Nutritional rickets without vitamin D deficiency in Bangladesh

Trace metal exposure and human health consequences through consumption of market-available Oreochromis niloticus (L.) in Bangladesh

Using Oreochromis niloticus (L.), commonly known as tilapia, as a model, this study evaluated the exposure of trace metal and their risk assessment on human health. In addition, the status of amino acids, fatty acids, vital elements, and their benefits is also studied. Estimating the nutrient composition of fish muscle is necessary to ensure that it meets the requirements for human health, food regulations, and commercial specifications. The species examined contained appreciable concentrations of amino acids, fatty acid content, and minerals, suggesting that the fish species could be a good source of protein, fat, and minerals. Hazardous heavy metals were found to be lower compared to their corresponding maximum tolerable limits. The order of trace metals is Zn (22,709 µg/kg) > Fe (19,878 µg/kg) > Cu (1261 µg /kg) > Mn (1228 µg/kg) > Cr (474 µg/kg) > Ni (152 µg/kg) As (318 µg /kg) > Pb (281 µg/kg) > Co (24 µg /kg) > Cd (13 µg/kg) > Hg (5 µg/kg); a number of health-related indices, including estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI), as well as carcinogenic risk (CR) indices for adult and children, were calculated to evaluate the human health hazard of the heavy metals. The THQ and HI of heavy metals for tilapia are lower than 1, posing a non-carcinogenic threat to human health due to the biomagnifications of these deadly poisonous metals. Principal component, cluster, and correlation analyses delineated the common probabilistic sources of metal contamination origin and significant inter-parameter associations. Although no human health risks for the consumption of tilapia was found, more attention must be paid for the monitoring of Oreochromis niloticus before entering the market.

Serum 1,25-dihydroxyvitamin D levels in the diagnosis and pathogenesis of nutritional rickets - a multivariable re-analysis of a case-control study

BACKGROUND

A multivariable logistic regression model resulting from a case-control study of nutritional rickets in Nigerian children suggested that higher levels of serum 25(OH)D may be required to prevent nutritional rickets in populations with low-calcium intakes.

OBJECTIVES

This current study evaluates if adding serum 1,25-dihydroxyvitamin D [1,25(OH)₂D] to that model shows that increased levels of serum 1,25(OH)₂D are independently associated with risk of children on low-calcium diets having nutritional rickets.

METHODS

Multivariable logistic regression analysis was used to model the association between serum 1,25(OH)₂D and risk of having nutritional rickets in cases (n = 108) and controls (n = 115) after adjusting for age, sex, weight-for age z-score, religion, phosphorus intake and age began walking and the interaction between serum 25(OH)D and dietary calcium intake (Full Model).

RESULTS

Serum 1,25(OH)₂D levels were significantly higher (320 pmol/L vs. 280 pmol/L) (P = 0.002), and 25(OH)D levels were lower (33 nmol/L vs. 52 nmol/L) (P < 0.0001) in children with rickets than in control children. Serum calcium levels were lower in children with rickets (1.9 mmol/L) than in control children (2.2 mmol/L) (P < 0.001). Dietary calcium intakes were similarly low in both groups (212 mg/d) (P = 0.973). In the multivariable logistic model, 1,25(OH)₂D was independently associated with risk of having rickets [coefficient = 0.007 (95% confidence limits: 0.002-0.011)] after adjusting for all variables in the Full Model.

CONCLUSIONS

Results confirmed theoretical models that in children with low dietary calcium intake, 1,25(OH)₂D serum concentrations are higher in children with rickets than in children without rickets. The difference in 1,25(OH)₂D levels is consistent with the hypothesis that children with rickets have lower serum calcium concentrations which prompt the elevation of PTH levels resulting in an elevation of 1,25(OH)₂D levels. These results support the need for additional studies to identify dietary and environmental risks for nutritional rickets.

Nutritional rickets - Vitamin D and beyond

Vitamin D deficiency has been considered to be the cause of nutritional rickets for most of the past century. During the past two decades, however, it has become clear that nutritional rickets may be caused by vitamin D deficiency or by dietary insufficiency of calcium. The combined deficiencies of calcium and vitamin D interact, and several other factors are also relevant in the pathogenesis of nutritional rickets.

