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Obese young adults exhibit lower total and lower free serum 25‐hydroxycholecalciferol in a randomized vitamin D intervention
Author(s) -
HolmlundSuila Elisa,
Pekkinen Minna,
Ivaska Kaisa K.,
Andersson Sture,
Mäkitie Outi,
Viljakainen Heli
Publication year - 2016
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13093
Subject(s) - medicine , cholecalciferol , vitamin d and neurology , endocrinology , obesity , placebo , vitamin d deficiency , body mass index , vitamin , anthropometry , randomized controlled trial , alternative medicine , pathology
Summary Objective Although obesity is a risk factor for vitamin D insufficiency, its impact on vitamin D‐binding protein ( DBP ) concentration, and thereby possibly also on free 25 OHD , is less well known. Our aim was to compare total and free serum 25 OHD , and DBP concentrations between obese and normal‐weight young adults at baseline and their responses to cholecalciferol supplementation. Design A 12‐week randomized, double‐blinded clinical trial. Patients Obese 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 μg (2000 IU ) daily. Measurements At baseline, 6‐week and 12‐week blood samples and anthropometric measurements were collected; baseline body composition was assessed by dual‐energy X‐ray absorptiometry. Results At baseline, obese subjects had, compared with normal‐weight, lower total and free serum 25 OHD (49 vs 62 nmol/l, P = 0·041; 2·8 vs 4·7 pg/ml, P = 0·001), without differences in DBP concentrations (309 vs 346 μg/ml, P = 0·212). Cholecalciferol 50 μg per day increased both total and free 25 OHD ( ancova P < 0·001 and P = 0·021). The response of total 25 OHD to supplementation was inferior in the obese compared with normal‐weight subjects ( P = 0·027). On the contrary, the change in free 25 OHD concentration was similar in groups ( P = 0·487). Conclusions Obese young adults exhibit lower total and free 25 OHD concentration, which is not directly explained by differences in DBP status. The response of free 25 OHD to supplementation did not differ between obese and normal‐weight subjects.