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International Journal of Endocrinology
Volume 2015, Article ID 896758, 11 pages
http://dx.doi.org/10.1155/2015/896758
Clinical Study

Determinants of Vitamin D Levels in Children and Adolescents with Down Syndrome

1Health Sciences Department, Anna Meyer Children’s University Hospital, University of Florence, Viale Pieraccini 24, 50139 Florence, Italy
2Genetics and Molecular Medicine Unit, Anna Meyer Children’s University Hospital, Viale Pieraccini 24, 50139 Florence, Italy

Received 21 September 2014; Accepted 28 December 2014

Academic Editor: Andre P. Kengne

Copyright © 2015 Stefano Stagi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Poor studies have evaluated 25-hydroxycholecalciferol (25(OH)D) levels in Down syndrome (DS). Objective. To assess in DS subjects serum 25(OH)D value, to identify risk factors for vitamin D deficiency, and to evaluate whether a normal 25(OH)D value can be restored with a 400 I.U. daily supplement of cholecalciferol in respect to controls. Methods. We have longitudinally evaluated 31 DS patients (aged 4.5–18.9 years old) and 99 age- and sex-matched healthy controls. In these subjects, we analysed calcium, phosphate, parathyroid hormone (PTH), 25(OH)D concentrations, and calcium and 25(OH)D dietary intakes, and we quantified outdoor exposure. After 12.3 months (range 8.1–14.7 months) of 25(OH)D supplementation, we reevaluated these subjects. Results. DS subjects showed reduced 25(OH)D levels compared to controls (), in particular DS subjects with obesity () and autoimmune diseases history (). PTH levels were significantly higher in DS subjects than controls (). After cholecalciferol supplementation, 25(OH)D levels were significantly ameliorated (), even if reduced compared to controls (), in particular in DS subjects with obesity () and autoimmune diseases (). Conclusions. Hypovitaminosis D is very frequent in DS subjects, in particular in presence of obesity and autoimmune diseases. In these subjects, there could be a need for higher cholecalciferol supplementation.