Is dietary deficiency of calcium a factor in rickets? Use of current evidence for our understanding of the disease in the past

OBJECTIVE

Rickets is considered an indicator of vitamin D deficiency in palaeopathology, but a strand of biomedical thought maintains that dietary calcium deficiency may sometimes play a part in its causation. Our aim is to evaluate the extent to which low calcium intake should be considered as a factor in biocultural interpretations of rickets.

METHODS

We assess published modern epidemiological studies that provide primary data to support claims for a role for dietary calcium deficiency in rickets. We also consider how we might identify, via indicators of calcium intake, populations at risk of calcium deficiency in the past.

RESULTS

Support for dietary calcium deficiency as a cause of rickets is equivocal. Direct measurement of dietary calcium in the past is not possible, but exposure to risk factors for low calcium intake can to some extent be identified.

CONCLUSION

Whilst there is little evidence to alter the view that rickets is essentially an indicator of a population's vitamin D status, occasionally, in very low calcium intake groups, dietary calcium deficiency may play a synergistic role by accentuating the need for vitamin D.

SIGNIFICANCE

The notion that dietary calcium deficiency may be a cause of rickets appears to be gaining currency in bioarchaeological studies. This paper shows that it is unusual for this to be the case, and even then the role of vitamin D remains crucial.

LIMITATIONS

This paper attempts to summarise the current state of biomedical study in an area that is subject to continuing investigation.

Moderate/subclinical calcium deficiency attenuates trabecular mass, microarchitecture and bone growth in growing rats

Adequate dietary calcium (Ca) intake is essential for bone accretion, peak bone mass (PBM) attainment, bone quality and strength during the mammalian growth period. Severe Ca deficiency during growing age results in secondary hyperparathyroidism (SHPT) and poor bone quality and strength. However, the impact of moderate Ca deficiency during rats early growth period on bone health and the reversibility with supplementing calcium later in adult life remains unclear. Female Sprague-Dawley (SD) rats (postnatal 28th day, P28) were initiated either with a moderate calcium-deficient diet (MCD, 0.25% w/w Ca) or a control diet (0.8% w/w Ca, control group) till P70. Thereafter, MCD rats were continued either with MCD diet or supplemented with calcium diet (0.8% w/w Ca, calcium supplemented group, CaS) till P150. Another group (control rats) were fed 0.8% w/w Ca containing diet from P28 till P150.

MCD group, as compared to the control group, had significantly reduced serum ionized Ca and procollagen type 1 N-terminal propeptide (P1NP) at P70 while no significant change was observed in serum corrected Ca, inorganic phosphate (P), alkaline phosphatase (ALP), 25-hydroxy vitamin D [25(OH)D], intact parathyroid hormone (iPTH), and urinary C-terminal telopeptide of collagen 1 (CTX-1), Ca, and P. Femoral and tibial metaphysis in MCD rats had significantly reduced linear growth, cortical and trabecular volumetric BMD (vBMD), trabecular microarchitecture (BV/TV%, trabecular thickness, separation and number, structural model index and connectivity density), cortical thickness, and bone stiffness despite the absence of secondary hyperparathyroidism (SHPT). Continued MCD at P70–P150 results in persistence of compromised bone strength while calcium supplementation (CaS group) improved all the parameters related to bone strength and microarchitecture. Our results indicate that uncorrected moderate/subclinical calcium deficiency in growing rats can result in poor bone quality and strength despite the absence of SHPT. This finding could have relevance in children with poor calcium intake in childhood and adolescence.

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Moderate Ca intake impairs bone growth and stiffness in critical growth phase via subclinical Ca deficiency.

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Ca supplementaion reverses the effects subclinical Ca deficiency on bone health.

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Conclusively, moderate Ca intake imposes different effects on the bone at different phases of life.

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.

