Impact of COVID-19 Pandemic and Associated Restrictions on Vitamin D Status in a Large Cohort of Italian Children and Adolescents

Abstract

Background and Objectives: Vitamin D is synthesized in the skin upon sunlight exposure, showing variations with season and latitude. We aimed to investigate the influence of age, sex, and season on vitamin D status in a large pediatric cohort during the COVID-19 pandemic period and the corresponding pre-pandemic period. Materials and Methods: Retrospective data concerning subjects aged < 18 years were extracted anonymously from the large database of a reference laboratory hospital (Sassari, Northern Sardinia, Italy). Serum 25-hydroxyvitamin D [25(OH)D] levels measured during the pre-pandemic period (1 March 2018 to 30 September 2019) were compared with those detected during the pandemic period (1 March 2020 to 30 September 2021). Results: A total of 2317 samples from subjects aged < 18 years were included in the analysis, 1303 (47.9% females) of which were collected in the pre-pandemic period and 1014 (51.3% females) in the pandemic period. No significant differences in 25(OH)D levels were found between the two periods, whereas, in children aged < 2 years, levels were higher than those in children aged 11-16 years (p < 0.05). Monthly levels of 25(OH)D between pre-pandemic and pandemic periods did not differ, although significant differences were detected across months (p < 0.0001). Similarly, 25(OH)D values did not differ significantly between males and females in both periods. Marked seasonal variations were observed in males and females across all age groups. Conclusions: Serum vitamin D levels and their season-related variations were not significantly affected by the COVID-19 pandemic and associated restrictions in a large cohort of Italian children and adolescents.

Keywords: COVID-19 pandemic; children; seasonal variation; sex-related difference; vitamin D.

Figure 1

Graphical representation of mean serum 25(OH)D values in subjects included in the “pre-pandemic” group as a function of age and stratified by sex.

Figure 2

Graphical representation of mean serum 25(OH)D values in subjects included in the “pandemic” group as a function of age and stratified by sex.

Figure 3

Monthly changes in mean serum 25(OH)D values of subjects tested over a 12-month period before the pandemic (1 March 2018–28 February 2019, green line) and during the pandemic (1 March 2020–28 February 2021, brown line).

Figure 4

Monthly changes in mean serum 25(OH)D values (ng/mL) of subjects tested over a 12-month period before the pandemic (1 March 2018–28 February 2019), divided by sex (a); Monthly changes in mean serum 25(OH)D values (ng/mL) of subjects tested over a 12-month period during the pandemic (1 March 2020–28 February 2021), divided by sex (b).