[Analysis on incidence trend of brucellosis based on age-period-cohort model in Shandong Province, 2004-2023].

Abstract

Objective: To understand the incidence trend of brucellosis over time in Shandong Province from 2004 to 2023, and provide evidence for the prevention and control of brucellosis. Methods: The incidence data of brucellosis in Shandong from 2004 to 2023 were collected from China Disease Prevention and Control Information System. The annual change percentage (APC) and annual average change percentage (AAPC) of the incidence rate were calculated by using Joinpoint regression model. A age-period-cohort model was used to analyze changes in brucellosis incidence with age, period, and birth cohort. Results: The average annual incidence of brucellosis was 1.76/100 000 in Shandong from 2004 to 2023. The Joinpoint regression analysis results showed that the reported incidence of brucellosis increased by an average of 92.0% and 18.9% each year from 2004 to 2010 and from 2010 to 2014, respectively, and decreased by an average of 0.2% each year from 2014 to 2023. The results of APC model showed that the incidence of brucellosis increased first and then decreased with age (χ²=176.92, P<0.001), and incidence of brucellosis showed slow increase and rapid increase first, then decrease (χ²=2 921.03, P<0.001) over time. The risk for brucellosis reached peak in 2016 (RR=5.29, 95%CI: 4.96-5.65) and became the lowest in 2006 (RR=0.24, 95%CI: 0.21-0.28). The incidence increased in later birth cohort (χ²=348.88, P<0.001), the AAPCs of all the age groups were between 15.0% and 40.0%, and the older the age, the greater the risk (χ²=348.77, P<0.001). Conclusions: From 2004 to 2023, the reported incidence of brucellosis in Shandong showed a significant age-period-cohort effect, which increased first and then decreased, first increased and then decreased with age, increased slowly and rapidly first, then decreased over time, and increased in later birth cohort. It is necessary to conduct targeted prevention and control, health education to reduce the risk for brucellosis.