ESPE Abstracts

Introduction: Vitamin D (VitD) is a prohormone that is synthesized in the skin after sun exposure. Mandatory lockdown during the COVID-19 Pandemic may have altered the sun exposure time of children.

Aim: to evaluate vitD levels in a sample of children and adolescents, and compare between pre-pandemic and pandemic periods.

Methoths Children and adolescents, from a Portuguese tertiary hospital, who had 25(OH)D level blood sampling between March 2019 and March 2021 were included. Children with less than 12 months were excluded given the routine VitD supplementation in this age group. When more than one test/child was performed, only the first blood sample was considered. The sample was divided in two groups: before and during pandemic.

Results: From a total 1455 of 25(OH)D blood samples, 1001 were eligible for analysis (69%): 51% male gender, 80% caucasian, median 11.2 years of age (IQR 8.1) and median SDS BMI 0.85 (IQR 2.28). The median VitD level was normal (58nmol/L, IQR 27), with 6% having VitD deficiency (< 30nmol/L) and 32% insufficiency (30-50nmol/L). The characteristic seasonal variability was observed, with maximal levels in summer (M_d=68nmol/L) and minimal in winter (M_d=49nmol/L). The 25(OH)D value correlated negatively with age (r= -0.26, P<0.001) and with SDS-IMC (r= -0.19, P<0.001). When comparing the pre-pandemic (n=665) and Pandemic groups (n=336), a statistically significant increase in the average level of 25(OH)D (54nmol/L vs. 63nmol/L, P<0.001), in all seasons except for summer (68 vs. 66 nmol/L). We also found a statistically significant reduction in SDS-BMI between the two groups (1.04 vs. 0.62, P=0.017). The cases of deficiency reduced from 8% to 2% and insufficiency from 35% to 22%. In the pandemic period, there was a reduction in obesity (27% vs. 19%). VitD supplementation was prescribed in 32%, and was statistically correlated with 25(OH)D value (44 vs. 65nmol/L, P<0.001), season (lower in summer, P<0.001), age group (more frequent in adolescents, P=0.007). It was not related to gender, ethnicity or SDS-IMC.

Discussion According to the literature reviewed by the authors, this is the first study to identify an improvement in Vitamin D status during the COVID-19 Pandemic. Contrary also to what has been described, we found a reduction in BMI in our sample. Although this is a retrospective study, we may presume that the improvement in Vit D levels may be related to the reduction in BMI and healthier lifestyles, with more outdoor activities.