Trend of brucellosis incidence and age-period-cohort model analysis in Shandong Province from 2005 to 2024

Trend of brucellosis incidence and age-period-cohort model analysis in Shandong Province from 2005 to 2024 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Trend of brucellosis incidence and age-period-cohort model analysis in Shandong Province from 2005 to 2024 Yu Xiaolin, Lin Maowen, Liu Lu, Fang Ming, Liu Xiaolin, Li Yan, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6176363/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 4 You are reading this latest preprint version Abstract Objective To analyse the trend of brucellosis incidence and the changes in incidence rate with age-period-cohort model in Shandong Province from 2005 to 2024, and provide theoretical basis for the prevention and control strategy of brucellosis. Methods The incidence rate data of human brucellosis reported by the infectious disease reporting system of China Disease Prevention and Control Information System from 2005 to 2024 in Shandong Province were collected. The annual change percentage (APC) and annual average change percentage (AAPC) of the incidence rate were calculated using the joinpoint software. The Age Period-cohort (APC) model was used to analyze changes in brucellosis incidence with age, period, and birth cohort effects. Results The average annual reported incidence of brucellosis in Shandong Province from 2005 to 2024 was 1.88per 100 000. The joinpoint results showed that the reported incidence of brucellosis showed an alternating trend of first decreasing and then increasing, with average annual decreasing and increasing rates of -0.7%, 75.3%, -12.4% and 6.7%, respectively. The results of APC model showed that the risk of brucellosis increased rapidly with the increase of age group, and the risk coefficient was the highest in the age group over 80 years old. The incidence of brucellosis increased slowly at first, increased rapidly and then decreased (χ2 = 795.63, P = 0.000), and reached a peak in 2017 (RR = 2.779, 95%CI:2.568–3.007), the lowest in 2007 (RR = 0.149, 95%CI:0.123–0.181); The incidence increased with the age of birth (χ2 = 126.74, P = 0. 000). Conclusion From 2005 to 2024, the reported incidence of brucellosis in Shandong Province showed a significant age-period-cohort effect, which showed an overall trend of first increasing and then decreasing. The incidence risk increased rapidly with the increase of age, slowly increasing first, rapidly increasing then decreasing with the passage of time, and increasing with the passage of birth cohort. Health education should be targeted. Reduce the risk of brucellosis. Brucellosis Age-period-cohort model Trend analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Brucellosis is the most important zoonotic disease caused by Brucella species comprising Gram negative, facultative, intracellular pathogens, The main clinical manifestations were chills, fever, hyperhidrosis, fatigue, muscle and joint pain [1-3] , Infected animals are the main source of infection, and people are infected mainly through contact with infected animals and their tissues or indirect contact with pollutants, The disease is prevalent in more than 170 worldwide [4-6] , Brucellosis in China mainly concentrated in the northern provinces [7] . If Brucella not treated in time, it was easy to cause various complications [8] . The chronic injury caused by Brucella was harmful to people's health and had become a serious public health problem [9-11] . The reported cases of brucellosis in Shandong province are at a high level, with the number of reported cases averaging more than 3000 cases per year in the past three years. In this study, the joinpoint regression model and Age-period-cohort (APC) model were used to analyze the incidence trend of human brucellosis in Shandong Province from 2005 to 2024, providing reference for brucellosis prevention and control. Materials and Methods 1.1 Material source: The data of human brucellosis cases in Shandong province between 2005 and 2024 were obtained from the China Information System for Disease Control and Prevention, The demographic information were obtained from the Statistical yearbook of Shandong Statistical Bureau. The diagnostic criteria were based on the national health industry standard-Brucellosis Diagnosis (WS 269-2019) [12] . 1.2 Joinpoint regression model analysis: The joinpoint regression model was developed by the National Cancer Institute of the United States and is widely used in the analysis of infectious disease trends. This model is a piecewise linear regression model, and piecewise linear regression is advertised as ln(y)= α+βx+ε (y is the incidence, x is the year, αis the intercept, βis the slope, ε is the random error). Joinpoint 4.8.0.1 software was used to calculate the average annual percentage change (AAPC)in human brucellosis incidence in Shandong Province from 2005 to 2024, annual percentage change (APC) and 95% Confidence interval (95% CI ), AAPC and APC all > 0, it indicates that the incidence rate in this period has an increasing trend, and vice versa, it indicates a decreasing trend, significance level a = 0.05. 