Prevalence of vitamin D insufficiency among adolescents and its correlation with bone parameters using high-resolution peripheral quantitative computed tomography

Distinguishing risk of curve progression in adolescent idiopathic scoliosis with bone microarchitecture phenotyping: a 6-year longitudinal study

Low bone mineral density and impaired bone quality have been shown to be important prognostic factors for curve progression in adolescent idiopathic scoliosis (AIS). There is no evidence-based integrative interpretation method to analyze high-resolution peripheral quantitative computed tomography (HR-pQCT) data in AIS. This study aimed to (1) utilize unsupervised machine learning to cluster bone microarchitecture phenotypes on HR-pQCT parameters in girls with AIS, (2) assess the phenotypes' risk of curve progression and progression to surgical threshold at skeletal maturity (primary cohort), and (3) investigate risk of curve progression in a separate cohort of girls with mild AIS whose curve severity did not reach bracing threshold at recruitment (secondary cohort). Patients were followed up prospectively for 6.22 ± 0.33 years in the primary cohort (n = 101). Three bone microarchitecture phenotypes were clustered by fuzzy C-means at time of peripubertal peak height velocity (PHV). Phenotype 1 had normal bone characteristics. Phenotype 2 was characterized by low bone volume and high cortical bone density, and phenotype 3 had low cortical and trabecular bone density and impaired trabecular microarchitecture. The difference in bone quality among the phenotypes was significant at peripubertal PHV and continued to skeletal maturity. Phenotype 3 had significantly increased risk of curve progression to surgical threshold at skeletal maturity (odd ratio [OR] = 4.88; 95% CI, 1.03-28.63). In the secondary cohort (n = 106), both phenotype 2 (adjusted OR = 5.39; 95% CI, 1.47-22.76) and phenotype 3 (adjusted OR = 3.67; 95% CI, 1.05-14.29) had increased risk of curve progression ≥6° with mean follow-up of 3.03 ± 0.16 years. In conclusion, 3 distinct bone microarchitecture phenotypes could be clustered by unsupervised machine learning on HR-pQCT-generated bone parameters at peripubertal PHV in AIS. The bone quality reflected by these phenotypes was found to have significant differentiating risk of curve progression and progression to surgical threshold at skeletal maturity in AIS.

Normative Bone Mineral Density Measured on Computed Tomography Scans in Children and Adolescents

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

To provide reference values for Hounsfield unit (HU) measured on computed tomography (CT) scans of children and adolescents.

SUMMARY OF BACKGROUND DATA

Spine surgeons increasingly use HU on spine CT as a measure of bone mineral density (BMD). This has not been described in children and adolescents.

PATIENTS AND METHODS

Pediatric patients who had a spine CT between 2012 and 2022 were identified. Patients who had more than 1 comorbidity or were syndromic were excluded. Using the bone window, 3 axial images (cephalad, middle, and caudal) of each vertebra were selected. In each axial view, the HU was measured using a "region of interest" (ROI) that included the total cancellous bone area and an ROI excluding the radiolucency present in the posterior vertebral body ("total" vs . "limited"). HU values were compared between total and limited areas and between the axial images at the cephalad, middle, and caudal levels. Each age category data were estimated and stratified.

RESULTS

A total of 144 patients (79 females and 65 males) from 2 to 17 years old were included. Mean limited HU was consistently lower than total HU across all images and lumbar levels except for L1. Limited HU taken mid-vertebral body was also consistently lower than those taken cephalad or caudad. Mean limited HU across all ages including all levels was 227 ± 50 (range: 109-357). Stratifying by age showed a gradual decrease in BMD from age 2 to 10 followed by an increase.

CONCLUSIONS

This is the first study to measure HU on lumbar CTs in children and adolescents. The technique of measuring BMD in adults should be modified in children by using an ROI that excludes the rarefaction present in the posterior vertebral body. Further studies are needed to evaluate the age-dependent changes in BMD seen in this study.