Calcium repletion to rats with calcipenic rickets fails to recover bone quality: A calcipenic "memory"

Calcipenic rickets is prevalent in underprivileged children in developing countries. Calcipenic rickets resulting from dietary calcium (Ca) deficiency decreases bone mass and deteriorates bone microstructure in humans. The effect of dietary Ca replenishment (CaR) on rachitic bones in animal models depends on the amount, critical period and duration of replenishment, however, the extent of recovery in various bone parameters including bone quality remains unclear. We investigated the effect of CaR in rat skeleton after inducing calcipenic rickets. Female SD rats (postnatal 28 days/P28) were rendered calcipenic by feeding calcium deficient (CaD) diet (0.1% Ca) till P70 while control SD rats were fed Ca sufficient diet (0.8% Ca). At P70, calcipenic rats were switched to 0.8% Ca diet till P150 for one group and P210 for another group (endpoint). The CaD groups received 0.1% Ca diet throughout the study (P210). In the CaD groups, serum Ca and phosphate, and bone mineral density (BMD) were significantly decreased whereas serum alkaline phosphatase (ALP), iPTH and CTX-1 were increased compared to age-matched controls. Moreover, at the endpoint, the CaD group had reduced bone mass, surface referent bone formation parameters, tissue mineralization and strength accompanied by the increased osteoid thickness and microarchitectural decay (measured by trabecular geometric parameters) with poor crystal packing. The CaR group showed complete recovery in serum Ca, iPTH, ALP and CTX-1, and BMD, however, the bone quality parameters including bone strength, microarchitectural decay, tissue mineralization, and crystallinity were incompletely restored. Decreased surface referent bone formation and increased unmineralized bones (osteoid) indicative of osteomalacia were also observed in the CaR group at P210 compared with control despite prolonged replenishment. We conclude that a prolonged Ca repletion following the induction of calcipenic rickets in rats although shows the recovery of biochemical measures of bone metabolism and bone mass, however, the bone quality remains compromised. This suggests that a "memory" of calcipenia occurring at the early growth stage persists in the skeleton of adult rats despite a prolonged Ca replenishment.

Aetiology of nutritional rickets in rural Bangladeshi children

OBJECTIVES

A high prevalence of rickets of unknown aetiology has been reported in Chakaria, Bangladesh. Classically, rickets is caused by vitamin D deficiency but increasing evidence from Africa and Asia points towards other nutritional deficiencies or excessive exposure to some metals. The aim of this study was to investigate the aetiology of rickets in rural Bangladeshi children.

METHODS

64 cases with rickets-like deformities were recruited at first presentation together with age-sex-village matched controls. Data and sample acquisition included anthropometry, radiographs, fasted plasma and urinary samples, 24 h weighed dietary intake together with a 24 h urine collection, and ¹³C-breath tests to detect Helicobacter (H.) pylori infection.

RESULTS

One child had active rickets and frank hypovitaminosis D (F, n = 1) and one had deformities with radiological features of Blount disease (M, n = 1). The remaining cases were grouped into those with active rickets, defined as a radiographic Thacher score ≥1.5 (Group A, n = 24, 12M, 12F) and rickets-like bone deformities but not active rickets (Group B, n = 38, 28M, 10F). All children had a low dietary calcium intake, but this was lower in Group A than their controls (mean (SD): 156 (80) versus 323 (249) mg/day, p = 0.005). Plasma 25-hydroxyvitamin D (25OHD) was lower in Group A compared to controls; 63% of Group A and 8% of controls had a concentration <25 nmol/L (p ≤ 0.0001). There was, however, no evidence of differences in skin sunshine exposure. Group A had lower plasma calcium and phosphate and higher 1,25-dihydroxyvitamin D (1,25(OH)₂D) and parathyroid hormone (PTH). 88% of Group A and 0% of controls had undetectable plasma intact fibroblast growth factor (iFGF23), with c-terminal FGF23 (cFGF23) concentrations in the normal range. Urinary phosphate and daily outputs of environmental metals relative to creatinine were higher and tubular maximal phosphate reabsorption per unit glomerular filtration rate (TmP/GFR) was lower in Group A compared to controls. Although less pronounced than Group A, Group B had higher alkaline phosphatase, 1,25(OH)₂D and PTH concentrations than controls but similar calcium intake, TmP/GFR, iFGF23 and cFGF23 concentrations. Mean 25OHD concentrations were also similar to controls and there was no significant difference in the percentage <25 nmol/L (Group B: 13%, controls: 5%, p = 0.2) No group differences were seen in prevalence of anaemia, iron deficiency or H. pylori infection.

