Spot the silent sufferers: A call for clinical diagnostic criteria for solar and nutritional osteomalacia

Metabolic Bone Disease

Metabolic bone diseases encompass a group of disorders characterized by abnormalities in bone metabolism, structure, or mineralization. These disorders negatively impact overall health and quality of life and place individuals at high risk for fracture, which may increase morbidity and mortality. Clinicians should understand who is at risk for these disorders, select individuals who warrant further workup, determine appropriate laboratory and imaging evaluation, interpret results in a clinical context, and choose an optimal management strategy based on the individual patient.

Optimisation of vitamin D status in global populations

Vitamin D is important for musculoskeletal health. Concentrations of 25-hydroxyvitamin D, the most commonly measured metabolite, vary markedly around the world and are influenced by many factors including sun exposure, skin pigmentation, covering, season and supplement use. Whilst overt vitamin D deficiency with biochemical consequences presents an increased risk of severe sequelae such as rickets, osteomalacia or cardiomyopathy and usually warrants prompt replacement treatment, the role of vitamin D supplementation in the population presents a different set of considerations. Here the issue is to keep, on average, the population at a level whereby the risk of adverse health outcomes in the population is minimised. This position paper, which complements recently published work from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, addresses key considerations regarding vitamin D assessment and intervention from the population perspective. This position paper, on behalf of the International Osteoporosis Foundation Vitamin D Working Group, summarises the burden and possible amelioration of vitamin D deficiency in global populations. It addresses key issues including screening, supplementation and food fortification.

Transdermal drug delivery via microneedles for musculoskeletal systems

As the population is ageing and lifestyle is changing, the prevalence of musculoskeletal (MSK) disorders is gradually increasing with each passing year, posing a serious threat to the health and quality of the public, especially the elderly. However, currently prevalent treatments for MSK disorders, mainly administered orally and by injection, are not targeted to the specific lesion, resulting in low efficacy along with a series of local and systemic adverse effects. Microneedle (MN) patches loaded with micron-sized needle array, combining the advantages of oral administration and local injection, have become a potentially novel strategy for the administration and treatment of MSK diseases. In this review, we briefly introduce the basics of MNs and focus on the main characteristics of the MSK systems and various types of MN-based transdermal drug delivery (TDD) systems. We emphasize the progress and broad applications of MN-based transdermal drug delivery (TDD) for MSK systems, including osteoporosis, nutritional rickets and some other typical types of arthritis and muscular damage, and in closing summarize the future prospects and challenges of MNs application.

Osteomalacia Prevalence, Biochemical Profile, and Histology in Patients with Low-Energy Hip Fractures Over the Age of 45

Our objective was to determine the prevalence of osteomalacia in low-energy hip fracture patients over the age of 45, based on biochemical and histological measures. This cross-sectional study included 72 patients over 45 with low-energy mechanism hip fractures. Samples of fasting venous blood were taken for hemograms and serum biochemistry analyses. Bicortical biopsies of the iliac crest were obtained, processed, and evaluated by an expert pathologist for osteomalacia. Biochemical osteomalacia (b-OM) is defined according to a distinct criterion. A low level of serum calcium, phosphorus, albumin, and 25OHD was found in 43.1, 16.7, 73.6, and 59.7% of patients, respectively. 50.0% of patients had high serum alkaline phosphatase (ALP) levels. b-OM was found in 30 (41.7%), and no significant association was found with PTH, Cr, Alb, age, sex, fracture type, side of the trauma, and season were not associated with osteomalacia. Osteomalacia was diagnosed on histopathological analysis in 19/72 (26.7%), and 54/72 (75.0%) of all cases fulfilled b-OM criteria. In the histologic evaluation, osteoid seam width, osteoid surface, and osteoid volume were 28.5 µm, 25.6, and 12.1%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the biochemical test for detecting osteomalacia were 73.6, 64.2, 42.4, 87.2, and 66.7%, respectively. Up to 30% of elderly patients with low-energy hip fractures are affected by osteomalacia. A biochemical screening along with a bone biopsy and histopathologic evaluation may be logical in a high-risk population for osteomalacia diagnosis.

