Vitamin D deficiency during the coronavirus disease 2019 (COVID-19) pandemic among healthcare workers

Background & aims: Vitamin D deficiency is a common nutritional problem worldwide that may have worsened during the coronavirus disease 2019 (COVID-19) pandemic. The present study sought to examine the prevalence and correlates of vitamin D deficiency among healthcare workers three years after the start of the COVID-19 pandemic. Methods: Participants comprised 2543 staff members from a medical research institute, who completed a questionnaire and donated blood samples in June 2023. 25-hydroxyvitamin D (25[OH]D) levels were measured using an electrochemiluminescence immunoassay. Logistic regression was used to calculate the odds ratio and its 95% confidence interval while adjusting for covariates. Results: The proportions of participants with vitamin D insufficiency (25[OH]D 20-29 ng/mL) and deficiency (25[OH]D < 20 ng/mL) were 44.9% and 45.9%, respectively. In a multivariable-adjusted model, factors associated with a higher prevalence of vitamin D deficiency included younger age, female sex, fewer hours of daytime outdoor physical activity during leisure time (without regular use of sunscreen), lower intake of fatty fish, no use of vitamin D supplements, smoking, and no alcohol consumption. Occupational factors, including shift work, were not independently associated with vitamin D deficiency. Conclusions: Our results suggest that vitamin D insufficiency and deficiency are highly prevalent among healthcare workers. Health education regarding lifestyle modifications for this occupational group are warranted to improve their vitamin D status in the COVID-19 era. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/li censes/by-nc-nd/4.0/).