Serum 25-Hydroxyvitamin D and Intact Parathyroid Hormone Influence Muscle Outcomes in Children and Adolescents

Abstract

Increases in 25-hydroxyvitamin D concentrations are shown to improve muscle strength in adults; however, data in pediatric populations are scant and equivocal. In this ancillary study of a larger-scale, multi-sited, double-blind, randomized, placebo-controlled vitamin D intervention in US children and adolescents, we examined the associations between changes in vitamin D metabolites and changes in muscle mass, strength, and composition following 12-weeks of vitamin D3 supplementation. Healthy male and female, black and white children and adolescents between the ages of 9-13 years old from two US states (Georgia 34°N and Indiana 40°N) were enrolled in the study and randomly assigned to receive an oral vitamin D3 dose of 0, 400, 1,000, 2,000 or 4,000 IU/d for 12 weeks between the winter months of 2009 to 2011 (N=324). Analyses of covariance, partial correlations, and regression analyses of baseline and 12-week changes (post-baseline) in vitamin D metabolites (serum 25(OH)D, 1,25(OH)2D, intact parathyroid hormone (iPTH)) and outcomes of muscle mass, strength, and composition (total body fat-free soft tissue (FFST), handgrip strength, forearm and calf muscle cross-sectional area (MCSA), muscle density, and intermuscular adipose tissue (IMAT)) were assessed. Serum 25(OH)D and 1,25(OH)2D, but not iPTH, increased over time, as did fat mass, FFST, forearm and calf MCSA, forearm IMAT, and handgrip strength (p<0.05). Vitamin D metabolites were not associated with muscle strength at baseline nor following the 12-week intervention. Changes in serum 25(OH)D correlated with decreases in forearm IMAT, while changes in serum iPTH predicted increases in forearm and calf MCSA and IMAT (p<0.05). Overall, increases in 25(OH)D did not influence muscle mass or strength in vitamin D sufficient children and adolescents; however, the role of iPTH on muscle composition in this population is unknown and warrants further investigation.

The role of serum levels of vitamin D in children’s muscle strength: A systematic review

“…One of the studies included in this review (22) presented data that considered the subjects' skin color and gender. In this study, white girls had higher levels of circulating 25OHD (80.5 ± 6.1 nmol/L) than black girls (58.9 ± 18.2 nmol/L) and white and black boys (79.8±3.0 nmol/L and 62.0±15.2 nmol/L, respectively).…”

“…The age range was 5-11 years. Three studies were identified with insufficient classification of vitamin D levels (22)(23)(24), and two studies (25,26) included subjects with deficient vitamin D levels as defined by the International Life Science Institute of Brazil (27). The characteristics of the included studies are listed in Table 1.…”

“…In one study (28), serum vitamin D levels were not evaluated, although variants of the VDR gene were analyzed in relation to HGS. Wright et al (22) presented data that took into account the subjects' race and sex. In this study, white girls had higher levels of circulating 25OHD (80.5 ± 6.1 nmol/L) than black girls (58.9±18.2 nmol/L) and white and black boys (79.8 ± 3.0 nmol/L and 62.0 25) analyzed the possible association of HGS with supplementation of 25OHD during the first 6 months of life in children aged 5 years.…”

The correlation between serum 25-hydroxyvitamin D and parathyroid hormone levels and orthostatic intolerance in children

“…When the concentration of 25(OH)D is higher than 32 ng/ml, the prevalence of cardiac metabolic risk in children will be reduced by 49% [36]. It has been found that increasing circulating 25(OH)D concentration can reduce the fat tissue (IMAT) between forearm muscles and increase the cross-sectional area (MCSA) of forearm and calf skeletal muscles [37], which may improve the contractility of lower limb muscles in OI children and avoid re ex hypotension due to upright.…”

The Correlation Between Serum 25-Hydroxyvitamin D and Parathyroid Hormone Levels and Orthostatic Intolerance in Children

“…When the concentration of 25(OH)D is higher than 32 ng/ml, the prevalence of cardiac metabolic risk in children will be reduced by 49% [36]. It has been found that increasing circulating 25(OH)D concentration can reduce the fat tissue (IMAT) between forearm muscles and increase the cross-sectional area (MCSA) of forearm and calf skeletal muscles [37], which may improve the contractility of lower limb muscles in OI children and avoid re ex hypotension due to upright. Chaudhari reported a case of 1-hydroxylase de cient POTS patients with improved palpitation symptoms after oral vitamin D treatment, suggesting that this kind of patients can be treated with calcitriol [38], but this still needs larger sample clinical trials to verify.…”