Iodized salt has large impacts on child health and test scores in Ethiopia

Iodized salt has large impacts on child health and test scores in Ethiopia | 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 Social Sciences - Article Iodized salt has large impacts on child health and test scores in Ethiopia Robel Alemu, Kibrom Tafere, Dawd Gashu, Edward Joy, Elizabeth Bailey, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5695594/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract This study quantifies the impact of iodized salt on child survival and academic achievement based on sudden nationwide changes in access to iodized salt, given naturally occurring geographic variation in iodine. We combine data on birth timing and test scores on national school-leaving exams from 2003 to 2019 with child health surveys and newly collected measures of soil and grain iodine concentrations, finding that children with longer exposure to iodized salt in utero and infancy during the 1990s went on to have lower mortality and higher scores, especially in places with less iodine in locally grown food. Among children with the longest exposure, our main estimates show a national average test score gain of 0.09 standard deviations from widespread iodization, with an additional gain of 0.08 standard deviations for each standard deviation reduction in soil iodine. Placebo tests confirm that effects are specific to iodine (vs. selenium) and specific to cognition and survival (vs. height and weight, which are not affected by iodine deficiency). This provides the first large-scale evidence of how educational achievement is affected by national salt iodization programs recommended by the World Health Organization but not yet universally implemented. Health sciences/Risk factors Earth and environmental sciences/Environmental social sciences Scientific community and society/Social sciences/Education Scientific community and society/Agriculture Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. 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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-5695594","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Social Sciences - Article","associatedPublications":[],"authors":[{"id":403077342,"identity":"5fbc4df9-d940-427b-b4dd-009a35e15d2d","order_by":0,"name":"Robel Alemu","email":"","orcid":"","institution":"Program in Medical and Population Genetics, Broad Institute of MIT and Harvard","correspondingAuthor":false,"prefix":"","firstName":"Robel","middleName":"","lastName":"Alemu","suffix":""},{"id":403077343,"identity":"01e3d6f1-66da-42a1-807e-19fc1846ee10","order_by":1,"name":"Kibrom 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