Vitamin D deficiency and prevention: Turkish experience

Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Numerous studies demonstrate associations between serum concentrations of 25-hydroxyvitamin D (25[OH]D) and a variety of common disorders, including musculoskeletal, metabolic, cardiovascular, malignant, autoimmune, and infectious diseases. Although a causal link between serum 25(OH)D concentrations and many disorders has not been clearly established, these associations have led to widespread supplementation with vitamin D and increased laboratory testing for 25(OH)D in the general population. The benefit-risk ratio of this increase in vitamin D use is not clear, and the optimal vitamin D intake and the role of testing for 25(OH)D for disease prevention remain uncertain.

OBJECTIVE

To develop clinical guidelines for the use of vitamin D (cholecalciferol [vitamin D3] or ergocalciferol [vitamin D2]) to lower the risk of disease in individuals without established indications for vitamin D treatment or 25(OH)D testing.

METHODS

A multidisciplinary panel of clinical experts, along with experts in guideline methodology and systematic literature review, identified and prioritized 14 clinically relevant questions related to the use of vitamin D and 25(OH)D testing to lower the risk of disease. The panel prioritized randomized placebo-controlled trials in general populations (without an established indication for vitamin D treatment or 25[OH]D testing), evaluating the effects of empiric vitamin D administration throughout the lifespan, as well as in select conditions (pregnancy and prediabetes). The panel defined "empiric supplementation" as vitamin D intake that (a) exceeds the Dietary Reference Intakes (DRI) and (b) is implemented without testing for 25(OH)D. Systematic reviews queried electronic databases for publications related to these 14 clinical questions. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and guide recommendations. The approach incorporated perspectives from a patient representative and considered patient values, costs and resources required, acceptability and feasibility, and impact on health equity of the proposed recommendations. The process to develop this clinical guideline did not use a risk assessment framework and was not designed to replace current DRI for vitamin D.

RESULTS

The panel suggests empiric vitamin D supplementation for children and adolescents aged 1 to 18 years to prevent nutritional rickets and because of its potential to lower the risk of respiratory tract infections; for those aged 75 years and older because of its potential to lower the risk of mortality; for those who are pregnant because of its potential to lower the risk of preeclampsia, intra-uterine mortality, preterm birth, small-for-gestational-age birth, and neonatal mortality; and for those with high-risk prediabetes because of its potential to reduce progression to diabetes. Because the vitamin D doses in the included clinical trials varied considerably and many trial participants were allowed to continue their own vitamin D-containing supplements, the optimal doses for empiric vitamin D supplementation remain unclear for the populations considered. For nonpregnant people older than 50 years for whom vitamin D is indicated, the panel suggests supplementation via daily administration of vitamin D, rather than intermittent use of high doses. The panel suggests against empiric vitamin D supplementation above the current DRI to lower the risk of disease in healthy adults younger than 75 years. No clinical trial evidence was found to support routine screening for 25(OH)D in the general population, nor in those with obesity or dark complexion, and there was no clear evidence defining the optimal target level of 25(OH)D required for disease prevention in the populations considered; thus, the panel suggests against routine 25(OH)D testing in all populations considered. The panel judged that, in most situations, empiric vitamin D supplementation is inexpensive, feasible, acceptable to both healthy individuals and health care professionals, and has no negative effect on health equity.

CONCLUSION

The panel suggests empiric vitamin D for those aged 1 to 18 years and adults over 75 years of age, those who are pregnant, and those with high-risk prediabetes. Due to the scarcity of natural food sources rich in vitamin D, empiric supplementation can be achieved through a combination of fortified foods and supplements that contain vitamin D. Based on the absence of supportive clinical trial evidence, the panel suggests against routine 25(OH)D testing in the absence of established indications. These recommendations are not meant to replace the current DRIs for vitamin D, nor do they apply to people with established indications for vitamin D treatment or 25(OH)D testing. Further research is needed to determine optimal 25(OH)D levels for specific health benefits.

Effect of vitamin D deficiency on postorthodontic relapse: An animal study

OBJECTIVES

This study aims to evaluate the effect of vitamin D deficiency (VDD) on orthodontic tooth movement (OTM), retention, and relapse and to assess the effect of systemic administration of vitamin D (VD) in a rat model.

MATERIALS AND METHODS

A total of 32 male Wistar rats were divided into two groups, a control group of 11 rats and an experimental group of 21 rats with VDD, after enhancement using a custom diet. Of the VDD group, 11 rats were supplemented with systemic vitamin D3 and categorized as vitamin (VD supplement [VDS]) groups. The VDS group received 40,000 IU/kg via intramuscular injection on Days 1 and 15 of the orthodontic treatment period. A modified orthodontic appliance was fitted to apply 0.5 N of force to move the maxillary right first molars mesially for 14 days, followed by retention and relapse periods for 7 days. Space created during OTM was measured and reassessed after the retention and relapse periods. The relapse ratio was estimated, and histomorphometric analysis was performed to assess the number of osteoblasts, osteoclast bone cells, and bone area.

RESULTS

A significant increase in the relapse ratio and a reduction in osteoblast cells and bone area were observed in the VDD group. By contrast, the amount of tooth movement was significantly higher together with osteoblast cells and bone marrow in VDS with a significant reduction in relapse ratio.

CONCLUSION

VDD was associated with a significant reduction in osteoblast cell count and total bone area in addition to a significant increase in relapse ratio. Routine screening of VD may be beneficial before commencing orthodontic treatment.

Comparison of cord blood and 6-month-old vitamin D levels of healthy term infants supplemented with 400 IU/day dose of vitamin D

OBJECTIVES

To determine the prevalence and risk factors of vitamin D deficiency in pregnant women and their infants at birth (cord blood) and at six months of age in Turkey, as well as to assess the compliance rates of families with vitamin D supplementation.

METHODS

Serum 25-hydroxyvitamin D [25(OH)D] level was measured of the mothers before delivery and of the infants both at birth (cord blood) and at six months of age. Infants who received and did not take regular vitamin D supplements were compared in terms of 25(OH) levels. Independent risk factors were determined by multiple logistic regression analysis.

RESULTS

The study included a total of 140 pregnant women and their infants. Vitamin D deficiency was found in 95.7% of the mothers. The prevalence of vitamin D deficiency was 87.1% in infants at birth but decreased to 5.8% at sixth month. 65.7% of infants received vitamin D supplements regularly. Despite regular vitamin D use, it was determined that 2.2% of the infants in the supplementation compliant group had vitamin D deficiency. Maternal age, maternal education level, and the number of siblings were determined to be determining factors on infants' 25(OH)D levels at six months (p < 0.05).

CONCLUSIONS

In Turkey, vitamin D deficiency still exists in both pregnant women and infants. Healthcare professionals and the public need to be more educated about the importance of regular supplementation. Serum 25(OH)D levels of infants should be tested periodically and personalized vitamin D supplementation planning is required based on test results.

Use of Parathyroid Function Index and Wisconsin Index to Differentiate Primary Hyperparathyroidism From Secondary Hyperparathyroidism: A Case-Control Study

Introduction: Patients with primary hyperparathyroidism (PHPT) can be asymptomatic or have a normal calcium level (NHPT). Patients with 25(OH) vitamin D insufficiency, on the other hand, may present with a similar presentation. In regions where 25(OH) vitamin D deficiency is common, patients are usually diagnosed with secondary hyperparathyroidism (SHPT). Therefore, it is necessary to separate PHPT and NHPT from SHPT. Parathormone and calcium values are used for differentiation in the clinic. The predictive value of the newly developed parathyroid function test (PFindex), which previously had a high diagnostic value, was evaluated in this patient population in our investigation.

Methods: The study comprised 163 PHPT and NHPT patients with pathological confirmation and 56 SHPT patients. The PHPT, NHPT, and SHPT properties were defined using PFindex. The diagnostic power of PFindex was investigated using a receiver operating characteristic (ROC) curve of the results assessed in three groups.

Results: The PHPT group had the highest PFindex (1365.4±784.6) compared to the other two groups (NHPT: 723.5±509.4; SHPT:227.2±49.9, all p < 0.001). A PFindex threshold of 327.8 yielded 91.9% and 90.9% sensitivity and specificity rates for distinguishing PHPT and NHPT from SHPT, respectively.

Conclusion: PFindex gave the outstanding diagnostic capacity to distinguish PHPT from SHPT due to our research. This straightforward tool can assist in making quick decisions about vitamin D therapy or surgery for PHPT.

