A1 Refereed original research article in a scientific journal
Obese young adults exhibit lower total and lower free serum 25-hydroxycholecalciferol in a randomized vitamin D intervention
Authors: Holmlund-Suila E, Pekkinen M, Ivaska KK, Andersson S, Mäkitie O, Viljakainen H
Publisher: WILEY-BLACKWELL
Publication year: 2016
Journal: Clinical Endocrinology
Journal name in source: CLINICAL ENDOCRINOLOGY
Journal acronym: CLIN ENDOCRINOL
Volume: 85
Issue: 3
First page : 378
Last page: 385
Number of pages: 8
ISSN: 0300-0664
DOI: https://doi.org/10.1111/cen.13093
Abstract
ObjectiveAlthough obesity is a risk factor for vitamin D insufficiency, its impact on vitamin D-binding protein (DBP) concentration, and thereby possibly also on free 25OHD, is less well known. Our aim was to compare total and free serum 25OHD, and DBP concentrations between obese and normal-weight young adults at baseline and their responses to cholecalciferol supplementation.DesignA 12-week randomized, double-blinded clinical trial.PatientsObese subjects N = 18 (BMI = 38, 67% men) with severe childhood-onset obesity and 24 normal-weight subjects (BMI = 23, 46% men), age between 15 and 25 years, were randomized into two groups to receive either placebo or cholecalciferol 50 g (2000 IU) daily.MeasurementsAt baseline, 6-week and 12-week blood samples and anthropometric measurements were collected; baseline body composition was assessed by dual-energy X-ray absorptiometry.ResultsAt baseline, obese subjects had, compared with normal-weight, lower total and free serum 25OHD (49 vs 62 nmol/l, P = 0041; 28 vs 47 pg/ml, P = 0001), without differences in DBP concentrations (309 vs 346 g/ml, P = 0212). Cholecalciferol 50 g per day increased both total and free 25OHD (ancova P < 0001 and P = 0021). The response of total 25OHD to supplementation was inferior in the obese compared with normal-weight subjects (P = 0027). On the contrary, the change in free 25OHD concentration was similar in groups (P = 0487).ConclusionsObese young adults exhibit lower total and free 25OHD concentration, which is not directly explained by differences in DBP status. The response of free 25OHD to supplementation did not differ between obese and normal-weight subjects.
ObjectiveAlthough obesity is a risk factor for vitamin D insufficiency, its impact on vitamin D-binding protein (DBP) concentration, and thereby possibly also on free 25OHD, is less well known. Our aim was to compare total and free serum 25OHD, and DBP concentrations between obese and normal-weight young adults at baseline and their responses to cholecalciferol supplementation.DesignA 12-week randomized, double-blinded clinical trial.PatientsObese subjects N = 18 (BMI = 38, 67% men) with severe childhood-onset obesity and 24 normal-weight subjects (BMI = 23, 46% men), age between 15 and 25 years, were randomized into two groups to receive either placebo or cholecalciferol 50 g (2000 IU) daily.MeasurementsAt baseline, 6-week and 12-week blood samples and anthropometric measurements were collected; baseline body composition was assessed by dual-energy X-ray absorptiometry.ResultsAt baseline, obese subjects had, compared with normal-weight, lower total and free serum 25OHD (49 vs 62 nmol/l, P = 0041; 28 vs 47 pg/ml, P = 0001), without differences in DBP concentrations (309 vs 346 g/ml, P = 0212). Cholecalciferol 50 g per day increased both total and free 25OHD (ancova P < 0001 and P = 0021). The response of total 25OHD to supplementation was inferior in the obese compared with normal-weight subjects (P = 0027). On the contrary, the change in free 25OHD concentration was similar in groups (P = 0487).ConclusionsObese young adults exhibit lower total and free 25OHD concentration, which is not directly explained by differences in DBP status. The response of free 25OHD to supplementation did not differ between obese and normal-weight subjects.
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