Socioeconomic Health Equity with Malaria Burden: Quantifying Slope (Relative) Index of Inequity in Malaria Infection Outcomes in the Southeastern-coastal Tanzania

Socioeconomic Health Equity with Malaria Burden: Quantifying Slope (Relative) Index of Inequity in Malaria Infection Outcomes in the Southeastern-coastal Tanzania | 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 Socioeconomic Health Equity with Malaria Burden: Quantifying Slope (Relative) Index of Inequity in Malaria Infection Outcomes in the Southeastern-coastal Tanzania Longsheng Liu, Shenning Lu, Wei Ding, Zhebin Wang, Salim Abdulla, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7854639/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Feb, 2026 Read the published version in BMC Public Health → Version 1 posted 10 You are reading this latest preprint version Abstract Background Malaria remains a significant public health challenge in Tanzania, with socioeconomic factors playing crucial roles in disease outcomes. While previous studies have explored the relationship between socioeconomic status and malaria infection, quantitative assessment of equity condition in malaria outcomes remains understudied. This study innovatively applies Slope Index of Inequality (SII) and Relative Index of Inequality (RII) to quantify the equity conditions between socioeconomics and malaria burden in three Districts located in the Southeastern coast of Tanzania. Methods Data from the baseline survey of the China-Tanzania Demonstration Project on Malaria Control conducted in 2019 were analyzed. Key variables included: 1) socioeconomic status quantified through Principal Component Analysis incorporating household infrastructure, asset ownership, and social potential; 2) malaria infection outcomes, including blood test results, treatment costs, and days absent from work/education (days off). Logistic and linear regression analyses were performed to assess socioeconomic impacts, while SII and RII were calculated to measure health equity conditions across socioeconomic strata in three districts of Rufiji, Kilwa, and Kibiti. Results Higher socioeconomic status was associated with a lower risk of malaria infection (OR = 0.9975, 95% CI: 0.9972–0.9978), lower treatment costs (coefficient = -3.13, P < 0.05), and fewer days off work (coefficient = -0.0017, P < 0.05). Rufiji district demonstrated the most significant socioeconomic equality in malaria infection risk (SII=-12.62%, 95%CI: -17.19% to -8.06%; RII = 1.28, 95%CI: 1.12 to 1.55), treatment cost (SII = 837.769, 95%CI: -1182.44 to -491.75; RII = 1.30, 95%CI: 1.09 to 1.63) and days off (SII=-0.46, 95%CI: -0.62 to -0.30; RII = 1.21, 95%CI: 1.05 to 1.46). Conclusion The findings highlight significant socioeconomic disparities in malaria-related outcomes across the studied districts, emphasizing the need for targeted public health interventions to address inequities. By prioritizing equity-focused policies, such as enhanced access to prevention and treatment, Tanzania can make strides toward more inclusive malaria control and health system strengthening, particularly for the most vulnerable populations. Furthermore, the use of SII and RII offered a nuanced understanding of health disparities across the socioeconomic spectrum. Malaria Health Equity Socioeconomic Factors Tanzania Slope Index of Inequality Relative Index of Inequality Full Text Additional Declarations No competing interests reported. Supplementary Files Appendix1.pdf Cite Share Download PDF Status: Published Journal Publication published 03 Feb, 2026 Read the published version in BMC Public Health → Version 1 posted Editorial decision: Revision requested 03 Nov, 2025 Reviews received at journal 03 Nov, 2025 Reviews received at journal 01 Nov, 2025 Reviewers agreed at journal 22 Oct, 2025 Reviewers agreed at journal 22 Oct, 2025 Reviewers invited by journal 22 Oct, 2025 Editor invited by journal 22 Oct, 2025 Editor assigned by journal 14 Oct, 2025 Submission checks completed at journal 14 Oct, 2025 First submitted to journal 14 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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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-7854639","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":538586016,"identity":"d58a3ff9-74a4-48f7-8f10-ae323c9aa4b9","order_by":0,"name":"Longsheng Liu","email":"","orcid":"","institution":"National Institute for Parasitic Diseases","correspondingAuthor":false,"prefix":"","firstName":"Longsheng","middleName":"","lastName":"Liu","suffix":""},{"id":538586017,"identity":"68353c6e-3f90-4d2b-9165-96d329f80146","order_by":1,"name":"Shenning Lu","email":"","orcid":"","institution":"National Institute for Parasitic Diseases","correspondingAuthor":false,"prefix":"","firstName":"Shenning","middleName":"","lastName":"Lu","suffix":""},{"id":538586018,"identity":"6778b50e-58ef-45da-ae6e-d90595955747","order_by":2,"name":"Wei Ding","email":"","orcid":"","institution":"National Institute for Parasitic Diseases","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Ding","suffix":""},{"id":538586019,"identity":"14a2affc-c2d0-4b36-a190-50d511d93e57","order_by":3,"name":"Zhebin Wang","email":"","orcid":"","institution":"Peking University","correspondingAuthor":false,"prefix":"","firstName":"Zhebin","middleName":"","lastName":"Wang","suffix":""},{"id":538586020,"identity":"f2b4b0ef-311a-4461-a5f4-94940993f757","order_by":4,"name":"Salim Abdulla","email":"","orcid":"","institution":"Ifakara Health Institute","correspondingAuthor":false,"prefix":"","firstName":"Salim","middleName":"","lastName":"Abdulla","suffix":""},{"id":538586021,"identity":"fe0cf36e-8be2-4e44-95ee-427d2747da7a","order_by":5,"name":"Shan Lv","email":"","orcid":"","institution":"National Institute for Parasitic Diseases","correspondingAuthor":false,"prefix":"","firstName":"Shan","middleName":"","lastName":"Lv","suffix":""},{"id":538586022,"identity":"55c83738-6cda-4ceb-a6ec-aced66c86164","order_by":6,"name":"Shizhu Li","email":"","orcid":"","institution":"National Institute for Parasitic Diseases","correspondingAuthor":false,"prefix":"","firstName":"Shizhu","middleName":"","lastName":"Li","suffix":""},{"id":538586023,"identity":"0ac77452-f8c1-4933-b532-bad05200cc6b","order_by":7,"name":"Prosper P. 