Bone turnover is not influenced by serum 25-hydroxyvitamin D in pubertal healthy black and white children

Bone turnover markers, and growth and bone parameters in infants participating in a vitamin D intervention study

Amino-terminal propeptide of type 1 procollagen (P1NP) and carboxy-terminal crosslinked telopeptide of type 1 collagen (CTX-I) are markers of bone metabolism. We examined the effect of vitamin D3 supplementation on these markers and their relationship with growth and bone parameters in 12-month-old infants. In a randomized, double-blinded, vitamin D intervention in infants (VIDI) study, 987 infants received daily vitamin D3 supplementation of 10 μg (group-10) or 30 μg (group-30) from age 2 weeks to 24 months. We conducted a secondary analysis of the original VIDI trial. At 12 months of age, P1NP (n = 812) and CTX-I (n = 786) concentrations were analyzed, and anthropometrics and total bone mineral content, volumetric bone mineral density, cross-sectional area and polar moment of inertia of tibia were measured by peripheral quantitative computed tomography. The growth rate in weight and length was calculated from birth to 12 months. The vitamin D dose did not influence mean (SD) levels of CTX-I (group-10: 0.90 (0.31); group-30: 0.89 (0.31) (P > 0.53)). The mean difference of P1NP (CI 95%) comparing group-10 with group-30 was 35 (-103, 33) ng/mL (P = 0.31) in boys and -63 (-4, 130) ng/mL (P = 0.064) in girls. In group-10, girls had higher mean (SD) value of P1NP (1509 (362) ng/mL) than boys (1407 (297) ng/mL) (P = 0.003); no sex differences were observed in group-30 (girls: 1446 (359); boys: 1442 (359), P = 0.91) or CTX-I. P1NP associated positively with the growth rate in length (B (CI 95%) 0.0003 (0.0001, 0.001), P = 0.022) in the whole cohort but not in subgroups divided by the intervention group or sex, adjusted for birth size and parental heights and corrected for multiple testing. P1NP associated positively with the growth rate in weight (0.01 (0.0003, 0.01), P < 0.001). An inverse association was observed between CTX-I and length (cm) in the whole cohort (-0.90 (-1.40, -0.40), P = 0.005) and in group-30 (-1.05 (-1.72, -0.39), P = 0.011). Furthermore, CTX-I associated negatively with weight (SDS) in the whole cohort (-0.33 (-0.55, -0.12), P = 0.015) and the growth rate in weight (-0.43 (-0.66, -0.20), P = 0.005), persisting in group-30 and in boys but not in group-10 or in girls. Neither marker was associated with bone parameters. The observed sex difference in P1NP might suggest that a higher vitamin D dose resulted in a small decrease in bone collagen matrix formation in girls but not in boys. P1NP and CTX-I associate with growth and body size but not with bone mineralization in infancy.

Characterizing the Adolescent Premature Ovarian Insufficiency Phenotype: A Case Control Study

STUDY OBJECTIVES

To characterize the skeletal, cardiometabolic, cognitive, and mental health phenotype of adolescents with idiopathic premature ovarian insufficiency (POI) DESIGN: Case control SETTING: Pediatric tertiary referral center in Cincinnati, Ohio PARTICIPANTS: Nine adolescents (ages 11-18.99 years) with newly diagnosed POI and 9 normally menstruating controls, matched by age and body mass index MAIN OUTCOME MEASURES: Between-group comparisons of bone characteristics assessed by dual energy x-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT), psychosocial health (anxiety, depression, and quality of life), and cognition and memory by questionnaire RESULTS: Adolescents with POI had lower bone density Z-scores by DXA (lumbar spine -1.93 vs 0.80; whole body less head -2.05 vs 0.00; total hip -1.03 vs 0.83; and femoral neck -1.23 vs 0.91; all P < .001), as well as lower trabecular volumetric bone mineral density (tibia 3% site 226 vs 288 mg/mm³, P < .001; radius 3% site 200 vs 251, P = .001), smaller cortical area (tibia 66% site 251 vs 292 mm², P = .028), and thickness (tibia 66% site 3.56 vs 4.30 mm, P = .001) than controls. No abnormalities in cardiometabolic biomarkers were detected in POI cases. Adolescents with POI were also more likely to report low energy (78% vs 22%, P = .02).

