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
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
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
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
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.
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
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