1.3 APC model analysis: The model explored the change of disease trend from three dimensions: age effect, period effect and birth cohort effect [13-15] , Among them, the age effect represents the different risk of disease incidence in different age groups, the period effect represents the influence of time change on disease incidence, and the cohort effect represents the change of disease incidence among cohorts with the same birth year. The estimation function of the APC model includes global changes (AAPC of disease incidence), local changes (AAPC of incidence of all age groups), Longitudinal age curve (Longitudinal age-specific incidence adjusted for period and cohort effects), Period or cohort relative risk (RR) was adjust age and the relative risk of a period or cohort after a non-linear cohort or period relative to a reference period or cohort. The significance of the corresponding effect is determined by the hypothesis test of the above estimation function. The incidence and population data of human brucellosis in Shandong Province from 2005 to 2024 were separated by 5 years, with the central age (37 years), period (2012), and birth cohort (1970) as the reference. The model was established by using the online analysistool (https://analysistools. cancer.gov/apc/), R4.4.0 software was used to sort out the results, and the "ggplot2" and "cowplot" packages of the software were used to draw graphs. Results 2.1 Incidence details: A total of 36,831 cases of brucellosis were reported in Shandong Province from 2005 to 2024, with an average annual incidence of 1.88/100 000. The average annual incidence of males and females was 2.65 per 100 000 and 1.08 per 100 000, respectively. The incidence of brucellosis in Shandong Province increased from 0.18 per 100,000 in 2005 to 3.95 per 100,000 in 2016, then decreased to 2.36 per 100,000 in 2020, and then increased to 3.26 per 100,000 in 2023. The incidence of male and female was consistent with the overall trend, (Fig. 1 ). 2.2 Joinpoint regression model analysis Joinpoint regression model analysis of the reported incidence of brucellosis in Shandong Province from 2005 to 2024 shows that there are 3 discontinuity points, respectively in 2009,2015and 2019, with an average annual increase of 17.9%, 95%CI of AAPC: 11.3%-24.9%, there were two significant increasing stages and two decreasing stages from 2005 to 2024, among which the incidence increased the fastest from 2009 to 2015, with an average annual increase of 75.3%, and from 2019 to 2024, with an average annual increase of 6.7%.The average annual decline was 0.7% from 2005 to 2009 and 12.4% from 2015 to 2019, and the difference was statistically significant only in the rising stage from 2009 to 2015 (P < 0.01), (Table 1 ). Table 1 Trends of reported incidence of brucellosis in Shandong Province from 2005 to 2024 Index Year APC(%) 95%CI P incidence rate 2005–2009 -0.7 -13.4-13.8 0.9 2009–2015 75.3 59.2–93.0 < 0.01 2015–2019 -12.4 -29.4-8.7 0.2 2019–2024 6.7 -3.1-17.5 0.2 2.3 APC model analysis 2.3.1 Age change From 2005 to 2024, the incidence of brucellosis in Shandong Province showed an increasing trend with age (χ 2 = 104.85, P = 0 000). The men (χ 2 = 161.26, P = 0. 000), female (χ 2 = 25.04, P = 0. 034) The trend of the incidence of brucellosis at all ages was consistent with the overall trend. The risk of brucellosis began to increase rapidly with the increase of age groups. The risk coefficient was the lowest in the age group less than 5 years old and the highest in the age group over 80 years old, with RR 0.001 and 2102.94, respectively. (Fig. 2 ). 2.3.2 Period change From 2005 to 2024, the incidence of brucellosis in Shandong Province was reported to have increased slowly at first, increased rapidly and then decreased (χ 2 = 795.63, P = 0. 000), reached the peak in 2017 (RR = 2.779,95%CI:2.568–3.007), and the lowest in 2007 (RR = 0.149,95%CI: 0.123–0.181); The incidence of male and female patients was consistent with the general trend (χ 2 = 738.13, P = 0. 000; χ 2 = 214.19, P = 0. 000), (Fig. 3 ). 2.3.3 Birth cohort change The incidence of brucellosis in Shandong Province from 2005 to 2024 showed an increasing trend with birth year (χ 2 = 126.74, P = 0.000), the highest in 2015 (RR = 2440.209,95%CI:803.417-7411.622), and the lowest in 1940 (χ 2 = 126.74, P = 0 000). RR = 0.002,95%CI: 0.001–0.002); The trend of incidence in men and women is consistent with the general trend ( χ 2 = 133.85,P = 0.000;χ 2 = 34.84,P = 0.007) ,( Fig. 4 ). 2.3.4 Local change The reported incidence of brucellosis in Shandong Province from 2005 to 2024 was between 13%-31% in all age groups, showing an increasing trend, and the older the age, the greater the increase (χ 2 = 125.194,P = 0. 000);The trend of incidence in male and female was consistent with the general trend (χ 2 = 133.453,P = 0.000; χ 2 = 32.083,P = 0. 010),( Fig. 5 ). Discussion A total of 36,831 cases of brucellosis were reported in Shandong Province from 2005 to 2024, with an average annual incidence of 1.88/100 000. The incidence of brucellosis in Shandong Province increased from 0.18 per 100,000 in 2005 to 3.95 per 100,000 in 2016, then decreased to 2.36 per 100,000 in 2020, and then increased to 3.26 per 100,000 in 2023. Since the middle and late 1990s, the epidemic of brucellosis in China has continued to develop, and the reported incidence of brucellosis in the country from 2008 to 2018 had always ranked in the top 10 infectious diseases [ 7 , 16 ] , From 2005 to 2014, the overall brucellosis epidemic in China was on the rise, with the reported incidence rising from 1.40 per 100,000 to 4.22 per 100,000 [ 7 ] , The joinpoint regression model analysis of the incidence of brucellosis in Shandong Province showed that the incidence increased the fastest from 2009 to 2015, with an average annual increase of 75.3%, which was consistent with the overall trend of brucellosis in the country from 2005 to 2014, and the average annual decrease from 