Potential Interaction between WNT16 and Vitamin D on Bone Qualities in Adolescent Idiopathic Scoliosis Patients and Healthy Controls

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that is associated with low bone mineral density (BMD). Vitamin D (Vit-D) supplementation has been suggested to improve BMD in AIS, and its outcomes may be related to genetic factors. The present study aimed to (a) investigate the synergistic effect between a low BMD-related gene (wingless-related integration site 16, WNT16) and two important Vit-D pathway genes (Vit-D receptor, VDR, and Vit-D binding protein, VDBP) on serum Vit-D and bone qualities in Chinese AIS patients and healthy adolescents, and (b) to further investigate the effect of ablating Wnt16 on the cortical bone quality and whether diets with different dosages of Vit-D would further influence bone quality during the rapid growth phase in mice in the absence of Wnt16. A total of 519 girls (318 AIS vs. 201 controls) were recruited, and three selected single-nucleotide polymorphisms (SNPs) (WNT16 rs3801387, VDBP rs2282679, and VDR rs2228570) were genotyped. The serum 25(OH)Vit-D level was significantly associated with VDBP rs2282679 alleles (OR = -4.844; 95% CI, -7.521 to -2.167, p < 0.001). Significant multi-locus models were identified by generalized multifactor dimensionality reduction (GMDR) analyses on the serum 25(OH)Vit-D level (p = 0.006) and trabecular area (p = 0.044). In the gene-edited animal study, Wnt16 global knockout (KO) and wildtype (WT) male mice were provided with different Vit-D diets (control chow (1000 IU/Kg) vs. Vit-D-deficient chow (Nil in Vit-D) vs. high-dose Vit-D chow (20,000 IU/Kg)) from 4 weeks to 10 weeks old. Wnt16 global KO mice had significantly lower serum 25(OH)Vit-D levels and higher liver Vdbp mRNA expression levels than WT mice. In addition, Wnt16 global KO mice showed a decrease in bone density, cortical thickness and cortical area compared with WT mice. Interestingly, high-dose Vit-D chow led to lower bone density, cortical thickness, and cortical area in WT mice, which were less obvious in Wnt16 global KO mice. In conclusion, WNT16 may regulate the serum 25(OH)Vit-D level and bone qualities, which might be associated with VDBP expression. Further investigations with a larger sample size and wider spectrum of scoliosis severity are required to validate our findings regarding the interaction between WNT16 and Vit-D status in patients with AIS.

Metabolic Imbalances and Bone Remodeling Agents in Adolescent Idiopathic Scoliosis: A Study in Postmenarcheal Girls

The causes and mechanisms underlying adolescent idiopathic scoliosis (AIS) remain unclear, and the available information regarding metabolic imbalances in AIS is still insufficient. This investigation aimed to evaluate the concentrations of specific bone remodeling-related agents in postmenarcheal girls diagnosed with AIS. The study encompassed thirty-six scoliosis patients and eighteen age-matched healthy individuals assigned to the control group. The patients underwent clinical and radiological examinations to assess the degree of the spinal deformity, type of curvature, and skeletal maturity. Blood and urine samples were collected from all participants and serological markers were measured using an enzyme-linked immunosorbent assay. Our study results demonstrated that the balance of phosphate-calcium and parathormone levels seems normal in individuals with AIS. Furthermore, no statistically significant differences were observed in the content of Klotho protein, osteocalcin, osteoprotegerin, C-terminal telopeptide of type I collagen (CTX), sclerostin, and alkaline phosphatase. Nevertheless, the serum levels of vitamin D (25-OH-D) were lowered, while N-terminal propeptide of type I procollagen (PINP), and fibroblast growth factor-23 (FGF23) were increased in the AIS group, with p-values of 0.044, 0.001, and 0.022, respectively. This finding indicates the potential involvement of these factors in the progression of AIS, which necessitates further studies to uncover the fundamental mechanisms underlying idiopathic scoliosis.

Serum 25-Hydroxyvitamin D is Associated With Bone Microarchitecture and Strength in a Multiracial Cohort of Young Adults

PURPOSE

To determine whether 25-hydroxyvitamin D (25-OH D) levels are associated with bone outcomes in a multiracial cohort of young adults.

METHODS

This cross-sectional study included 165 participants (83 men, 82 women, 18-30 years of age) who self-identified as Asian, Black, or White. We measured bone microarchitecture and strength of the distal radius and tibia using high-resolution peripheral quantitative computed tomography. We used linear regression to estimate the association between 25-OH D (ng/mL) and bone measurements, adjusting for race, sex, age, weight, height, calcium intake, physical activity, and season.

