Adequate vitamin D status and adiposity contribute to bone health in peripubertal nonobese children

Vitamin D level and bone profile among 1- to 5-year-old children in Galle municipality and Bope-Poddala areas in Sri Lanka

Objective

Identify the incidence and risk factors of vitamin D deficiency/vitamin D insufficiency in children aged 1-5 years.

Methods

A cross-sectional survey was conducted among children between the ages of 1 and 5 in the Bope-Poddala and Galle municipality areas. The sample was obtained by cluster sampling method. Data on socio-demography, pregnancy, sun exposure, and diet were obtained. Serum 25(OH)D concentrations were measured and the cutoff value was determined as per the global consensus in 2016.

Results

Among 100 children, the mean serum 25(OH)D level was 86.4 nmol/L (24.06 ng/mL). The prevalence of vitamin D deficiency and vitamin D insufficiency was 7% and 28%, respectively. Birth weight and sunlight exposure were significantly different among vitamin D deficiency/vitamin D insufficiency and sufficient groups. Both were found to be risk factors for vitamin D deficiency/vitamin D insufficiency in logistic regression.

Conclusion

Vitamin D deficiency/vitamin D insufficiency is significant among children aged 1-5 years and decreased sun exposure and low birth weight are the main risk factors.

Free, bioavailable 25-hydroxyvitamin D levels and their association with diabetic ketoacidosis in children with type 1 diabetes at diagnosis

BACKGROUND

Considering the roles of 25-hydroxyvitamin D (25OHD) in glucose homeostasis and immune modulation, vitamin D deficiency may be related to the development of type 1 diabetes (T1DM) and diabetic ketoacidosis (DKA). We evaluated the total, free, bioavailable 25OHD levels and vitamin D binding protein (VDBP) levels and genotypes between T1DM patients and controls.

METHODS

This retrospective, cross-sectional study included 84 children with T1DM (38 boys and 46 girls, 8.0 ± 3.6 years) and 1:1 age- and sex-matched healthy controls. A multiplex liquid chromatography-tandem mass spectrometry-based assay was used to simultaneously measure vitamin D metabolites.

RESULTS

Patients with T1DM had lower levels of total 25OHD (16.3 ± 5.1 vs. 19.9 ± 6.5 ng/mL, P< 0.001) and VDBP (146.0 ± 27.8 vs. 224.9 ± 36.1 µg/mL, P = 0.001), but higher free 25OHD (8.0 ± 2.5 vs. 6.5 ± 2.3 pg/mL, P< 0.001) than controls. Patients who presented with DKA had lower levels of 25OHD in the total (15.0 ± 4.6 vs. 17.6 ± 5.2 ng/mL, P = 0.020), free (7.5 ± 2.6 vs. 8.4 ± 2.4 pg/mL, P = 0.059), and bioavailable (2.3 ± 0.9 vs. 2.8 ± 0.8 ng/mL, P = 0.014) forms than those without DKA at the T1DM diagnosis. The lower the total, free, and bioavailable 25OHD levels at diagnosis, the lower the pH and HCO3-. The proportions of the VDBP genotypes did not differ between the patients and controls.

CONCLUSION

Patients with T1DM had higher levels of free 25OHD than healthy children, despite lower levels of total 25OHD. However, patients with DKA exhibited lower levels of bioavailable 25OHD than those without DKA at the T1DM diagnosis. The lower the concentrations of free and bioavailable 25OHD, the more severe the acidosis at the initial T1DM presentation.

Total, bioavailable and free 25-hydroxyvitamin D levels as functional indicators for bone parameters in healthy children

Objectives

Vitamin D is essential for bone health. Not only total but also free 25-hydroxyvitamin D (25OHD) may contribute to bone mass. We sought to determine which vitamin D measure best reflected clinical and bone parameters in healthy children.

Methods

A cross-sectional study including 146 healthy children (71 boys, 9.5 ± 1.9 years) conducted at a tertiary medical center. We used a multiplex liquid chromatography-tandem mass spectrometry-based assay to simultaneously measure vitamin D metabolites. The bioavailable and free 25OHD (25OHD_BioA and 25OHD_Free) levels were calculated using the genotype-specific or genotype-constant affinity coefficients of vitamin D-binding proteins (yielding spe-25OHD_BioA, spe-25OHD_Free and con-25OHD_BioA, con-25OHD_Free respectively). The 25OHD_Free level was directly measured (m-25OHD_Free). Bone mineral content (BMC) and bone mineral density (BMD) were assessed via dual-energy X-ray absorptiometry.