Association of bone mineralization markers with dietary nutrient intake in adolescents with and without biochemical osteomalacia

Background

Dietary intake is widely known to play a crucial role in achieving peak bone mass among children and adolescents. Unfortunately, this information is lacking among Arab adolescents, an understudied demographic that has recently been observed to have a high prevalence of abnormal mineralization markers [low serum 25(OH)D, high serum alkaline phosphatase (ALP), low calcium (Ca) and/or inorganic phosphate (Pi)] suggestive of biochemical osteomalacia (OM, defined as any 2 of the 4 parameters). In order to fill this gap, we aimed to evaluate the associations of serum markers of biochemical OM with dietary intake of macronutrients, vitamins and trace minerals.

Methods

Saudi adolescents (N = 2,938, 57.8% girls), aged 12-17 years from 60 different schools in Riyadh, Saudi Arabia were included. Dietary intake of nutrients was calculated following a semi-quantitative 24 h dietary recall over 3 weekdays and 1 weekend-day using a validated food frequency questionnaire. Compliance to reference daily intake (RDI) of macronutrients, vitamins and trace minerals were calculated. Fasting blood samples were collected and circulating levels of 25(OH)D, ALP, Ca, and Pi were analyzed.

Results

A total of 1819 (1,083 girls and 736 boys) adolescents provided the dietary recall data. Biochemical OM was identified in 175 (9.6%) participants (13.5% in girls, 3.9% in boys, p < 0.01) while the rest served as controls (N = 1,644). All participants had serum 25(OH)D levels <50 nmoL/L. Most participants had very low dietary intakes of Ca (median ~ 290 mg) and vitamin D (median ~ 4 μg) which are far below the RDI of 1,300 mg/day and 20 μg/day, respectively. In contrast, excess dietary intakes of Pi, Na, K, and Fe were observed in all participants. In the biochemical OM group, thiamine and protein intake were significant predictors of serum 25(OH)D, explaining 4.3% of the variance perceived (r = 0.23, adjusted r² = 4.3%, p = 0.01). Among controls, dietary vitamin C and vitamin D explained 0.6% of the total variation in serum 25(OH)D (r = 0.09, adjusted r² = 0.6%, p = 0.004).

Conclusion

Arab adolescents do not meet the RDI for dietary Ca and vitamin D, and none have sufficient vitamin D status (25(OH)D levels >50 nmol/L) but they exceed the RDI for dietary Pi. Interpreting these data in the light of the increased prevalence of rickets in Arab countries, food fortification to optimise vitamin D and Ca intake in Saudi adolescents should be considered.

Nutritional rickets presenting with developmental regression: a rare presentation of rickets

Rickets is a disorder of defective mineralisation of the growth plate. Vitamin D deficiency remains the leading cause of nutritional rickets worldwide.We present the case of a 3.5-year-old breastfed boy who presented with dental abscess when a history of developmental regression was noted. Clinical assessment revealed hypotonia, poor growth and stunting. Biochemistry identified hypocalcaemia (1.63mmol/L, [normal range (NR) 2.2-2.7mmol/L]), severe vitamin D deficiency (25hydroxyvitamin D 5.3nmol/L, [NR > 50nmol/L]) with secondary hyperparathyroidism (Parathormone 159pmol/L, [NR 1.6-7.5pmol/L]) and rickets on radiographs. Growth failure screening suggested hypopituitarism with central hypothyroidism and low IGF1 at baseline, however, dynamic tests confirmed normal axis. Management included nasogastric nutritional rehabilitation, cholecalciferol and calcium supplementation and physiotherapy. A good biochemical response in all parameters was observed within 3 weeks and reversal of developmental regression by 3 months from treatment. Developmental regression as a presentation of nutritional rickets is rare and requires a high index of suspicion.

Vitamin D Deficiency in Chronic Childhood Disorders: Importance of Screening and Prevention

Vitamin D plays a vital role in regulating calcium and phosphate metabolism and maintaining bone health. A state of prolonged or profound vitamin D deficiency (VDD) can result in rickets in children and osteomalacia in children and adults. Recent studies have demonstrated the pleiotropic action of vitamin D and identified its effects on multiple biological processes in addition to bone health. VDD is more prevalent in chronic childhood conditions such as long-standing systemic illnesses affecting the renal, liver, gastrointestinal, skin, neurologic and musculoskeletal systems. VDD superimposed on the underlying disease process and treatments that can adversely affect bone turnover can all add to the disease burden in these groups of children. The current review outlines the causes and mechanisms underlying poor bone health in certain groups of children and young people with chronic diseases with an emphasis on the proactive screening and treatment of VDD.

