Monitoring changes in vitamin D levels during the COVID-19 pandemic with routinely-collected laboratory data

Monitoring changes in vitamin D levels during the COVID-19 pandemic with routinely-collected laboratory data | 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 Article Monitoring changes in vitamin D levels during the COVID-19 pandemic with routinely-collected laboratory data Eva Grill, Lea Skapetze, Daniela Koller, Andreas Zwergal, Stefan Feuerriegel, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5931470/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Oct, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Vitamin D is critical for bone health and immune function, but the COVID-19 pandemic,characterized by lockdowns and reduced outdoor activity, raised concerns about potential declines in vitamin D levels due to dietary changes and limited sunlight exposure. In this study, we analyzed routinely-collected laboratory data (N = 292,791 patients) from a large laboratory chain in Bavaria, Germany, to assess changes in vitamin D levels before (March 2018 to February 2020) and during (March 2020 to February 2022) the pandemic. Different statistical approaches (i.e., descriptive statistics, propensity score matching, and a causal forest) were used to evaluate confounder-adjusted changes in vitamin D levels and deficiency rates. Mean vitamin D levels decreased significantly from 26.7 µg/l pre-pandemic to 26.0 µg/l during the pandemic (p-value < 0.001), with a corresponding increase in deficiency rates from 31.3% to 35.2% (p-value < 0.001). Across all statistical approaches, the decline in mean levels and the increase in deficiency rates were particularly pronounced among elderly women. These findings highlight the importance of public health strategies to monitor and improve vitamin D status, especially during periods of restricted outdoor activity. Health sciences/Health care/Public health/Epidemiology Health sciences/Medical research/Epidemiology Full Text Additional Declarations Yes there is potential Competing Interest. L.S. and A.R. are employed by Health Data Technologies GmbH ("Honic"), the data platform that provided access to the data used in this study Supplementary Files MonitoringchangesinvitaminDlevelscode.txt R script - Code for data analysis Cite Share Download PDF Status: Published Journal Publication published 02 Oct, 2025 Read the published version in Nature Communications → 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. 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