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Crohn disease (CD) and ulcerative colitis (UC),
collectively known as inflammatory bowel disease (IBD),
are idiopathic, lifelong, chronic inflammatory conditions of the
gastrointestinal (GI) tract which typically manifest during late
childhood to young adulthood. The physical and psychological burden
of these chronic relapsing diseases and their devastating effects
imposed on affected children and teenagers may be considerable.
Crohn disease and ulcerative colitis are grouped together in view
of many similarities in their epidemiologic, genetic, immunologic,
and clinical features. Diagnostic approaches are similar, but treatment
approaches and prognosis differ.
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Inflammatory bowel disease (IBD) is unevenly distributed throughout
the world with the highest disease rates occurring in industrialized
countries of Europe, North America, and Australia.1,2However,
the incidence of IBD is rapidly increasing in other emerging industrialized
countries. European studies have suggested that the incidence of
IBD in children and adolescents has significantly increased over
the last 35 years.3Although population-based studies
are difficult to perform in North America, an epidemiological population-based
study in Wisconsin found the incidence of IBD to be 7 per 100,000
in children under 18 years of age.4 In children,
about two thirds of IBD cases are Crohn disease (CD), and one half
are ulcerative colitis (UC), and in the adult population the prevalence
CD and UC are equal.5 The geographical and chronological
variation of IBD since its description early in the 20th century
is represented in eFigure 410.1.
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Onset of disease has a bimodal distribution, with the greatest
incidence being adolescents and young adults, with a second peak
in the fifth to sixth decade of life. Median age of onset of disease
is between 10 and 11 years and is not different from CD. However,
significant IBD cohorts have been described under 5 years of age.6 Population-based
studies have not demonstrated an altered risk of IBD associated
with gender, ethnicity, or urban versus rural setting.4In
adults, exposure to tobacco smoke is associated with a lower incidence
of UC, but the opposite effect has been seen in CD.7,8 A
prospective cohort study of childhood exposure to smoke (active
or passive) showed an increased risk with smoke exposure for both
CD and UC in adulthood.9 Appendectomy is associated
with a decreased incidence of UC but appears to increase the risk
for CD, especially for worsening of disease for the first year following
surgery.10,11 Controversy exists regarding the
clinical significance of this in UC and whether the risk associated ...