2015 to 2019 was 12.4%, which was consistent with the national trend From 2015 to 2017, the national incidence showed a downward trend, with an average incidence of 3.469 per 100,000 [ 17 ] . The epidemic trend of brucellosis in Shandong Province is basically consistent with the national situation, The downward trend of the epidemic after 2016 was related to the National Brucellosis Prevention and Control Plan (2016–2020) jointly formulated by the former Ministry of Agriculture and the National Health Commission [ 18 ] , The prevention and control work in Shandong Province had played a positive role in controlling the epidemic. The average annual reported incidence was significantly higher in males than in females, consistent with the results of studies in many places across the country [ 19 – 21 ] , associated with different exposure risks between males and females, Men engaged in livestock breeding, buying and trafficking, slaughtering and other occupations with more contact opportunities with livestock, more contact opportunities with sick animals and their products, and relatively high risk of infection. From 2005 to 2024, the risk of brucellosis began to increase rapidly with the increase of age groups, and the risk coefficient was lowest in the age group less than 5 years old and highest in the age group over 80 years old, with RR 0.001 and 2102.94, respectively, It shows that the risk of the elderly population is at a high risk level, especially in the rural areas of Shandong Province, the majority of the elderly population, and Brucella infection in humans is closely related to improper animal feeding management or excessive intake of unpasteurized dairy products [ 15 ] , People are infected mainly through direct contact with brucellosis infected animals and their secretions or processed products such as meat, milk, fur of infected animals, through digestive tract, respiratory tract, damaged skin mucosa, etc. After infection, fever, sweating, fatigue, joint pain and other clinical symptoms will appear [ 22 ] . The annual percentage change of incidence of brucellosis in Shandong Province from 2005 to 2024 was between 13%-31% in all age groups, and the higher the age, the greater the increase (χ2 = 125.194,P = 0. 000), The focus should be on the high age group, the management of the middle-aged and elderly people engaged in breeding and grazing should be strengthened, and the awareness of protection should be improved through targeted health education to avoid infection caused by life contact. Change the bad behavior of family enclosure, people and animals mixing, and advocate scientific and standardized raising of cattle and sheep and other livestock. In Shandong Province, the incidence of brucellosis was reported to be on the rise with the year of birth, with the highest in 2015 and the lowest in 1940. The exposure environment was different due to different birth times, and the overall risk of brucellosis increased with the passing of the birth cohort, indicating that the incidence of brucellosis in the younger generation will be at a higher level in the future, which may be due to the rapid development of animal husbandry, cross-regional livestock and livestock products are frequently traded and circulated, and the risk factors of brucellosis are increasing. If the prevention and control measures are not timely, there is still a high risk trend. Sum up, brucellosis can be prevented and treated. According to the epidemic characteristics of Shandong Province, targeted surveillance and prevention and control of brucellosis should be strengthened. Health departments, market supervision departments, agricultural departments and other departments should jointly prevent and control the epidemic, regularly notify each other of the epidemic situation, strengthen the monitoring of animal epidemics and human brucellosis in key areas, increase the investment in prevention and control, and carry out screening and health education for high-risk groups. Various forms of health education and behavioral intervention have been actively carried out for key groups, such as the distribution of intervention kits to guide occupational groups such as livestock breeding and livestock product processing to do a good job of personal protection, and the intensity and frequency of propaganda and education have been increased through short videos and leaflets of health education, so as to improve the protection awareness of occupational groups. Through comprehensive prevention and control measures to reduce the infection rate of brucellosis, to achieve early prevention and early treatment, in order to ensure the health of the people. Declarations Ethics approval and consent to participate We confirm that all methods were carried out in accordance with relevant guidelines and regulations of Helsinki declaration. All implementation plan were approved by ethics Committee of Shandong CDC. Consent for publication Not applicable. Availability of data and materials The datasets generated during and analyzed during the current study are not publicly available but are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding Medical and health Science and Technology Development Project of Shandong Province (202412051230) Authors' contributions KZQ, DSJ participated in the review of manuscript. YXL carried out data analysis and drafted the manuscript. LMW participated in the production of charts. LL,FM, LY and LXL participated in the revision of the article. All authors read and approved the final manuscript. Acknowledgements The authors would like to thank all the reviewers for their review and revision suggestions, Thanks to staff from the city and county CDC for their efforts in brucellosis surveillance. Thanks to the corresponding author for his comments and suggestions, Thanks to all authors for their cooperation. Authors' details 1* Department of Infectious Disease Control and Prevention, Shandong Provincial Center for Disease Control and Prevention, Jinan 250014, China 2 Jingzhou Center for Disease Control and Prevention, Jingzhou 434000, China References Sulayman S, Bora RS, Sabir J, et al. Brucellosis: current status of the disease and future perspectives [J]. Postepy Mikrobiologii. 