Rickets

Association between 25 hydroxyvitamin D and serum uric acid level in the Chinese general population: a cross-sectional study

BACKGROUD

The relationship between serum uric acid (SUA) and 25-hydroxyvitamin D (25(OH)D) has been variably characterized in existing literature, with inconsistent results regarding its nature and implications in the Chinese population. This study aims to clarify this association, considering the potential impact of vitamin D levels on SUA.

METHODS

This cross-sectional study involved 7,086 individuals from the Second Affiliated Hospital of Zhejiang University School of Medicine, screened throughout 2020. We collected data on 25(OH)D, SUA, and other metabolic markers. Logistic regression models adjusted for confounding factors were utilized to analyze the relationships.

RESULTS

Our findings illustrate a statistically significant inverted U-shaped relationship between 25(OH)D and SUA. The identified threshold effect at 28.82 ng/ml is pivotal; with 25(OH)D levels below this point associated with an increased risk of hyperuricemia (odds ratio: 1.0146, p = 0.0148), and levels above it offering protective benefits (odds ratio: 0.9616, p = 0.0164).

CONCLUSIONS

Our findings confirm a nonlinear, inverted U-shaped correlation between 25(OH)D and SUA, emphasizing the importance of maintaining vitamin D levels within a specific range to effectively manage hyperuricemia. These results support the implementation of personalized vitamin D supplementation strategies to optimize metabolic health outcomes, highlighting the complex interplay between vitamin D status and uric acid levels.

Squamosal Craniosynostosis Associated with Rickets

Rickets results from defective bone mineralization, leading to skeletal deformities. Among those deformities, rickets has been associated with craniosynostosis, the premature closure of cranial sutures. Most of these patients have fusion of major sutures. Rarely, squamosal craniosynostosis in association with rickets has been described. Squamosal craniosynostosis is noted as lacking a definitive head abnormality and difficult visualization on standard imaging modalities, leading to poor recognition. Careful attention should be given to rickets patients to monitor for these unusual suture closures. Additionally, craniosynostosis could be a presenting feature of rickets, and further rickets evaluation of the patient is indicated.

Vitamin D Receptor Regulates the Expression of the Grainyhead-Like 1 Gene

Vitamin D plays an important pleiotropic role in maintaining global homeostasis of the human body. Its functions go far beyond skeletal health, playing a crucial role in a plethora of cellular functions, as well as in extraskeletal health, ensuring the proper functioning of multiple human organs, including the skin. Genes from the Grainyhead-like (GRHL) family code for transcription factors necessary for the development and maintenance of various epithelia. Even though they are involved in many processes regulated by vitamin D, a direct link between vitamin D-mediated cellular pathways and GRHL genes has never been described. We employed various bioinformatic methods, quantitative real-time PCR, chromatin immunoprecipitation, reporter gene assays, and calcitriol treatments to investigate this issue. We report that the vitamin D receptor (VDR) binds to a regulatory region of the Grainyhead-like 1 (GRHL1) gene and regulates its expression. Ectopic expression of VDR and treatment with calcitriol alters the expression of the GRHL1 gene. The evidence presented here indicates a role of VDR in the regulation of expression of GRHL1 and correspondingly a role of GRHL1 in mediating the actions of vitamin D.

Diagnosis, treatment, and management of rickets: a position statement from the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology

Rickets results from impaired mineralization of growing bone due to alterations in calcium and phosphate homeostasis. Clinical signs of rickets are related to the age of the patient, the duration of the disease, and the underlying disorder. The most common signs of rickets are swelling of the wrists, knees or ankles, bowing of the legs (knock-knees, outward bowing, or both) and inability to walk. However, clinical features alone cannot differentiate between the various forms of rickets. Rickets includes a heterogeneous group of acquired and inherited diseases. Nutritional rickets is due to a deficiency of vitamin D, dietary calcium or phosphate. Mutations in genes responsible for vitamin D metabolism or function, the production or breakdown of fibroblast growth factor 23, renal phosphate regulation, or bone mineralization can lead to the hereditary form of rickets. This position paper reviews the relevant literature and presents the expertise of the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology (SIEDP). The aim of this document is to provide practical guidance to specialists and healthcare professionals on the main criteria for diagnosis, treatment, and management of patients with rickets. The various forms of rickets are discussed, and detailed references for the discussion of each form are provided. Algorithms to guide the diagnostic approach and recommendations to manage patients with rare forms of hereditary rickets are proposed.

Vitamin D Status in Belgian Children: A Regional Study

Background: Vitamin D deficiency is the most frequent cause of impaired skeletal growth, and can lead to the development of nutritional rickets. The aim of this study was to evaluate the vitamin D status in a large group of children aged 0-18 years. Methods: We collected laboratory data on vitamin D levels from children who underwent blood sampling between 2014 and 2021. Results: We included 14,887 samples. In this group, 17.7% were vitamin D severely deficient (<12 ng/mL), 25.2% were insufficient (12-20 ng/mL), and another large proportion (28.3%) was borderline (20-30 ng/mL). Sufficient levels (>30 ng/mL) were met in 28.8% of children. We observed no association between gender and vitamin D status (p = 0.132). Adolescents aged 13-18 years (n = 3342) had the highest prevalence of severe vitamin D deficiency (24.9%). Vitamin D levels were higher in summer/autumn compared to winter/spring. Conclusions: Vitamin D deficiency/insufficiency has a high prevalence in children, mostly in children above 7 years of age. Many of these children (over 80%) do not meet the 30 ng/mL sufficiency threshold. It is essential that Belgian Health Authorities are aware of this high prevalence, as the current Belgian recommendation suggests ceasing vitamin D supplementation at the age of six. Additional research is required to investigate the consequences of our findings, and what specific approach is needed to achieve normal vitamin D levels in children aged 0 to 18 years.

Does rickets carry an increased risk of osteomyelitis and septic arthritis? An aggregated electronic health record data study

To investigate the prevalence of osteomyelitis and septic arthritis in pediatric patients with rickets, compared to the general population. A retrospective cohort study was conducted using the TriNetX analytics network, which aggregates deidentified electronic health record data from over 105 million US patients. We queried pediatric patients with rickets, based on ICD-10-CM (International Classification of Diseases, Tenth Revision, Clinical Modification) encounter diagnoses. Patients with any ICD-10-CM encounter diagnoses of osteomyelitis or septic arthritis were reported. We established a control cohort of pediatric patients without rickets. Of 7337 pediatric patients (≤18 years old) with a rickets diagnosis, 96 [1.31%, 95% confidence interval (CI): 1.05%-1.57%] had a diagnosis of osteomyelitis and 28 (0.38%, 95% CI: 0.24%-0.52%) had a diagnosis of septic arthritis. In comparison, of the 17 240 604 pediatric patients without a rickets diagnosis, 16 995 (0.10%, 95% CI: 0.10%-0.10%) had a diagnosis of osteomyelitis and 8521 (0.05%, 95% CI: 0.05%-0.05%) had a diagnosis of septic arthritis. The relative risk for an osteomyelitis diagnosis in pediatric patients with a rickets diagnosis was 13.27 (95% CI: 10.86-16.23), while the relative risk for a septic arthritis diagnosis was 7.72 (95% CI: 5.33-11.18). Pediatric patients with a diagnosis of rickets have over 10- and 5-times higher relative risks for having a diagnosis of osteomyelitis and septic arthritis, respectively, compared to those without a diagnosis of rickets. This is the first study to explore musculoskeletal infections in rickets patients, highlighting the importance of clinicians being vigilant about these conditions.

Exome Sequencing in Monogenic Forms of Rickets

OBJECTIVE

To understand the phenotypic and genotypic spectrum of genetic forms of rickets in 10 families.

METHODS

Detailed clinical, radiographic, and biochemical evaluation of 10 families with phenotypes suggestive of a genetic cause of rickets was performed. Molecular testing using exome sequencing aided in the diagnosis of six different forms of known genetic causes.