RESULTS

A total of 43.6% of participants were 25-OH D deficient (<20 ng/mL) with greater prevalence in Asian (38.9%) and Black (43.1%) compared with White (18.0%) participants (P < 0.001). At the distal radius, 25-OH D was positively associated with cortical area, trabecular density, cortical thickness, cortical porosity, and failure load (P < 0.05 for all). At the distal tibia, higher 25-OH D was associated with higher cortical area, trabecular density, trabecular number, failure load, and lower trabecular separation and cortical density (P < 0.05 for all). After multivariable adjustment, those with 25-OH D deficiency had generally worse bone microarchitecture than those with 25-OH D sufficiency. Black individuals had largely more favorable bone outcomes than Asian and White individuals, despite higher prevalence of 25-OH D deficiency.

CONCLUSIONS

We found a high prevalence of 25-OH D deficiency in a multiracial cohort of young adults. Lower 25-OH D was associated with worse bone outcomes at the distal radius and tibia at the time of peak bone mass, warranting further attention to vitamin D status in young adults.

Decreased cortical bone density and mechanical strength with associated elevated bone turnover markers at peri-pubertal peak height velocity: a cross-sectional and longitudinal cohort study of 396 girls with adolescent idiopathic scoliosis

Decreased cortical bone density and bone strength at peak height velocity (PHV) were noted in girls with adolescent idiopathic scoliosis (AIS). These findings could provide the link to the previously reported observation that low bone mineral density (BMD) could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

INTRODUCTION

As part of the studies related to aetiopathogenesis of AIS, we assessed bone qualities, bone mechanical strength and bone turnover markers (BTMs) focusing at the peri-pubertal period and PHV in AIS girls.

METHODS

396 AIS girls in two separate cohorts were studied. Skeletal maturity was assessed using the validated thumb ossification composite index (TOCI). Bone qualities and strength were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA).

RESULTS

Cohort-A included 179 girls (11.95 ± 0.95 years old). Girls at TOCI-4 had numerically the highest height velocity (0.71 ± 0.24 cm/month) corresponding to the PHV. Subjects at TOCI-4 had lower cortical volumetric BMD (672.36 ± 39.07 mg/mm³), cortical thickness (0.68 ± 0.08 mm) and apparent modulus (1601.54 ± 243.75 N/mm²) than: (a) those at TOCI-1-3 (724.99 ± 32.09 mg/mm³ (p < 0.001), 0.79 ± 0.11 mm (p < 0.001) and 1910.88 ± 374.75 N/mm² (p < 0.001), respectively) and (b) those at TOCI-8 (732.28 ± 53.75 mg/mm³ (p < 0.001), 0.84 ± 0.14 mm (p < 0.001), 1889.11 ± 419.37 N/mm² (p < 0.001), respectively). Cohort-B included 217 girls (12.22 ± 0.89 years old). Subjects at TOCI-4 had higher levels of C-terminal telopeptide of type 1 collagen (1524.70 ± 271.10 pg/L) and procollagen type 1 N-terminal propeptide (941.12 ± 161.39 µg/L) than those at TOCI-8 (845.71 ± 478.55 pg/L (p < 0.001) and 370.08 ± 197.04 µg/L (p < 0.001), respectively).

CONCLUSION

AIS girls had decreased cortical bone density and bone mechanical strength with elevated BTMs at PHV. Coupling of PHV with decreased cortical and FEA parameters could provide the link to the previously reported observation that low BMD could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

Does the serum level of vitamin D affect marginal bone loss around dental implants?

Vitamin D is effective in bone healing. The aim of this study was to assess marginal bone loss (MBL) around dental implants in patients with sufficient and insufficient serum levels of vitamin D. This was a prospective cohort study with a pre-protocol population. Patients who underwent dental implantation in the first or second molar region and had a long-cone peri-apical digital radiograph taken at the time of loading and 12 months later were studied. Patients were assigned to one of three groups based on their serum vitamin D level: group 1, the serum level of vitamin D was deficient, group 2 insufficient, and group 3 sufficient. The marginal bone level change from immediately after loading to 12 months later was considered as MBL. Analysis of variance (ANOVA) was applied to compare MBL between the three groups. Ninety patients were included (30 in each group). The mean MBL was 1.38 ± 0.33 mm in group 1, 0.89 ± 0.16 mm in group 2, and 0.78 ± 0.12 mm in group 3. Analysis of the data demonstrated a significant difference in the mean MBL among the three groups (P < 0.001). There was a correlation between MBL and vitamin D serum levels (P < 0.001). It appears that a low serum level of vitamin D may be associated with increased MBL.