Factors influencing initiation and discontinuation of vitamin D supplementation among children 1-24-months-old

OBJECTIVES

To determine vitamin D supplementation frequency among children aged 1-24 months, factors that influence adherence, and reasons for discontinuation of initiated vitamin D.

METHODS

This cross-sectional study was conducted using a questionnaire administered to the mothers via face-to-face interview of 560 children aged from 1 to 24 months admitted to outpatient clinics from June to December 2017.

RESULTS

A total of 351 children were administered vitamin D, and the rate of supplementation in the first year of life was 83%, while it was only 28% between 13 and 24 months. The rate of vitamin D supplementation was higher among exclusively formula-fed children (p < .05). When the data were analyzed using logistic regression analysis, only visit family physicians were statistically significant independent variable in increasing supplementation (p < .05). Compared with family refusal, the rate of discontinuation of vitamin D by the healthcare providers was higher after the first year of life (p < .05). The rate of vitamin D discontinuation by healthcare providers, especially by nurses who considered the duration of supplementation adequate, was statistically significantly higher when compared with the fontanel closure and other independent variables (p < .05).

CONCLUSION

The rate of vitamin D supplementation was higher among families who visited family physicians, which suggests the importance of well-baby visits. Since vitamin D supplementation was less common among exclusively breastfed children, mothers should be educated. Healthcare professionals need further education about the importance of vitamin D supplementation and indications for discontinuation.

Questioning the adequacy of standardized vitamin D supplementation protocol in very low birth weight infants: a prospective cohort study

OBJECTIVES

Preterm infants are at increased risk for vitamin D deficiency (VDD). We aimed to assess the adequacy of standardized vitamin D supplementation protocol in very low birth weight (VLBW) infants. Additionally, vitamin D status of mother/infant couples and the associations between vitamin D status at birth and morbidities of the infants were investigated.

METHODS

In this single-center, prospective cohort study blood samples were collected from 55 mothers just before delivery and from their infants at birth and on the 30th day of life (DOL) for 25 hydroxy vitamin D (25OHD) measurements. Vitamin D was initiated in dose of 160 IU/kg by parenteral nutrition on the first DOL and oral vitamin D supplementation (400 IU/day) was administered when enteral feedings reached 50% of total intake or on the 15th DOL.

RESULTS

The median 25OHD levels of the infants were 16.12 (9.14-20.50) in cord blood and 36.32 (31.10-44.44) in venous blood on the 30th DOL (p<0.01). In 98% of the VLBW infants 25OHD reached sufficient levels on the 30th DOL. None of the mothers had sufficient vitamin D levels (25OHD >30 ng/mL). Maternal 25OHD levels were correlated with the 25OHD levels of the infants in cord blood (r=0.665, p<0.001). There was a significant difference in mean cord 25OHD levels between winter (13.65 ± 5.69 ng/mL) and summer seasons (19.58 ± 11.67 ng/mL) (p=0.021). No association was found between neonatal morbidity and vitamin D status.

CONCLUSIONS

The results clearly show that by utilizing the current supplementation protocol, the majority of VLBW infants with deficient/insufficient serum 25OHD levels reached sufficient levels on the 30th DOL. Furthermore, vitamin D levels in mother/infant couples were found to be highly correlated.

Trends in Vitamin D Status Around the World

Vitamin D status varies across all continents and countries. Vitamin D status usually is adequate in Latin America and Australia, but in contrast it is very low in the Middle East and some countries in Asia. Trends in vitamin D status, whether it improves or declines over the years, carry important messages. Trends usually are small, but can be predictors and indicators of general health. Vitamin D status has improved in the older population in the United States, and improvement relates to dairy use and vitamin D supplements. To the contrary, vitamin D status has declined in the Inuit population of Canada due to a change from a traditional fish diet to a Western diet. A large improvement was seen in Finland after mandatory fortification of dairy products was introduced. Determinants of decline are less sun exposure, increased use of sunscreen, increase of body mass index (BMI), less physical activity, and poor socioeconomic status. Determinants of increase are food fortification with vitamin D and vitamin D supplements. Food fortification can lead to a population-wide increase in vitamin D status as shown by the Finnish example. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Vitamin D Deficiency Prevalence in Late Neonatal Hypocalcemia: A Multicenter Study

OBJECTIVE

Late neonatal hypocalcemia (LNH) is a common metabolic problem associated with hypoparathyroidism, high phosphate intake and vitamin D deficiency, often presenting with seizures. In this cross-sectional study, we aimed to evaluate the role of vitamin D deficiency in LNH in Turkey and to describe the characteristics of affected newborns.

METHODS

Conducted with a cross-sectional design and with the participation of 61 neonatal centers from December 2015 to December 2016, the study included term neonates with LNH (n=96) and their mothers (n=93). Data were registered on the FAVOR Web Registry System. Serum samples of newborns and mothers were analyzed for calcium, phosphate, magnesium, albumin, alkaline phosphatase, intact parathyroid hormone (iPTH) and 25 hydroxyvitamin D [25(OH)D] levels.

RESULTS

The median (range) onset time of hypocalcemia was 5.0 (4.0-8.0) days of age, with a male preponderance (60.4%). The median (range) serum 25(OH)D levels of the neonates and their mothers were 6.3 (4.1-9.05) and 5.2 (4.7-8.8) ng/mL, respectively. The prevalence of vitamin D deficiency (<12 ng/mL) was high in both the neonates (86.5%) and mothers (93%). Serum 25(OH)D levels of the infants and mothers showed a strong correlation (p<0.001). While the majority (93.7%) of the neonates had normal/high phosphorus levels, iPTH levels were low or inappropriately normal in 54.2% of the patients.

CONCLUSION

Vitamin D deficiency prevalence was found to be high in LNH. Efforts to provide vitamin D supplementation during pregnancy should be encouraged. Evaluation of vitamin D status should be included in the workup of LNH.

Age, gender and season dependent 25(OH)D levels in children and adults living in Istanbul

Background

We evaluated population characteristics of serum 25-hydroxyvitamin D (25(OH)D) levels and determined the influence of age, gender and season in an extensive dataset.

Materials and methods

Laboratory results of 103,509 adults and 19,186 children were retrospectively evaluated. Study group was classified regarding ages as; <40, 40–50, 50–60 and >60 years for adults and 0–1, 1–12 months,1–3, 4–6, 7–9, 10–12, 13–15 and 16–18 years for children. Seasonal values were also determined. Levels were measured by Architect i1000 SR (Abbott Diagnostics, USA).

Results

The median (2.5–97.5 percentiles) of 25(OH)D levels were 38.75 (9.5–158.25) nmol/L for adults and 43.25 (11.25–125.5) nmol/L for children. There were significant gender differences for both adults and children. Values differed significantly among age subgroups (p’s < 0.01). A total of 63% of adults and 59.5% of children had 25(OH)D levels below 50 nmol/L (p < 0.001). 25(OH)D levels were significantly lower in the winter compared with summer (p’s < 0.001). Even levels in summer were moderate deficient for all group.

Conclusion

The rate of 25(OH)D deficiency was remarkable during the whole year. This will provide large-scale data about 25(OH)D status in Turkish people and may contribute to the prevention and treatment of this condition for better healthcare outcomes.

Vitamin D Status Across Age Groups in Turkey: Results of 108,742 Samples from a Single Laboratory

OBJECTIVE

The aim was to determine vitamin D status in the general population in Turkey between 2011 and 2016, and to evaluate the effectiveness of the national vitamin D supplementation programme.

METHODS

Serum 25-hydroxyvitamin D (25-OHD) measurement data were retrieved from an internationally accredited laboratory, operating nationwide. A total of 108,742 measurements of 25-OHD were analyzed using the cut-off values of 0-11 ng/mL, 12-19 ng/mL, 20-49 ng/mL, 50-70 ng/mL and >70 ng/mL for vitamin D deficiency, insufficiency, sufficiency, possibly harmful and excess respectively.

RESULTS

The mean±standard deviation 25-OHD level was 21.6±13.3 ng/mL. Mean 25-OHD concentrations by age groups were: 37.3 ng/mL, 30.1 ng/mL and 23.7 ng/mL for <1, 1-10 and 11-18 year old groups, respectively. Mean 25-OHD levels of children <1 year and 1-3 years of age were significantly higher than those found in other age groups. The prevalence of vitamin D deficiency (<12 ng/mL) was lowest in children at 1-3 years of age (5%). In subjects older than 18 years of age, mean 25-OHD levels were 18.2 ng/mL, 20.1 ng/mL, 21.9 ng/mL and 21.1 ng/mL for age groups 19-30, 31-50, 51-70 and >70 years, respectively.