RESULTS

Eleven disease-causing variants including five previously reported variants (CYP27B1:c.1319_1325dup, p.(Phe443Profs*24), VDR:c.1171C>T, p.(Arg391Cys), PHEX: c.1586_1586+1del, PHEX: c.1482+5G>C, PHEX: c.58C>T, p.(Arg20*)) and six novel variants (CYP27B1:c.974C>T, p.(Thr325Met), CYP27B1: c.1376G>A, p.(Arg459His), CYP2R1: c.595C>T, p.(Arg199*), CYP2R1:c.1330G>C, p.(Gly444Arg),SLC34A3:c.1336-11_1336-1del, SLC2A2: c.589G>C, p.(Val197Leu)) in the genes known to cause monogenic rickets were identified.

CONCLUSION

The authors hereby report a case series of individuals from India with a molecular diagnosis of rickets and provide the literature review which would help in enhancing the clinical and molecular profile for rapid and differential diagnosis of rickets.

Nutritional rickets masquerading as spinal muscular atrophy type III

Muscle atrophy, weakness, and loss of ambulation in the pediatric population are signs of progressive neuromuscular diseases. Rapid identification of such diseases is important to prevent further progression. In pediatric neurology, it is well understood to include neuromuscular disorders in the differential for such presentations. We report a case of severe nutritional rickets that mimicked the presentation of spinal muscular atrophy type III and discuss the importance of including rickets in the differential for muscle atrophy and loss of ambulation. A 33-month-old African American boy with several months of gait abnormality was referred to outpatient neurology. The initial diagnostic evaluation focused primarily on neuromuscular disorders, specifically SMA type III, given the absence of reflexes on examination and the history of prior ambulation. After an unfruitful genetic workup, it was elucidated that the child had very poor dietary intake and minimal sun exposure causing nutritional rickets that improved with intervention.

Guided growth: angular deformity correction through temporary hemiepiphysiodesis with a novel flexible staple (FlexTack)

Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a). Overall, 79% (109/138) of patients treated with flexible staples achieved sufficient deformity correction. The median treatment duration was 16 months (interquartile range (IQR) 8 to 21). The flexible staples achieved a median MAD correction of 1.2 mm/month/HED site (IQR 0.6 to 2.0) in valgus deformities and 0.6 mm/month/HED site (IQR 0.2 to 1.5) in varus deformities. Wound infections occurred in 1%, haematomas and joint effusions in 4%, and implant-associated complications in 1% of patients treated with flexible staples. Valgus AD were corrected faster using flexible staples than two-hole plates and Blount staples. Furthermore, the median MAD after treatment was lower in varus and valgus AD, fewer implant-associated complications were detected, and reduced implantation times were recorded using flexible staples. The flexible staple seems to be a viable option for guided growth, showing comparable or possibly better results regarding correction speed and reducing implant-associated complications. Further comparative studies are required to substantiate these findings.

The role of dietary calcium in the etiology of childhood rickets in the past and the present

For more than two centuries, lack of sunlight has been understood to cause vitamin D deficiency and documented as a primary cause of rickets. As such, evidence of rickets in the archeological record has been used as a proxy for vitamin D status in past individuals and populations. In the last decade, a clinical global consensus has emerged wherein it is recognized that dietary calcium deficiency also plays a role in the manifestation of rickets and classic skeletal deformities may not form if dietary calcium is normal even if vitamin D is deficient. This disease is now clinically called "nutritional rickets" to reflect the fact that rickets can take calcium deficiency-predominant or vitamin D deficiency-predominant forms. However, there are currently no paleopathological studies wherein dietary calcium deficiency is critically considered a primary etiology of the disease. We review here the interplay of calcium, vitamin D, and phosphorous in bone homeostasis, examine the role of dietary calcium in human health, and critically explore the clinical literature on calcium deficiency-predominant rickets. Finally, we report a case of rickets from the late Formative Period (~2500-1500 years ago) of the Atacama Desert and argue the disease in this infant is likely an example of calcium deficiency-predominant rickets. We conclude that most archeological cases of rickets are the result of multiple micronutrient deficiencies that compound to manifest in macroscopic skeletal lesions. For clinicians, these factors are important for implementing best treatment practice, and for paleopathologists they are necessary for appropriate interpretation of health in past communities.

Vitamin D deficiency in South-East Asian children: a systematic review

OBJECTIVE

To describe the prevalence and determinants of vitamin D deficiency (VDD) among healthy children aged between 0 and 18 years living in South-East Asia (SEA).

DESIGN

We systematically searched Ovid MEDLINE and Ovid EMBASE for observational studies assessing VDD among healthy children in the SEA region as the primary or secondary outcome from database inception to 6 April 2021. PubMed was used for e-pubs and publications not indexed in Medline. Publications that included abstracts in English were included. We performed a systematic review to describe the prevalence of VDD in SEA children.

RESULTS

Our initial search identified 550 publications with an additional 2 publications from manual screening. Of those, 21 studies from 5 different countries (Thailand, Indonesia, Vietnam, Malaysia and Cambodia) were summarised and included in forest plots. The prevalence of VDD (<50 nmol/L) ranged from 0.9% to 96.4%, with >50% of newborns having VDD, and severe VDD (<30 nmol/L) ranged from 0% to 55.8%. Female sex and urban living were the most common determinants of VDD.

CONCLUSIONS

VDD among healthy children living in the SEA region is common. Efforts to detect VDD and the implementation of preventive measures, including education on safe sun exposure and oral vitamin D supplementation or food fortification, should be considered for key target groups, including adolescent females and pregnant and lactating women to improve the vitamin D status of newborns.

PROTOCOL REGISTRATION NUMBER

This study is registered with PROSPERO (CRD42020181600).

800 IU versus 400 IU per day of vitamin D3 in term breastfed infants: a randomized controlled trial from an LMIC

This open-label, block-randomized controlled trial compared the effect of 800 IU/day and 400 IU/day of oral vitamin D₃ supplementation in reducing vitamin D insufficiency (VDI) among healthy-term breastfed infants at 14 weeks of postnatal age. All eligible infants were randomized to receive either 800 or 400 IU/day of oral vitamin D₃ (starting within the first week until 14 weeks). The primary outcome was the proportion of infants with VDI (25-OH-D < 20 ng/ml) at 14 weeks. Secondary outcomes were vitamin D deficiency (VDD, < 12 ng/ml), severe VDD (< 5 ng/ml), anthropometry, biochemical or clinical rickets, and any adverse events related to vitamin D toxicity (VDT). Among 102 enrolled infants, the distribution of baseline variables (including cord 25-OH-D levels; 13.0 versus 14.2 ng/ml) was similar in both groups. On intention-to-treat analysis, the proportions of infants with VDI at 14 weeks were significantly lower in the 800 IU group compared to those in the 400 IU group [24% versus 55%; RR 0.44; 95% CI: 0.25-0.76]. The proportions of infants with elevated parathormone (6% versus 26.5%; p = 0.012) and severe VDD (0% versus 12.2%; p = 0.033) were significantly lower in the 800 IU group. Clinical rickets developed in three (6.2%) infants in the 400 IU group. No infant developed VDT.      Conclusions: Daily oral supplementation with 800 IU of vitamin D₃ resulted in an almost 50% reduction in the proportion of infants with VDI and prevented the occurrence of severe VDD at 14 weeks of age compared to 400 IU with no evidence of vitamin D toxicity.     Trial Registration: Clinical Trial Registry of India (CTRI/2019/02/017374). What is Known: • Breastfeeding is the ideal source of nutrition for healthy-term breastfed infants; however, vitamin D content of breastmilk is suboptimal. • AAP recommends daily oral supplementation of 400 IU of vitamin D to all healthy-term breastfed infants; however, trials from high-income countries support insufficiency of this dose in maintaining serum 25-OH-D levels >20 ng/ml with no such information from low-middle-income countries. What is New: • 800 IU/day of oral vitamin D3 supplementation among term breastfed infants significantly reduces vitamin D insufficiency at 14 weeks' age as compared to the recommended dose of 400 IU/day. • This higher supplemental dose is safe with no evidence of vitamin D toxicity.

