Some Statistics

Incidence of Crohn's disease and ulcerative colitis

Both Crohn's disease and ulcerative colitis are found worldwide, although they are more common in the Western world. The incidence of IBD has been increasing worldwide and the geographical incidence varies considerably. The highest incidence rates are traditionally reported in Northern and Western Europe as well as North America, whereas lower rates are recorded in Africa, South America, and Asia, including China (Lakatos & Lakatos, 2006; Russel & Stockbrugger, 1996). The highest incidence rates and prevalence for both Crohn's disease and ulcerative colitis have been reported from Northern Europe, the United Kingdom, and North America (Fonager et al, 1997; Moum et al, 1996 - two studies; Rubin et al, 2000; Loftus et al, 2007). The lowest figures are found in southern countries; however, few studies on the incidence of IBD have been carried out in Southern Europe (Trallori et al, 1991; Tragnone et al, 1993).

In Europe, the number of people with IBD is estimated to be 2.2 million (Loftus, 2004). Regional differences range from 1/1000 to 1/500, with the highest numbers in Northern Europe. IBD affects men and women equally, although ulcerative colitis is slightly more common in men and Crohn's disease is slightly more common in women (Life and IBD website, 2010).

Reports of increasing incidence and prevalence from other areas of the world such as Southern or Central Europe, Asia, Africa, and Latin America underscore the fact that the occurrence of IBD is a dynamic process (Loftus, 2004; Tragnone et al, 1996). The multicenter European Collaborative Study on Inflammatory Bowel Disease (ECIBD) reported blended incidence rates in Europe between 8.7 and 11.8 cases per 100,000 person years for Ulcerative colitis and between 3.9 and 7.0 cases per 100,000 person-years for Crohn's disease (Shivananda et al, 1996). A north-south gradient in IBD incidence has been found in Europe and the United States but recent studies have shown that this gradient is narrower than previously believed (Tragnone et al, 1993; Nerich et al, 2006). It is widely estimated that between 1 and 1.4 million people in the United States have IBD although some experts indicate that this number may be an overestimate.

The incidence of Crohn's in the UK is 6.7 (range 1.6 to 14.6) cases per 100,000 annually and the prevalence is 140 (range 10-199) cases per 100,000.  The onset of Crohn's disease has a bimodal distribution. The first and largest peak occurs between the ages of 15-30 years; the second much smaller peak is between 60-80 years. In the United States, the incidence of Crohn's disease is thought to be higher in Ashkenazi Jews (Podolsky & Daniel, 2002) and in smokers (Seksik, 2009). Children who have one parent with Crohn's disease have a 7 to 9% lifetime risk of developing the condition and a 10% risk of developing some form of IBD (Peeters et al, 1996). According to the Crohn's and Colitis Foundation of America (CCFA), in the US, 10 %of those affected, or an estimated 140,000 are youngsters under the age of 18. In a study on incidence and prevalence rates of IBD in Midwestern part of Sao Paulo State, Brazil, (Victoria et al, 2009) found that incidence of IBD in the studied area was as low as in other countries of Latin America and smaller than that found in countries of Southern Europe.

Ulcerative colitis affects about 1 in 1000 people in the Western world and peak incidence is between the ages of 10 and 40 years. It may affect people of any age and 15% of people are over the age of 60 at diagnosis (Patient UK, 2010).

In the first Maltese study in which the incidence of IBD in Malta has been recorded (Cachia et al, 2008), the incidence of ulcerative colitis was found to be similar to the overall incidence of other European countries, while the incidence of Crohn's disease was lower. In fact, the incidence rates of Crohn's disease were found to be among the lowest in Europe, similar to other southern European countries. From this retrospective study, the mean incidence of ulcerative colitis in males was 8.16 per 100,000 per year and for females was 7.59 per 100,000 per year. For Crohn's disease, the mean incidence in males was 0.96 per 100,000 per year and for females 1.622 per 100,000 per year.

Using linear regression analysis, in Crohn's disease an almost significant increasing trend with time was noted but no difference by gender. On the other hand, in Crohn's disease no significant trend with time was noted but almost a significant difference by gender (Cachia et al, 2008).

In Malta currently there are about 1600 patients receiving  treatment for IBD. However the number of patients is on the increase. The prevalence of the disease is 400 per 100,000 people in the population. Treatment costs for IBD in Malta match those for diabetes or cancer and are increasing yearly. The costs of a flare-up in the disease is calculated to be 20 times higher than remission costs (Vella, 2010).