2020;59(4):337–44. Pappas G, Akritidis N, Bosilkovski M, et al. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6176363","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":428529806,"identity":"3bb962c7-0895-4bb0-97a5-6d84989c6b5a","order_by":0,"name":"Yu Xiaolin","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Yu","middleName":"","lastName":"Xiaolin","suffix":""},{"id":428529807,"identity":"52437fe4-4766-4eff-b060-e997a6ccfb4c","order_by":1,"name":"Lin Maowen","email":"","orcid":"","institution":"Jingzhou Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Lin","middleName":"","lastName":"Maowen","suffix":""},{"id":428529808,"identity":"74e6e4af-f93f-4882-a0db-b0cf884cb09e","order_by":2,"name":"Liu Lu","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Liu","middleName":"","lastName":"Lu","suffix":""},{"id":428529809,"identity":"e37f38e6-a012-4ad0-90a2-163d36cc62c8","order_by":3,"name":"Fang Ming","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Fang","middleName":"","lastName":"Ming","suffix":""},{"id":428529810,"identity":"eb50636c-ea25-4887-8253-203d934f020c","order_by":4,"name":"Liu Xiaolin","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Liu","middleName":"","lastName":"Xiaolin","suffix":""},{"id":428529811,"identity":"4c53a406-6c03-4b0c-aafd-e7653f339de9","order_by":5,"name":"Li Yan","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Yan","suffix":""},{"id":428529812,"identity":"bfce7a7e-d344-4862-950c-9b727b5a7fdf","order_by":6,"name":"Ding Shujun","email":"","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":false,"prefix":"","firstName":"Ding","middleName":"","lastName":"Shujun","suffix":""},{"id":428529813,"identity":"495bb0dc-9f15-4037-bb00-1a576c054734","order_by":7,"name":"Kou Zengqiang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAs0lEQVRIiWNgGAWjYBACxgYGZjCDn5n58APStEi2s6UZEGsRRIvBeR4FCeLUtx9+bMBQY5O4+TAPA4gRTdhhPWnGCQzH0hK3HeY98ADIyG0gqKUhh/nw34bDQC18CQaMDYeJ0NL/hvkAUGXi5mYeAwnitMzIYU4AadnATLyWZ8YGQC8YzzgMDOQEYvxi2J/8WAIYULL9/YcPP/hQY0OEFhQVCYSUg4A8MYpGwSgYBaNghAMADdI8QFdP3M0AAAAASUVORK5CYII=","orcid":"","institution":"Shandong Provincial Center for Disease Control and Prevention","correspondingAuthor":true,"prefix":"","firstName":"Kou","middleName":"","lastName":"Zengqiang","suffix":""}],"badges":[],"createdAt":"2025-03-07 08:23:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6176363/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6176363/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78507071,"identity":"24506a3c-ff29-4542-80a6-fcbf9c0c9cd5","added_by":"auto","created_at":"2025-03-14 08:32:48","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":66697,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of reported cases and incidence of brucellosis in Shandong Province, 2005-2024\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/0f6b03a28d811aee371830bf.png"},{"id":78507057,"identity":"59405665-5246-494f-8256-7c5871930e02","added_by":"auto","created_at":"2025-03-14 08:32:47","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":53965,"visible":true,"origin":"","legend":"\u003cp\u003eAPC model analysis of reported incidence of brucellosis in Shandong Province from 2005 to 2024 - age change\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/93c342e8b30256fa9cdf21b5.png"},{"id":78507059,"identity":"990f9607-e4af-4c43-8ffb-fa37da26467d","added_by":"auto","created_at":"2025-03-14 08:32:47","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":47032,"visible":true,"origin":"","legend":"\u003cp\u003eAPC model analysis of reported incidence of brucellosis in Shandong Province from 2005 to 2024 - Period change\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/6504f7f095b4c624f6ff1709.png"},{"id":78509104,"identity":"08f83ff3-d614-4e0b-956f-722d90a134fc","added_by":"auto","created_at":"2025-03-14 09:04:47","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":46549,"visible":true,"origin":"","legend":"\u003cp\u003eAPC model analysis of reported incidence of brucellosis in Shandong Province from 2005 to 2024 - birth cohort change\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/9bea39933693afc3ba5b908d.png"},{"id":78507528,"identity":"41c5dc7f-6140-4e06-8dfd-2978f5aa6e20","added_by":"auto","created_at":"2025-03-14 08:40:47","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":45294,"visible":true,"origin":"","legend":"\u003cp\u003eAPC model analysis of reported incidence of brucellosis in Shandong Province from 2005 to 2024 - Local changes\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/d7cd09d6d4729287f7fa5d55.png"},{"id":78509105,"identity":"f75e721d-51d8-4c71-836e-40313dcc9544","added_by":"auto","created_at":"2025-03-14 09:04:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":646622,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6176363/v1/cc8ea692-f52a-43c3-aa8c-70787a219d21.