AUTHOR=Yegorov Sergey , Bromage Sabri , Boldbaatar Ninjin , Ganmaa Davaasambuu 

TITLE=Effects of Vitamin D Supplementation and Seasonality on Circulating Cytokines in Adolescents: Analysis of Data From a Feasibility Trial in Mongolia

JOURNAL=Frontiers in Nutrition

VOLUME=6

YEAR=2019

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2019.00166

DOI=10.3389/fnut.2019.00166

ISSN=2296-861X

ABSTRACT=<p>Vitamin D deficiency is prevalent in human populations and has been linked to immune dysfunction. Here we explored the effects of cholecalciferol supplementation on circulating cytokines in severely vitamin D deficient [blood 25(OH)D &lt;&lt; 30 nmol/L] adolescents aged 12–15 from Mongolia. The study included 28 children receiving 800 IU daily cholecalciferol for 6 months spanning winter and spring, and 30 children receiving placebo during the same period. The levels of 25(OH)D were assessed at baseline, 3 and 6 months. Twenty-one cytokines were measured in serum at baseline and at 6 months. Changes in 25(OH)D and cytokines were assessed using paired parametric tests. The median blood 25(OH)D concentration at baseline was 13.7 nmol/L (IQR = 10.0–21.7). Supplementation tripled blood 25(OH)D levels (<italic>p</italic> &lt; 0.001) and was associated with elevated interleukin (IL)-6 (<italic>p</italic> = 0.043). The placebo group had reduced macrophage inflammatory protein (MIP)-1α (<italic>p</italic> = 0.007) and IL-8 (<italic>p</italic> = 0.034) at 6 months. Although limited by a small sample size, these findings suggest that cholecalciferol supplementation and seasonality may impact systemic immunity in adolescents, identifying chemokines as potentially important biomarkers of vitamin D status in this Northeast Asian population. Larger clinical trials are warranted to validate these results.</p><p><bold>Clinical Trial Registration:</bold><ext-link ext-link-type="uri" xlink:href="https://www.ClinicalTrial.org" xmlns:xlink="http://www.w3.org/1999/xlink">www.ClinicalTrial.org</ext-link>, Identifier: NCT01244204.</p>