CONCLUSION

Estrogen deficiency adversely affects bone health in adolescents with POI. However, we did not find associations with cardiometabolic, mental health, or cognitive outcomes in this small sample.

Effect of Vitamin D Levels on Bone Remodeling in Healthy Women

BACKGROUND

Vitamin D deficiency is prevalent among Indian women. Subclinical vitamin D deficiency is a significant risk factor for osteopenia and fractures. However, its effect on bone metabolism and bone mineral density (BMD) is still debatable.

OBJECTIVES

This study aimed to determine relationships of the vitamin D status with bone turnover markers, carboxy-terminal telopeptide of type-I collagen (CTX), N-terminal propeptide of type I procollagen (PINP), and BMD in healthy Indian women.

METHODS

In this cross-sectional study, we determined serum levels of 25-hydroxy vitamin D (25(OH)D), parathyroid hormone, serum CTX, and PINP using commercial ELISA kits in 310 healthy Indian women aged 25 - 65 years who underwent BMD measurements with DXA scan.

RESULTS

The prevalence of vitamin D deficiency was 53.87% and vitamin D insufficiency 31.29%. A direct correlation of BMD with vitamin D levels was not observed. PINP negatively correlated with vitamin D in both premenopausal (Spearman's r = -0.169, P < 0.05) and postmenopausal (Spearman's r = -0.241, P < 0.05) women. However, CTX positively correlated with vitamin D in both premenopausal (Spearman's r = 0.228, P < 0.01) and postmenopausal (Spearman's r = 0.244, P < 0.05) women.

CONCLUSIONS

Vitamin D deficiency is more prevalent in premenopausal women than in postmenopausal ones. Although vitamin D does not show any association with BMD, it affects bone remodeling, which is reflected by changes in the bone formation marker PINP and the bone resorption marker CTX.

Effect of Vitamin D Supplementation on Bone Turnover Markers in Children and Adolescents from North India

OBJECTIVES

Vitamin D is known to play an important role in bone mineral metabolism. Its deficiency may affect growth and status of bone markers in children. Hence, we undertook to study the status of bone markers in children with vitamin D deficiency (VDD) and impact of vitamin D3 supplementation on them.

MATERIALS AND METHODS

Total 468 out of 615 children and adolescents with VDD, who were given either of the three doses (600, 1000, and 2000) of vitamin D supplementation, were included in the study. These 468 children with pre- and postsupplementation preserved samples with available anthropometry, serum biochemistry, 25-hydroxy-vitamin D, and parathormone were evaluated for bone formation (procollagen type 1 amino-terminal propeptide [P1NP]) and resorption (β-cross laps [CTx]) markers.

RESULTS

The mean age and body mass index of these children were 11.3 ± 2.3 years (boys: 11.5 ± 2.4; girls: 12.2 ± 1.2 years; P = 0.03) and 18.1 ± 3.8 kg/m² (boys: 18.2 ± 3.9; girls: 17.6 ± 3.2 kg/m²; P = 0.208), respectively. There were 8.8% subjects with severe, 42.7% with moderate, and 48.5% with mild VDD. There was a significant decline in serum P1NP (from 691 ± 233 ng/ml to 640 ± 259 ng/ml, P < 0.001) and CTx (from 1.67 ± 0.53 ng/ml to 1.39 ± 0.51 ng/ml, P < 0.001) following supplementation. Though decline in serum P1NP and CTx levels was observed in both boys and girls, among all three supplementation groups and VDD categories, the effect was more marked in serum CTx than P1NP levels.

