TY - JOUR T1 - Serious vitamin D deficiency in healthcare workers during the COVID-19 pandemic JF - BMJ Nutrition, Prevention & Health JO - BMJ Nutrition DO - 10.1136/bmjnph-2021-000364 SP - e000364 AU - Takanori Funaki AU - Makiko Sanpei AU - Naho Morisaki AU - Tetsuya Mizoue AU - Koushi Yamaguchi Y1 - 2022/01/03 UR - http://nutrition.bmj.com/content/early/2022/01/03/bmjnph-2021-000364.abstract N2 - Several reports suggest that vitamin D (VitD) deficiency could increase the predisposition to systemic infection, including respiratory tract infections and impaired immune response.1–4 A recent meta-analysis demonstrated that VitD supplementation can reduce the risk of respiratory tract infections overall based on data from randomised controlled trials.5 Moreover, an article reported a possible association of VitD level with cytokine storm and unregulated inflammation in elderly patients with COVID-19.6 It supported the potential protective impact of VitD by enhancing the immune system and possibly reducing the risk of complications associated with cytokine storm and unregulated inflammation in patients with severe COVID-19. VitD is a lipid-soluble vitamin that acts as a ligand to the intranuclear receptor superfamily and plays a significant role in regulating between innate and acquired immunity.1 25-Hydroxy vitamin D (25(OH)D) is the major circulating form of VitD in humans and currently accepted as the best marker of VitD status.7 To date, there are only a few reports focusing on nutritional status including 25(OH)D in healthcare workers (HCWs) during the COVID-19 pandemic.8During the COVID-19 pandemic, we conducted a prospective observational study to evaluate several blood markers in HCWs at high risk of SARS-CoV-2 infection at the National Center for Child Health and Development in Tokyo, Japan.7 Blood sampling was performed from the enrolled participants … ER -