Osteomalacia in Adults: A Practical Insight for Clinicians

The term osteomalacia (OM) refers to a series of processes characterized by altered mineralization of the skeleton, which can be caused by various disorders of mineral metabolism. OM can be genetically determined or occur due to acquired disorders, among which the nutritional origin is particularly relevant, due to its wide epidemiological extension and its nature as a preventable disease. Among the hereditary diseases associated with OM, the most relevant is X-linked hypophosphatemia (XLH), which manifests in childhood, although its consequences persist into adulthood where it can acquire specific clinical characteristics, and, although rare, there are XLH cases that reach the third or fourth decade of life without a diagnosis. Some forms of OM present very subtle initial manifestations which cause both considerable diagnosis and treatment delay. On occasions, the presence of osteopenia and fragility fractures leads to an erroneous diagnosis of osteoporosis, which may imply the prescription of antiresorptive drugs (i.e., bisphosphonates or denosumab) with catastrophic consequences for OM bone. On the other hand, some radiological features of OM can be confused with those of axial spondyloarthritis and lead to erroneous diagnoses. The current prevalence of OM is not known and is very likely that its incidence is much higher than previously thought. Moreover, OM explains part of the therapeutic failures that occur in patients diagnosed with other bone diseases. Therefore, it is essential that clinicians who treat adult skeletal diseases take into account the considerations provided in this practical review when focusing on the diagnosis and treatment of their patients with bone diseases.

Rolling circle transcription/G-quadruplex/QnMorpholine probe for highly selective and sensitive detection of alkaline phosphatase activity

In this study, we combined a rolling circle transcription (RCT) system producing 22AG G-quadruplex RNA with a QnMorpholine (QNM) fluorescent probe for the selective and sensitive detection of alkaline phosphatase (ALP). ALP is involved in various biological functions, with monophosphate cleavage being one of its characteristic properties. Here, we developed a padlock RCT probing system in which a large amount of RCT 22AG RNA G-quadruplex was produced in the absence of ALP, providing a high fluorescence signal. In contrast, no RNA G-quadruplex was produced in the presence of ALP, with minimal fluorescence. This huge deviation in signal intensity allowed us to identify the presence or absence of ALP in a test sample. Under practical conditions, our system allowed the differentiation for ALP even when it was present at an extremely low concentration (0.0085 U/L), along with very high specificity. The simplicity and efficiency of this approach for ALP detection suggest its potential for use as a reliable diagnostic tool.

Bariatric Surgery and Vitamin D: Trends in Older Women and Association with Clinical Features and VDR Gene Polymorphisms

(1) Background: Obesity and its comorbidities can cause burdens and limitations. Bariatric surgery (BS) is indicated as a safe procedure to reduce body mass and improve present comorbidities. However, several complications were reported, such as vitamin D [25(OH)D] deficiency. We evaluated if 25(OH)D serum levels relate to clinical characteristics, symptoms, or habits in women after their BS, and whether the vitamin D receptor (VDR) gene's TaqI and FokI polymorphisms affected 25(OH)D levels and the total body bone mineral density (TBBMD). (2) Methods: This cohort cross-sectional comparative analytical prospective study consisted of 27 women, 61.6 ± 5.0 years, submitted to BS one year prior at a public reference hospital, DF-Brazil. All participants were asked to follow the physical and dietary activity recommendations and received vitamin D3 supplements. Their anthropometric, biochemical, and immunological measurements and blood samples were obtained. (3) Results: 73.3% of participants had low 25(OH)D levels, and their levels correlated positively with TBBMD and negatively with systolic pressure. VDR TaqI did not affect 25(OH)D levels, whereas VDR FokI's allele f presence correlated to a median rise in 25(OH)D levels. Neither polymorphism correlated to TBBMD. (4) Conclusions: 25(OH)D levels were positively correlated with TBBMD, negatively with systolic blood pressure, and were higher in those with the VDR FokI allele f.