Association of serum 25(OH)Vit-D levels with risk of pediatric fractures: a systematic review and meta-analysis

The association between the risk of fractures and suboptimal vitamin D (Vit-D) status remains controversial in children. This meta-analysis suggested that serum 25(OH)Vit-D levels were lower in pediatric cases with fractures. 25-hydroxyvitamin D (25(OH)Vit-D) levels less than 50 nmol/L were associated with increased fracture risk in children.

INTRODUCTION

This study aimed to assess the association between serum 25(OH)Vit-D and the risk of fractures in children, and to explore the sources of heterogeneity and investigate their impact on results.

METHODS

Systematic review and meta-analysis were conducted for observational studies comparing serum 25(OH)Vit-D levels between fracture and non-fracture pediatric cases. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

Analysis on 17 case-control and 6 cross-sectional studies (2929 fracture cases and 5000 controls) suggested that 25(OH)Vit-D was lower in fracture cases than in controls (pooled mean difference (MD) = - 3.51 nmol/L; 95% confidence interval (CI): - 5.60 to - 1.42) with a heterogeneity (I²) of 73.9%. The sensitivity analysis which merged the case-control studies that had a NOS score ≥ 4 showed a pooled MD of - 4.35 nmol/L (95% CI: - 6.64 to - 2.06) with a heterogeneity (I²) of 35.9%. Pooled odds ratio of fracture in subjects with 25(OH)Vit-D ≤ 50 nmol/L compared to subjects with 25(OH)Vit-D > 50 nmol/L was 1.29 (95% CI: 1.10 to 1.53; I² < 1%).

CONCLUSION

This study indicated that serum 25(OH)Vit-D levels were lower in pediatric patients with fractures. 25(OH)Vit-D ≤ 50 nmol/L was associated with increased fracture risk in children.

Trends in Incidence of Adolescent Idiopathic Scoliosis: A Modern US Population-based Study

BACKGROUND

A successful disease screening strategy requires a high incidence of the condition, efficacy of early treatment, and efficient detection. There is limited population-based data describing trends in incidence of adolescent idiopathic scoliosis (AIS) in the United States and potential role of school screening programs on the incidence of AIS. Thus, we sought to evaluate the incidence of AIS over a 20-year period between 1994 and 2013 using a population-based cohort.

METHODS

The study population comprised 1782 adolescents (aged 10 to 18 y) with AIS first diagnosed between January 1, 1994 and December 31, 2013. The complete medical records and radiographs were reviewed to confirm diagnosis and coronal Cobb angles at first diagnosis. Age-specific and sex-specific incidence rates were calculated and adjusted to the 2010 United States population. Poisson regression analyses were performed to examine incidence trends by age, sex, and calendar period.

RESULTS

The overall age-adjusted and sex-adjusted annual incidence of AIS was 522.5 [95% confidence interval (CI): 498.2, 546.8] per 100,000 person-years. Incidence was about 2-fold higher in females than in males (732.3 vs. 338.8/100,000, P<0.05). The incidence of newly diagnosed AIS cases with radiographs showing a Cobb angle >10 degrees was 181.7 (95% CI: 167.5, 196.0) per 100,000 person-years. The overall incidence of AIS decreased significantly after discontinuation of school screening in 2004 (P<0.001). The incidence of bracing and surgery at initial diagnosis was 16.6 (95% CI: 12.3, 20.9) and 2.0 (95% CI: 0.5, 3.4) per 100,000 person-years, respectively.

CONCLUSIONS

Overall population-based incidence of AIS decreased after school screening was discontinued. However, incidence of patients with a Cobb angle >10 degrees, initiation of bracing and surgery did not change significantly over time. This provides further data to help determine the role of scoliosis screening.

LEVEL OF EVIDENCE

Level III.

Elucidating the inherent features of IS to better understand idiopathic scoliosis etiology and progression

Idiopathic Scoliosis (IS) is a relatively common condition and is estimated to affect as many as 3 % of youth aged 10-17 years (in the United States an estimated approximately 1.4 million otherwise healthy individuals). A clear understanding of the etiology will better direct optimization of evaluation, treatments and therapies, especially early treatments with less invasive methods. A mechanistic explanation of factors combining to initiate and then cause progression of this common condition-- in otherwise healthy pre-teenage and teenage patients--will be discussed. A recent well-designed structured systematic review states that 'strong evidence is lacking for a consistent pattern of occurrence and any abnormality', in other words there is no strong evidence for 'other associated diagnoses' in IS. And so, certain important inherent factors of IS merit greater discussion. Inherent, or intrinsic factors include: a natural susceptibility to develop a lateral and rotational deformity in the immature rapidly growing erect human spine, inherent torsion associated at the induction of deformity, biomechanics related to curve progression, and anthropology/bipedal gait. We know more today about factors related to the condition and its etiology than we have previously. Across multiple disciplines, a mechanistic approach to understanding the etiopathogenesis of IS, allows a reasonable 'theory' for IS etiology and its progression. We will discuss these inherent intrinsic factors in order to further add to our understanding of the theoretical etiopathogenesis. A better understanding of the etiology (and progression) may better direct ways to optimize evaluation, treatments and therapies, especially early treatments with less invasive methods.