CONCLUSION

Successful implementation of the national vitamin D supplementation programme, appears to have nearly eliminated vitamin D deficiency for children under 1-years of age. However, the positive impact of the vitamin D supplementation diminishes as children get older suggesting that supplementation may be required in the older children and adults. In addition, improved awareness of the benefits and risks of excess vitamin D should prevent unnecessary and excessive use of vitamin D supplements.

Adherence to the infant vitamin D supplementation policy in Ireland

PURPOSE

From September 2010 until November 2019, Ireland's infant vitamin D supplementation policy recommended administration of 5 μg/day of vitamin D₃ from birth to 12 months to all infants, regardless of feeding method. This study aims to examine policy adherence.

METHODS

In the prospective COMBINE birth cohort study (recruited 2015-2017), detailed longitudinal supplement data were examined in 364 infants across the first year of life, according to product type, dose, frequency, and duration. Vitamin D supplement use at 2, 6, and 12 months in COMBINE was compared with the BASELINE cohort (recruited 2008-2011, n = 1949).

RESULTS

In COMBINE, 92% of infants initiated supplementation at birth. The median supplementation duration was 51 (40, 52) weeks, with a range of 3-52 weeks. While supplementing, most parents (92%) used an exclusive vitamin D supplement as recommended and 88% gave 5 µg/day. Half (51%) gave vitamin D daily and a further 33% supplemented at least 3-6 times/week. Overall, 30% adhered fully to the policy, providing 5 µg vitamin D₃ daily from birth to 12 months. A further 16% were broadly compliant, giving 5 µg frequently for the full 12 months. Vitamin D supplement use at 2, 6, and 12 months in COMBINE was 93%, 89%, and 72%, considerably higher than our earlier BASELINE cohort at 49%, 64%, and 44% at the same time points (all P < 0.001).

CONCLUSIONS

We report a high level of vitamin D supplementation initiation at birth, with full to broad policy adherence among more than half of infants. There is scope to improve overall compliance by focusing on supplementation frequency.

Nutritional rickets: Historic overview and plan for worldwide eradication

Rickets was first described in great detail in the mid 17th century and was affecting a great number of children in major European cities. The disease, however, existed already in the Roman times. The etiology of this disease remained enigmatic until the 1920s when two different mechanisms, lack of exposure to sunlight and lack of a dietary factor were finally solved by the discovery of vitamin D and its dual origin. Soon thereafter, the implementation of vitamin D supplementation for all infants and small children largely eliminated nutritional rickets in Europe and North America. It took nearly a century to elucidate the complex chemistry, metabolism, mode and spectrum of activity of the vitamin D endocrine system. Nutritional rickets, whether due to simple vitamin D or calcium deficiency or both, remains widely ravaging many infants and children around the world. Asian countries and the Middle East are mainly confronted with vitamin D deficiency whereas many African and some Asian countries face calcium deficiency rickets. Immigrants and refugees or in general people with a darker skin living in moderate climate zone are also confronted with this disease. There is great consensus how this disease could be prevented or cured. In collaboration with most international professional societies, we prepare a memorandum, in line with the successful battle against iodine deficiency disorders, to convince the World Health Organization and its member states to start an implementation program to eradicate nutritional rickets by 2030.

Vitamin D: Newer Concepts of Its Metabolism and Function at the Basic and Clinical Level

The interest in vitamin D continues unabated with thousands of publications contributing to a vast and growing literature each year. It is widely recognized that the vitamin D receptor (VDR) and the enzymes that metabolize vitamin D are found in many cells, not just those involved with calcium and phosphate homeostasis. In this mini review I have focused primarily on recent studies that provide new insights into vitamin D metabolism, mechanisms of action, and clinical applications. In particular, I examine how mutations in vitamin D metabolizing enzymes-and new information on their regulation-links vitamin D metabolism into areas such as metabolism and diseases outside that of the musculoskeletal system. New information regarding the mechanisms governing the function of the VDR elucidates how this molecule can be so multifunctional in a cell-specific fashion. Clinically, the difficulty in determining vitamin D sufficiency for all groups is addressed, including a discussion of whether the standard measure of vitamin D sufficiency, total 25OHD (25 hydroxyvitamin) levels, may not be the best measure-at least by itself. Finally, several recent large clinical trials exploring the role of vitamin D supplementation in nonskeletal diseases are briefly reviewed, with an eye toward what questions they answered and what new questions they raised.

Vitamin D in Breastfed Infants: Systematic Review of Alternatives to Daily Supplementation

Daily oral vitamin D supplementation (400 IU) is recommended for breastfeeding infants (≤1 y). Recent studies have examined alternative approaches to preventing vitamin D deficiency in this population. This systematic review and meta-analysis aimed to estimate the effects of maternal postpartum (M-PP) or infant intermittent (I-INT) vitamin D supplementation on infant 25-hydroxyvitamin D [25(OH)D] concentrations in comparison to routine direct infant daily (I-D) oral supplementation (400 IU). MEDLINE, MEDLINE In-Process, Embase, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched up to December 2018. Inclusion criteria consisted of published, peer-reviewed, vitamin D intervention trials involving lactating women and/or exclusively or partially breastfed term infants. Two reviewers independently extracted study characteristics (e.g., sample size, intervention dose, and duration and mode of administration) and related biochemical and clinical outcomes. Of 28 included trials, 5 randomized controlled trials were incorporated in meta-analyses examining infant 25(OH)D. Overall, M-PP supplementation resulted in modestly lower infant 25(OH)D compared with I-D supplementation (weighted mean difference = -8.1 nmol/L; 95% CI: -15.4, -0.9; I2 = 45%; P = 0.14; 3 trials), but the 2 most recent trials found M-PP to achieve similar infant 25(OH)D as I-D. Comparison of I-INT with I-D was confined to 2 trials with contradictory findings, and it was considered inappropriate for pooled analysis. Meta-analysis was therefore limited by a small number of eligible trials with variable quality of analytically derived 25(OH)D data and inconsistent reporting of safety outcomes, including effects on calcium homeostasis. Considering all 28 included trials, this systematic review highlights M-PP and I-INT regimens as plausible substitutes for routine daily infant vitamin D supplementation, but evidence remains too weak to support a policy update. Dose-ranging, adequately powered trials are required to establish the efficacy, safety, and feasibility of alternative strategies to prevent vitamin D deficiency in breastfeeding infants. This review was registered with PROSPERO as CRD42017069905.

Vitamin D: Giveth to Those Who Needeth

Severe vitamin D deficiency may cause rickets. While this point is not disputed, the use of vitamin D in the elderly to prevent fractures has been challenged recently by a meta‐analysis of 81 RCTs, suggesting that the effects of vitamin D were trivial. As is true for any review of the literature, the interpretation of a meta‐analysis can be confounded by the choice of publications to include or exclude. Indeed, the authors excluded RCTs with combined vitamin D and calcium supplementation, included futile studies of very short duration, or studies with high bolus doses known to transiently increase fracture risk. The best available data show that calcium and vitamin D supplementation of elderly subjects can decrease the risk of hip and other non‐vertebral fractures, especially in institutionalized subjects or elderly subjects with poor calcium and vitamin D status. Vitamin D deficiency is associated with many chronic diseases. The VIDA and VITAL trials did not show a protective effect on cardiovascular diseases and cancer. The D2d study also did not influence the progress of prediabetes to diabetes. However, the baseline 25OHD concentrations of the majority of the participants of all these trials were essentially normal. Post‐hoc analysis of these studies suggest some possibly beneficial health outcomes in vitamin D deficient subjects. A meta‐analysis suggested that vitamin D could partly prevent upper respiratory infections. Mendelian randomization studies suggest a causal link between lifelong low vitamin D status and multiple sclerosis. A vitamin D supplement in pregnant women may decrease maternal morbidity and improve the health of their offspring. Better‐designed studies are needed to answer all outstanding questions. However, based on all available data, it seems that correction of vitamin D and/or calcium deficiency of infants, pregnant women and elderly subjects can improve their health. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

New developments in our understanding of vitamin metabolism, action and treatment

Although vitamin D has been reported to have pleiotropic effects including effects on the immune system and on cancer progression, the principal action of vitamin D is the maintenance of calcium and phosphate homeostasis. The importance of vitamin D in this process is emphasized by the consequences of vitamin D deficiency which includes rickets in children and osteomalacia in adults. Vitamin D deficiency has also been reported to increase the risk of falls and osteoporotic fractures. Although vitamin D fortification of foods (including dairy products) has contributed to a marked decrease in rickets in the Western world, vitamin D deficiency in children and adults is still prevalent world-wide. This review summarizes new developments in our understanding of vitamin D endocrine system and addresses clinical syndromes related to abnormalities in vitamin D metabolism and action. In addition, the current understanding of the evaluation of vitamin D deficiency and sufficiency and recommendations for achieving vitamin D sufficiency are discussed.