Establishing the Prevalence of Osteomalacia in Arab Adolescents Using Biochemical Markers of Bone Health

Nutrition-acquired osteomalacia is a bone mineralization disorder associated with dietary calcium and/or solar vitamin D deficiency, risk factors considered common in the Middle Eastern region. Establishing less invasive, cheap, and widely available diagnostic markers for this underdiagnosed entity is essential, in particular for screening in high-risk groups. This study assessed the prevalence of biochemical osteomalacia in Arab adolescents. In this cross-sectional study performed between September 2019 and March 2021, adolescents aged 12−17 years from 60 different secondary and preparatory year schools in Riyadh, Saudi Arabia were included. Anthropometrics and fasting blood samples were collected. Biochemical osteomalacia was defined as any two of the following four serum markers of hypomineralization, namely low 25 hydroxyvitamin D (25OHD < 30 nmol/L), high alkaline phosphatase (ALP), low calcium (Ca), and/or inorganic phosphorous (Pi). A total of 2938 Arab adolescents [1697 girls; mean age (years) 14.8 ± 1.8; 1241 boys; mean age 15.1 ± 1.6] were recruited. Vitamin D deficiency was noted in 56.2% (n = 953) of girls and 27.1% (n = 336) of boys (p < 0.001). The overall prevalence of biochemical osteomalacia was 10.0% (n = 295/2938) and was higher in girls than boys (14.7% vs. 3.6%, p < 0.001). The prevalence of low serum Ca and/or Pi was also higher in girls than in boys (24.2% vs. 12.5%, respectively, p < 0.001), as well as elevated ALP (5.1% vs. 1.5%, p < 0.001). Overall, girls were 4.6 times (95% CI 3.3−6.4) more likely to have biochemical osteomalacia than boys. Screening of apparently healthy Arab adolescents revealed a high prevalence of deranged mineralization markers suggestive of biochemical osteomalacia, which was significantly more common in girls than boys and was likely associated with Arab traditional clothing and diet. The proposed combination of typically altered mineralization markers for the diagnosis of osteomalacia is, at best, suggestive until further comparisons with established diagnostic tools (histological analysis of bone biopsies) are conducted.

Atraumatic Displaced Femoral Neck Insufficiency Fracture Because of Severe Hypocalcemia in a Pediatric Patient: A Case Report

CASE

This is a case of a 14-year-old autistic boy who presented with an atraumatic transcervical femoral neck fracture in the setting of significant hypocalcemia and vitamin D deficiency. We discuss his surgical and medical management and metabolic derangements associated with atraumatic femoral neck fractures.

CONCLUSION

Pediatric femoral neck fractures in the absence of trauma are uncommon and often have underlying metabolic abnormalities. In addition, autism poses unique challenges in caring for these patients who are at an increased risk of complications. Interdisciplinary care is integral to achieving successful outcomes.

Adiposity Metabolic Consequences for Adolescent Bone Health

Infancy and adolescence are crucial periods for bone health, since they are characterized by intense physical growth and bone development. The unsatisfactory acquisition of bone mass in this phase has consequences in adult life and increases the risk of developing bone diseases at more advanced ages. Nutrient deficiencies, especially calcium and vitamin D, associated with a sedentary lifestyle; lack of sun exposure; and epigenetic aspects represent some of the main risk factors for poor bone quality. In addition, recent studies relate childhood obesity to impaired bone health; however, studies on the adiposity effects on bone health are scarce and inconclusive. Another gap concerns the implications of obesity on child sexual maturity, which can jeopardize their genetic potential bone mass and increase fracture risk. Therefore, we reviewed the analyzed factors related to bone health and their association with obesity and metabolic syndrome in adolescents. We concluded that obesity (specifically, accumulated visceral fat) harms bones in the infant–juvenile phase, thereby increasing osteopenia/osteoporosis in adults and the elderly. Thus, it becomes evident that forming and maintaining healthy eating habits is necessary during infancy and adolescence to reduce the risk of fractures caused by bone-metabolic diseases in adulthood and to promote healthy ageing.

