Influence of the COVID-19 pandemic on the vitamin D status of children: A cross-sectional study

Coronavirus disease 2019 (COVID-19), as well as its prevention and control measures, seriously affected people's livehood, which may have affected the body's level of vitamin D (VD). This study aimed to investigate the effect of the COVID-19 pandemic on the VD status of children in Zhengzhou, China. In this study, we included 12272 children in 2019 (before the COVID-19 pandemic) and 16495 children in 2020 (during the COVID-19 pandemic) to examine the changes in VD levels and deficiency rates among children before and during the COVID-19 pandemic. Total VD levels in 2020 were significantly higher than those in 2019 (26.56 [18.15, 41.40] vs. 25.98 [17.92, 40.09]ng/ml, p < 0.001). Further analysis revealed that during the COVID-19 pandemic control period in 2020, the VD levels in February, March, and April were lower than those in the same months of 2019, while the VD deficiency rates were significantly higher. Additionally, our data revealed that VD levels decreased significantly with age. Among children older than 6 years, the VD deficiency rate exceeded 50%. These results indicate that we should pay close attention to VD supplementation during the COVID-19 pandemic control period and in children older than 6 years of age.