Skeletal and Extraskeletal Actions of Vitamin D: Current Evidence and Outstanding Questions

The etiology of endemic rickets was discovered a century ago. Vitamin D is the precursor of 25-hydroxyvitamin D and other metabolites, including 1,25(OH)2D, the ligand for the vitamin D receptor (VDR). The effects of the vitamin D endocrine system on bone and its growth plate are primarily indirect and mediated by its effect on intestinal calcium transport and serum calcium and phosphate homeostasis. Rickets and osteomalacia can be prevented by daily supplements of 400 IU of vitamin D. Vitamin D deficiency (serum 25-hydroxyvitamin D <50 nmol/L) accelerates bone turnover, bone loss, and osteoporotic fractures. These risks can be reduced by 800 IU of vitamin D together with an appropriate calcium intake, given to institutionalized or vitamin D-deficient elderly subjects. VDR and vitamin D metabolic enzymes are widely expressed. Numerous genetic, molecular, cellular, and animal studies strongly suggest that vitamin D signaling has many extraskeletal effects. These include regulation of cell proliferation, immune and muscle function, skin differentiation, and reproduction, as well as vascular and metabolic properties. From observational studies in human subjects, poor vitamin D status is associated with nearly all diseases predicted by these extraskeletal actions. Results of randomized controlled trials and Mendelian randomization studies are supportive of vitamin D supplementation in reducing the incidence of some diseases, but, globally, conclusions are mixed. These findings point to a need for continued ongoing and future basic and clinical studies to better define whether vitamin D status can be optimized to improve many aspects of human health. Vitamin D deficiency enhances the risk of osteoporotic fractures and is associated with many diseases. We review what is established and what is plausible regarding the health effects of vitamin D.

Vitamin D Deficiency and Insufficiency According to the Current Criteria for Children: Vitamin D Status of Elementary School Children in Turkey

OBJECTIVE

This study aimed to determine the ratio of seasonal vitamin D deficiency and insufficiency in elementary school children aged between 6-9 years old, living in one of the largest metropols of Europe, İstanbul.

METHODS

Serum 25(OH)D levels of 640 children aged 6-9 years old were scanned retrospectively from the hospital information system records between September 2017-August 2018 period. Vitamin D deficiency was defined as a serum 25(OH)D level less than 12 ng/mL (30 nmol/L) and insufficiency as levels between 12 and 20 ng/mL (30-50 nmol/L).

RESULTS

Serum 25(OH)D levels ranged from 3.90 to 64.60 ng/mL, the median value was 25.95 ng/mL for all subjects. Of all the primary school children, 485 (75.78%) had adequate levels of 25(OH)D. Vitamin D deficiency was observed in 36 of children (5.62%), whereas insufficient levels of 25(OH)D were found in 119 children (18.60%). The ratio of vitamin D insufficiency and deficiency together was highest in spring (31.87%) and lowest in summer (13.12%).

CONCLUSION

Vitamin D deficiency is a widely observed and preventable public health problem among children of different ages. It is necessary to increase the awareness among health professionals, and providing 25(OH)D supplements will yield generations with healthy bone structure and well growth.

Current vitamin D status in European and Middle East countries and strategies to prevent vitamin D deficiency: a position statement of the European Calcified Tissue Society

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) <50 nmol/L or 20 ng/mL) is common in Europe and the Middle East. It occurs in <20% of the population in Northern Europe, in 30-60% in Western, Southern and Eastern Europe and up to 80% in Middle East countries. Severe deficiency (serum 25(OH)D <30 nmol/L or 12 ng/mL) is found in >10% of Europeans. The European Calcified Tissue Society (ECTS) advises that the measurement of serum 25(OH)D be standardized, for example, by the Vitamin D Standardization Program. Risk groups include young children, adolescents, pregnant women, older people (especially the institutionalized) and non-Western immigrants. Consequences of vitamin D deficiency include mineralization defects and lower bone mineral density causing fractures. Extra-skeletal consequences may be muscle weakness, falls and acute respiratory infection, and are the subject of large ongoing clinical trials. The ECTS advises to improve vitamin D status by food fortification and the use of vitamin D supplements in risk groups. Fortification of foods by adding vitamin D to dairy products, bread and cereals can improve the vitamin D status of the whole population, but quality assurance monitoring is needed to prevent intoxication. Specific risk groups such as infants and children up to 3 years, pregnant women, older persons and non-Western immigrants should routinely receive vitamin D supplements. Future research should include genetic studies to better define individual vulnerability for vitamin D deficiency, and Mendelian randomization studies to address the effect of vitamin D deficiency on long-term non-skeletal outcomes such as cancer.

25-hydroxy Vitamin D Levels in Pediatric Asthma Patients and its Link with Asthma Severity

Aim

Although the relationship between 25-hydroxy (25-OH) vitamin D and asthma is known, it is unknown if 25-OH vitamin D levels are correlated with asthma severity in pediatric patients. The aim of this study was to compare the blood 25-OH vitamin D levels of asthma patients and healthy control groups and to evaluate any correlation between asthma severity and blood 25-OH vitamin D levels in pediatric asthma patients.

Methods

This is a cross-sectional study which shows the 25-OH vitamin D levels of asthma patients and compared to healthy controls followed by a tertiary pediatric clinic. We investigated the effect of 25-OH vitamin D levels on the severity of asthma. The severity of asthma was determined mainly by the duration of asthma diagnosis, a number of attacks in the previous year, anti-inflammatory medication usage in a previous year, atopy presence in the family, skin prick test positivity, and immunoglobulin E (IgE) levels of asthma patients.

Results

Compared with control groups, asthma patients had significantly lower 25-OH vitamin D, calcium (Ca) levels, and higher number of patients who had a 25-OH vitamin D deficiency, (p<0.0001, p<0.0001, p<0.0001, respectively). We found a correlation between blood 25-OH vitamin D levels and force expiratory capacity in one second (FEV1) and forced vital capacity (FVC) respectively (p< 0.001, r=0.512), (p< 0.001, r=0.513). There was an association between FEV1, FVC and blood 25-OH vitamin D levels in terms of deficient levels (<20 ng/mL) or insufficient levels (≥20 and <30 ng/mL) (p<0.001, r=0.459), (p< 0.001, r=0.450), respectively.

Conclusions

The 25-OH vitamin D levels were lower in pediatric asthma patients with worse spirometry results. Effects of Vitamin D supplementation need to be evaluated by well-designed studies.

Use of Vitamin D in Children and Adults: Frequently Asked Questions

In recent years, the increase in interest and use of vitamin D has been attributed mainly to the extra-skeletal effects of vitamin D and confusion about normal reference values for serum 25-hydroxy vitamin D (25-OHD). However, The Institute of Medicine, which determines daily intake of nutrients, vitamins and minerals in the United States, emphasizes that there is no additional benefit of having a 25-OHD level above 20 ng/mL in terms of parathyroid hormone suppression, calcium absorption and “fall risk”. Taking into consideration that there has not been a significant increase in vitamin D deficiency and related conditions in Turkey over the past five years, it is not hard to suppose that this increased interest is due to doctors, using mass media platforms, who have made claims that vitamin D is a “panacea”. This paper aims to answer some frequently asked questions such as the threshold values recommended for the evaluation of vitamin D status, the clinical indications for measuring 25-OHD and suggestions on the use of lifelong vitamin D starting from pregnancy.