Investigating factors of metabolic bone disease in baboons (Papio spp.) using museum collections

OBJECTIVES

To assess manifestations of metabolic bone disease (MBD) and their potential environmental and phenotypic factors in captive and non-captive baboon (Papio spp.) specimens.

MATERIALS AND METHODS

Our sample consisted of 160 baboon specimens at the Smithsonian's National Museum of Natural History accessioned from 1890 to 1971. Combining cranial indicators of MBD and the museum's historical data, we examined factors contributing to likely instances of MBD. We used binomial-family generalized linear models to assess differences in MBD frequency by environment (captive, non-captive), specimen accession year, and skin color (light, medium, dark).

RESULTS

Indicators of MBD were most frequently observed in captive baboons, with a decrease in MBD frequency over time. Fifteen non-captive individuals showed indicators of MBD, which are the first published cases of MBD in non-captive nonhuman primates (NHPs) to our knowledge. The most common MBD indicators were bone porosity (n = 35) and bone thickening/enlargement (n = 35). Fibrous osteodystrophy was observed frequently in our sample, likely relating to nutritional deficiencies. We found no association between exposed facial skin color variation and MBD.

CONCLUSIONS

Our findings are consistent with historical accounts of MBD prevalence in captive facilities, especially earlier in the 20th century. A decrease in MBD prevalence later in the 20th century likely reflects improvements in housing, diet, and veterinary care in captive settings. Causes of MBD development in non-captive baboons should be further explored, as understanding the potential health impacts that anthropogenic environments impose on NHPs is imperative as humans increasingly alter the natural world in the 21st century.

The genetic and epigenetic contributions to the development of nutritional rickets

Nutritional rickets is an important disease in global health. Although nutritional rickets commonly manifests as bony deformities, there is an increased risk of life-threatening seizures secondary to hypocalcaemia. Dietary vitamin D deficiency is associated with the development of nutritional rickets among children and infants. This is especially true in populations of darker skinned individuals in high-latitude environments due to decreased ultraviolet light exposure, and in populations in tropical and subtropical climates due to cultural practices. A growing body of evidence has demonstrated that genetic factors might influence the likelihood of developing nutritional rickets by influencing an individual's susceptibility to develop deficiencies in vitamin D and/or calcium. This evidence has been drawn from a variety of different techniques ranging from traditional twin studies to next generation sequencing techniques. Additionally, the role of the epigenome in the development of rickets, although poorly understood, may be related to the effects of DNA methylation and non-coding RNAs on genes involved in bone metabolism. This review aims to provide an overview of the current evidence that investigates the genetic and epigenetic determinants of nutritional rickets.

Vitamin D pathway gene variation rs3740165 is associated with serological uric acid levels in healthy Chinese women

AIM

To investigate the relationship between gene polymorphisms involved in the vitamin D metabolic pathway and serum uric acid (UA) levels in Chinese women.

METHODS

Fifteen key genes within the vitamin D metabolic pathway were screened using 96 single nucleotide polymorphisms in a group of 1,206 (37.96 ± 13.08 years) unrelated healthy Chinese women (aged 20-85 years). Blood and urine tests were performed at the same time. The Wilcoxon Mann-Whitney test was used to compare groups aged ≤50 years and >50 years. The mean serum UA values were computed within each group of homozygous referent, heterozygous, and homozygous variant genotypes for each single nucleotide polymorphism.

RESULTS

The exclusion process left 1,169 participants (38.16 ± 13.13 years) for analysis. One single nucleotide polymorphism in the CUBN gene (rs3740165) was identified as being significantly associated with serum UA levels in the group aged over 50 years. The wild type (C/C) population had higher serum UA levels in this group (P<0.001). In women aged over 50 years, allele C was associated with a higher risk of hyperuricemia than allele T (odds ratio 2.752, 95% confidence interval 1.458-5.192; P = 0.002). There was also a higher risk of hyperuricemia in genotype TC + CC compared with genotype TT (odds ratio 3.326, 95% confidence interval 1.513-7.313; P = 0.003) in women over 50 years of age.

CONCLUSION

The results suggest that the CUBN gene contributes to variability in serum UA levels in healthy Chinese Han women over 50 years of age.

Time out: should vitamin D dosing be based on patient's body mass index (BMI): a prospective controlled study

The recommended daily dose of vitamin D is 2000 IU was found to be insufficient in many patients. The objective of the present study is to find whether the daily dose of vitamin D should be based on BMI. Two hundred and thirty patients with an established vitamin D deficiency (serum level of 25 Hydroxy vitamin D3 (25OHD3) of ≤20 ng/ml) and patients with BMI ≥30 kg/m2 were included in the study. Demographic data, comorbidities and BMI were recorded. Pre-treatment and post-treatment serum 25OHD3, calcium, phosphorus and parathyroid hormone (PTH) were tested at 0-, 3- and 6-month periods. Patients were treated with a standard dose of 50 000 IU of vitamin D weekly and 600/1200 mg of calcium a day. Once their level of 25OHD3 reached ≥30 ng/ml, patients were randomised into two groups. Group A received a standard recommended maintenance dose of 2000 IU daily and Group B patients received 125 IU/kg/m2 of vitamin D3. The data were entered in the database and analysed. The mean age of Group A was 50⋅74 ± 7⋅64 years compared to 52⋅32 ± 7⋅21 years in Group B. In both groups, pre-treatment vitamin D level was ≤15 ng/ml and increased to 34⋅6 ± 2⋅6 and 33⋅7 ± 2⋅4 ng/ml at the end of 3 months treatment with a dose 50 000 IU of vitamin D3 and calcium 600/1200 mg once a day for group A and group B, respectively. At 6 months, patients in Group A 25OHD3 level was 22⋅8 ± 3⋅80 and in Group B was 34⋅0 ± 1⋅85 ng/ml (P < 0⋅001). This preliminary study suggests that obese patients need higher dosage of vitamin D than the recommended dose. It is prudent that the dosage should be based on the BMI to maintain normal levels for a healthy musculoskeletal system.

Patients with higher vitamin D levels show stronger improvement of self-reported depressive symptoms in psychogeriatric day-care setting

Depression is a common psychiatric disorder among geriatric patients that decreases the quality of life and increases morbidity and mortality. Vitamin D as a neuro-steroid hormone might play a role in the onset and treatment of depression. In the present study, the association between depressive symptoms and vitamin D concentration in serum was evaluated. 140 patients of a psychogeriatric day-care unit were included. The geriatric depression scale (GDS) and the Hamilton depression rating scale (HDRS) were assessed at the beginning and end of treatment, GDS scores additionally 6 weeks after discharge from the day-care unit. Vitamin D levels were measured at the beginning of the treatment, routinely. Patients with levels below 30 µg/L were treated with 1000 IU vitamin D per day. There was no association between the severity of depressive symptoms and the concentration of vitamin D at the beginning of the treatment. Patients with higher vitamin D levels showed a stronger decline of depressive symptoms measured by the GDS during their stay in the day-care unit. We provide evidence that vitamin D serum levels might influence antidepressant therapy response in a geriatric population. Prospective studies are necessary to determine which patients may profit from add-on vitamin D therapy.

Association Between the TaqI (rs731236 T>C) Gene Polymorphism and Dental Caries Risk: A Meta-analysis

Objective: This study investigated the association of the TaqI (rs731236 T>C) polymorphism in the VDR gene with dental caries.

Methods: A comprehensive literature search was performed in PubMed, Web of Science, Embase, SinoMed (the Chinese biomedical literature service system), and the Wiley Online Library. Overall comparisons and subgroup analyses based on ethnicity and the presence of dental caries in dentition were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess associations between gene polymorphisms and the risk of dental caries.

