Marker of vitamin D status in healthy children: Free or total 25-hydroxyvitamin D?

Laura Mantecón, Mª Agustina Alonso, Vanessa Moya, Ana Gloria Andrés, Noelia Avello, Eduardo Martínez-Morillo, Fernando Santos, Sakamuri V. Reddy
2018 PLoS ONE  
Objective To assess if serum free 25-hydroxyvitamin D (25OHD) is a better indicator of vitamin D status than total 25OHD in healthy children. Methods Cross-sectional prospective clinical study was designed. We measured serum free 25OHD concentrations and its correlation with calculated free 25OHD, total 25OHD, intact parathyroid hormone (PTH), and vitamin D binding protein (DBP) in children. The influence of age, sex, ethnicity, body mass index (BMI), season of the year, diet intake, vitamin
more » ... intake, vitamin supplements, time spent outdoors and albumin concentrations on free 25OHD was also analyzed. 241 children aged from 0 days to 14 years, and living in the northern Spain (latitude 43˚N), were included. Results Mean (SD) free 25OHD concentrations were 2.48 (1.39), 5.46 (3.12), 4.12 (1,72), 3.82 (1.43) pg/ml in children aged 0 days, 1 month-2 years, 2-6 years and >6 years, respectively. Correlation between directly measured and calculated free 25OHD was high and significant (r = 0.66) as well as the correlation between serum free and total 25OHD concentrations (r = 0.61). No significant correlation was found between PTH and free 25OHD (r = -0.08). The total 25OHD and PTH concentrations' correlation was inverse (r = -0.25) and significant. Neither free nor total 25OHD concentrations correlated with DBP concentrations. Among the analyzed variables, free 25OHD values were higher in spring/summer than in autumn/ winter in children older than 6 years. These findings do not support that free 25OHD is a better marker of vitamin D deficiency than total 25OHD in healthy pediatric population. Free 25-hydroxyvitamin D in healthy children PLOS ONE | https://doi.
doi:10.1371/journal.pone.0202237 pmid:30138329 fatcat:bbo4ioywqbac3jzf6ymwqzjxcq