Global prevalence and disease burden of vitamin D deficiency: a roadmap for action in low- and middle-income countries

Vitamin D is an essential nutrient for bone health and may influence the risks of respiratory illness, adverse pregnancy outcomes, and chronic diseases of adulthood. Because many countries have a relatively low supply of foods rich in vitamin D and inadequate exposure to natural ultraviolet B (UVB) radiation from sunlight, an important proportion of the global population is at risk of vitamin D deficiency. There is general agreement that the minimum serum/plasma 25-hydroxyvitamin D concentration (25(OH)D) that protects against vitamin D deficiency-related bone disease is approximately 30 nmol/L; therefore, this threshold is suitable to define vitamin D deficiency in population surveys. However, efforts to assess the vitamin D status of populations in low- and middle-income countries have been hampered by limited availability of population-representative 25(OH)D data, particularly among population subgroups most vulnerable to the skeletal and potential extraskeletal consequences of low vitamin D status, namely exclusively breastfed infants, children, adolescents, pregnant and lactating women, and the elderly. In the absence of 25(OH)D data, identification of communities that would benefit from public health interventions to improve vitamin D status may require proxy indicators of the population risk of vitamin D deficiency, such as the prevalence of rickets or metrics of usual UVB exposure. If a high prevalence of vitamin D deficiency is identified (>20% prevalence of 25(OH)D < 30 nmol/L) or the risk for vitamin D deficiency is determined to be high based on proxy indicators (e.g., prevalence of rickets >1%), food fortification and/or targeted vitamin D supplementation policies can be implemented to reduce the burden of vitamin D deficiency-related conditions in vulnerable populations.

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.

A high weekly dose of cholecalciferol and calcium supplement enhances weight loss and improves health biomarkers in obese women

Obesity, a chronic condition associated with several life-threatening diseases, affects a significant proportion of the global population and has long been associated with vitamin D deficiency. The prevalence of both obesity and vitamin D deficiency has increased dramatically in Jordan in recent decades, especially among women. Few studies in Jordan and the surrounding area address this issue. In this study, we hypothesize that calcium and vitamin D have beneficial effects on weight reduction and metabolic profile in obese women. The objective of this study is to examine the effect of vitamin D₃ and calcium supplementation on anthropometric measurements and some blood metabolites. Forty-five obese female subjects with vitamin D deficiency were recruited by a dietitian and randomly assigned to the same weight loss diet in addition to the following treatments (4 groups): control (CON), no prescribed supplements; vitamin D₃ (Diet/D), given a high weekly dose of cholecalciferol (50 000 IU/subject/week); calcium (Diet/Ca), given 1200 mg/dL calcium/subject/day; vitamin D₃ plus Ca (Diet/Ca/D), given cholecalciferol (50 000 IU/subject/week) and calcium (1200 mg/dL calcium/subject/day). Results revealed that after 3 months of supplementation, the Diet/Ca/D group subjects experienced a significant reduction (P ≤ .05) in weight (10.49 kg), BMI (4.61 ± 2 kg/m²), waist circumference (11.41 ± 8.9 cm), body fat percentage (2.43 ± 1.7%), FBG (25.81 ± 11.4 mg/dL), PTH (27.58 ± 8.9 pg/mL), cholesterol (0.56 ± 0.2 mmol/L), and triglycerides (0.53 ± 0.21 mmol/L) when compared to the Diet/Ca and the CON groups. Interestingly, however, the CON group showed a significant increase in serum PTH concentration (9.51 ± 3.8 pg/mL, P ≤ .05). Based on these results, a combined Ca and vitamin D₃ supplement appears to enhance weight loss and improve some of the blood metabolic profiles in obese women subjected to a weight loss diet, thus supporting our study hypothesis.

[Relationship between vitamin D deficiency and necrotizing enterocolitis in preterm infants]

OBJECTIVE

To evaluate the relationship of vitamin D level with the development of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A total of 429 preterm infants with a gestational age of <36 weeks, who were admitted to the department of neonatology within 2 hours after birth between January and December, 2016, were enrolled in the study. According to whether these infants developed NEC, the 429 subjects were divided into NEC group (n=22) and non-NEC group (n=407). Peripheral venous blood was collected from these preterm infants and their mothers at admission to measure the level of 25-hydroxyvitamin D (25-OHD). The two groups were compared in terms of the serum 25-OHD levels of preterm infants and their mothers. Pearson correlation analysis was used to investigate the correlation between the serum 25-OHD levels of preterm infants and their mothers. The distribution of vitamin D levels in preterm infants was compared between the two groups. The univariate logistic regression analysis was used to determine the risk factors for NEC in preterm infants.

RESULTS

The serum 25-OHD levels of preterm infants and their mothers in the NEC group were significantly lower than in the non-NEC group (P<0.001). In both groups, the serum 25-OHD levels of mothers and preterm infants were positively correlated with each other (P<0.001). The distribution of vitamin D levels (normal vitamin D level, low vitamin D level, vitamin D deficiency, and severe vitamin D deficiency) was significantly different between the NEC and non-NEC groups (P<0.001). The univariate logistic regression analysis showed that gestational age, birth weight, 25-OHD levels of preterm infants and their mothers, the duration of mechanical ventilation, the duration of oxygen inhalation, and the length of hospital stay were associated with the development of NEC (P<0.05).

CONCLUSIONS

The serum 25-OHD levels of preterm infants and their mothers may be related to the development of NEC in preterm infants, suggesting that vitamin D supplementation during pregnancy is important for preventing the development of NEC in preterm infants.

Vitamin D Deficiency in Pregnant Women and Their Infants

OBJECTIVE

Vitamin D deficiency is a serious health problem despite a general improvement in socio-economic status in Turkey. The aim of this study was to evaluate maternal vitamin D status and its effect on neonatal vitamin D concentrations after a support programme for pregnant women was introduced. A second aim was to identify risk factors for vitamin D deficiency in a district of İstanbul.

METHODS

A total of 97 pregnant women and 90 infants were included in this study, conducted between January and October 2016. The demographic data, risk factors and daily vitamin intake were recorded. Serum levels of vitamin D, calcium, phosphorus and alkaline phosphatase in all subjects were measured. The mothers and newborns were divided into groups based on their vitamin D levels. The relationship between vitamin D levels and risk factors was analyzed.

RESULTS

Mean ± standard deviation vitamin D levels for the women and their infants were found to be 14.82±11.45 and 13.16±7.16 ng/mL, respectively. The number of mothers and infants was significantly higher in the deficient group, and their mean vitamin D levels significantly lower (9.02±1.34 and 8.80±1.06 ng/mL, respectively) (p<0.001, p<0.001). Only 14.4% of pregnant women took 1000-1200 IU/day of vitamin D. When the mother groups were evaluated in terms of risk factors, there were significant differences in daily vitamin intake and clothing style (p<0.001 and p<0.001 respectively).

CONCLUSION

Vitamin D deficiency in pregnant women and their infants is still a serious health problem in Turkey, although a vitamin D support programme during pregnancy has been launched by the department of health.

Genetic Causes of Rickets

Rickets is a metabolic bone disease that develops as a result of inadequate mineralization of growing bone due to disruption of calcium, phosphorus and/or vitamin D metabolism. Nutritional rickets remains a significant child health problem in developing countries. In addition, several rare genetic causes of rickets have also been described, which can be divided into two groups. The first group consists of genetic disorders of vitamin D biosynthesis and action, such as vitamin D-dependent rickets type 1A (VDDR1A), vitamin D-dependent rickets type 1B (VDDR1B), vitamin D-dependent rickets type 2A (VDDR2A), and vitamin D-dependent rickets type 2B (VDDR2B). The second group involves genetic disorders of excessive renal phosphate loss (hereditary hypophosphatemic rickets) due to impairment in renal tubular phosphate reabsorption as a result of FGF23-related or FGF23-independent causes. In this review, we focus on clinical, laboratory and genetic characteristics of various types of hereditary rickets as well as differential diagnosis and treatment approaches.

Rickets

Rickets is a bone disease associated with abnormal serum calcium and phosphate levels. The clinical presentation is heterogeneous and depends on the age of onset and pathogenesis but includes bowing deformities of the legs, short stature and widening of joints. The disorder can be caused by nutritional deficiencies or genetic defects. Mutations in genes encoding proteins involved in vitamin D metabolism or action, fibroblast growth factor 23 (FGF23) production or degradation, renal phosphate handling or bone mineralization have been identified. The prevalence of nutritional rickets has substantially declined compared with the prevalence 200 years ago, but the condition has been re-emerging even in some well-resourced countries; prematurely born infants or breastfed infants who have dark skin types are particularly at risk. Diagnosis is usually established by medical history, physical examination, biochemical tests and radiography. Prevention is possible only for nutritional rickets and includes supplementation or food fortification with calcium and vitamin D either alone or in combination with sunlight exposure. Treatment of typical nutritional rickets includes calcium and/or vitamin D supplementation, although instances infrequently occur in which phosphate repletion may be necessary. Management of heritable types of rickets associated with defects in vitamin D metabolism or activation involves the administration of vitamin D metabolites. Oral phosphate supplementation is usually indicated for FGF23-independent phosphopenic rickets, whereas the conventional treatment of FGF23-dependent types of rickets includes a combination of phosphate and activated vitamin D; an anti-FGF23 antibody has shown promising results and is under further study.