References

Cachia E., Calleja N., Aakeroy, R., Degaetano, J. & Vassallo, M. (2008). Incidence of Inflammatory Bowel Disease in Malta Between 1993 and 2005: A Retrospective Study, Inflamm Bowel Dis 2008;14: 550 -553.

Fonager K., Sorensen H., Olsen J. (1997). Change in the incidence of Crohn's disease and Ulcerative colitis in Denmark. A study based on the national registry of patients 1981-1992. Int J Epidemiol. 1997; 26:1003-1008.

Lakatos L, Lakatos PL. (2006). Is the incidence and prevalence of inflammatory bowel diseases increasing in Eastern Europe? Postgrad Med J. 2006; 82: 332-337.

Life and IBD website: accessed from http://www.lifeandibd.org

Loftus E. Jr. (2004). Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences. Gastroenterology. 2004;126: 1504 -1517.

Loftus CG., Loftus EV. Jr, Harmsen WS., et al. (2007). Update on the incidence and prevalence of Crohn's disease and ulcerative colitis in Olmsted County, Minnesota, 1940-2000. Inflamm Bowel Dis. 2007; 13:254 -261.

Moum B., Vatn MH., Ekbom A., et al. (1996). Incidence of Crohn's disease in four counties in southeastern Norway, 1990-93. A prospective population-based study. Scand J Gastroenterol. 1996; 31:355-361.

Moum B., Vatn MH., Ekbom A., et al. (1996). Incidence of ulcerative colitis and indeterminate colitis in four counties of southeastern Norway, 1990-93. A prospective population-based study. Scand J Gastroenterol. 1996; 31: 362-366.

Nerich V., Monnet E., Etienne A., et al. (2006). Geographical variations of inflammatory bowel disease in France: a study based on national health insurance data. Inflamm Bowel Dis. 2006; 12:218 -226.

Patient UK: “Crohn's disease” accessed from http://www.patient.co.uk/doctor/Crohn's-Disease.htm

Patient UK: “Ulcerative Colitis” accessed from http://www.patient.co.uk/doctor/Ulcerative-Colitis.htm

Peeters M, Nevens H, Baert F, et al. (1996). Familial aggregation in Crohn's disease: Increased age, adjusted risk and concordance in clinical characteristics. Gastroenterology. 1996; 111:597-603. 

Podolsky, Daniel K. (2002). "Inflammatory bowel disease". New England Journal of Medicine 346 (6): 417-29. doi:10.1056/NEJMra020831. PMID 12167685.

http://content.nejm.org/cgi/content/extract/347/6/417. Retrieved 2006-07-02.

Rubin GP., Hungin APS., Kelly PJ., et al. (200). Inflammatory bowel disease: epidemiology and management in an English general practice population. Aliment Pharmacol Ther. 2000; 14:1553-1559.

Russel MG, Stockbrugger RW. (1996). Epidemiology of inflammatory bowel disease: an update. Scand J Gastroenterol. 1996; 31:417- 427.

Seksik P., Nion-Larmurier I., Sokol H., Beaugerie L., Cosnes J. (2009). Effects of light smoking consumption on the clinical course of Crohn's disease.. Inflamm Bowel Dis. 2009

Shivananda S., Lennard-Jones J., Logan R., et al. (1996). Incidence of inflammatory bowel disease across Europe: is there a difference between north and south? Results of the European Collaborative Study on Inflammatory Bowel Disease (EC-IBD). Gut. 1996; 39:690-697.

Tragnone A., Hanau C., Bazzocchi G., et al. (1993). Epidemiological characteristics of inflammatory bowel disease in Bologna, Italy. Incidence and risk factors. Digestion. 1993; 54:183-188.

Tragnone A., Corrao G., Miglio F., et al. (1996). Incidence of inflammatory bowel disease in Italy: a nationwide population-based study. Intl J Epidemiol.1996; 25:1044 -1052.

Trallori G., d'Albasio G., Palli D,, et al. (1991). Epidemiology of inflammatory bowel disease over a 10-year period in Florence (1978-1987). Int J Gastroenterol. 1991; 23:559 -563.

Vella V. (2010). Inflammatory Bowel Disease: Powerpoint presentation during launch of MACC

Victoria CR., Sassak LY., & Nunes HR de C. (2009). Incidence and prevalence rates of inflammatory bowel diseases, in midwestern of São Paulo State, Brazil, Arq. Gastroenterol. vol. 46 no.1 São Paulo Jan./Mar. 2009