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Trend of brucellosis incidence and age-period-cohort model analysis in Shandong Province from 2005 to 2024","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBrucellosis is the most important zoonotic disease caused by Brucella species comprising Gram negative, facultative, intracellular pathogens, The main clinical manifestations were chills, fever, hyperhidrosis, fatigue, muscle and joint pain\u003csup\u003e[1-3]\u003c/sup\u003e, Infected animals are the main source of infection, and people are infected mainly through contact with infected animals and their tissues or indirect contact with pollutants, The disease is prevalent in more than 170 worldwide\u003csup\u003e[4-6]\u003c/sup\u003e, Brucellosis in China mainly concentrated in the northern provinces \u003csup\u003e[7]\u003c/sup\u003e. If Brucella not treated in time, it was easy to cause various complications \u003csup\u003e[8]\u003c/sup\u003e. The chronic injury caused by Brucella was harmful to people\u0026apos;s health and had become a serious public health problem\u003csup\u003e\u0026nbsp;[9-11]\u003c/sup\u003e. The reported cases of brucellosis in Shandong province are at a high level, with the number of reported cases averaging more than 3000 cases per year in the past three years. In this study, the joinpoint regression model and Age-period-cohort (APC) model were used to analyze the incidence trend of human brucellosis in Shandong Province from 2005 to 2024, providing reference for brucellosis prevention and control.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003e1.1\u0026nbsp;\u003c/strong\u003eMaterial source: The data of human brucellosis cases in Shandong province between 2005 and 2024 were obtained from the China Information System for Disease Control and Prevention, The demographic information were obtained from the Statistical yearbook of Shandong Statistical Bureau. The diagnostic criteria were based on the national health industry standard-Brucellosis Diagnosis (WS 269-2019)\u003csup\u003e\u0026nbsp;[12]\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.2\u003c/strong\u003e Joinpoint regression model analysis: The joinpoint regression model was developed by the National Cancer Institute of the United States and is widely used in the analysis of infectious disease trends. This model is a piecewise linear regression model, and piecewise linear regression is advertised as ln(y)=\u0026nbsp;\u0026alpha;+\u0026beta;x+\u0026epsilon; (y is the incidence, x is the year, \u0026alpha;is the intercept, \u0026beta;is the slope, \u0026epsilon; is the random error). Joinpoint 4.8.0.1 software was used to calculate the average annual percentage change (AAPC)in human brucellosis incidence in Shandong Province from 2005 to 2024, annual percentage change (APC) and 95% Confidence interval (95%\u003cem\u003eCI\u003c/em\u003e), AAPC and APC all \u0026gt; 0, it indicates that the incidence rate in this period has an increasing trend, and vice versa, it indicates a decreasing trend, significance level\u0026nbsp;a\u0026nbsp;= 0.05.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.3\u003c/strong\u003e APC model analysis: The model explored the change of disease trend from three dimensions: age effect, period effect and birth cohort effect \u003csup\u003e[13-15]\u003c/sup\u003e, Among them, the age effect represents the different risk of disease incidence in different age groups, the period effect represents the influence of time change on disease incidence, and the cohort effect represents the change of disease incidence among cohorts with the same birth year. The estimation function of the APC model includes global changes (AAPC of disease incidence), local changes (AAPC of incidence of all age groups), Longitudinal age curve (Longitudinal age-specific incidence adjusted for period and cohort effects), Period or cohort relative risk (RR) was adjust age and the relative risk of a period or cohort after a non-linear cohort or period relative to a reference period or cohort. The significance of the corresponding effect is determined by the hypothesis test of the above estimation function. The incidence and population data of human brucellosis in Shandong Province from 2005 to 2024 were separated by 5 years, with the central age (37 years), period (2012), and birth cohort (1970) as the reference. The model was established by using the online analysistool (https://analysistools. cancer.gov/apc/), R4.4.0 software was used to sort out the results, and the \u0026quot;ggplot2\u0026quot; and \u0026quot;cowplot\u0026quot; packages of the software were used to draw graphs.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cb\u003e2.1\u003c/b\u003e Incidence details: A total of 36,831 cases of brucellosis were reported in Shandong Province from 2005 to 2024, with an average annual incidence of 1.88/100 000. The average annual incidence of males and females was 2.65 per 100 000 and 1.08 per 100 000, respectively. The incidence of brucellosis in Shandong Province increased from 0.18 per 100,000 in 2005 to 3.95 per 100,000 in 2016, then decreased to 2.36 per 100,000 in 2020, and then increased to 3.26 per 100,000 in 2023. The incidence of male and female was consistent with the overall trend, (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e2.2\u003c/b\u003e Joinpoint regression model analysis\u003c/p\u003e \u003cp\u003eJoinpoint regression model analysis of the reported incidence of brucellosis in Shandong Province from 2005 to 2024 shows that there are 3 discontinuity points, respectively in 2009,2015and 2019, with an average