Variations in infant and childhood vitamin D supplementation programmes across Europe and factors influencing adherence

BACKGROUND

Nutritional rickets is a growing global public health concern despite existing prevention programmes and health policies. We aimed to compare infant and childhood vitamin D supplementation policies, implementation strategies and practices across Europe and explore factors influencing adherence.

METHODS

European Society for Paediatric Endocrinology Bone and Growth Plate Working Group members and other specialists completed a questionnaire on country-specific vitamin D supplementation policy and child health care programmes, socioeconomic factors, policy implementation strategies and adherence. Factors influencing adherence were assessed using Kendall's tau-b correlation coefficient.

RESULTS

Responses were received from 29 of 30 European countries (97%). Ninety-six per cent had national policies for infant vitamin D supplementation. Supplements are commenced on day 1-5 in 48% (14/29) of countries, day 6-21 in 48% (14/29); only the UK (1/29) starts supplements at 6 months. Duration of supplementation varied widely (6 months to lifelong in at-risk populations). Good (≥80% of infants), moderate (50-79%) and low adherence (<50%) to supplements was reported by 59% (17/29), 31% (9/29) and 10% (3/29) of countries, respectively. UK reported lowest adherence (5-20%). Factors significantly associated with good adherence were universal supplementation independent of feeding mode (P = 0.007), providing information at neonatal unit (NNU) discharge (P = 0.02), financial family support (P = 0.005); monitoring adherence at surveillance visits (P = 0.001) and the total number of factors adopted (P < 0.001).

CONCLUSIONS

Good adherence to supplementation is a multi-task operation that works best when parents are informed at birth, all babies are supplemented, and adherence monitoring is incorporated into child health surveillance visits. Implementation strategies matter for delivering efficient prevention policies.

How should we give vitamin D supplementation? evaluation of the pediatricians' knowledge in Turkey

Background

We aimed to determine the knowledge and attitudes of Turkish pediatricians concerning vitamin D supplement.

Methods

The study was planned cross-sectional to be carried out between April–May 2015 in Turkey. A questionnaire form that determined the participants’ opinions and practices concerning vitamin D supplement was completed via face-to-face interview.

Results

A total of 107 pediatricians (49.3%) and 110 pediatric residents (50.7%) participated in the study. Of the physicians, 85.2% recommended vitamin D supplement for all infants and children regardless of diet, 13.4% recommended for the infants which are solely breastfed. Vitamin D supplement is recommended at a dose of 400 IU/day by 88.8% of pediatricians and by 90% of pediatric residents. Of the pediatricians and pediatric residents, 72% and 68.2%, respectively commence vitamin D supplement when the newborn is 15 days old. The rates of recommending vitamin D supplement until the age of one and two years were higher among pediatricians (48.6% and 41.1%, respectively) than pediatric residents (40.9% and 32.7%, respectively). The rate of starting vitamin D supplement for fontanelle closure was significantly higher among pediatric residents (15.5%) than pediatricians (3.7%) (p = 0.002). It was determined that the rate of prescribing vitamin D supplement until fontanelle closure was higher among pediatric residents (18.2%) than pediatricians (0.9%).

Conclusions

The present study suggest that the knowledge of pediatricians about recommendation of vitamin D needs to be enhanced by education programs in addition to free vitamin D supplement provided by the Ministry of Health.

Nutritional Rickets and Osteomalacia in the Twenty-first Century: Revised Concepts, Public Health, and Prevention Strategies

PURPOSE OF REVIEW

Nutritional rickets and osteomalacia are common in dark-skinned and migrant populations. Their global incidence is rising due to changing population demographics, failing prevention policies and missing implementation strategies. The calcium deprivation spectrum has hypocalcaemic (seizures, tetany and dilated cardiomyopathy) and late hypophosphataemic (rickets, osteomalacia and muscle weakness) complications. This article reviews sustainable prevention strategies and identifies areas for future research.

RECENT FINDINGS

The global rickets consensus recognises the equal contribution of vitamin D and dietary calcium in the causation of calcium deprivation and provides a three stage categorisation for sufficiency, insufficiency and deficiency. For rickets prevention, 400 IU daily is recommended for all infants from birth and 600 IU in pregnancy, alongside monitoring in antenatal and child health surveillance programmes. High-risk populations require lifelong supplementation and food fortification with vitamin D or calcium. Future research should identify the true prevalence of rickets and osteomalacia, their role in bone fragility and infant mortality, and best screening and public health prevention tools.

The Association of Oral Vitamin D and Calcium Supplementation With Bone Mineral Density in Pediatric Acute Lymphoblastic Leukemia Patients

AIM

To investigate the association of calcium (Ca) and vitamin D (vit D) supplementation with bone mineral density (BMD) in pediatric acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

Group I (n=11): de novo ALL patients aged 1 to 18 years. Group II (n=46): pediatric ALL survivors in first complete remission and ALL patients on maintenance chemotherapy. We stratified group II into 3 subgroups according to the postdiagnosis period (group IIa: 8 to 24 mo, group IIb: 24 to 48 mo, group IIc: >48 mo). Group III (n=22): healthy siblings of group II. Daily oral vit D3 and Ca carbonate was given only to group I. In group I, BMD was measured at diagnosis and after completion of intensive chemotherapy (TP1 and TP2).

RESULTS

A significant increase in Ca (P=0.024) and 25-OH vit D (P=0.01), and a decrease in magnesium (P=0.023) were detected at TP2 compared with TP1 in group I. Mean plasma levels of 25-OH vit D were <20 ng/mL in all the groups. Total body (P=0.005), total body less head (P=0.005), and L1 to L4 BMD Z scores (P=0.025) decreased significantly at TP2 compared with TP1. The lowest BMD scores were found at 8 to 24 months after diagnosis in unsupplemented patients. A gradual increase in BMD Z scores was shown, with the highest scores in group IIc.

CONCLUSION

Vit D and Ca supplementation in pediatric ALL patients during intensive chemotherapy may not prevent bone mineral loss. BMD scores of pediatric ALL patients described by other studies, as a major decrease in the first 2 years and gradual increase afterward, was also observed in our patients.

Prevention and treatment of nutritional rickets

Nutritional rickets continues to be a significant health problem for children worldwide with recent evidence of increasing incidence in many developed countries. It is due to vitamin D deficiency and/or inadequate dietary calcium intake with variation in the relative contributions of each of these dependant on environmental factors such a dietary intake and sunlight exposure. Key to the prevention of rickets is ensuring that pregnant women and their infants receive vitamin D supplementation with good evidence from randomised controlled trials that infants who receive 400iu daily can achieve levels of 25 hydroxyvitamin D of >50nmol/l. However, public health implementation of daily supplementation is more challenging with a need to revisit food fortification strategies to ensure optimal vitamin D status of the population. Treatment of nutritional rickets has traditionally been with vitamin D2 or D3, often given as a daily oral dose for several weeks until biochemical and radiological evidence of healing. However, other treatment regimes with single or intermittent high doses have also proved to be effective. It is now recognised that oral calcium either as dietary intake or supplements should be routinely used in conjunction with vitamin D for treatment.

The Return of Congenital Rickets, Are We Missing Occult Cases?

Congenital rickets is the term given to fetus born with clinical features of rickets, but those born with biochemical evidence of rickets without obvious clinical features still can be considered occult congenital rickets. Some of the affected babies with this disease have the intrauterine rachitic environment, but a calcium trans-placental pump prevents the fetus from having clinical features of rickets. They may present with hypocalcemia few days after birth or later with more florid features of rickets. Congenital rickets cases born with florid features reported over the last 40 years are few and can be divided into two groups. The first due to severe maternal osteomalacia in which their bones were so decalcified to have enough calcium to be pumped to their fetus. Another group in which newborn babies were hypocalcemic due to other maternal diseases as malabsorption, celiac disease, pre-eclampsia, and prematurity. All inherited rickets cases per se, or as part of other syndromes can be considered congenital rickets. Most cases seen in our region are due to maternal vitamin D deficiency with symptoms becoming obvious when the infants are breastfed, or may present with hypocalcemic convulsions or craniotabes. This is a review of congenital rickets with the aim of shedding light on this potentially acute disease that needs more attention and awareness in the neonatal period to avoid rare serious complications as cardiomyopathy or myelofibrosis and the complications of hypocalcemic convulsions. Congenital rickets cases seen simulate a tip of an ice-burg and its prevention is an important issue, especially with the tremendous urbanization with tall buildings living in sun-deprived flats as the commonest type of residence leading to the increasing incidence of maternal osteomalacia and rickets.