Results

The total 25OHD (25OHD_Total), the two forms of 25OHD_BioA, the three forms of 25OHD_Free, and 24,25-dihydroxyvitamin D₃ levels correlated with parathyroid hormone level (all p < 0.01). Serum 25OHD_Total and m-25OHD_Free levels were influenced by age, pubertal status, season, body mass index (BMI), daylight hours, and vitamin D intake (all p < 0.05). The con-25OHD_BioA and con-25OHD_Free levels better reflected pubertal status and daylight hours than did the spe-25OHD_BioA and spe-25OHD_Free levels (both p < 0.01). The association between the 25OHD_Total level and bone parameters varied according to the BMI (interaction p < 0.05). In 109 normal-weight children, the con-25OHD_BioA and con-25OHD_Free levels correlated with total body BMC and BMD (both p < 0.05), whereas the 25OHD_Total and 24,25-dihydroxyvitamin D₃ levels were associated with total body BMC (both p < 0.05). No such association was found in overweight or obese children.

Conclusions

In healthy children, total, bioavailable, and free 25OHD levels comparably reflected lifestyle factors. In normal-weight children, the con-25OHD_BioA and con-25OHD_Free, but not m-25OHD_Free levels, reflected bone mass, as did the 25OHD_Total level.

Effect of circulating 25-hydroxyvitamin D and antioxidant capacity level on cognitive function parameters of children with idiopathic short stature

Background

An optimal level of vitamin D is necessary for normal bone growth. Recently, vitamin D has been linked to many neurological disorders, changes in antioxidant capacity levels, and cognitive function decline in old age; thus, the aim was to evaluate the effect of vitamin D and antioxidant levels on the cognitive function parameters of children with idiopathic short stature (ISS).

Results

A prospective case-control study was conducted with 60 primary school-aged children with ISS who were compared to 60 unrelated healthy age- and sex-matched children as a control group. A complete clinical evaluation; anthropometric measurements; neurocognitive function parameters using the Stanford-Binet test, fifth edition; vitamin D level; total antioxidant capacity (TAC); total oxidative stress (TOS); and oxidative stress index (OSI) were measured. A total of 83.3% of children with ISS had a vitamin D level < 30 ng/ml with significantly lower vitamin D levels than the control group. The TAC level was significantly lower in children with ISS than in healthy children. Children with ISS had an average level for all of the cognitive function parameters but a lower non-verbal IQ, full-scale IQ, fluid reasoning, knowledge, quantitative reasoning, and working memory than healthy controls. A positive correlation was found between vitamin D level and all anthropometric measurements, all IQ parameters, and TAC levels in the studied children. A positive correlation was found between TAC and all IQ parameters.

Conclusion

Vitamin D level and antioxidant capacity level have a major impact on cognitive function parameters in children with ISS.

Bone Health, Body Composition, and Vitamin D Status of Black Preadolescent Children in South Africa

Optimal bone health is important in children to reduce the risk of osteoporosis later in life. Both body composition and vitamin D play an important role in bone health. This study aimed to describe bone health, body composition, and vitamin D status, and the relationship between these among a group of conveniently sampled black preadolescent South African children (n = 84) using a cross-sectional study. Body composition, bone mineral density (BMD), and bone mineral content (BMC) were assessed using dual x-ray absorptiometry. Levels of 25-hydroxyvitamin D (25(OH)D) (n = 59) were assessed using dried blood spots. A quarter (25%) of children presented with low bone mass density for their chronological age (BMD Z-score < -2) and 7% with low BMC-for-age (BMC Z-score < -2), while only 34% of the children had sufficient vitamin D status (25(OH)D ≥ 30 ng/mL). Lean mass was the greatest body compositional determinant for variances observed in bone health measures. Body composition and bone health parameters were not significantly different across vitamin D status groups (p > 0.05), except for lumbar spine bone mineral apparent density (LS-BMAD) (p < 0.01). No association was found between bone parameters at all sites and levels of 25(OH)D (p > 0.05). Further research, using larger representative samples of South African children including all race groups is needed before any conclusions and subsequent recommendation among this population group can be made.

High Prevalence of Insufficient Vitamin D Intake and Serum 25-Hydroxyvitamin D in Chinese School-Age Children: A Cross-Sectional Study