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Tanzania","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Malaria, Health Equity, Socioeconomic Factors, Tanzania, Slope Index of Inequality, Relative Index of Inequality","lastPublishedDoi":"10.21203/rs.3.rs-7854639/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7854639/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eMalaria remains a significant public health challenge in Tanzania, with socioeconomic factors playing crucial roles in disease outcomes. While previous studies have explored the relationship between socioeconomic status and malaria infection, quantitative assessment of equity condition in malaria outcomes remains understudied. This study innovatively applies Slope Index of Inequality (SII) and Relative Index of Inequality (RII) to quantify the equity conditions between socioeconomics and malaria burden in three Districts located in the Southeastern coast of Tanzania.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eData from the baseline survey of the China-Tanzania Demonstration Project on Malaria Control conducted in 2019 were analyzed. Key variables included: 1) socioeconomic status quantified through Principal Component Analysis incorporating household infrastructure, asset ownership, and social potential; 2) malaria infection outcomes, including blood test results, treatment costs, and days absent from work/education (days off). Logistic and linear regression analyses were performed to assess socioeconomic impacts, while SII and RII were calculated to measure health equity conditions across socioeconomic strata in three districts of Rufiji, Kilwa, and Kibiti.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eHigher socioeconomic status was associated with a lower risk of malaria infection (OR\u0026thinsp;=\u0026thinsp;0.9975, 95% CI: 0.9972\u0026ndash;0.9978), lower treatment costs (coefficient = -3.13, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and fewer days off work (coefficient = -0.0017, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Rufiji district demonstrated the most significant socioeconomic equality in malaria infection risk (SII=-12.62%, 95%CI: -17.19% to -8.06%; RII\u0026thinsp;=\u0026thinsp;1.28, 95%CI: 1.12 to 1.55), treatment cost (SII\u0026thinsp;=\u0026thinsp;837.769, 95%CI: -1182.44 to -491.75; RII\u0026thinsp;=\u0026thinsp;1.30, 95%CI: 1.09 to 1.63) and days off (SII=-0.46, 95%CI: -0.62 to -0.30; RII\u0026thinsp;=\u0026thinsp;1.21, 95%CI: 1.05 to 1.46).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThe findings highlight significant socioeconomic disparities in malaria-related outcomes across the studied districts, emphasizing the need for targeted public health interventions to address inequities. By prioritizing equity-focused policies, such as enhanced access to prevention and treatment, Tanzania can make strides toward more inclusive malaria control and health system strengthening, particularly for the most vulnerable populations. Furthermore, the use of SII and RII offered a nuanced understanding of health disparities across the socioeconomic spectrum.\u003c/p\u003e","manuscriptTitle":"Socioeconomic Health Equity with Malaria Burden: Quantifying Slope (Relative) Index of Inequity in Malaria Infection Outcomes in the Southeastern-coastal Tanzania","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-03 19:24:31","doi":"10.21203/rs.3.rs-7854639/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-03T09:23:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-03T08:39:05+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-01T10:41:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"306477664567082171816735703519264371428","date":"2025-10-22T18:17:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"101672361764417692536134345220353505471","date":"2025-10-22T12:22:13+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-22T11:40:40+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-22T11:27:12+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-15T00:41:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-15T00:40:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Public Health","date":"2025-10-14T06:05:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2da61936-1c41-4b22-9101-059169dffa69","owner":[],"postedDate":"November 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-09T16:05:04+00:00","versionOfRecord":{"articleIdentity":"rs-7854639","link":"https://doi.org/10.1186/s12889-026-26462-w","journal":{"identity":"bmc-public-health","isVorOnly":false,"title":"BMC Public Health"},"publishedOn":"2026-02-03 15:58:49","publishedOnDateReadable":"February 3rd, 2026"},"versionCreatedAt":"2025-11-03 19:24:31","video":"","vorDoi":"10.1186/s12889-026-26462-w","vorDoiUrl":"https://doi.org/10.1186/s12889-026-26462-w","workflowStages":[]},"version":"v1","identity":"rs-7854639","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7854639","identity":"rs-7854639","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}