Attitudes of Pediatricians Regarding Prevention and Treatment of Vitamin D Deficiency

To determine the adherence of pediatricians to the nationwide 'Vitamin D Prophylaxis Program' and to evaluate their attitudes about vitamin D intake. The study was conducted using the Turkish National Pediatrics Association network. The pediatricians were asked to respond to an online questionnaire that included five questions on 'What dose of vitamin D they recommend for supplementation?', 'At what age they start vitamin D supplementation?', 'Supplementation method', 'Clichés and truths about vitamin D', and 'High-dose vitamin D therapy indications'. Responses of 167 pediatricians were evaluated in this study. 75.5% of pediatricians indicated that they recommended vitamin D supplementation in a daily dose of 400 IU. 47.1% started vitamin D supplementation by the end of the 2nd week. 7.83% of pediatricians suggested doubling the daily dose of vitamin D supplementation in infants with delayed tooth eruption, 19.9% suggested immediate cessation of vitamin D supplementation in infants with small anterior fontanels. This study showed that the majority of the pediatricians still prescribe vitamin D prophylaxis late, recommend high doses of vitamin D in cases of delayed tooth eruption, and think that low serum 25-hydroxy vitamin D level regardless of alkaline or phosphatase parathyroid hormone measurement is an indication for high-dose vitamin D (stoss) therapy. These results suggest a need for new training programs focusing on vitamin D supplementation.

Nutritional rickets in immigrant and refugee children

Immigrant and refugee populations bring public health challenges to host nations. In the current global refugee crisis, children are the most vulnerable subpopulation. Diseases that were considered rare in the host nation may be highly prevalent among immigrant children. The prevalence of nutritional rickets is increasing in high-income countries, largely driven by an influx of immigrant populations. Nutritional rickets is a bone disease in early childhood resulting in bone pain, delayed motor development, and bending of the bones, caused by vitamin D deficiency and/or inadequate dietary calcium intake. The consequences of nutritional rickets include stunted growth, developmental delay, lifelong bone deformities, seizures, cardiomyopathy, and even death. Nutritional rickets is most commonly seen in children from the Middle East, Africa, and South Asia in high-income countries. Dark skin pigmentation, sun avoidance, covering the skin, and prolonged breast feeding without vitamin D supplementation, are important risk factors for vitamin D deficiency, and combined with a lack of dairy products in the diet, these deficiencies can result in insufficient calcium supply for bone mineralization. We recommend screening all immigrant and refugee children under 5 years of age from these ethnic groups for nutritional rickets, based on clinical features, and confirming the diagnosis with radiographs of the wrists and knees. Because nutritional rickets is entirely preventable, public health policies must address the need for universal vitamin D supplementation and adequate dietary calcium to protect children from this scourge. Vitamin D supplementation of all infants and children with 400 IU/d during the first year of life and dietary or supplemental intakes of at least 600 IU/d of vitamin D and 500 mg/d of calcium thereafter, will effectively prevent nutritional rickets. We call on national health authorities of host countries to implement health check lists and prevention programs that include screening for micronutrient deficiencies, in addition to assessing infections and vaccination programs. Due to their high prevalence of vitamin D deficiency, refugee children of all ages from these ethnic groups should be supplemented with vitamin D, beginning upon arrival.

Factors Influencing Serum Vitamin D Concentration in Turkish Children Residing in İzmir: A Single-Center Experience

OBJECTIVE

The aim of this study was to examine the vitamin D status of children and to determine the factors influencing serum 25-hydroxyvitamin D [25(OH)D] concentration in Turkish infants living in İzmir.

METHODS

In this study, we examined the serum 25(OH)D levels of 100 infants aged 1 to 24 months and of 22 mothers from İzmir, Turkey. The study also included a questionnaire given to the mothers to acquire data on the demographic characteristics of the infants and their mothers as well as information on vitamin D supplementation, clothing habits, and sunlight exposure.

RESULTS

Vitamin D deficiency was present in 31% of infants and 81.8% of mothers. Twenty-four male (42.9%) and 7 female (15.9%) infants were found to be vitamin D deficient (<20 mg/dL); 9 male (16.1%) and 17 female (38.6%) infants to be vitamin D insufficient (20-30 mg/dL); and 23 male (41.1%) and 20 female (45.5%) infants were vitamin D sufficient (>30 mg/dL). Only 63% of the infants were receiving vitamin D supplementation and 52% were said to be having regular exposure to sunlight. Mean serum vitamin D levels were lower in infants whose mothers were dressed according to the culture of traditional covered clothing (44%) compared to those infants whose mothers' dressing style provided more exposure to sunlight.

CONCLUSION

We conclude that low exposure to sunlight, inadequate use of vitamin D supplementation, and large family size are factors influencing the vitamin D status of Turkish children living in the inner city of İzmir.

Contribution of vitamin D deficiency to the risk of coronary heart disease in subjects with essential hypertension

BACKGROUND

Vitamin D deficiency is proposed as a risk factor for coronary heart disease (CHD). An inverse relation was observed between serum 25-Hydroxy-Vitamin-D level and incidence of hypertension. This study aimed to evaluate the predictive value of serum 25-Hydroxy-Vitamin-D in improvement of CHD risk-stratification in patients with hypertension.

METHODS

In this cohort, we followed 1586 patients with essential hypertension (1078 diabetic and 508 non-diabetic) for 8.5 years. Physician-adjudicated first hard CHD event was the primary outcome. Cox regression analysis was used to investigate the association between 25-Hydroxy-Vitamin-D quartiles and incident CHD. 25-Hydroxy-Vitamin-D was also added to the Framingham Risk Score (FRS) and Net-Reclassification-Improvement (NRI) and Integrated-Discriminant-Improvement (IDI) were used to examine improved reclassification.

RESULTS

During follow-up, 176 events were recorded. Patients in the lowest quartile of 25-Hydroxy-Vitamin-D experienced the most number of hard CHD events. A significant linear trend was observed in hazard ratios (HR) of incident hard CHD events in 25-Hydroxy-Vitamin-D quartiles which remained significant after multiple adjustments for conventional CHD risk-factors (HRs in full-adjusted model: 2.87 [1.76-4.70] for 1st quartile, 2.31 [1.39-3.83] for 2nd quartile and 1.87 [1.15-3.03] for 3rd quartile, compared with the highest quartile; p-for-trend<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS could improve CHD risk-estimation (relative-IDI = 15%, p-value<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS successfully reclassified 33% [18-49] of patients with hypertension among CHD risk groups (p-value<0.001).

CONCLUSION

We observed that serum 25-Hydroxy-Vitamin-D is independently associated with future hard CHD events and improves its prediction in patients with essential hypertension. Addition of serum 25-Hydroxy-Vitamin-D to CHD risk-estimation models may have additive values.

Vitamin D Deficiency in Children and Adolescents in Bağcılar, İstanbul

OBJECTIVE

This study aimed to evaluate the frequency of seasonal 25-hydroxyvitamin D [25(OH)D] deficiency and insufficiency in children and adolescents living in Bağcılar, district of İstanbul city.

METHODS

Serum vitamin D levels of 280 children aged 3-17 years old were measured at the end of winter and at the end of summer. Of the total group, vitamin D levels were re-measured in 198 subjects. Vitamin D deficiency was defined as a serum 25(OH)D level less than 15 ng/mL and insufficiency-as levels between 15 and 20 ng/mL. Patients whose vitamin D levels were less than 15 ng/mL at the end of winter were treated with 2000 units/day of vitamin D for 3 months.

RESULTS

In the "end of winter" samples, 25(OH)D deficiency was present in 80.36% of the subjects and insufficiency in 11.79%. In the "end of summer" samples, vitamin D deficiency was detected in 3.44% and insufficiency in 27.75%. Vitamin D levels in the "end of winter" samples were not significantly different between boys and girls, while "end of summer" levels were significantly lower in girls (p=0.015). Sunlight exposure was significantly higher in boys (p=0.011). The group with sufficient dairy product consumption had significantly higher vitamin D levels in both "end of summer" and "end of winter" samples. Limb pain was frequently reported in children with low vitamin D levels in the "end of winter" samples (p=0.001). Negative correlations were observed between vitamin D levels and season and also between vitamin D levels and age.