Despite the importance of vitamin D in early stages of life, data are lacking on the levels of vitamin D intake and serum 25-hydroxyvitamin D (25-(OH)D) among Chinese school-age children. The aims of this study were to investigate the vitamin D intake and serum 25-(OH)D concentration of children aged 7 to 12 years in China, and to measure the associations between vitamin D status and children's growth and development parameters. We obtained data on vitamin D intake, serum 25-(OH)D concentration, and anthropometric measurements from a cross-sectional study on school-aged children in China. Multiple linear regression and multivariable logistic regression analyses assessed the associations mentioned above. A total of 563 children (9.5 ± 1.6 years) from six areas of China were included. Among them, 86.1% had a vitamin D intake below the recommended nutrient intake (10 μg/day), and 54.7% had vitamin D deficiency (serum 25-(OH)D <15 ng/mL). We also found that high vitamin D intake was inversely associated with the risk of vitamin D deficiency (OR = 0.836, 95% confidence interval: 0.713, 0.980), and serum 25-(OH)D concentration was positively associated with the intelligence score and body mass index-for-age Z-score (BAZ) (p < 0.05). Insufficient vitamin D intake and serum 25-(OH)D are prevalent among Chinese school-aged children. A negative association was observed between vitamin D intake and the risk of vitamin D deficiency. Moreover, vitamin D status was positively associated with intelligence and BAZ, which await confirmation in future studies.

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.

Associations of Low Vitamin D and Elevated Parathyroid Hormone Concentrations With Bone Mineral Density in Perinatally HIV-Infected Children

BACKGROUND

Perinatally HIV-infected (PHIV) children have, on average, lower bone mineral density (BMD) than perinatally HIV-exposed uninfected (PHEU) and healthy children. Low 25-hydroxy vitamin D [25(OH)D] and elevated parathyroid hormone (PTH) concentrations may lead to suboptimal bone accrual.

METHODS

PHIV and PHEU children in the Pediatric HIV/AIDS Cohort Study had total body (TB) and lumbar spine (LS) BMD and bone mineral content (BMC) measured by dual-energy x-ray absorptiometry; BMD z-scores (BMDz) were calculated for age and sex. Low 25(OH)D was defined as ≤20 ng/mL and high PTH as >65 pg/mL. We fit linear regression models to estimate the average adjusted differences in BMD/BMC by 25(OH)D and PTH status and log binomial models to determine adjusted prevalence ratios of low 25(OH)D and high PTH in PHIV relative to PHEU children.

RESULTS

PHIV children (n = 412) were older (13.0 vs. 10.8 years) and more often black (76% vs. 64%) than PHEU (n = 207). Among PHIV, children with low 25(OH)D had lower TB-BMDz [SD, -0.38; 95% confidence interval (CI), -0.60 to -0.16] and TB-BMC (SD, -59.1 g; 95% CI, -108.3 to -9.8); high PTH accompanied by low 25(OH)D was associated with lower TB-BMDz. Among PHEU, children with low 25(OH)D had lower TB-BMDz (SD, -0.34; 95% CI, -0.64 to -0.03). Prevalence of low 25(OH)D was similar by HIV status (adjusted prevalence ratio, 1.00; 95% CI, 0.81 to 1.24). High PTH was 3.17 (95% CI, 1.25 to 8.06) times more likely in PHIV children.

CONCLUSIONS

PHIV and PHEU children with low 25(OH)D may have lower BMD. Vitamin D supplementation trials during critical periods of bone accrual are needed.

Comparative analysis of nutritional guidelines for vitamin D

Vitamin D is essential for calcium and bone homeostasis. Humans are largely dependent on UVB-radiation-induced photosynthesis of vitamin D, as few foods contain vitamin D. However, the same radiation that produces vitamin D is also carcinogenic, albeit with a long lag time, and causes DNA damage. In view of the increasing life expectancy, avoiding excessive sun exposure is prudent. Several groups of people have a shortfall between their requirements for vitamin D and their combined endogenous synthesis and intake from natural foods, and therefore need vitamin D supplementation. Governments and scientific societies are regularly updating their recommendations for intake of vitamin D, especially for groups that should (infants) or prefer to (especially elderly individuals) avoid direct sunlight. An overview of such guidelines is presented in this Review. A fairly large consensus exists that all infants should receive 400 international units (IU) (10 μg) daily during their first year of life and that elderly individuals should have access to vitamin D supplementation (at recommended dosages varying from 400 IU to 800 IU daily in most governmental guidelines but at higher dosages in other guidelines). All guidelines unanimously agree that serum levels of 25-hydroxyvitamin D (25OHD) <25 nmol/l (10 ng/ml) should be avoided at all ages. Children and adults who have limited sun exposure should receive vitamin D supplementation, but the recommended doses vary widely (from 200 IU to 2,000 IU daily), in line with disagreement regarding the minimal desirable serum concentration of 25OHD (which varies from 25 nmol/l to >100 nmol/l).

Vitamin D deficiency in children aged 6 to 12 years: single center's experience in Busan

PURPOSE

This study investigated the prevalence and risk factors associated with vitamin D deficiency in children.