annual increase of 17.9%, 95%CI of AAPC: 11.3%-24.9%, there were two significant increasing stages and two decreasing stages from 2005 to 2024, among which the incidence increased the fastest from 2009 to 2015, with an average annual increase of 75.3%, and from 2019 to 2024, with an average annual increase of 6.7%.The average annual decline was 0.7% from 2005 to 2009 and 12.4% from 2015 to 2019, and the difference was statistically significant only in the rising stage from 2009 to 2015 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01), (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTrends of reported incidence of brucellosis in Shandong Province from 2005 to 2024\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndex\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAPC(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95%CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eincidence rate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2005\u0026ndash;2009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-13.4-13.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2009\u0026ndash;2015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e75.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e59.2\u0026ndash;93.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2015\u0026ndash;2019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-12.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-29.4-8.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2019\u0026ndash;2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-3.1-17.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e2.3\u003c/b\u003e APC model analysis\u003c/p\u003e\u003cp\u003e \u003cb\u003e2.3.1 Age change\u003c/b\u003e \u003c/p\u003e \u003cp\u003eFrom 2005 to 2024, the incidence of brucellosis in Shandong Province showed an increasing trend with age (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;104.85, P\u0026thinsp;=\u0026thinsp;0 000). The men (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;161.26, P\u0026thinsp;=\u0026thinsp;0. 000), female (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;25.04, P\u0026thinsp;=\u0026thinsp;0. 034) The trend of the incidence of brucellosis at all ages was consistent with the overall trend. The risk of brucellosis began to increase rapidly with the increase of age groups. The risk coefficient was the lowest in the age group less than 5 years old and the highest in the age group over 80 years old, with RR 0.001 and 2102.94, respectively. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003e2.3.2 Period change\u003c/b\u003e \u003c/p\u003e \u003cp\u003eFrom 2005 to 2024, the incidence of brucellosis in Shandong Province was reported to have increased slowly at first, increased rapidly and then decreased (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;795.63, P\u0026thinsp;=\u0026thinsp;0. 000), reached the peak in 2017 (RR\u0026thinsp;=\u0026thinsp;2.779,95%CI:2.568\u0026ndash;3.007), and the lowest in 2007 (RR\u0026thinsp;=\u0026thinsp;0.149,95%CI: 0.123\u0026ndash;0.181); The incidence of male and female patients was consistent with the general trend (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;738.13, P\u0026thinsp;=\u0026thinsp;0. 000; χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;214.19, P\u0026thinsp;=\u0026thinsp;0. 000), (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e \u003cb\u003e2.3.3 Birth cohort change\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe incidence of brucellosis in Shandong Province from 2005 to 2024 showed an increasing trend with birth year (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;126.74, P\u0026thinsp;=\u0026thinsp;0.000), the highest in 2015 (RR\u0026thinsp;=\u0026thinsp;2440.209,95%CI:803.417-7411.622), and the lowest in 1940 (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;126.74, P\u0026thinsp;=\u0026thinsp;0 000). RR\u0026thinsp;=\u0026thinsp;0.002,95%CI: 0.001\u0026ndash;0.002); The trend of incidence in men and women is consistent with the general trend ( χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;133.85,P\u0026thinsp;=\u0026thinsp;0.000;χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;34.84,P\u0026thinsp;=\u0026thinsp;0.007) ,( Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003e2.3.4 Local change\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe reported incidence of brucellosis in Shandong Province from 2005 to 2024 was between 13%-31% in all age groups, showing an increasing trend, and the older the age, the greater the increase (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;125.194,P\u0026thinsp;=\u0026thinsp;0. 000);The trend of incidence in male and female was consistent with the general trend (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;133.453,P\u0026thinsp;=\u0026thinsp;0.000; χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;32.083,P\u0026thinsp;=\u0026thinsp;0. 