Epidemiology of proctocolitis in the region of Leiden, The Netherlands. A population study from 1979 to 1983.

An epidemiologic study of proctocolitis in the Leiden Health Care Region was conducted between 1979 and 1983. One hundred and seven cases were diagnosed before 1979 and 150 between 1979 and 1983. Most of the patients had proctocolitis (42%), and only 11% had pancolitis. The incidence was 6.8/10(5)/year and was similar in men and women. There was no specific age group at additional risk of developing the disease. The prevalence was 58.4/10(5). Patients with proctocolitis tended to live in country or city areas; people living in dormitory suburbs were at a reduced risk (chi-square test, p less than 0.001). However, there was a significant difference in incidence between Leiden (10.8/10(5)/year) and Alphen (4.1/10(5)/year) (corrected chi-square = 7.3; p less than 0.001). This was also true for the prevalence in these two cities. The prevalence of the disease in migrants (85.3/10(5)) was not significantly different from that in the indigenous population (58/10(5)).