Verminderte Mineralisation des Knochens: Rachitis und Osteomalazie

Die Mineralisation der Wachstumsfuge und des Knochens benötigt suffiziente Mengen an Kalzium und Phosphat, um ein adäquates Körperwachstum und eine adäquate Knochenstärke zu gewährleisten. Bei Mangelzuständen nehmen Härte und Stärke des Knochens ab (Osteomalazie), mit typischen Veränderungen an der Wachstumsfuge (Rachitis). Die vermeidbaren Komplikationen einer erworbenen Rachitis können lebensbedrohlich sein und sind auch deshalb ein global wichtiges Public-Health-Thema. Typische klinische Zeichen, Laborparameter und radiologische Veränderungen sollten zur unverzüglichen Diagnose führen. Erbliche und erworbene Formen der Rachitis wie X‑chromosomale Hypophosphatämie oder Hypophosphatasie werden, wie oftmals bei seltenen Erkrankungen, spät diagnostiziert. Diagnose, Therapie und Management von Rachitiden sollten durch tertiäre kinderosteologische Spezialisten erfolgen, die in internationalen „Rare-diseases“-Netzwerken arbeiten und in enger Kooperation mit Selbsthilfegruppen stehen.

The burden of vitamin D deficiency in household members of children presenting with symptomatic vitamin D deficiency

BACKGROUND

Micronutrient deficiencies are common among household/family members due to shared lifestyle and dietary habits. The extent of biochemical abnormalities in household members of children presenting with symptomatic vitamin D deficiency remains unknown.

AIM

Investigate the prevalence of vitamin D deficiency and biochemical osteomalacia in the mothers and siblings of children presenting with symptomatic vitamin D deficiency.

METHODS

All mothers and sibling of children referred to a single tertiary endocrine centre between January 2018 and December 2021, with symptomatic vitamin D deficiency were investigated prospectively for vitamin D deficiency [defined as 25 hydroxyvitamin D (25OHD) < 30nmol/L] and biochemical osteomalacia [vitamin D deficiency and elevated alkaline phosphatase (ALP) and/or parathormone (PTH)] as per clinical guidelines.

REULTS

Ninety-seven family members (68 siblings and 29 mothers) of 29 index cases (median age 1.7 years, 55.5% male) were investigated. The majority (65.5%, n=19) were of Asian ethnic background. The mean (SD) 25OHD levels of the index, maternal and sibling cohorts were 15 (10), 15 (7) and 20 (10) nmol/L respectively. Vitamin D deficiency was noted in 93% of the maternal and 79% of the sibling cohorts. Biochemical osteomalacia was present in 72% of the maternal and 79% of the sibling cohorts. Mothers of infants had significantly lower mean 25OHD levels compared to mothers of older children [11 (n=12) vs 18 nmol/L (n=17) respectively, p=0.006)], most of whom were symptomatic (66.6%, n=8/12). None of the mothers had hypocalcaemia. Among the 10% (n=7) of the siblings with hypocalcaemia, 86% (n=6/7) had concurrent dietary calcium deficiency and 71.4% (n= 5/7) reported symptoms in retrospect. Hypocalcaemic siblings had significantly lower 25OHD (7 vs 15 nmol/L, p<0.001), higher PTH (175 vs 58 ng/L, p<0.001) and ALP (846 vs 318 IU/L, p<0.001), respectively compared to normocalcaemic siblings.

CONCLUSIONS

In view of the substantial morbidity uncovered in household/family members of children diagnosed with symptomatic vitamin D deficiency, we recommend universal supplementation of all risk groups. Biochemical testing and treatment is indicated to replenish stores only in those at highest risk such as mothers of infants, individuals with concurrent dietary calcium deficiency and those with clinical symptoms.

Bone Phenotyping Approaches in Human, Mice and Zebrafish - Expert Overview of the EU Cost Action GEMSTONE ("GEnomics of MusculoSkeletal traits TranslatiOnal NEtwork")

A synoptic overview of scientific methods applied in bone and associated research fields across species has yet to be published. Experts from the EU Cost Action GEMSTONE ("GEnomics of MusculoSkeletal Traits translational Network") Working Group 2 present an overview of the routine techniques as well as clinical and research approaches employed to characterize bone phenotypes in humans and selected animal models (mice and zebrafish) of health and disease. The goal is consolidation of knowledge and a map for future research. This expert paper provides a comprehensive overview of state-of-the-art technologies to investigate bone properties in humans and animals - including their strengths and weaknesses. New research methodologies are outlined and future strategies are discussed to combine phenotypic with rapidly developing -omics data in order to advance musculoskeletal research and move towards "personalised medicine".