Results: Seven articles were included in this meta-analysis. The pooled results revealed a significant association of the TaqI (rs731236 T>C) polymorphism with dental caries in the allele contrast model (C vs. T: OR = 1.24, 95% CI = 1.07–1.44, I² = 42%, p = 0.005) and in the recessive genetic model (CC vs. TT/CT: OR = 1.38, 95% CI = 1.03–1.84, I² = 0%, p = 0.03). A stratified analysis based on ethnicity revealed a significant association between the TaqI (rs731236 T>C) polymorphism and the risk of dental caries in Asians (C vs. T: OR = 1.28, 95% CI = 1.06–1.54, I² = 60%, p = 0.009). Subgroup analysis based on the presence of dental caries in dentition found a significant association of the TaqI (rs731236 T>C) polymorphism with permanent tooth caries in the allele contrast model (C vs. T: OR = 1.40, 95% CI = 1.11–1.77, I² = 76%, p = 0.005) and the recessive genetic model (CC vs. TT/CT: OR = 1.44, 95% CI = 1.03–2.00, I² = 0%, p = 0.03).

Conclusion: The results of this meta-analysis suggest that the C allele and CC genotype of the TaqI (rs731236 T>C) polymorphism in the VDR gene are associated with an increased risk of dental caries.

Influence of maternal use of tenofovir disoproxil fumarate or zidovudine in Vietnamese pregnant women with HIV on infant growth, renal function, and bone health

Tenofovir disoproxil fumarate (TDF) is still widely prescribed for human immunodeficiency virus (HIV)-infected pregnant women, despite its renal and bone toxicity. Although TDF-exposed infants often show transient growth impairment, it is not clear whether maternal TDF causes infantile rickets via maternal/fetal renal dysfunction in Asian populations. This prospective observational study was conducted in Vietnam and involved pregnant HIV-infected women treated with TDF-based regimen (TDF group) or zidovudine-based regimen (AZT-group). At birth, 3, 12, and 18 months of age, and included body length, weight, head circumference, serum alkaline phosphatase (ALP), creatinine, calcium, phosphorus, urine-β2-microglobulin (U-BMG), percentage of tubular reabsorption of phosphate (%TRP), and radiographic wrist score for rickets. Age-adjusted multivariate linear regression analysis evaluated the association of TDF/AZT use during pregnancy with fetal renal function and bone health. The study included 63 mother-infant pairs (TDF group = 53, AZT group = 10). In the mothers, detectable U-BMG (>252 μg/L) was observed more frequently in the TDF- than AZT group (89 vs 50%, p<0.001), but other renal/bone parameters were similar. In infants, maternal TDF use was not associated with growth impairment, renal dysfunction, or abnormal bone findings, but with a slightly higher ALP levels (p = 0.019). However, shorter length was associated with maternal AZT (p = 0.021), and worse radiographic scores were associated with LPV/r (p = 0.024). In Vietnamese population, TDF usage during pregnancy was not associated with infant transient rickets, growth impairment, or renal dysfunction, despite mild maternal tubular impairment. Maternal AZT and LPV/r influenced infant growth and bone health, though further studies are needed to confirm this finding.

Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health

BACKGROUND

Vitamin D deficiency is common worldwide, contributing to nutritional rickets and osteomalacia which have a major impact on health, growth, and development of infants, children and adolescents. Vitamin D levels are low in breast milk and exclusively breastfed infants are at risk of vitamin D insufficiency or deficiency.

OBJECTIVES

To determine the effect of vitamin D supplementation given to infants, or lactating mothers, on vitamin D deficiency, bone density and growth in healthy term breastfed infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to 29 May 2020 supplemented by searches of clinical trials databases, conference proceedings, and citations.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in breastfeeding mother-infant pairs comparing vitamin D supplementation given to infants or lactating mothers compared to placebo or no intervention, or sunlight, or that compare vitamin D supplementation of infants to supplementation of mothers.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 19 studies with 2837 mother-infant pairs assessing vitamin D given to infants (nine studies), to lactating mothers (eight studies), and to infants versus lactating mothers (six studies). No studies compared vitamin D given to infants versus periods of infant sun exposure. Vitamin D supplementation given to infants: vitamin D at 400 IU/day may increase 25-OH vitamin D levels (MD 22.63 nmol/L, 95% CI 17.05 to 28.21; participants = 334; studies = 6; low-certainty) and may reduce the incidence of vitamin D insufficiency (25-OH vitamin D < 50 nmol/L) (RR 0.57, 95% CI 0.41 to 0.80; participants = 274; studies = 4; low-certainty). However, there was insufficient evidence to determine if vitamin D given to the infant reduces the risk of vitamin D deficiency (25-OH vitamin D < 30 nmol/L) up till six months of age (RR 0.41, 95% CI 0.16 to 1.05; participants = 122; studies = 2), affects bone mineral content (BMC), or the incidence of biochemical or radiological rickets (all very-low certainty). We are uncertain about adverse effects including hypercalcaemia. There were no studies of higher doses of infant vitamin D (> 400 IU/day) compared to placebo. Vitamin D supplementation given to lactating mothers: vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels (MD 24.60 nmol/L, 95% CI 21.59 to 27.60; participants = 597; studies = 7; low-certainty), may reduce the incidences of vitamin D insufficiency (RR 0.47, 95% CI 0.39 to 0.57; participants = 512; studies = 5; low-certainty), vitamin D deficiency (RR 0.15, 95% CI 0.09 to 0.24; participants = 512; studies = 5; low-certainty) and biochemical rickets (RR 0.06, 95% CI 0.01 to 0.44; participants = 229; studies = 2; low-certainty). The two studies that reported biochemical rickets used maternal dosages of oral D3 60,000 IU/day for 10 days and oral D3 60,000 IU postpartum and at 6, 10, and 14 weeks. However, infant BMC was not reported and there was insufficient evidence to determine if maternal supplementation has an effect on radiological rickets (RR 0.76, 95% CI 0.18 to 3.31; participants = 536; studies = 3; very low-certainty). All studies of maternal supplementation enrolled populations at high risk of vitamin D deficiency. We are uncertain of the effects of maternal supplementation on infant growth and adverse effects including hypercalcaemia. Vitamin D supplementation given to infants compared with supplementation given to lactating mothers: infant vitamin D supplementation compared to lactating mother supplementation may increase infant 25-OH vitamin D levels (MD 14.35 nmol/L, 95% CI 9.64 to 19.06; participants = 269; studies = 4; low-certainty). Infant vitamin D supplementation may reduce the incidence of vitamin D insufficiency (RR 0.61, 95% CI 0.40 to 0.94; participants = 334; studies = 4) and may reduce vitamin D deficiency (RR 0.35, 95% CI 0.17 to 0.72; participants = 334; studies = 4) but the evidence is very uncertain. Infant BMC and radiological rickets were not reported and there was insufficient evidence to determine if maternal supplementation has an effect on infant biochemical rickets. All studies enrolled patient populations at high risk of vitamin D deficiency. Studies compared an infant dose of vitamin D 400 IU/day with varying maternal vitamin D doses from 400 IU/day to > 4000 IU/day. We are uncertain about adverse effects including hypercalcaemia.

AUTHORS' CONCLUSIONS

For breastfed infants, vitamin D supplementation 400 IU/day for up to six months increases 25-OH vitamin D levels and reduces vitamin D insufficiency, but there was insufficient evidence to assess its effect on vitamin D deficiency and bone health. For higher-risk infants who are breastfeeding, maternal vitamin D supplementation reduces vitamin D insufficiency and vitamin D deficiency, but there was insufficient evidence to determine an effect on bone health. In populations at higher risk of vitamin D deficiency, vitamin D supplementation of infants led to greater increases in infant 25-OH vitamin D levels, reductions in vitamin D insufficiency and vitamin D deficiency compared to supplementation of lactating mothers. However, the evidence is very uncertain for markers of bone health. Maternal higher dose supplementation (≥ 4000 IU/day) produced similar infant 25-OH vitamin D levels as infant supplementation of 400 IU/day. The certainty of evidence was graded as low to very low for all outcomes.