CONCLUSIONS

Vitamin D supplementation in VDD children resulted in decrease in both bone formation (P1NP) and resorption (CTx). The impact, however, was more marked on bone resorption than bone formation.

Associations between serum 25-hydroxyvitamin D and bone turnover markers in a population based sample of German children

Severe vitamin D deficiency is known to cause rickets, however epidemiological studies and RCTs did not reveal conclusive associations for other parameters of bone health. In our study, we aimed to investigate the association between serum levels of 25(OH) vitamin D and bone turnover markers in a population-based sample of children. 25(OH)D, calcium (Ca), osteocalcin (OC), and β-Crosslaps (β-CTx) were measured in 2798 ten-year-old children from the German birth cohorts GINIplus and LISAplus. Linear regression was used to determine the association between bone turnover markers and 25(OH)D levels. 25(OH)D, OC, and β-CTx showed a clear seasonal variation. A 10 nmol/l increase in 25(OH)D was significantly associated with a 10.5 ng/l decrease (p < 0.001) in β-CTx after adjustment for design, sex, fasting status, time of blood drawn, BMI, growth rate, and detectable testosterone/estradiol. For OC alone no significant association with 25(OH)D was observed, whereas the β-CTx-to-OC ratio was inversely associated with 25(OH)D (−1.7% change, p < 0.001). When stratifying the analyses by serum calcium levels, associations were stronger in children with Ca levels below the median. This study in school-aged children showed a seasonal variation of 25(OH)D and the bone turnover markers OC and β-CTx. Furthermore a negative association between 25(OH)D and the bone resorption marker β-CTx was observed.

Effect of Vitamin D3 Supplementation in Black and in White Children: A Randomized, Placebo-Controlled Trial

CONTEXT

Dosages of vitamin D necessary to prevent or treat vitamin D deficiency in children remain to be clarified.

OBJECTIVE

To determine the effects of vitamin D3 1000 IU/d on serum 25-hydroxyvitamin D [25(OH)D], PTH, and markers of bone turnover (osteocalcin and collagen type 1 cross-linked C-telopeptide) in black children and white children, and to explore whether there is a threshold level of 25(OH)D associated with maximal suppression of serum PTH concentration.

DESIGN

Healthy 8- to 14-year-old Pittsburgh-area black (n = 84) and white (n = 73) children not receiving vitamin supplements, enrolled from October through March from 2008 through 2011, were randomized to vitamin D3 1000 IU or placebo daily for 6 months.

RESULTS

The mean baseline concentration of 25(OH)D was <20 ng/mL in both the vitamin D-supplemented group and the placebo group (19.8 ± 7.6 and 18.8 ± 6.9 ng/mL, respectively). The mean concentration was higher in the supplemented group than in the placebo group at 2 months (26.4 ± 8.1 vs 18.9 ± 8.1 ng/mL; P < .0001) and also at 6 months (26.7 ± 7.6 vs 22.4 ± 7.3; P = .003), after adjusting for baseline 25(OH)D, race, gender, pubertal status, dietary vitamin D intake, body mass index, and sunlight exposure. Increases were only significant in black children, when examined by race. The association between 25(OH)D and PTH concentrations was inverse and linear, without evidence of a plateau. Overall, vitamin D supplementation had no effect on PTH and bone turnover.

CONCLUSIONS

Vitamin D3 supplementation with 1000 IU/d in children with mean baseline 25(OH)D concentration <20 ng/mL effectively raised their mean 25(OH)D concentration to ≥20 ng/mL but failed to reach 30 ng/mL. Vitamin D supplementation had no effect on PTH concentrations.

Rapid normalization of vitamin D levels: a meta-analysis

BACKGROUND

Vitamin D deficiency may represent a modifiable risk factor to improve outcome in severe illness. The efficacy of high-dose regimens in rapid normalization of vitamin D levels is uncertain.