Vitamin D supplementation for improving children with bone mineral density: A protocol for systematic review and meta-analysis

BACKGROUND

Osteoporosis is usually one of the less perceived complications of chronic illness among children. Previous studies have shown that vitamin D supplementation may be valuable to bone density, especially among children with a deficiency of vitamin D. Yet, the results often remain inconsistent. Therefore, the present study investigates the clinical therapeutic effects of vitamin D supplementation to enhance children with bone mineral density.

METHODS

We will search the randomised controlled experiment literature of vitamin D supplementation for bone mineral density, focusing on children, in 3 distinct English databases (EMBASE, MEDLINE via PubMed, and Cochrane Library) and 2 specific Chinese databases (China National Knowledge Infrastructure (CNKI) and WanFang databases). Additionally, we intend to explore the Clinical Trials.gov, reference lists of identified publication and the grey literature. Accordingly, we will use 2 independent authors to screen the literature, extract data, and research quality assessment. We will carry out all statistical analyses using RevMan 5.3 software.

RESULTS

We will systematically evaluate the clinical therapeutic effects of vitamin D supplementation to enhance children with bone mineral density.

CONCLUSION

The present study will summarise the currently published pieces of evidence of vitamin D supplementation for bone mineral density in children to further comprehend its promotion and application.

ETHICS AND DISSEMINATION

The present study is a systematic review and meta-analysis founded upon existing or published studies; therefore, ethical approval is not applicable.

OSF REGISTRATION NUMBER

October 24, 2020. osf.io/7vtey. (https://osf.io/7vtey/).

Vitamin D for Improved Bone Health and Prevention of Stress Fractures: A Review of the Literature

Vitamin D is a vital nutrient and hormone needed for many essential functions in overall health. There is growing literature examining the role of vitamin D not only in the general population but also in athletes. The most predominantly studied area of vitamin D pertains to bone health. Recently, there has been increased investigation into the relationship of vitamin D and stress fractures, including genetic polymorphisms, levels of 25-hydroxyvitamin D, and bioavailable vitamin D. This review will address the most recent developments of vitamin D research and its important role in bone health in athletes.

Early characteristics of bone deficits in children with Fontan palliation

BACKGROUND

This is a cross-sectional study aiming to understand the early characteristics and background of bone health impairment in clinically well children with Fontan circulation.

METHODS

We enrolled 10 clinically well children with Fontan palliation (operated >5 years before study entrance, Tanner stage ≤3, age 12.1 ± 1.77 years, 7 males) and 11 healthy controls (age 12.0 ± 1.45 years, 9 males) at two children's hospitals. All patients underwent peripheral quantitative CT. For the Fontan group, we obtained clinical characteristics, NYHA class, cardiac index by MRI, dual x-ray absorptiometry, and biochemical studies. Linear regression was used to compare radius and tibia peripheral quantitative CT measures between Fontan patients and controls.

RESULTS

All Fontan patients were clinically well (NYHA class 1 or 2, cardiac index 4.85 ± 1.51 L/min/m2) and without significant comorbidities. Adjusted trabecular bone mineral density, cortical thickness, and bone strength index at the radius were significantly decreased in Fontan patients compared to controls with mean differences -30.13 mg/cm3 (p = 0.041), -0.31 mm (p = 0.043), and -6.65 mg2/mm4 (p = 0.036), respectively. No differences were found for tibial measures. In Fontan patients, the mean height-adjusted lumbar bone mineral density and total body less head z scores were -0.46 ± 1.1 and -0.63 ± 1.1, respectively, which are below the average, but within normal range for age and sex.

CONCLUSIONS

In a clinically well Fontan cohort, we found significant bone deficits by peripheral quantitative CT in the radius but not the tibia, suggesting non-weight-bearing bones may be more vulnerable to the unique haemodynamics of the Fontan circulation.