Is sunlight enough for sufficient vitamin D status in children and adolescents? A survey in a sunny region of southern Italy

OBJECTIVES

Because it is involved in calcium homeostasis, vitamin D is a prohormone with many implications for health, especially bone health. Hypovitaminosis D is considered pandemic worldwide, with important health health consequences. The aim of our study was to evaluate vitamin D levels in children living in a southern region of Italy with high exposure to sunlight for at least 5 mo a year along with contributing factors.

METHODS

A total of 1484 children and adolescents (age 0.02-17.74 y) living in the Apulia region (Southern Italy) were studied. Serum 25-hydroxyvitamin D (25[OH]D) concentrations were assessed and vitamin status defined as follows: deficiency with serum 25(OH)D < 20 ng/mL, insufficiency from 20 to 29.9 ng/mL, and sufficiency with serum 25(OH)D from 30 to 100 ng/mL.

RESULTS

The median serum 25(OH)D levels were 20.2 ng/mL (interquartile range, 14.5-26.4 ng/mL): 48.9% of the overall population had 25(OH)D < 20 ng/mL and only 15% had sufficient 25(OH)D values. There was an inverse association between blood levels of 25(OH)D and age (P < 0.001, ρ: -0.113). Significant 25(OH)D variations were recorded according to the season in which blood samples were drawn, but even during summer only 32.6% of analyzed children had sufficient 25(OH)D levels.

CONCLUSIONS

More than 80% of our population had 25(OH)D less than sufficiency cutoff levels. Results highlight a high prevalence of 25(OH)D deficiency in our area, even during summer. It is important to establish screening, supplementation guidelines, and pediatric cutoff levels to optimize vitamin D status in children, taking into account age, nutritional status, and seasonality.

The Role of Vitamin D in Small Animal Bone Metabolism

Dogs and cats have differences in vitamin D metabolism compared to other mammalian species, as they are unable to perform vitamin D cutaneous synthesis through sun exposure. Therefore, they are dependent on the dietary intake of this nutrient. The classic functions of vitamin D are to stimulate intestinal calcium and phosphate absorption, renal calcium and phosphate reabsorption and regulate bone mineral metabolism. Thus, it is an important nutrient for calcium and phosphorus homeostasis. This review highlights the evidence of the direct and indirect actions of vitamin D on bone mineral metabolism, the consequences of nutritional imbalances of this nutrient in small animals, as well as differences in vitamin D metabolism between different size dogs.

Understanding the Biological Activities of Vitamin D in Type 1 Neurofibromatosis: New Insights into Disease Pathogenesis and Therapeutic Design

Vitamin D is a fat-soluble steroid hormone playing a pivotal role in calcium and phosphate homeostasis as well as in bone health. Vitamin D levels are not exclusively dependent on food intake. Indeed, the endogenous production-occurring in the skin and dependent on sun exposure-contributes to the majority amount of vitamin D present in the body. Since vitamin D receptors (VDRs) are ubiquitous and drive the expression of hundreds of genes, the interest in vitamin D has tremendously grown and its role in different diseases has been extensively studied. Several investigations indicated that vitamin D action extends far beyond bone health and calcium metabolism, showing broad effects on a variety of critical illnesses, including cancer, infections, cardiovascular and autoimmune diseases. Epidemiological studies indicated that low circulating vitamin D levels inversely correlate with cutaneous manifestations and bone abnormalities, clinical hallmarks of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumour predisposition syndrome causing significant pain and morbidity, for which limited treatment options are available. In this context, vitamin D or its analogues have been used to treat both skin and bone lesions in NF1 patients, alone or combined with other therapeutic agents. Here we provide an overview of vitamin D, its characteristic nutritional properties relevant for health benefits and its role in NF1 disorder. We focus on preclinical and clinical studies that demonstrated the clinical correlation between vitamin D status and NF1 disease, thus providing important insights into disease pathogenesis and new opportunities for targeted therapy.

Development of Enthesopathies and Joint Structural Damage in a Murine Model of X-Linked Hypophosphatemia

X-linked hypophosphatemia (XLH) is characterized by rickets and osteomalacia, caused by inactivating mutations in the Phosphate-regulating endopeptidase homolog X-linked (PHEX) gene. With aging, adult patients develop paradoxical heterotopic calcifications of tendons and ligaments at their insertion sites (enthesophytes), and joint alterations. Understanding the progression of this structural damage that severely affects patients’ quality of life will help to improve the management of XLH. Here, we characterized the occurrence of enthesophytes and joint alterations through a 12 month in vivo micro-CT follow-up in the Hyp mouse, a murine model of XLH (n = 5 mice per group). Similar to adult patients with XLH, Hyp mice developed calcaneal enthesophytes, hip joint alterations, erosions of the sacroiliac joints and periarticular calcifications. These lesions were already present at month 3 and gradually worsened over time. In sharp contrast, no abnormalities were observed in control mice at early time points. Histological analyses confirmed the presence of bone erosions, calcifications and expansion of mineralizing enthesis fibrocartilage in Hyp mice and their absence in controls and suggested that new bone formation is driven by altered mechanical strain. Interestingly, despite a strong deformation of the curvature, none of the Hyp mice displayed enthesophyte at the spine. Peripheral enthesophytes and joint alterations develop at the early stages of the disease and gradually worsen overtime. Overall, our findings highlight the relevance of this preclinical model to test new therapies aiming to prevent bone and joint complications in XLH.

Prevalence of Vitamin D Deficiency in a Large Newborn Cohort from Northern United States and Effect of Intrauterine Drug Exposure

Vitamin D is not only a vital element in bone health but is also a prohormone. Data regarding distribution of vitamin D status among preterm and term neonates in the United States are limited. There are no data on the effect of intrauterine drug exposure on vitamin D status. Our objective was to determine the distribution of vitamin D levels among preterm and term neonates and the effect of intrauterine illicit drug exposure. We did a retrospective chart review of neonates admitted from 2009 to 2016 to our neonatal intensive care unit with serum 25-hydroxycholecalciferol (25[OH]D) levels measured during the hospital stay. Of 1517 neonates, the median 25[OH]D level was 19 ng/mL with 31% deficient and 49% insufficient, even though 75% of mothers took prenatal vitamins. In pregnant women, 38% were vitamin-D-deficient and 44% were vitamin-D-insufficient. Four hundred seventy-one neonates had intrauterine drug exposure, with a median 25[OH]D level of 22.9 ng/mL versus 17.8 ng/mL in nonexposed neonates (p = 0.001). Despite maternal prenatal vitamin intake, neonates are at risk of vitamin D deficiency. Maternal illicit drug use was not related to lower 25[OH]D levels in neonates.

An Overview of Rickets in Children

Rickets is a common bone disease worldwide that is associated with disturbances in calcium and phosphate homeostasis and can lead to short stature and joint deformities. Rickets can be diagnosed based on history and physical examination, radiological features, and biochemical tests. It can be classified into 2 major groups based on phosphate or calcium levels: phosphopenic and calcipenic. Knowledge of categorization of the type of rickets is essential for prompt diagnosis and proper management. Nutritional rickets is a preventable disease through adequate intake of vitamin D through both dietary and sunlight exposure. There are other subtypes of rickets, such as vitamin D-dependent type 1 rickets and vitamin D-dependent type 2 rickets (due to defects in vitamin D metabolism), renal rickets (due to poor kidney function), and hypophosphatemic rickets (vitamin D-resistant rickets secondary to renal phosphate wasting wherein fibroblast growth factor-23 (FGF-23) often plays a major role), which requires closer monitoring and supplementation with activated vitamin D with or without phosphate supplements. An important development has been the introduction of burosumab, a human monoclonal antibody to FGF-23, which is approved for the treatment of X-linked hypophosphatemia among children 1 year and older.

