Impact of vitamin D supplementation on the clinical outcomes of COVID-19 pneumonia patients: a single-center randomized controlled trial.

"Declarations Ethics approval and consent to participateThis study was conducted according to the Declaration of Helsinki of 1964 and its later amendments and Ethical approval was granted by the Faculty of Medicine Research Ethics Committee, Ramathibodi Hospital, Mahidol University (approval no. MURA2020/862) and was also retrospectively registered at Thai Clinical Trials Registry (TCTR20210906005) on 6 September 2021. The committee approved using patient samples and data in publishing this study. All patients provided written informed consent. Authors confirm that methods were carried out in accordance with relevant guidelines and regulations. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding Open access funding provided by Mahidol University This study was supported by the Faculty of Medicine Ramathibodi Hospital, Mahidol University (RF_64066). The funder had no role in the study design, data collection, analysis, decision to publish, or manuscript preparation."

"Trial registration Thai Clinical Trials Registry TCTR20210906005 (retrospectively registered, 6 September 2021)."