ABSTRACT
OBJECTIVES: To investigate vitamin D nutritional status in children after outbreak of coronavirus disease 2019 (COVID-19), as well as the effect of strict epidemic prevention and control measures for the COVID-19 epidemic on vitamin D nutritional status in children. METHODS: A total of 7 460 children who underwent routine physical examinations from February to August, 2020 and had normal results were retrospectively enrolled as the observation group, and 10 102 children who underwent routine physical examinations from February to August, 2019 (no epidemic of COVID-19) and had normal results were enrolled as the control group. The serum level of 25-hydroxy vitamin D [25(OH)D] was compared between the two groups. The children in the observation and control groups who underwent physical examinations in March and April were selected as the epidemic prevention subgroup (n=1 710) and non-epidemic subgroup (n=2 877) respectively. The subjects were divided into five age groups (infancy, early childhood, preschool, school age and adolescence), and serum 25(OH)D levels of children of all ages were compared between the epidemic prevention and non-epidemic subgroups. RESULTS: The observation group had a lower serum level of 25(OH)D than the control group in March and April (P<0.001). The epidemic prevention subgroup had a lower serum level of 25(OH)D than the non-epidemic subgroup in all age groups (P<0.001). The vitamin D sufficiency rate in early childhood, preschool, school and adolescent children from the epidemic prevention subgroup was lower than the non-epidemic subgroup (P<0.001), with a reduction of 10.71%, 18.76%, 59.63% and 56.29% respectively. CONCLUSIONS: Strict prevention and control measures for the COVID-19 epidemic may lead to a significant reduction in vitamin D level in children, especially school-aged and adolescent children. It is recommended to timely monitor vitamin D level in children, take vitamin D supplements, and increase the time of outdoor sunshine as far as possible under the premise of adherence to epidemic prevention regulations.