大腸憩室疾患の疫学

Epidemiology of Diverticular Disease of the Colon in Japan

要旨　大腸憩室は，欧米のみならず本邦においても増加してきており，1995年以降の発表では15.0～34.6％の頻度と報告されている．その罹患率は年齢とともに増加し，80歳以上では42～60％に認められる．欧米では左側大腸に群発するが，本邦では右側大腸に単発で認められる場合が多い．しかしながら，加齢とともに本邦でも左側大腸憩室を有する割合が増加している．大腸憩室の合併症として最も頻度の高い疾患は大腸憩室炎である．その10～30％に認められ，膿瘍や瘻孔のため外科手術を要する症例もあり，本邦では虫垂炎との鑑別が臨床上に重要である．大腸憩室出血の頻度は5～10％とされており，その頻度は低いが，高齢者の大腸憩室患者に多く，今後増加していくことが予想される．

　In the past, colonic diverticulosis was rare in Japan. However, recently the increasing prevalence of this disease has been reported. Although the prevalence of colonic diverticulosis in Japan was reported to be only 5.5％ in 1980, recently published data since 1995 indicate its prevalence ranging from 15.0％ to 34.6％. The prevalence of colonic diverticulosis also increases with age and it has been now estimated to be from 42％ to 62％ in elderly persons more than 80 years old. There are several differences in characteristics of colonic diverticulosis between Western countries and Japan : Colonic diverticulosis is detected mainly in the left-sided colon in Western countries, while the affected site of Japanese patients with colonic diverticulosis is usually the right-sided colon. However, the prevalence of left-sided diverticulosis has also increased with age even among Japanese patients.

　The most common complication of colonic diverticulosis is colonic diverticulitis, which accounts for from 10％ to 30％ of colonic diverticulosis. It sometimes leads to serious conditions such as abscess formation or colonic perforation, which require emergency surgery.

　Diverticular bleeding can be observed in 5％ to 10％ of patients with colonic diverticulosis. In the near future, the prevalence of diverticular bleeding might increase which will be a wide-spread disorder because its prevalence increases with age.