Tension-Sided Femoral Neck Stress Fracture in an Adolescent with Vitamin D Deficiency and Osteomalacia: A Case Report

CASE

An adolescent girl presented with groin pain without any history of trauma. Imaging showed a tension-sided stress fracture of the femoral neck. Vitamin D deficiency (VDD), and raised alkaline phosphatase and parathyroid hormone levels were found. Pain relief was not achieved with nonoperative treatment. Considering the risk of fracture progression and displacement, the fracture was fixed with cannulated cancellous screws. Fracture healed without any complications.

CONCLUSION

A tension-sided femoral neck stress fracture, with VDD and osteomalacia, is a rare cause of hip pain in an adolescent. Surgical fracture stabilization is necessary in addition to medical treatment.

Nutritional rickets & osteomalacia: A practical approach to management

Defective mineralization of the growth plate and preformed osteoid result in rickets and osteomalacia, respectively. The leading cause of rickets worldwide is solar vitamin D deficiency and/or dietary calcium deficiency collectively termed as nutritional rickets. Vitamin D deficiency predominates in high-latitude countries in at-risk groups (dark skin, reduced sun exposure, infants and pregnant and lactating women) but is emerging in some tropical countries due to sun avoidance behaviour. Calcium deficiency predominates in tropical countries, especially in the malnourished population. Nutritional rickets can have devastating health consequences beyond bony deformities (swollen wrist and ankle joints, rachitic rosary, soft skull, stunting and bowing) and include life-threatening hypocalcaemic complications of seizures and, in infancy, heart failure due to dilated cardiomyopathy. In children, diagnosis of rickets (always associated with osteomalacia) is confirmed on radiographs (cupping and flaring of metaphyses) and should be suspected in high risk individuals with the above clinical manifestations in the presence of abnormal blood biochemistry (high alkaline phosphatase and parathyroid hormone, low 25-hydroxyvitamin D and calcium and/or low phosphate). In adults or adolescents with closed growth plates, osteomalacia presents with non-specific symptoms (fatigue, malaise and muscle weakness) and abnormal blood biochemistry, but only in extreme cases, it is associated with radiographic findings of Looser's zone fractures. Bone biopsies could confirm osteomalacia at earlier disease stages, for definitive diagnosis. Treatment includes high-dose cholecalciferol or ergocalciferol daily for a minimum of 12 wk or stoss therapy in exceptional circumstances, each followed by lifelong maintenance supplementation. In addition, adequate calcium intake through diet or supplementation should be ensured. Preventative approaches should be tailored to the population needs and incorporate multiple strategies including targeted vitamin D supplementation of at-risk groups and food fortification with vitamin D and/or calcium. Economically, food fortification is certainly the most cost-effective way forward.

Efficacy of Calcium-Containing Eggshell Powder Supplementation on Urinary Fluoride and Fluorosis Symptoms in Women in the Ethiopian Rift Valley

Dietary calcium binds Fluoride (F), thus preventing excess F absorption. We aimed to assess the efficacy of supplementing calcium-containing Eggshell Powder (ESP) on F absorption using urine F excretion and on fluorosis symptoms. In total, 82 women (41 Intervention Group, IG; 41 Control Group, CG) were recruited; overall, 39 in each group completed the trial. Morning spot urine was collected before (baseline, BL) and after (endline, EL) the intervention that was 6-months daily supplementation with 2.4 g ESP (providing ~1000 mg of calcium). Dental, skeletal, and non-skeletal fluorosis assessments was carried out at BL and, except for dental, at EL. Relative risk (RR) and linear generalized estimating equation were used to compare outcomes between groups. At BL, urinary F excretion in the IG and CG groups was similar, ~10 mg/L. At EL, urinary F excretion in IG women was six-fold lower (β = -6.1 (95% CI: -7.1, -5.1)) compared to CG. The risk of developing skeletal and non-skeletal fluorosis were significantly (p < 0.001) reduced in the intervention group. A significant reduction in urinary F excretion and reduction in many fluorosis symptoms were observed among women supplemented with calcium-containing ESP, thus providing evidence for using this dietary calcium source for mitigation of fluorosis. Clinical trials registration: NCT03355222.