METHODS

We conducted a systematic review of pediatric clinical trials administering high-dose vitamin D to evaluate 25-hydroxyvitamin D (25[OH]D) response and characteristics associated with final 25(OH)D levels by using Medline, Embase, and the Cochrane Central Register of Controlled Trials, including reference lists of systematic reviews and eligible publications. Uncontrolled and controlled trials reporting 25(OH)D levels after high-dose (≥1000 IU) ergocalciferol or cholecalciferol were selected. Two reviewers independently extracted and verified predefined data fields.

RESULTS

We identified 88 eligible full-text articles. Two of 6 studies that administered daily doses approximating the Institute of Medicine's Tolerable Upper Intake Level (1000-4000 IU) to vitamin D-deficient populations achieved group 25(OH)D levels >75 nmol/L within 1 month. Nine of 10 studies evaluating loading therapy (>50 000 IU) achieved group 25(OH)D levels >75 nmol/L. In meta-regression, baseline 25(OH)D, regimen type, dose, age, and time factors were associated with final 25(OH)D levels. Adverse event analysis identified increased hypercalcemia risk with doses >400 000 IU, but no increased hypercalcemia or hypercalciuria with loading doses <400 000 IU (or 10 000 IU/kg). Few studies in adolescents evaluated loading dose regimens >300 000 IU.

CONCLUSIONS

Rapid normalization of vitamin D levels is best achieved by using loading therapy that considers disease status, baseline 25(OH)D, and age (or weight). Loading doses >300 000 IU should be avoided until trials are conducted to better evaluate risk and benefit.

Reference values of osteocalcin and procollagen type I N-propeptide plasma levels in a healthy Central European population aged 0-18 years

The aim of this study was to assess the relationships between both a marker of bone formation and a marker of bone turnover and age, sex, and pubertal stage in a group (n = 439) of healthy children and adolescents. These reference data should be instrumental in interpretation of results.

INTRODUCTION

The skeletal system has high metabolic activity. In children, bone markers may be useful in diagnostics and treatment management of skeletal diseases but there could be difficulties with interpretation of results. Compared with adults, children have elevated bone marker levels due to high skeletal growth velocity and rapid bone turnover. Thus, valid age- and sex-specific reference data should be obtained for each pediatric population living in a particular climate and with a similar lifestyle. The aim of this study was to assess the relationships between both a marker of bone formation (procollagen type I N-terminal propeptide [PINP]) and a marker of bone turnover (osteocalcin [OC]) and age, sex, and pubertal stage in a group of healthy children and adolescents.

METHODS

Four hundred thirty-nine healthy Caucasian children participated. Their height, weight, and pubertal stage were recorded. Fasting PINP and OC were measured using a morning blood sample.

RESULTS

The highest levels of PINP were observed during the first year of life. There is no OC postnatal peak, but levels are higher than the adult reference interval throughout childhood. OC peaks with the pubertal growth spurt at second-third Tanner stage of breast development in girls and at second-third Tanner stage of genital development in boys. PINP peaks during second-third Tanner stage of breast development in girls and at third Tanner stage of genital development in boys.

CONCLUSION

This study provides reference data for OC and PINP in healthy Caucasian children from a Central European population.

The relationship between serum 25-hydroxy vitamin D, parathormone and bone mineral density in Indian population

OBJECTIVES

Vitamin D deficiency (VDD) is a global problem. Not all patients with VDD have clinical manifestations or secondary hyperparathyroidism. We studied the interaction between serum 25-hydroxy vitamin D (25OHD), parathormone (PTH) and bone mineral density (BMD) in Indian adolescents and adults.

DESIGN

Population survey.

PATIENTS

A total of 1829 adolescents and 1346 adults aged 50 years and above were analysed in this study.