METHODS

We analyzed the medical records of 330 patients from the age of 6 to 12, who visited the endocrinology clinic of the Department of Pediatrics at Pusan National University Hospital, from September, 2013 to May, 2014. According to their serum 25-hydroxyvitamin D (25(OH)D) levels, the patients were grouped into either the deficiency group (25(OH)D<20 ng/mL), or the sufficiency group (25(OH)D≥20 ng/mL). The differences between the 2 groups were compared.

RESULTS

There were 195 patients (59.1%) who had vitamin D deficiency. Their mean serum 25(OH)D level was 14.86±3.20 ng/mL. The differences in sex, age, and pubertal status between the 2 groups were not statistically significant. Weight standard deviation score (SDS), and body mass index SDS, were significantly higher in the vitamin D deficiency group (P=0.002 for each), compared to the sufficiency group. Compared with Autumn, both Spring (odds ratio [OR], 9.7; 95% confidence interval [CI], 4.3-22.0), and Winter (OR, 5.9; 95% CI, 3.5-10.0), were risk factors for vitamin D deficiency. In multiple logistic regression analysis, only seasonal differences have been confirmed to have an effect on vitamin D deficiency.

CONCLUSION

Vitamin D deficiency in children aged 6 to 12 years is very common. Spring and Winter are the most important risk factors for vitamin D deficiency. We suggest that it is necessary to supplement the guideline for the vitamin D intake according to our situation.

The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations

Lifestyle choices influence 20-40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1]. [Table: see text] Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge. The best evidence (grade A) is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years-a critical period for bone accretion. Good evidence is also available for a role of vitamin D and dairy consumption and a detriment of DMPA injections. However, more rigorous trial data on many other lifestyle choices are needed and this need is outlined in our research agenda. Implementation strategies for lifestyle modifications to promote development of peak bone mass and strength within one's genetic potential require a multisectored (i.e., family, schools, healthcare systems) approach.

Vitamin D Deficiency in Children Undergoing Vertical Expandable Prosthetic Titanium Rib Treatment

BACKGROUND

Vitamin D deficiency is prevalent in the pediatric population and multiple risk factors have been identified. Low vitamin D levels can result in poor bone mineralization and have been associated with a significantly higher risk of forearm fracture in children. Vitamin D deficiency has also been associated with pediatric critical illness. The purpose of this study was to determine whether children undergoing vertical expandable prosthetic titanium rib (VEPTR) treatment have low vitamin D levels.

METHODS

Patients undergoing VEPTR treatment at a single institution were prospectively enrolled (VEPTR). All patients either had a diagnosis of thoracic insufficiency syndrome (TIS), or were at risk of developing TIS secondary to progressive scoliosis or chest wall deformity. Exclusion criteria were patients with rickets and patients receiving vitamin D supplementation at the time of VEPTR insertion. A group of healthy children who presented with fractures during the winter season were used as controls (FX). Vitamin D status and risk factors for vitamin D deficiency were evaluated. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25-OH-D) <20 ng/mL and vitamin D insufficiency as serum 25-OH-D between 20 and 29 ng/mL.

RESULTS

Twenty-eight VEPTR and 25 FX patients were compared. The average age was 8.6 years in the VEPTR group and 9.1 years in the FX group. Twenty VEPTR patients (71%) and 19 FX patients (76%) demonstrated low vitamin D levels. The average 25-OH-D level was 27.3 ng/mL in the VEPTR group and 25.4 ng/mL in the FX group. Patient characteristics and vitamin D levels were similar between the groups. No association was found between vitamin D status and sex, race, obesity, or multivitamin use.

CONCLUSIONS

Low vitamin D levels are common in children undergoing VEPTR treatment. In our series, the prevalence of vitamin D deficiency in this patient population was similar to reported rates in the general pediatric population. Vitamin D status should be routinely monitored in children undergoing VEPTR treatment and supplementation should be initiated if necessary.

Vitamin D and skeletal health in infancy and childhood

During growth, severe vitamin D deficiency in childhood can result in symptomatic hypocalcaemia and rickets. Despite the suggestion from some studies of a secular increase in the incidence of rickets, this observation may be driven more by changes in population demographics than a true alteration to age, sex and ethnicity-specific incidence rates; indeed, rickets remains uncommon overall and is rarely seen in fair-skinned children. Additionally, the impact of less severe vitamin D deficiency and insufficiency has received much interest in recent years, and in this review, we consider the evidence relating vitamin D status to fracture risk and bone mineral density (BMD) in childhood and adolescence. We conclude that there is insufficient evidence to support the suggestion that low serum 25-hydroxyvitamin D [25(OH)D] increases childhood fracture risk. Overall, the relationship between 25(OH)D and BMD is inconsistent across studies and across skeletal sites within the same study; however, there is evidence to suggest that vitamin D supplementation in children with the lowest levels of 25(OH)D might improve BMD. High-quality randomised trials are now required to confirm this benefit.