Nutritional rickets under 16 years: UK surveillance results

OBJECTIVE

The UK national incidence of nutritional rickets is unknown. We aimed to describe the incidence, presentation and clinical management of children under 16 years with nutritional rickets in the UK presenting to secondary care.

METHODS

Prospective data were collected monthly between March 2015 and March 2017 from 3500 consultant paediatricians using British Paediatric Surveillance Unit methodology. Clinicians completed online clinical questionnaires for cases fitting the surveillance case definition.

RESULTS

125 cases met the case definition, an annual incidence of 0.48 (95% CI 0.37 to 0.62) per 100 000 children under 16 years. 116 children were under 5 years (annual incidence of 1.39 (95% CI 1.05 to 1.81) per 100 000. Boys (70%) were significantly more affected than girls (30%) (OR 2.17, 95% CI 1.25 to 3.78). The majority were of Black (43%) or South Asian (38%) ethnicity. 77.6% of children were not taking vitamin D supplements despite being eligible. Complications included delayed gross motor development (26.4%), fractures (9.6%), hypocalcaemic seizures (8%) and dilated cardiomyopathy (3%). Two children died (1.6%). In eight cases, rickets was confirmed radiologically and biochemically [raised serum alkaline phosphatase (ALP) and parathyroid hormone (PTH) levels ] but were excluded from the incidence analysis for not meeting the case definition of 25-hydroxyvitamin D of <25 nmol/L.

CONCLUSION

The incidence of nutritional rickets in the UK is lower than expected. Serious complications and unexpected deaths, particularly in Black and South Asian children under 5 years, occurred. Both vitamin D deficiency and dietary calcium deficiency are role players in pathogenesis. Uptake of vitamin D supplementation remains low.

Population-Based Incidence of Potentially Life-Threatening Complications of Hypocalcemia and the Role of Vitamin D Deficiency

OBJECTIVES

To determine the incidence of potentially life-threatening complications of hypocalcemia in infants and children in Olmsted County, Minnesota; and to determine if vitamin D deficiency contributed to these events and was, at the time of clinical presentation, considered as a possible cause.

STUDY DESIGN

In this population-based descriptive study, data were abstracted from the Rochester Epidemiology Project, a medical record linkage system covering 95% of patients in Olmsted County, Minnesota. Participants were children aged 0-5 years who resided in Olmsted County between January 1, 1996 and June 30, 2017, and who received diagnoses of seizures, cardiomyopathy, cardiac arrest, respiratory arrest, laryngospasm, and/or tetany. The incidence of hypocalcemia plus a potentially life-threatening complication was calculated.

RESULTS

Among 15 419 patients aged 0-5 years in Olmsted County during the study period, 1305 had eligible complications: 460 had serum calcium checked within 14 days of presentation and 85 had hypocalcemia. Patients were excluded when causes other than hypocalcemia likely triggered the complication, leaving 16 children whose complication was attributed to hypocalcemia. Three of these 16 patients had a serum 25-hydroxyvitamin D measurement and 2 were deficient (≤6 ng/mL [15 nmol/L]). Among children aged 0-5 years, the incidence of hypocalcemia plus a potentially life-threatening complication was 6.1 per 100 000 person-years (95% CI, 3.5-10.0).

CONCLUSIONS

Vitamin D deficiency is an underinvestigated cause of complications of hypocalcemia in children. Serum calcium and 25-hydroxyvitamin D should be measured in children with these complications to identify possibly life-threatening vitamin D deficiency.

Prevalence and determinants of vitamin D deficiency in infants and toddlers in the Netherlands: a pilot study

Background

Little is known of the vitamin D status of young infants and toddlers and its determinants in West Europe. The prevalence and determinants of vitamin D deficiency of children aged 6–48 months in the centre of the Netherlands (52°N) is investigated.

Methods

In a cross-sectional population study, randomly recruited infants and toddlers ( n = 150) were studied using an online questionnaire and a physical examination either in late summer ( n = 52) or in late winter ( n = 98). Vitamin D analysis was performed by capillary blood sampling using dried bloodspots plus LC-MS/MS.

Results

In late winter, 32% of the children were vitamin D deficient (<50 nmol/L 25OH vitamin D3) with 5% severely deficient (<25 nmol/L). In late summer, 2% were deficient. The odds of vitamin D deficiency were higher in children aged 24–48 months, for those not using formula milk and those not adhering to the supplementation guidelines.

Conclusion

One-third of Dutch infants and toddlers were found to be vitamin D deficient in late winter. Suggested strategies for raising the vitamin D status may include improving the adherence to supplementation, a sensible sun exposure or the use of fortified foods. Special attention is needed for the children aged 24–48 months.

Increased risk of rickets but not fractures during childhood and adolescence following necrotizing enterocolitis among children born preterm in Sweden

BACKGROUND

The aim was to clarify whether children born preterm with a history of necrotizing enterocolitis (NEC) had an increased risk of rickets, fractures, and/or vitamin D deficiency during childhood and adolescence compared to controls without NEC, matched for gestational age.

METHODS

All infants born in Sweden between 1987 and 2009 with a gestational age <32 + 0 weeks and a diagnosis of NEC were identified. Totally, 465 children with a history of NEC and 2127 controls were included. International Classification of Diseases codes for all categories of fractures, rickets, vitamin D deficiency, and malnutrition were analyzed.

RESULTS

In total, 94 of the 465 children with NEC died within 28 days. Of the 2127 controls, 288 died within 28 days. Among the remaining 371 NEC cases, 39 fracture occasions were identified. The 1839 controls had 204 fracture occasions. There was no significant difference in fractures. Rickets was diagnosed in 11 (3%) of the children with a history of NEC compared to 21 (1%) of the controls (odds ratio 2.65, 95% CI 1.26-5.53, p = 0.007).

CONCLUSIONS

This study showed an increased risk of rickets but not fractures during childhood and adolescence in children born preterm and with a history of NEC, compared to matched controls.

Elevated Bone Remodeling Markers of CTX and P1NP in Addition to Sclerostin in Patients with X-linked Hypophosphatemia: A Cross-Sectional Controlled Study

Aspects of bone remodeling have only been scarcely studied in X-linked hypophosphatemia (XLH). In this cross-sectional controlled study, we assessed biochemical indices of bone remodeling and sclerostin in 27 adult patients (median age 47 [range 24-79] years, 19 women, 8 men) with XLH matched with 81 healthy control subjects (1:3) with respect to age-, sex-, and menopausal status. Markers of bone resorption (carboxyterminal cross-linked telopeptide of type 1 collagen, CTX) and formation (N-terminal propeptide of type 1 procollagen, P1NP) were higher in XLH patients compared to controls (median [IQR] 810 [500-1340] vs 485 [265-715] ng/l and 90 [57-136] vs 49 [39-65] ug/l, respectively, both p < 0.001) as well as sclerostin (0.81 [0.60-1.18] vs 0.54 [0.45-0.69] ng/ml, p < 0.001). Similar differences were found when comparing currently treated (with phosphate and alfacalcidol) (n = 11) and untreated (n = 16) XLH patients with their respective controls. We found no significant associations with treatment status and indices of bone remodeling or sclerostin although sclerostin tended to be increased in untreated versus treated (p = 0.06). In contrast to previous histomorphometric studies suggesting a low remodeling activity in XLH, these biochemical indices suggest high osteoblast and osteoclast activity. Further studies are needed to ascertain if the higher sclerostin level in XLH is related to osteocyte dysfunction or represents a secondary phenomenon.

Eight-year-old Boy with New-onset Seizure

An eight-year-old boy presented to the emergency department for a first-time seizure. The patient had only signs of mild dehydration on physical exam and had an uneventful postictal recovery. First-time seizures in pediatric patients are often benign and require only an outpatient workup; some are dangerous. This case takes the reader through the differential diagnosis and systematic work-up of new-onset pediatric seizures, leading to an unanticipated diagnosis.