MEASUREMENTS

Serum biochemistry, 25OHD, PTH and BMD were estimated. Subjects were grouped according to quartiles of serum PTH. VDD was defined as severe (25OHD ≤ 5 ng/ml), moderate (25OHD ≤ 10 ng/ml) and mild (25OHD ≤ 20 ng/ml) and secondary hyperparathyroidism (SHPT) when serum PTH levels >65 pg/ml.

RESULTS

Only 30-40% of subjects with moderate and severe VDD, respectively, had SHPT. BMD decreased from Quartile 1 to Quartile 4 of PTH at all sites among adolescents and adults, with only a marginal decline in serum 25OHD levels between these quartiles. Further, within each PTH quartile, there was no difference in BMD according to categories of VDD. Analysing BMD in the different PTH quartiles, the PTH cut-offs beyond which BMD showed a significant decline, was 35 pg/ml in adolescents and 53 pg/ml in adults.

CONCLUSIONS

Less than half of the subjects with VDD have SHPT. BMD levels start to decline at PTH values currently considered to be normal. These data suggest the need to redefine SHPT in different age groups keeping in mind the relationship between PTH and BMD. This may also influence the decision to supplement subjects with VDD.

Vitamin D and skeletal growth and development

Vitamin D is critical to bone mineral metabolism and to the growth and development of the skeleton. Optimizing vitamin D status could be one of the cornerstones to optimize skeletal growth and achieving the maximum peak bone mass soon after the completion of adolescence. Maximizing peak bone mass is considered to be the key to primary prevention of osteoporosis. There is controversy, however, about what constitutes a healthy vitamin D status based on the most abundant circulating metabolite of vitamin D, namely 25 hydroxyvitamin D (25 OHD) in plasma or serum; and even the value of 25 OHD that should be used to define vitamin D deficiency. We reviewed the recent data on circulating 25 OHD concentrations and its relationship with skeletal growth in apparently healthy children and in those with nutritional vitamin D deficiency.

Racial differences in cortical bone and their relationship to biochemical variables in Black and White children in the early stages of puberty

Osteoporotic fracture rates differ according to race with Blacks having up to half the rate of Whites. The current study demonstrates that racial divergence in cortical bone properties develops in early childhood despite lower serum 25-hydroxyvitamin D in Blacks.

INTRODUCTION

Racial differences in bone structure likely have roots in childhood as bone size develops predominantly during growth. This study aimed to compare cortical bone health within the tibial diaphysis of Black and White children in the early stages of puberty and explore the contributions of biochemical variables in explaining racial variation in cortical bone properties.

METHODS

A cross-sectional study was performed comparing peripheral quantitative computed tomography-derived cortical bone measures of the tibial diaphysis and biochemical variables in 314 participants (n = 155 males; n = 164 Blacks) in the early stages of puberty.

RESULTS

Blacks had greater cortical volumetric bone mineral density, mass, and size compared to Whites (all p < 0.01), contributing to Blacks having 17.0 % greater tibial strength (polar strength-strain index (SSIP)) (p < 0.001). Turnover markers indicated that Blacks had higher bone formation (osteocalcin (OC) and bone-specific alkaline phosphatase) and lower bone resorption (N-terminal telopeptide) than Whites (all p < 0.01). Blacks also had lower 25-hydroxyvitamin D (25(OH)D) and higher 1,25-dihydroxyvitamin D (1,25(OH)2D) and parathyroid hormone (PTH) (all p < 0.05). There were no correlations between tibial bone properties and 25(OH)D and PTH in Whites (all p ≥ 0.10); however, SSIP was negatively and positively correlated with 25(OH)D and PTH in Blacks, respectively (all p ≤ 0.02). Variation in bone cross-sectional area and SSIP attributable to race was partially explained by tibial length, 25(OH)D/PTH, and OC.

CONCLUSIONS

Divergence in tibial cortical bone properties between Blacks and Whites is established by the early stages of puberty with the enhanced cortical bone properties in Black children possibly being explained by higher PTH and OC.