[Epidemiological study on the incidence of inflammatory bowel disease in Yinzhou District, Ningbo City from 2011 to 2020].

OBJECTIVE

To describe the distribution characteristics of inflammatory bowel disease among permanent residents in Yinzhou District, Ningbo City, and to understand the disease burden and development trend of inflammatory bowel disease in this area.

METHODS

Using the retrospective cohort design, we collected the registration information of all permanent residents in the residents' health files of the Yinzhou Regional Health Information Platform from 2010 to 2020, and used electronic medical records to follow up their inflammatory bowel disease visits. A one-year wash-out period was set, and the patients who were diagnosed with the primary diagnosis for the first time after one year of registration were re-garded as new cases. The incidence density and 95% confidence interval () of inflammatory bowel disease were estimated by Poisson distribution.

RESULTS

From 2011 to 2020, a total of 1 496 427 permanent residents in Yinzhou District were included, of which 729 996 were male (48.78%). The total follow-up person-years were 8 081 030.82, and the median follow-up person-years were 5.41 [interquartile range (): 5.29]. During the study period, there were 1 217 new cases of inflammatory bowel disease, of which males (624 cases, 51.27%) were more than females (593 cases, 48.73%). The total incidence density was 15.06/100 000 person-years (95%: 14.23, 15.93). Among all new cases, there were 1 106 cases (90.88%) of ulcerative colitis, with an incidence density of 13.69 per 100 000 person-years (95%: 12.89, 14.52); 70 cases (5.75%) of Crohn's disease, with an incidence density of 0.87 per 100 000 person-years (95%: 0.68, 1.09); and 41 cases (3.37%) of indeterminate colitis, with an incidence density of 0.51 per 100 000 person-years (95%: 0.36, 0.69). The median age of onset of ulcerative colitis was 50.82 years old (: 18.77), with the highest proportion (15.01%) in the 45-49 years group. The incidence density of ulcerative colitis gradually increased with age, reaching a relatively high level in the 45-49 years group (20.53/100 000 person-years; 95%: 17.63, 23.78), followed by a slight increase. And the incidence density in the 65-69 years group was the highest (25.44/100 000 person-years; 95%: 20.85, 30.75), with a rapid decrease in the 75-79 years group. The median age of onset of Crohn's disease was 44.34 years (: 33.41), with the highest proportion (12.86%) in the 25-29 years group. Due to the small number of new cases of Crohn's disease, the age distribution fluctuated greatly, with peaks both in young and old people. From 2011 to 2020, the incidence density of inflammatory bowel disease in Yinzhou District was at a low level from 2011 to 2013, and showed a rapid upward trend from 2014 to 2016, reaching a peak of 24.62 per 100 000 person-years in 2016 (95%: 21.31, 28.30), and slightly decreased in 2017-2020.

CONCLUSION

The incidence density of inflammatory bowel disease in Yinzhou District from 2011 to 2020 was at a relatively high level, and medical institutions and health departments need to pay attention to the burden of disease caused by it.