Persistent low-normal bone mineral density in adolescent idiopathic scoliosis with different curve severity: A longitudinal study from presentation to beyond skeletal maturity and peak bone mass

OBJECTIVES

Low bone mineral status has been reported in patients first presented with adolescent idiopathic scoliosis (AIS). We aimed to study whether low-normal bone mineral density (BMD) is persistent among AIS girls during puberty and at peak bone mass, and whether if such persistence is associated with curve severity and differed from healthy controls.

METHOD

This prospective longitudinal study comprised 550 AIS girls and 194 healthy control subjects followed from 1997 till 2016. Low-normal BMD was defined as z-standardized bone mineral density (z-BMD) of bilateral femoral neck ≤ -1. Markov Chain 2-stages analysis was conducted to investigate the low-normal BMD transition rate. Linear mixed-effects model and Bland-Altman plot were used to investigate whether low-normal BMD is persistent among a subgroup of AIS patients that reached peak bone mass.

RESULTS

The average z-BMD were comparable between AIS cohort and controls at 11 years old (-0.532 vs -0.602), but at 19 years old z-BMD worsened among AIS subjects (-0.860) while controls z-BMD improved (-0.455). During growth period until skeletal maturity, persistence of low-normal BMD was high in both cohorts (>80%) and the AIS group with severe curve presented 100% persistence. Subgroup analysis revealed that z-BMD of AIS patients at skeletal maturity and peak bone mass were highly correlated (r² = 0.905) and with good agreement.

CONCLUSION

AIS patients had poorer BMD that is associated with curve severity and more likely to persist beyond peripubertal period and at peak bone mass when compared to controls.

Effects of milk powder intervention on bone mineral density and indicators related to bone metabolism in Chinese adolescents

The study is to determine the effects of milk powder on bone density and metabolism in healthy adolescents. Vitamin D and calcium supplements increased IGF-1 but did not affect bone mineralization or turnover. Higher vitamin D in combination with sufficient calcium supplementation in such populations requires attention.

INTRODUCTION

Both calcium and vitamin D play an important role in bone mineralization in adolescents.

METHODS

In this one and a half-year randomized controlled trial, 232 participants (aged 12-15 years) were randomly assigned to three intervention groups receiving milk powder fortified with vitamin D 400 IU plus calcium 300, or 600, or 900 mg [Ca3D (n = 54), Ca6D (n = 56), and Ca9D (n = 49)], or one control group maintaining habitual diet [control (n = 73)]. Bone turnover markers, serum intact PTH, 25(OH)D, and IGF-1 levels were measured at baseline and one and a half years, and bone mineral contents and bone areal mineral density were measured by Dual-energy X-ray absorptiometry (DXA) at baseline, one year, and one and a half years.

RESULTS

Baseline average serum 25(OH)D level and calcium intake were 29.4 nmol/L and 363.5 mg/day, respectively. There was a significant increase in bone turnover, total body, hip, lumbar spine bone mineral density (BMD), and total body BMC as well as slight fluctuations in 25(OH)D levels over one and a half years without between-group differences. Significantly decreased serum PTH level was only observed in the Ca6D group (31%, p < 0.0001), in which the intervention effect was also significant (p = 0.0029) compared with the control group. IGF-1 levels increased significantly in all intervention groups (18.5 to 22.8%, p < 0.05) but decreased in the control group (16.5%, p < 0.05), and the group by time interaction was also significant (p = 0.0029).

CONCLUSIONS

Our study showed that in healthy adolescents with low vitamin D status and calcium intake, mild vitamin D and mild to modest calcium supplements increased IGF-1 but did not affect bone mineralization or turnover. Higher vitamin D in combination with sufficient calcium supplementation in such populations requires attention.

pQCT bone geometry and strength: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To describe the epidemiology and concordance of bone health in a population-based sample of Australian parent-child dyads at child age 11-12 years.

DESIGN

Population-based cross-sectional study (the Child Health CheckPoint) nested between waves 6 and 7 of the Longitudinal Study of Australian Children (LSAC).

SETTING

Assessment centres in seven cities around Australia, February 2015-March 2016.

PARTICIPANTS

of all participating CheckPoint families (n=1874), bone data were available for 1222 dyads (1271 children, 50% girls; 1250 parents, 86% mothers).

