
IBD-U 86
Paediatric (<16 yrs at onset)13 mths (June 1998–June 1999)
Armitage et al., Gastroenterology 2004. [9] Scotland580Paediatric (<16 yrs at onset)15 yrs (1981–1995)CD 
2.3 (95% CI: 2.0–2.5)
(Northern Scotland 3.1, 95% CI: 2.6–3.8; Southern Scotland 2.1 95% CI: 1.9–2.4, )

Pozler et al., J. Pediatr. Gastroenterol. Nutr. 2006 [10] Czech Republic470
CD 223
Paediatric (<15 yrs at onset)12 yrs (1990–2001)CD 
In 1990: 0.25/100,000, in 2001: 1.25/100,000

Castro et al., Inflamm Bowel Dis 2008. [11] Italy1576
UC 810
CD 635
IBD-U 131
Paediatric (<18 yrs)8 yrs (1996–2003)IBD incidence:
0.39/100,000 (1996)–0.89/100,000 (2003)

Rocchi et al., Can. J. Gastroenterol. 2012 [12] Canada233,000
CD 129,000
UC 104,000
(5900 children with IBD)
Paediatric and adult (<18 yrs at onset)12 yrs (1998–2009)IBD
Prevalence 0.67%
Incidence: 10,200 cases/yr

Zeng et al., J. Gastroenterol. Hepatol. 2013 [13]China (Guangdong province)48
CD 17
UC 31
Paediatric and adult1 yr (2011-2012) IBD 3.14/100,000
CD 1.09/100,000
UC 2.05/100,000

Kugathasan et al., J. Paediatr. 2003 [14] Winsconsin, USPaediatric2 yrsIBD 
7.05/100,000
CD  4.56/100,000,
UC
2.14/100,000

Basu et al., Am J. Gastroenterol. 2005 [15] Houston, Texas, US148
Whites 40%, African Americans 37%, Mexican Americans 20%, Asians 3%
Paediatric and adult4 yrs (June 1999–November 2003)

Tozun et al., J. Clin. Gastroenterol 2009. [16] Turkey877
CD 216
UC 661
Paediatric and adult3 yrs (2001–2003)CD 2.2/100,000
UC 4.4/100,000

Abdul-Baki et al. Inflamm Bowel Dis 2007 [17] Lebanon251
UC 142
CD 100
IBD-U 9
Paediatric and adult5 yrs (2000–2004)CD 1.4/100,000
UC 4.1/100,000
(range, 0–6.9/100,000 for both)

El Mouzan et al., J. Trop. Pediatr. 2006 [18] Saudi Arabia (Riyadh region)50
CD 38%
UC 48%
IBD-U 16%
Paediatric (<18 yrs at onset)
<12 yrs: 16%
10 yrs
(1993–2002)
0.5 cases/100,000

Tsai et al., J. Formos. Med. Assoc. 2004 [19]Taiwan17
CD 9 (53%)
UC 6 (35%)
IBD-U 2 (12%)
Paediatric (<18 yrs at onset)22 yrs
(1979–2000)
CD 
From 1979 to 1995: 0.85%
From 1996 to 2000: 2.6%
( ),
UC 
From 1979 to 1995: 0.85%
From 1996 to 2000: 0.99%
( )

Ng et al., Gastroenterology 2013 [20] Asia-Pacific
(8 countries between Asia and Australia)
419
CD 166
UC 232
IBD-U 21
Paediatric and adult1 yr (2011-2012) Asia 
IBD 
1.37/100,000
(95% CI: 1.25–1.51)
CD 0.54
UC 0.76
IBD-U 0.07
China
3.44 per 100,000 individuals
Australia 
IBD 
23.67/100,000
(95% CI: 18.46–29.85)
CD 14
UC 7.33
IBD-U 2.33

Pinsk et al., Am. J. Gastroenterol. 2007. [21] South Asian population in British Columbia, Canada75
CD 48%
UC 33.3%
IBD-U 18.7%
Paediatric
(<16 yrs)
21 yrs (1985–2005)In 1996–2001:
IBD 15.19/100,000
CD 6.41/100,000, UC
6.70/100,000 IBD-U
2.08/100,000

IBD: Inflammatory Bowel Disease, CD: Crohn’s Disease, UC: Ulcerative Colitis, IBD-U: Unclassified IBD, yrs: years, CI: confidence interval.