Failure of national antenatal vitamin D supplementation programme puts dark skinned infants at highest risk: A newborn bloodspot screening study

OBJECTIVES

To determine the prevalence of vitamin D deficiency on dried blood spots (DBS) obtained at newborn blood spot screening (NBS) and thereby test the efficacy of the UK national antenatal supplementation programme in an increasingly ethnically diverse English population. To evaluate the seasonal and ethnic variation in neonatal plasma 25 hydoxyvitamin D (25OHD) and its determinants.

DESIGN

Three thousand random DBS samples received at a single regional newborn screening laboratory (52° N) over two one-week periods, one in winter (February 2019) and one in summer (August 2019), were collected. Data was collected from NBS cards on birth weight, gestational age, maternal age, ethnicity, and post code which was replaced with index of multiple deprivation (IMD). 25OHD concentrations were measured on 6 mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry adjusted to equivalent plasma values. 25OHD variation with season was assessed using Mann-Whitney U test and ethnic groups compared using Kruskal-Wallis test. Linear regression was used to assess the determinants of 25OHD concentrations.

RESULTS

25OHD measurements were available in 2999 (1580 males) subjects [1499 winter-born and 1500 summer-born]. The majority were white British (59.1%) and born at term (mean ± SD gestational age of 38.8 ± 1.8 weeks) with a mean (±SD) birth weight of 3306 (±565) grams. The overall prevalence of vitamin D deficiency [25OHD<30 nmol/L (12 μg/L)] was 35.7% (n = 1070) and insufficiency [30-50 nmol/L (12-20 μg/L)] 33.7% (n = 1010). The median (IQR) 25OHD concentration was significantly lower in the winter-born compared to summer-born [29.1 (19.8, 40.6) vs 49.2 (34.3, 64.8) nmol/L respectively; p < 0.001]. Across both seasons, when compared to white British babies (41.6 nmol/L), the median 25OHD concentrations were significantly lower in babies of black (30.3 nmol/L; p < 0.001), Asian (31.3 nmol/L; p < 0.001), any other mixed (32.9 nmol/L; p < 0.001), mixed white and black (33.7 nmol/L; p < 0.05) and any other white (37.7 nmol/L; p < 0.05) ethnicity. The proportion of deficiency was also higher in babies of Asian (48%), black (47%) and mixed ethnicity (38-44%) compared to any other white (34%) or white British (30%) ethnicity. Season of birth, ethnicity, gestation and maternal age accounted for almost 24% of the variation in 25OHD concentrations.

CONCLUSION

The current UK antenatal supplementation programme fails to protect newborns from vitamin D deficiency, especially those from minority ethnic groups who are at high risk of vitamin D deficiency. Nearly 70% of all newborns and 85% of winter-borns had 25OHD concentrations below 50 nmol/L (20 μg/L). Almost 50% of babies of Black or Asian origin were deficient at birth, which explains their high risk of hypocalcaemic complications and rickets if left unsupplemented. Our findings call for an immediate review of the delivery of antenatal and infant vitamin D supplementation programmes and implementation of food fortification in the long term.

Kombinierte Vitamin-D- und Vitamin-K-Supplemente für Kinder und Jugendliche: Nutzen oder Risiko?

Eine tägliche Vitamin-D-Supplementierung für Säuglinge bis zum zweiten erlebten Frühsommer zur Prävention der Rachitis und die Gabe von Vitamin K1 bei Neugeborenen zur Prävention von Vitamin-K-Mangel-Blutungen sind empfohlen.

Seit einiger Zeit sind in Österreich Kombinationsprodukte der beiden fettlöslichen Vitamine D3 und K2 auf dem Markt erhältlich, die mit gesundheitsfördernden Effekten wie verbesserter Knochenmineralisation und Schutz vor vaskulärer Kalkeinlagerung beworben werden.