OUTCOME MEASURES

Peripheral quantitative CT (pQCT) of the non-dominant leg scanned at the 4% (distal) and 66% (mid-calf) tibial sites. Stratec XCT 2000 software generated estimates of bone density, geometry and polar stress-strain index.Parent-child concordance were assessed using Pearson's correlation coefficients and multivariable linear regression models. Percentiles were determined using survey weights. Survey weights and methods accounted for LSAC's complex sampling, stratification and clustering within postcodes.

RESULTS

Concordances were greater for the geometric pQCT parameters (periosteal circumference 0.38, 95% CI 0.33 to 0.43; endosteal circumference 0.42, 95% CI 0.37 to 0.47; total cross-sectional area 0.37, 95% CI 0.32 to 0.42) than density (cortical density 0.25, 95% CI 0.19 to 0.30). Mother-child and father-child values were similar. Relationships attenuated only slightly on adjustment for age, sex and body mass index. Percentiles and concordance are presented for the whole sample and by sex.

CONCLUSIONS

There is strong parent-child concordance in bone geometry and, to a lesser extent, density even before the period of peak adolescent bone deposition. This geometrical concordance suggests that future intergenerational bone studies could consider using pQCT rather than the more commonly used dual X-ray absorptiometry (DXA).

The effect of exogenous melatonin on reducing scoliotic curvature and improving bone quality in melatonin-deficient C57BL/6J mice

It is well-documented that melatonin deficiency has been linked to the etiopathogenesis of adolescent idiopathic scoliosis. In this study, we intended to apply melatonin in melatonin-deficient mice to ascertain whether melatonin could reduce the incidence/severity of scoliosis, and investigate the role of melatonin on bone mineral density in scoliosis. A total of 80 mice were divided into 4 groups: 20 quadrupedal mice and 20 bipedal mice served as controls; 20 quadrupedal and 20 bipedal mice received oral melatonin (8 mg/kg BW) daily. After 5th, 10th, 15th and 20th weeks of treatment, radiographs and in vivo micro-CT were used to determine the incidence of scoliosis and bone qualities, respectively. Upon sacrifice, the levels of melatonin were measured in each group. At 20th week, the occurrence of scoliosis was 80%, 30%, 22% and 5% in bipedal, quadrupedal, bipedal + melatonin and quadrupedal + melatonin group, respectively. The trabecular bone quality of the vertebral body was significantly ameliorated in the melatonin-treated bipedal models. Likewise, the number of osteoclasts was significantly less in those treated with melatonin. Our results indicated that melatonin deficiency may be crucial for scoliotic development, and restoration of melatonin levels can prevent scoliotic development with the improvement in bone density.

Bone Microstructure in Response to Vitamin D3 Supplementation: A Randomized Placebo-Controlled Trial

Vitamin D supplementation is often used in the prevention and treatment of osteoporosis, but the role of vitamin D has lately been questioned. We aimed to investigate the effect of 3 months of daily vitamin D3 supplementation (70 µg [2800 IU] vs. placebo) initiated in winter months on bone health. This study is a double-blinded placebo-controlled randomized trial. Bone health was assessed by bone turnover markers, DXA, HRpQCT, and QCT scans. The participants were 81 healthy postmenopausal women with low 25(OH)D (< 50 nmol/l) and high PTH levels (> 6.9 pmol/l) at screening. Vitamin D3 supplementation significantly increased levels of 25(OH)D and 1,25(OH)₂D by 59 nmol/l and 19 pmol/l, respectively, whereas PTH was reduced by 0.7 pmol/l (all p < 0.0001). Compared with placebo, vitamin D3 did not affect bone turnover markers, aBMD by DXA or trabecular bone score. Vitamin D3 increased trabecular vBMD (QCT scans) in the trochanter region (0.4 vs. - 0.7 g/cm³) and the femoral neck (2.1 vs. - 1.8 g/cm³) p_all < 0.05. HRpQCT scans of the distal tibia showed reduced trabecular number (- 0.03 vs. 0.05 mm^-1) and increased trabecular thickness (0.001 vs. - 0.005 mm), as well as an improved estimated bone strength as assessed by failure load (0.1 vs. - 0.1 kN), and stiffness (2.3 vs. - 3.1 kN/mm p_all ≤ 0.01). Changes in 25(OH)D correlated significantly with changes in trabecular thickness, stiffness, and failure load. Three months of vitamin D3 supplementation improved bone strength and trabecular thickness in tibia, vBMD in the trochanter and femoral neck, but did not affect aBMD.