010),( Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e "},{"header":"Discussion","content":"\u003cp\u003eA total of 36,831 cases of brucellosis were reported in Shandong Province from 2005 to 2024, with an average annual incidence of 1.88/100 000. The incidence of brucellosis in Shandong Province increased from 0.18 per 100,000 in 2005 to 3.95 per 100,000 in 2016, then decreased to 2.36 per 100,000 in 2020, and then increased to 3.26 per 100,000 in 2023. Since the middle and late 1990s, the epidemic of brucellosis in China has continued to develop, and the reported incidence of brucellosis in the country from 2008 to 2018 had always ranked in the top 10 infectious diseases \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e, From 2005 to 2014, the overall brucellosis epidemic in China was on the rise, with the reported incidence rising from 1.40 per 100,000 to 4.22 per 100,000 \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e, The joinpoint regression model analysis of the incidence of brucellosis in Shandong Province showed that the incidence increased the fastest from 2009 to 2015, with an average annual increase of 75.3%, which was consistent with the overall trend of brucellosis in the country from 2005 to 2014, and the average annual decrease from 2015 to 2019 was 12.4%, which was consistent with the national trend From 2015 to 2017, the national incidence showed a downward trend, with an average incidence of 3.469 per 100,000 \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. The epidemic trend of brucellosis in Shandong Province is basically consistent with the national situation, The downward trend of the epidemic after 2016 was related to the National Brucellosis Prevention and Control Plan (2016\u0026ndash;2020) jointly formulated by the former Ministry of Agriculture and the National Health Commission\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e, The prevention and control work in Shandong Province had played a positive role in controlling the epidemic. The average annual reported incidence was significantly higher in males than in females, consistent with the results of studies in many places across the country \u003csup\u003e[\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e, associated with different exposure risks between males and females, Men engaged in livestock breeding, buying and trafficking, slaughtering and other occupations with more contact opportunities with livestock, more contact opportunities with sick animals and their products, and relatively high risk of infection.\u003c/p\u003e \u003cp\u003eFrom 2005 to 2024, the risk of brucellosis began to increase rapidly with the increase of age groups, and the risk coefficient was lowest in the age group less than 5 years old and highest in the age group over 80 years old, with RR 0.001 and 2102.94, respectively, It shows that the risk of the elderly population is at a high risk level, especially in the rural areas of Shandong Province, the majority of the elderly population, and Brucella infection in humans is closely related to improper animal feeding management or excessive intake of unpasteurized dairy products \u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e, People are infected mainly through direct contact with brucellosis infected animals and their secretions or processed products such as meat, milk, fur of infected animals, through digestive tract, respiratory tract, damaged skin mucosa, etc. After infection, fever, sweating, fatigue, joint pain and other clinical symptoms will appear \u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. The annual percentage change of incidence of brucellosis in Shandong Province from 2005 to 2024 was between 13%-31% in all age groups, and the higher the age, the greater the increase (χ2\u0026thinsp;=\u0026thinsp;125.194,P\u0026thinsp;=\u0026thinsp;0. 000), The focus should be on the high age group, the management of the middle-aged and elderly people engaged in breeding and grazing should be strengthened, and the awareness of protection should be improved through targeted health education to avoid infection caused by life contact. Change the bad behavior of family enclosure, people and animals mixing, and advocate scientific and standardized raising of cattle and sheep and other livestock.\u003c/p\u003e \u003cp\u003eIn Shandong Province, the incidence of brucellosis was reported to be on the rise with the year of birth, with the highest in 2015 and the lowest in 1940. The exposure environment was different due to different birth times, and the overall risk of brucellosis increased with the passing of the birth cohort, indicating that the incidence of brucellosis in the younger generation will be at a higher level in the future, which may be due to the rapid development of animal husbandry, cross-regional livestock and livestock products are frequently traded and circulated, and the risk factors of brucellosis are increasing. If the prevention and control measures are not timely, there is still a high risk trend.\u003c/p\u003e \u003cp\u003eSum up, brucellosis can be prevented and treated. According to the epidemic characteristics of Shandong Province, targeted surveillance and prevention and control of brucellosis should be strengthened. Health departments, market supervision departments, agricultural departments and other departments should jointly prevent and control the epidemic, regularly notify each other of the epidemic situation, strengthen the monitoring of animal epidemics and human brucellosis in key areas, increase the investment in prevention and control, and carry out screening and health education for high-risk groups. Various forms of health education and behavioral intervention have been actively carried out for key groups, such as the distribution of intervention kits to guide occupational groups such as livestock breeding and livestock product processing to do a good job of personal protection, and the intensity and frequency of propaganda and education have been increased through short videos and leaflets of health education, so as to improve the protection awareness of occupational groups. Through comprehensive prevention and control measures to reduce the infection rate of brucellosis, to achieve early prevention and early treatment, in order to ensure the health of the people.