@article {643189,
	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},
	number = {166},
	year = {2019},
	pages = {1-6},
	abstract = {
	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{\textendash}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{\textendash}21.7). Supplementation tripled blood 25(OH)D levels (p\&nbsp;\&lt; 0.001) and was associated with elevated interleukin (IL)-6 (p\&nbsp;= 0.043). The placebo group had reduced macrophage inflammatory protein (MIP)-1α (p\&nbsp;= 0.007) and IL-8 (p\&nbsp;= 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.

},
	url = {https://www.frontiersin.org/articles/10.3389/fnut.2019.00166/full},
	author = {Sergey Yegorov and Sabri Bromage and Ninjin Boldbaatar and Davaasambuu Ganmaa}
}