Symptomatic Correlates of Vitamin D Deficiency in First-Episode Psychosis

Previous studies indicate that low levels of vitamin D are associated with increased severity of psychiatric symptoms in chronic multiepisode psychosis (MEP). We aimed to compare vitamin D levels between first-episode psychosis (FEP) and MEP and to investigate the correlations between vitamin D levels and symptoms in FEP patients. The participants were adults aged 18-45 years who presented with affective and non-affective FEP to an early intervention team in Portugal. Depression was assessed using the Beck Depression Inventory, and positive and negative symptoms and general psychopathology were measured with the Positive and Negative Syndrome Scale. Blood samples were analyzed for 25-hydroxyvitamin D (25OHD). Thirty-three patients completed the study in the FEP group and 33 in the MEP group. FEP patients had low levels of 25OHD (18.16 ± 7.48 ng/mL), with no significant differences from MEP patients. Low 25OHD was significantly correlated with high severities of depressive (r=-0.484, p=0.004) and negative (r=-0.480, p=0.005) symptoms as well as general psychopathology (r=-0.569, p=0.001) in FEP patients. Multiple regression revealed an inverse association between general psychopathology and vitamin D level (p=0.027). More investigation of the association of vitamin D and schizophrenia is needed, namely, using a nonpatient control group and trying to clarify possible causality between vitamin D and psychiatric symptoms.

Dietary Calcium Intake and Hypertension: Importance of Serum Concentrations of 25-Hydroxyvitamin D

The relationship among dietary calcium, hypertension and vitamin D status currently remains unclear. This population-based cross-sectional study examined the association between dietary calcium intake and hypertension and the influence of serum concentrations of 25-hydroxyvitamin D [25(OH)D] in Japanese subjects. A total of 619 subjects aged from 40 years were recruited. Dietary intake was measured using a validated brief self-administered diet history questionnaire. Hypertension was defined as the use of antihypertensive medication or a blood pressure of 140/90 mmHg. Serum concentrations of 25(OH)D were used as the biomarker of vitamin D status. The prevalence of hypertension and low serum 25(OH)D levels (<20 ng/mL) were 55 and 32%, respectively. Dietary calcium intake inversely correlated with hypertension in subjects with serum 25(OH)D levels higher than 20 ng/mL (OR: 0.995; 95% CI: 0.991, 0.999) but it was not significant in those with serum 25(OH)D levels of 20 ng/mL or lower. Furthermore, dietary vitamin D intake correlated with serum concentrations of 25(OH)D after adjustments for various confounding factors. The present results demonstrate that the regular consumption of calcium may contribute to the prevention and treatment of hypertension in subjects with a non-vitamin D deficiency and also that dietary vitamin D intake may effectively prevents this deficiency.

The effects of indoor and outdoor sports participation and seasonal changes on vitamin D levels in athletes

OBJECTIVE

Nowadays, people tend to spend more time in the closed areas and benefit less from sunlight. In this study, we examined the results of vitamin D measurements of athletes from different disciplines in different months and aimed to determine if the synthesis of vitamin D decreases or not according to exercise environment and month.

METHODS

The study was conducted in participants aged 5-52 years. A total of 555 elite-level sportsmen who were admitted to our Sports Medicine Clinic in the study participated in this study. Indoor and outdoor environmental and seasonal effects on the measurements in different months were statistically evaluated. Independent-samples test and definitive statistics were used for statistical analyses and a p-value less than 0.05 has been considered significant.

RESULTS

The study group consisted of 229 male and 326 female athletes. The serum 25-hydroxyvitamin D concentration was observed; 120 (21.6%) athletes have severe serum vitamin D deficiency (<11-20 ng/mL). Vitamin D levels were not significantly different from outdoor athletes (393; 70.8%). Winter measurements of vitamin D levels were significantly lower than those measured in autumn (p = 0.000).

CONCLUSION

Increasing vitamin D levels are very important especially in participating athletes and additional supplements are recommended whenever necessary. Gender and indoor/outdoor sports participation showed no statistically significant outcomes on vitamin D levels. However, winter season had a negative effect on vitamin D levels. Therefore, adequate precautions should be taken to increase vitamin D, especially during winter, to maintain the best performance of the athletes.

Vitamin D status, oxidative stress, and inflammation in children and adolescents: A systematic review

Vitamin D deficiency is considered a global public health problem with high prevalence in children and adolescents. The majority of the studies in the literature have identified a relationship between vitamin D insufficiency/deficiency and obesity, as well as other traditional cardiometabolic risk factors in children and adolescents. Scarce studies address vitamin D status with oxidative stress and inflammation in the young population. The aim of this systematic review was to evaluate the evidence of the association of vitamin D status with oxidative stress and inflammation in children and adolescents. This is a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) guideline on reporting systematic reviews. Eight studies were selected for this review. All included studies evaluated inflammatory biomarkers and two out of eight evaluated biomarkers of oxidative stress. The majority of the studies (five out of eight) found association of vitamin D status with biomarkers of oxidative stress and inflammation such as C-reactive protein (CRP), interleukin-6 (IL-6), cathepsin S, vascular cell adhesion molecule-1 (VCAM-1), malondialdehyde (MDA), myeloperoxidase, 3-nitrotyrosine, and superoxide dismutase (SOD). Vitamin D status is associated with oxidative stress and inflammation in the majority of the studies with children and adolescents. Thus, the assessment of vitamin D status is important because it is associated with nontraditional cardiometabolic markers in the pediatric population (review registration: PROSPERO CRD42018109307).

Rare paleopathological insights into vitamin D deficiency rickets, co-occurring illnesses, and documented cause of death in mid-19th century London, UK

Growing evidence suggests that vitamin D supports immune responses to infections, autoimmune conditions and cancers, although evidence from large-scale studies is limited. There is scope to better understand how vitamin D deficiency interacted with other diseases to affect health in past groups. This study investigated paleopathological evidence and documentary records of individual cause of death to examine disease co-occurrence in a group of mid-19th century child burials from London, UK. Twenty-one percent of children had vitamin D deficiency rickets (138/642) and 36 children with rickets had an identified cause of death. Cyclical episodes of metabolic and nutritional deficiencies (rickets and scurvy) had occurred during childhood. Active rickets co-occurred with respiratory and gastrointestinal infections in a small number of children, likely reflecting vitamin D's role in supporting immune function. Consideration of the stage of the vitamin D deficiency showed that the majority of children were affected by chronic disease loads indicative of multiple episodes of illness. Reconstructions of the wider health consequences of vitamin D deficiency in past groups are dependent on recognising whether the deficiency was active or healed. The variability of diseases identified illustrates the high disease burden that affected children in this socially disadvantaged group.

Sun behaviour and physical activity associated with autumn vitamin D status in 4–8-year-old Danish children

Objective

To explore determinants of serum 25-hydroxyvitamin D (s-25(OH)D) during autumn in young, Caucasian children not consuming vitamin D-fortified foods or supplements, and explore differences in sun behaviours between pre-school and school children.

Design

In September–October, s-25(OH)D was measured by LC–MS/MS; physical activity, sun behaviours and vitamin D intake were assessed with questionnaires.

Setting

Baseline data from the ODIN Junior trial at 55°N.

Subjects

Children aged 4–8 years (n130), of whom 96% gave blood samples.

Results

Mean s-25(OH)D was 56·8 (sd12·5) nmol/l and positively associated with fat-free mass index (P=0·014). Children being active 6–7 h/week had 5·6 (95% CI 1·1, 10·0) nmol/l higher s-25(OH)D than less active children (P=0·014). Children seeking shade sometimes or rarely/never had 7·0 (95% CI 1·2, 12·9;P=0·018) and 7·2 (95% CI 0·8, 13·6;P=0·028) nmol/l higher s-25(OH)D, respectively, than children always/often seeking shade. Pre-school children had more sun-safe behaviour than school children in terms of use of a hat, sunscreen and sunscreen sun protection factor (P<0·05). In school but not pre-school children, using a hat rarely/never was associated with 12·1 (95% CI 2·5, 21·7;P=0·014) nmol/l higher s-25(OH)Dv. always/often (Pinteraction=0·019). Vitamin D intake was not associated with s-25(OH)D (P=0·241).