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe confirm that all methods were carried out in accordance with relevant guidelines and regulations of Helsinki declaration. All implementation plan were approved by ethics Committee of Shandong CDC.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and analyzed during the current study are not publicly available but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMedical and health Science and Technology Development Project of Shandong Province (202412051230)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKZQ, DSJ\u0026nbsp;participated in the review of manuscript. YXL carried out data analysis and drafted the manuscript. LMW participated in the production of charts. LL,FM, LY and LXL participated in the revision of the article. All authors read and approved the final manuscript.\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank all the reviewers for their review and revision suggestions, Thanks to staff from the city and county CDC for their efforts in brucellosis surveillance. Thanks to the corresponding author for his comments and suggestions,\u0026nbsp;Thanks to all authors for their cooperation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; details\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1*\u003c/sup\u003eDepartment of Infectious Disease Control and Prevention, Shandong Provincial Center for Disease Control and Prevention, Jinan 250014, China\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e2\u003c/sup\u003eJingzhou Center for Disease Control and Prevention, Jingzhou 434000, China\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSulayman S, Bora RS, Sabir J, et al. Brucellosis: current status of the disease and future perspectives [J]. Postepy Mikrobiologii. 2020;59(4):337\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePappas G, Akritidis N, Bosilkovski M, et al. 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Front Microbiol. 2014;5:213.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Brucellosis, Age-period-cohort model, Trend analysis","lastPublishedDoi":"10.21203/rs.3.rs-6176363/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6176363/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective \u003c/strong\u003eTo analyse the trend of brucellosis incidence and the changes in incidence rate with age-period-cohort model in Shandong Province from 2005 to 2024, and provide theoretical basis for the prevention and control strategy of brucellosis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e The incidence rate data of human brucellosis reported by the infectious disease reporting system of China Disease Prevention and Control Information System from 2005 to 2024 in Shandong Province were collected. The annual change percentage (APC) and annual average change percentage (AAPC) of the incidence rate were calculated using the joinpoint software. The Age Period-cohort (APC) model was used to analyze changes in brucellosis incidence with age, period, and birth cohort effects.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e The average annual reported incidence of brucellosis in Shandong Province from 2005 to 2024 was 1.88per 100 000. The joinpoint results showed that the reported incidence of brucellosis showed an alternating trend of first decreasing and then increasing, with average annual decreasing and increasing rates of -0.7%, 75.3%, -12.4% and 6.7%, respectively. The results of APC model showed that the risk of brucellosis increased rapidly with the increase of age group, and the risk coefficient was the highest in the age group over 80 years old. The incidence of brucellosis increased slowly at first, increased rapidly and then decreased (χ2 = 795.63, P = 0.000), and reached a peak in 2017 (RR = 2.779, 95%CI:2.568–3.007), the lowest in 2007 (RR = 0.149, 95%CI:0.123–0.181); The incidence increased with the age of birth (χ2 = 126.74, P = 0. 000).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e From 2005 to 2024, the reported incidence of brucellosis in Shandong Province showed a significant age-period-cohort effect, which showed an overall trend of first increasing and then decreasing. The incidence risk increased rapidly with the increase of age, slowly increasing first, rapidly increasing then decreasing with the passage of time, and increasing with the passage of birth cohort. Health education should be targeted. Reduce the risk of brucellosis.\u003c/p\u003e","manuscriptTitle":"Trend of brucellosis incidence and age-period-cohort model analysis in Shandong Province from 2005 to 2024","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-14 08:32:42","doi":"10.21203/rs.3.rs-6176363/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-03-13T19:32:33+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-12T10:05:04+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-12T10:03:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Infectious Diseases","date":"2025-03-07T08:11:29+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2d3022c1-9bea-4586-bc77-018294987505","owner":[],"postedDate":"March 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T13:42:03+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-14 08:32:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6176363","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6176363","identity":"rs-6176363","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}