Die Wirkung einer kombinierten Supplementierung von Vitamin D und Vitamin K2 bei Kindern ist aus physiologischer Sicht gesehen zwar potenziell sinnvoll, um Effekt, Risiken oder unerwünschte Nebenwirkungen zu evaluieren. Zuvor werden aber Dosisfindungs- und Sicherheitsstudien für die kombinierte Verabreichung benötigt. Insbesondere sind randomisierte kontrollierte Studien bei Risikokindern und Frühgeborenen notwendig. Solange diese Daten nicht vorliegen, erscheint die Gabe von Vitamin D in Kombination mit Vitamin K2 im Kindesalter nicht gerechtfertigt und kann daher auch nicht empfohlen werden.

Vitamin D in Toddlers, Preschool Children, and Adolescents

BACKGROUND

Vitamin D supplementation is known to both prevent and treat rickets, a disease of hypomineralized bone. Childhood is a period of great bone development and, therefore, attention to the vitamin D needed to optimize bone health in childhood is imperative.

SUMMARY

Observational studies have pointed to a vitamin D status, as indicated by a 25-hydroxyvitamin D concentration, of 50 nmol/L to ensure avoidance of rickets and of 75 nmol/L to optimize health. However, the benefits of achieving these levels of vitamin D status are less evident when pediatric randomized, controlled trials are performed. In fact, no specific pediatric vitamin D supplementation has been established by the existing evidence. Yet, study of vitamin D physiology continues to uncover further potential benefits to vitamin D sufficiency. This disconnection between vitamin D function and trials of supplementation has led to new paths of investigation, including establishment of the best method to measure vitamin D status, examination of genetic variation in vitamin D metabolism, and consideration that vitamin D status is a marker of another variable, such as physical activity, and its association with bone health. Nevertheless, vitamin D supplementation in the range of 10-50 μg/day appears to be safe for children and remains a promising intervention that may yet be supported by clinical trials as a method to optimize pediatric health. Key Message: Pediatric vitamin D status is associated with avoidance of rickets. Randomized, controlled trials of vitamin D supplementation for pediatric bone health are limited and equivocal in their results. Beyond bone, decreased risk for autoimmune, infectious, and allergic diseases has been associated with higher vitamin D status. The specific vitamin D supplementation to optimize toddler, child, and adolescent outcomes is unknown, but doses 10-50 μg/day are safe and may be beneficial.

Low bone mineral density due to secondary hyperparathyroidism in the GlatmTg(CAG-A4GALT) mouse model of Fabry disease

Low bone mineral density (BMD)-diagnosed as osteoporosis or osteopenia-has been reported as a new characteristic feature of Fabry disease; however, the mechanism underlying the development of low BMD is unknown. We previously revealed that a mouse model of Fabry disease [GlatmTg(CAG-A4GALT)] exhibits impaired functioning of medullary thick ascending limb (mTAL), leading to insufficient Ca2+ reabsorption and hypercalciuria. Here, we investigated bone metabolism in GlatmTg(CAG-A4GALT) mice without marked glomerular or proximal tubular damage. Low BMD was detected by 20 weeks of age via micro-X-ray-computed tomography. Bone histomorphometry revealed that low BMD results by accelerated bone resorption and osteomalacia. Plasma parathyroid hormone levels increased in response to low blood Ca2+-not plasma fibroblast growth factor 23 (FGF-23) elevation-by 5 weeks of age and showed progressively increased phosphaturic action. Secondary hyperparathyroidism developed by 20 weeks of age and caused hyperphosphatemia, which increased plasma FGF-23 levels with phosphaturic action. The expression of 1α-hydroxylase [synthesis of 1α,25(OH)2D3] in the kidney did not decrease, but that of 24-hydroxylase [degradation of 1α,25(OH)2D3] decreased. Vitamin D deficiency was ruled out as the cause of osteomalacia, as plasma 1α,25(OH)2D3 and 25(OH)D3 levels were maintained. Results demonstrate that secondary hyperparathyroidism due to mTAL impairment causes accelerated bone resorption and osteomalacia due to hyperphosphaturia and hypercalciuria, leading to low BMD in Fabry model mice.