Vitamin D level and fractures in children and adolescents: a systematic review and meta-analysis

Serum 25-Hydroxyvitamin D and Intact Parathyroid Hormone as Functional Biomarkers of Bone Mass in Early Childhood

BACKGROUND

The 25-hydroxyvitamin D (25(OH)D) concentration at which parathyroid hormone (PTH) concentration plateaus has been considered to benchmark vitamin D deficiency. However, in young children, there is limited evidence for a suppression point in the 25(OH)D-PTH relationship or its relevance to bone mass accrual.

OBJECTIVES

To determine whether the threshold of 25(OH)D at PTH suppression in young children is corroborated by associations of 25(OH)D (or PTH) with bone mineral content (BMC) and areal bone mineral density (aBMD).

METHODS

In a cross-sectional secondary analysis of data from the BONe and mUScle health in Kids (BONUSKids) study of 4-y-old children in Bangladesh, serum 25(OH)D and intact PTH (iPTH) were analyzed by liquid chromatography-tandem mass spectrometry and a chemiluminescent immunoassay, respectively. BMC and aBMD were measured by dual-energy X-ray absorptiometry. Associations between 25(OH)D, iPTH, and bone outcomes (BMC, BMC z-score, aBMD, and aBMD z-score) were modeled using multivariable-adjusted linear regression and spline models. Model fit was compared using Akaike's Information Criteria.

RESULTS

Of 534 participants (51% female), 28% had 25(OH)D concentrations <25 nmol/L and 34% had iPTH >6.7 pmol/L. Model fit of the inverse relationship between 25(OH)D and iPTH was optimized with an inflection point at 25 nmol/L [<25 nmol/L: -0.16 pmol/L per 1 nmol/L increase in 25(OH)D; 95% confidence interval (CI): -0.22, -0.10; P < 0.001), above which the slope attenuated (≥25 nmol/L: -0.02 pmol/L; 95% CI: -0.04, -0.003; P = 0.019]. However, the positive linear associations between 25(OH)D and bone mass outcomes were monotonic (P < 0.05), and iPTH was not associated with any bone outcome in adjusted models (P > 0.05 for all). Associations were similar in males and females.

CONCLUSIONS

Among 4-y-old children in Dhaka, Bangladesh, we did not identify a 25(OH)D threshold to define vitamin D deficiency based on its association with bone mass. However, efforts to raise 25(OH)D to ≥25 nmol/L may be warranted based on the relatively strong inverse association of 25(OH)D with iPTH below this threshold. This trial was registered at clinicaltrials.gov as #NCT03537443.

Bone Health in Young Athletes: a Narrative Review of the Recent Literature

PURPOSE OF REVIEW

The aim of this review is to discuss the most recent published scientific evidence regarding bone health in the pediatric athlete.

RECENT FINDINGS

Pediatric athletes commonly suffer from overuse injuries to the physes and apophyses, as well as bone stress injuries, for which magnetic resonance imaging grading of the severity of injuries may be useful in guiding return to sport. Adolescent athletes, particularly those who train indoors and during the winter season, are at risk for vitamin D deficiency, which has important implications for bone mineral density. However, the relationship between vitamin D status and traumatic fracture risk is still unclear. While the female athlete triad is a well-established condition, the current work has led to the recognition of parallel pathophysiology in male athletes, referred to as the male athlete triad. Recent evidence suggests that transdermal 17β-estradiol treatment in amenorrhoeic female athletes is an effective adjunctive treatment to improve bone mineral density in treatment of the female athlete triad. Young athletes are at risk for musculoskeletal injuries unique to the growing skeleton. Optimizing nutritional intake, particularly related to adequate vitamin D intake and prevention of the athlete triad, is critical to optimize bone health in the young athlete.

Vitamin D and adolescent idiopathic scoliosis, should we stop the hype? A cross-sectional observational prospective study based on a geometric morphometrics approach

PURPOSE

There is strong evidence supporting the presence of fluctuating asymmetry (FA) in Adolescents with Idiopathic Scoliosis (AIS). Additionally, recent research investigating the relationship between vitamin D and AIS found a relation between them. We hypothesize a negative correlation between FA and vitamin D.

METHODS

We performed a surface scan of the torso of 53 AIS patients, a blood test to measure vitamin D and the radiographic Cobb angle. A correlation analysis between vitamin D and FA was carried out to test our hypothesis, and a regression of vitamin D on 3D shape was performed to observe shape differences between the vitamin D deficiency and insufficiency groups.

RESULTS

There was no correlation between vitamin D and FA. We found a strong negative correlation between vitamin D and the Cobb angle only in the premenarche group (n = 7; r = - 0.92). Differences in shape were observed between the deficiency and insufficiency groups, and that differences were related to the width of the torso, but not the rotation or lateral flexion.

CONCLUSIONS

Our results do not support the massive screening of vitamin D in AIS. Shape analysis revealed differences between the shape of the deficiency and insufficiency groups related to robustness. However, this finding had no relation with the scoliosis characteristics, it just reflected different body composition, and its importance should be explored in future.

The Relationship between Dietary Pattern and Bone Mass in School-Age Children

Early bone accrual significantly influences adult bone health and osteoporosis incidence. We aimed to investigate the relationship between dietary patterns (DPs), bone mineral content (BMC) and bone mineral density (BMD) in school-age children in China. Children aged six-nine years (n = 465) were enrolled in this cross-sectional study. DPs were identified by principal component factor analysis. Total body (TB) and total body less head (TBLH) BMC and BMD were measured using dual-energy X-ray absorptiometry. Five DPs were identified. After adjustment for covariates, multiple linear regression analysis showed that the "fruit-milk-eggs" dietary pattern was positively associated with TB (β = 10.480; 95% CI: 2.190, 18.770) and TBLH (β = 5.577; 95% CI: 0.214, 10.941) BMC, the "animal organs-refined cereals" pattern was associated with low TB BMC (β = -10.305; 95% CI: -18.433, -2.176), TBLH BMC (β = -6.346; 95% CI: -11.596, -1.096), TB BMD (β = -0.006; 95% CI: -0.011, -0.001) and TBLH BMD (β = -0.004; 95% CI: -0.007, -0.001). In conclusion, our study recommends home or school meals should be rich in fruit, milk, eggs with a moderate amount of vegetables, coarse grains and meat to promote bone development for school-age children.