CONCLUSION

It is essential to provide supplemental vitamin D to children and adolescents to overcome the deficiency seen especially at the end of winter.

Complications of vitamin D deficiency from the foetus to the infant: One cause, one prevention, but who's responsibility?

Calcium and phosphorus represent building material for bones. The supplier of these bone minerals is the hormone calcitriol, which originates from vitamin D, itself made by sunshine in human skin. Requirement for bone minerals is highest during phases of rapid growth, and no one grows faster than the foetus and the infant, making them particularly vulnerable. Deprivation of calcium, whether through low calcium intake or low vitamin D, leads to serious health consequences throughout life, such as hypocalcaemic seizures, dilated cardiomyopathy, skeletal myopathy, congenital and infantile rickets, and osteomalacia. These 5 conditions are often summarised as 'symptomatic vitamin D deficiency', are fully reversible but also fully preventable. However, the increasing prevalence of rickets and osteomalacia, and the deaths from hypocalcaemic cardiomyopathy, demand action from global health care providers. Clarification of medical and parental responsibilities is a prerequisite to deliver successful prevention programmes. The foetus and infant have the human right to be protected against harm, and vitamin D supplementation has the same public health priority as vaccinations.

Lower vitamin D levels are associated with increased risk of early-onset neonatal sepsis in term infants

OBJECTIVE

To evaluate the effect of vitamin D levels on early-onset sepsis (EOS) in term infants.

STUDY DESIGN

Fifty term infants with clinical and laboratory findings of EOS (study group) and 50 healthy infants with no signs of clinical/laboratory infection (control group) were enrolled. Blood was drawn at the time of admission during the first 3 postnatal days of life in both groups for measurement of 25-hydroxyvitamin D (25-OHD) levels.

RESULT

Maternal and neonatal 25-OHD levels (22.2/8.6 ng ml(-1), respectively) in the study group were significantly lower than those of the control group (36.2/19 ng ml(-1), respectively, P<0.001). A positive correlation was detected between maternal and neonatal 25-OHD levels. Severe vitamin D deficiency was significantly more common in the sepsis group.

CONCLUSION

Lower maternal and neonatal 25-OHD levels are associated with EOS. These data suggest that adequate vitamin D supplementation during pregnancy may be helpful to prevent EOS in term neonates.

Vitamin D: An overview of vitamin D status and intake in Europe

In recent years, there have been reports suggesting a high prevalence of low vitamin D intakes and vitamin D deficiency or inadequate vitamin D status in Europe. Coupled with growing concern about the health risks associated with low vitamin D status, this has resulted in increased interest in the topic of vitamin D from healthcare professionals, the media and the public. Adequate vitamin D status has a key role in skeletal health. Prevention of the well-described vitamin D deficiency disorders of rickets and osteomalacia are clearly important, but there may also be an implication of low vitamin D status in bone loss, muscle weakness and falls and fragility fractures in older people, and these are highly significant public health issues in terms of morbidity, quality of life and costs to health services in Europe. Although there is no agreement on optimal plasma levels of vitamin D, it is apparent that blood 25-hydroxyvitamin D [25(OH)D] levels are often below recommended ranges for the general population and are particularly low in some subgroups of the population, such as those in institutions or who are housebound and non-Western immigrants. Reported estimates of vitamin D status within different European countries show large variation. However, comparison of studies across Europe is limited by their use of different methodologies. The prevalence of vitamin D deficiency [often defined as plasma 25(OH)D <25 nmol/l] may be more common in populations with a higher proportion of at-risk groups, and/or that have low consumption of foods rich in vitamin D (naturally rich or fortified) and low use of vitamin D supplements. The definition of an adequate or optimal vitamin D status is key in determining recommendations for a vitamin D intake that will enable satisfactory status to be maintained all year round, including the winter months. In most European countries, there seems to be a shortfall in achieving current vitamin D recommendations. An exception is Finland, where dietary survey data indicate that recent national policies that include fortification and supplementation, coupled with a high habitual intake of oil-rich fish, have resulted in an increase in vitamin D intakes, but this may not be a suitable strategy for all European populations. The ongoing standardisation of measurements in vitamin D research will facilitate a stronger evidence base on which policies can be determined. These policies may include promotion of dietary recommendations, food fortification, vitamin D supplementation and judicious sun exposure, but should take into account national, cultural and dietary habits. For European nations with supplementation policies, it is important that relevant parties ensure satisfactory uptake of these particularly in the most vulnerable groups of the population.

Differential low uptake of free vitamin D supplements in preterm infants: the Quebec experience

Background

Vitamin D is essential for bone mineralization, particularly in premature infants. For nearly 20 years, Quebec has offered a program of free vitamin D supplements via its public medication insurance plan Régie de l’Assurance Maladie du Québec (RAMQ). The objective of this study is to evaluate the number of preterm infants that obtained at least one bottle (50 doses) of vitamin D supplement through this program and to determine if uptake varied by gestational age.

Methods

This was a retrospective cohort study of preterm infants covered by RAMQ and born from 1998 to 2008; all infants had 1 year of follow-up data regarding supplement use. Data were extracted from the Quebec Pregnancy Cohort, a linked administrative database and were stratified by early (<34 weeks) or late gestational age premature infants. The number of infants obtaining supplements was the primary outcome and their characteristics were compared across gestational age groups. Predictors for participation (obtaining at least 1 bottle) or adherence (2 or more bottles) were identified via logistic regression (GEE).

Results

10288 infants were eligible; the percentage exposed to vitamin D was 24.5% (37.4%- early; 20.7%-late preterm infants, p < 0.001). The median number of bottles obtained was 2 for early and 1 for late preterms. For all premature infants, there was an apparent geometric decline in the infants obtaining subsequent bottles of supplements over the 12 month period. Additionally, there was a significant decline in program participation over time (OR = 0.90/year, 95% CI: 0.89-0.90) regardless of gestational age. Older or more educated mothers were positive predictors for participation. A prescription from a pediatrician significantly increased the odds of obtaining the supplement.

Conclusion

Early preterm infants were more likely to obtain the supplement post-discharge; uptake was low and decreased with time for both age categories. Specifically, targeting late preterm infants and young mothers with less education could improve vitamin D uptake.

Programme to provide Quebec infants with free vitamin D supplements failed to encourage participation or adherence

AIM

The aim of this study was to evaluate the uptake of a free vitamin D infant prescription programme and to determine the incidence of nutritional rickets.

METHODS

This was a retrospective cohort study of infants from Quebec, Canada, involving term infants born between 1998 and 2008 and covered by the public insurance programme. Data were extracted from the Quebec Pregnancy Cohort. Predictors of programme participation were identified through logistic regression.

RESULTS

A total of 123 018 infants were eligible, and the mean annual prevalence of supplemental vitamin D exposure was 17.9 ± 5.6%. The median age for obtaining the first bottle was 36 days and half only obtained one bottle of 50 doses. Mothers with higher socio-economic status, those who lived as a couple, older mothers or a prescription by a paediatrician significantly increased the odds of obtaining vitamin D. There was a decline in programme participation over time (OR 0.89/year, 95% CI = 0.88-0.90). The incidence of rickets was 23.9 cases per 100 000 live births, with an annual increase of 1.12 cases/year (95% CI = 1.01-1.24).

CONCLUSION

Without educational measures, a free prescription programme for vitamin D failed to encourage participation or adherence. Moreover, participation decreased with time. New strategies, including educational support, need to be developed to increase vitamin D supplementation rates.

Vitamin D and maternal and child health: overview and implications for dietary requirements

The essentiality of vitamin D for normal growth and development has been recognized for over 80 years, and vitamin D fortification programs have been in place in the United States for more than 70 years. Despite the above, vitamin D deficiency continues to be a common finding in certain population groups. Vitamin D deficiency has been suggested as a potential risk factor for the development of preeclampsia, and vitamin D deficiency during infancy and early childhood is associated with an increased risk for numerous skeletal disorders, as well as immunological and vascular abnormalities. Vitamin D deficiency can occur through multiple mechanisms including the consumption of diets low in this vitamin and inadequate exposure to environmental ultraviolet B rays. The potential value of vitamin D supplementation in high-risk pregnancies and during infancy and early childhood is discussed. Currently, there is vigorous debate concerning what constitutes appropriate vitamin D intakes during early development as exemplified by differing recommendations from the Institute of Medicine Dietary Reference Intake report and recent recommendations by the Endocrine Society. As is discussed, a major issue that needs to be resolved is what key biological endpoint should be used when making vitamin D recommendations for the pregnant woman and her offspring.