Conclusions

Physical activity and sun behaviours are associated with s-25(OH)D in young children. Identifying factors influencing autumn s-25(OH)D is relevant to optimize levels before sun exposure diminishes. Strategies to reduce risk of inadequacy should consider risk of skin cancer and sunburn, and could include fortification and/or vitamin D supplementation.

A closer look at rickets and vitamin D deficiency in Manitoba: The tip of the iceberg

Objectives

Vitamin D deficiency rickets remains a problem in Canada. Our primary objective was to determine the annual incidence of rickets and/or early vitamin D deficiency in Manitoba. Secondarily, we investigated if there was an increase in the annual incidence.

Methods

A retrospective chart review was undertaken to identify cases in our catchment area from 2003 to 2015. Data sources included endocrine and hospital charts and radiology reports. Early vitamin D deficiency was determined by review of all 25(OH)D tests from 2011 to 2015. Values less than 30 nmol/L with an elevated bone marker prompted a chart review in children under 7 years.

Results

We identified 46 cases of rickets and 68 with early vitamin D deficiency. For Manitoba, the annual incidence of rickets was 8.2 cases per 100,000 in infants, and 1.6 per 100,000 in children aged 1 to 7 years. Those with early vitamin D deficiency had annual incidences of 2.7 per 100,000 infants and 9.9 per 100,000 Manitoban children. No temporal trends were noted for either. For both disorders, most cases were from northern or rural locales; about 50% were of self-declared Indigenous or Inuit heritage, and the majority (>75%) of children were from families with high material deprivation using area-based socioeconomic measures.

Conclusion

Despite several decades of preventative efforts, the incidence of rickets was comparable to previous Canadian reports, particularly in infants. Greater education across the lifespan and engagement with communities and public health agencies will be needed to reduce the high incidence of this preventable disease.

Vitamin D and the Skin: An Update for Dermatologists

Vitamin D plays a key role in skeletal and cardiovascular disorders, cancers, central nervous system diseases, reproductive diseases, infections, and autoimmune and dermatological disorders. The two main sources of vitamin D are sun exposure and oral intake, including vitamin D supplementation and dietary intake. Multiple factors are linked to vitamin D status, such as Fitzpatrick skin type, sex, body mass index, physical activity, alcohol intake, and vitamin D receptor polymorphisms. Patients with photosensitive disorders tend to avoid sun exposure, and this practice, along with photoprotection, can put this category of patients at risk for vitamin D deficiency. Maintaining a vitamin D serum concentration within normal levels is warranted in atopic dermatitis, psoriasis, vitiligo, polymorphous light eruption, mycosis fungoides, alopecia areata, systemic lupus erythematosus, and melanoma patients. The potential determinants of vitamin D status, as well as the benefits and risks of vitamin D (with a special focus on the skin), will be discussed in this article.

Vitamin D3 Supplementation Does Not Improve Sprint Performance in Professional Rugby Players: A Randomized, Placebo-Controlled, Double-Blind Intervention Study

Vitamin D insufficiency is common in athletes and may lower physical performance. Many cross-sectional studies associate vitamin D status with physical performance in athletes; however, there have been few prospective randomized controlled trials with adequate statistical power to test this relationship, and none in the southern hemisphere. Thus, a prospective double-blind, randomized, placebo-controlled intervention trial was conducted involving 57 professional rugby union players in New Zealand. Participants were randomized to receive 50,000 IU of cholecalciferol (equivalent to 3,570 IU/day) or placebo once every two weeks over 11-12 weeks. Serum 25(OH)D concentrations and physical performance were measured at baseline, weeks 5-6, and weeks 11-12. Mean (SD) serum 25(OH)D concentrations for all participants at baseline was 94 (18) nmol/L, with all players above 50 nmol/L. Vitamin D supplementation significantly increased serum 25(OH)D concentrations compared to placebo, with a 32 nmol/L difference between groups at 11-12 weeks (95% CI, 26-38; p < 0.001). Performance in five of the six tests at study completion, including the primary outcome variable of 30-m sprint time, did not differ between the vitamin D supplemented and placebo groups (p > 0.05). Performance on the weighted reverse-grip chin up was significantly higher in players receiving vitamin D compared with placebo, by 5.5 kg (95% CI, 2.0-8.9; p = 0.002). Despite significantly improving vitamin D status in these professional rugby union players, vitamin D supplementation had little impact on physical performance outcomes. Thus, it is unlikely that vitamin D supplementation is an ergogenic aid in this group of athletes.

Effects of vitamin D status on oral health

Normal humans of all ages have the innate ability to produce vitamin D following sunlight exposure. Inadequate vitamin D status has shown to be associated with a wide variety of diseases, including oral health disorders. Insufficient sunlight exposure may accelerate some of these diseases, possibly due to impaired vitamin D synthesis. The beneficial effects of vitamin D on oral health are not only limited to the direct effects on the tooth mineralization, but are also exerted through the anti-inflammatory functions and the ability to stimulate the production of anti-microbial peptides. In this article, we will briefly discuss the genesis of various oral diseases due to inadequate vitamin D level in the body and elucidate the potential benefits of safe sunlight exposure for the maintenance of oral and general health.

Sunlight exposure: Do health benefits outweigh harm?

Vitamin D is a fat-soluble vitamin whose levels within the body are elevated following sunlight exposure. Numerous studies have shown that sunlight exposure can provide protection to a wide variety of diseases, ranging from different types of tumors to hypertension to type 1 diabetes to multiple sclerosis. Moreover, studies have shown that avoiding sunlight may influence the initiation and progression of some of these diseases. Avoidance of sunlight, coupled with the inclination towards consuming supplements, is becoming the primary choice to obtain vitamin D. The purpose of this article is to present evidences from published literature, to show that the expected benefits of vitamin D supplements are minimized by the potential risk of cardiovascular events and beyond. Since hypovitaminosis D status usually reflects reduced sunlight exposure, the obvious primary replacement should be safe sunlight exposure, and not exogenous supplements.

Impact of air pollution on vitamin D deficiency and bone health in adolescents

The association between air pollution and bone health was evaluated in adolescents in the city of Tehran. This study is essentially ecological. Vitamin D deficiency among adolescents has been reported at higher rates in polluted areas than in non-polluted areas. Additionally, residence in polluted areas is associated with lower levels of bone alkaline phosphatase.

PURPOSE

The aim of this study was to evaluate the association between ambient air pollution and bone turnover in adolescents and to compare the prevalence of vitamin D deficiency between polluted and non-polluted areas of Tehran.

METHODS

This cross-sectional population-based study was conducted on 325 middle- and high-school students (both girls and boys) in Tehran in the winter. During the study period, detailed daily data on air pollution were obtained from archived data collected by Tehran Air Quality Control Company (AQCC). Serum levels of calcium, phosphorus, parathyroid hormone (PTH), bone-specific alkaline phosphatase, 25(OH) vitamin D, osteocalcin, cross-linked C-telopeptide (CTX), total protein, albumin, and creatinine were obtained from the study group.

RESULTS

Vitamin D deficiency was more prevalent in polluted areas than in non-polluted areas. After adjustment for age and sex, residence in the polluted area showed a statistically significant positive association with vitamin D deficiency and a statistically significant negative association with bone turnover. Interestingly, high calcium intake (>5000 mg/week) protects against the effects of air pollution on bone turnover.

CONCLUSIONS

Air pollution is a chief factor determining the amount of solar UVB that reaches the earth's surface. Thus, atmospheric pollution may play a significant independent role in the development of vitamin D deficiency.