The Role of Vitamin D in the Pathogenesis of Adolescent Idiopathic Scoliosis

Several theories have been proposed to explain the etiology of adolescent idiopathic scoliosis (AIS) until present. However, limited data are available regarding the impact of vitamin D insufficiency or deficiency on scoliosis. Previous studies have shown that vitamin D deficiency and insufficiency are prevalent in adolescents, including AIS patients. A series of studies conducted in Hong Kong have shown that as many as 30% of these patients have osteopenia. The 25-hydroxyvitamin D3 level has been found to positively correlate with bone mineral density (BMD) in healthy adolescents and negatively with Cobb angle in AIS patients; therefore, vitamin D deficiency is believed to play a role in AIS pathogenesis. This study attempts to review the relevant literature on AIS etiology to examine the association of vitamin D and various current theories. Our review suggested that vitamin D deficiency is associated with several current etiological theories of AIS. We postulate that vitamin D deficiency and/or insufficiency affects AIS development by its effect on the regulation of fibrosis, postural control, and BMD. Subclinical deficiency of vitamin K2, a fat-soluble vitamin, is also prevalent in adolescents; therefore, it is possible that the high prevalence of vitamin D deficiency is related to decreased fat intake. Further studies are required to elucidate the possible role of vitamin D in the pathogenesis and clinical management of AIS.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

Precision of bone density and micro-architectural properties at the distal radius and tibia in children: an HR-pQCT study

Precision errors need to be known when monitoring bone micro-architecture in children with HR-pQCT. Precision errors for trabecular bone micro-architecture ranged from 1 to 8% when using the standard evaluation at the radius and tibia. Precision errors for cortical bone micro-architecture ranged from 1 to 11% when using the advanced cortical evaluation.

INTRODUCTION

Our objective was to define HR-pQCT precision errors (CV%_RMS) and least significant changes (LSCs) at the distal radius and tibia in children using the standard evaluation and the advanced cortical evaluation.

METHODS

We scanned the distal radius (7% of ulnar length) and tibia (8% of tibia length) of 32 children (age range 8-13; mean age 11.3; SD 1.6 years) twice (1 week apart) using HR-pQCT (XtremeCT1). We calculated root-mean-squared coefficients of variation (CV%_RMS) to define precision errors and LSC to identify differences required to detect change.

RESULTS

Precision errors ranged between 1-8 and 1-5% for trabecular bone outcomes (obtained with standard evaluation) and between 1.5-11 and 0.5-6% for cortical bone outcomes (obtained with advanced cortical evaluation) at the distal radius and tibia, respectively. Related LSCs ranged between 3-21 and 3-14% for trabecular bone outcomes and between 4-30 and 2-16% for cortical bone outcomes at the distal radius and tibia, respectively.

CONCLUSIONS

HR-pQCT precision errors were between 1 and 8% (LSC 3-21%) for trabecular bone outcomes and 1 and 11% (LSC 2-30%) for cortical bone outcomes at the radius and tibia in children. Cortical bone outcomes obtained using the advanced cortical evaluation appeared to have lower precision errors than cortical outcomes derived using the standard evaluation. These findings, combined with better-defined cortical bone contours with advanced cortical evaluation, indicate that metrics from advanced cortical evaluation should be utilized when monitoring cortical bone properties in children.

Peripheral quantitative computed tomography (pQCT) for the assessment of bone strength in most of bone affecting conditions in developmental age: a review

Peripheral quantitative computed tomography provides an automatical scan analysis of trabecular and cortical bone compartments, calculating not only their bone mineral density (BMD), but also bone geometrical parameters, such as marrow and cortical Cross-Sectional Area (CSA), Cortical Thickness (CoTh), both periosteal and endosteal circumference, as well as biomechanical parameters like Cross-Sectional Moment of Inertia (CSMI), a measure of bending, polar moment of inertia, indicating bone strength in torsion, and Strength Strain Index (SSI). Also CSA of muscle and fat can be extracted. Muscles, which are thought to stimulate bones to adapt their geometry and mineral content, are determinant to preserve or increase bone strength; thus, pQCT provides an evaluation of the functional 'muscle-bone unit', defined as BMC/muscle CSA ratio. This functional approach to bone densitometry can establish if bone strength is normally adapted to the muscle force, and if muscle force is adequate for body size, providing more detailed insights to targeted strategies for the prevention and treatment of bone fragility. The present paper offers an extensive review of technical features of pQCT and its possible clinical application in the diagnostic of bone status as well as in the monitoring of the skeleton's health follow-up.