CONCLUSION

Nutritional rickets in this region is likely to be predominantly due to low calcium intake in the context of poor vitamin D status and exposure to environmental metals, but not H. pylori infection, anaemia or iron deficiency.

Paradoxical Response of Parathyroid Hormone to Vitamin D-Calcium Supplementation in Indian Children

OBJECTIVES

To investigate the effect of oral vitamin D-calcium supplementation on serum intact parathyroid hormone (PTH), calcium, phosphorous, and alkaline phosphatase (ALK-P) concentrations in children with habitually low calcium intakes.

STUDY DESIGN

In this follow-up study to a randomized controlled trial that aimed to assess the effect of vitamin D-calcium supplementation on immunity, data related to dietary intake, anthropometry, and biochemistry [serum 25(OH)D and bone profile] were collected from 178 children-79 in the vitamin D group and 99 in the non-vitamin D group.

RESULTS

Dietary calcium to phosphorus intake ratio was 0.4:1. Baseline serum 25(OH)D concentration was 58.2 ± 10.9 nmol/L; 66% children were vitamin D sufficient and none deficient. After supplementation, vitamin D group, compared with the non-vitamin D group, had significantly (P < .05) greater 25(OH)D (83.9 ± 30.1 nmol/L vs 58.3 ± 15.7 nmol/L), significantly greater PTH (6.7 ± 3.6 pmol/L vs 5.5 ± 3.2 pmol/L), and positive correlation (r_s = 0.24) between serum 25(OH)D and PTH (vs negative correlation [r_s = -0.1] in non-vitamin D group). Mean concentrations of serum bone measures in the vitamin D group were calcium (2.2 ± 0.1 mmol/L), phosphorus (1.7 ± 0.2 mmol/L), and ALK-P (178.7 ± 40.7 IU/L). At follow-up, 1-year post-supplementation, in the vitamin D group, PTH concentrations continued to remain high (but not significantly different from levels at 6 months), with low normal serum calcium, high normal phosphate, and ALK-P in reference range.

CONCLUSIONS

In children who are vitamin D sufficient but with habitually low dietary calcium intake, vitamin D-calcium supplementation paradoxically and significantly increased serum PTH concentrations with no apparent effect on other bone biochemistry. Chronic low dietary calcium to phosphorus ratio is likely to have caused this paradoxical response.

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.

Prevalence and risk factors of vitamin D insufficiency and deficiency among 6-24-month-old underweight and normal-weight children living in an urban slum of Bangladesh

OBJECTIVE

We quantified the prevalence of vitamin D status in 6-24-month-old underweight and normal-weight children and identified the socio-economic and dietary predictors for status.

DESIGN

Cross-sectional, baseline data from a nutritional intervention study were analysed. Multinomial logistic regression was used to estimate the odds of being vitamin D deficient or insufficient with the reference being vitamin D sufficient.

SETTING

Urban slum area of Mirpur field site, Dhaka, Bangladesh.

SUBJECTS

Underweight (weight-for-age Z-score <-2·00) and normal-weight (weight-for-age Z-score ≥-1·00) children aged 6-24 months.

RESULTS

Among 468 underweight children, 23·1 % were sufficient, 42·3 % insufficient, 31·2 % deficient and 3·4 % severely vitamin D deficient. Among 445 normal-weight children, 14·8 % were sufficient, 39·6 % insufficient and 40·0 % deficient and 5·6 % severely deficient. With adjusted multinominal regression analysis, risk factors (OR (95 % CI)) for vitamin D deficiency in underweight children were: older age group (18-24 months old; 2·9 (1·5-5·7)); measurement of vitamin D status during winter (3·0 (1·4-6·4)) and spring (6·9 (3·0-16·1)); and maternal education (≥6 years of institutional education; 2·2 (1·0-4·9)). In normal-weight children, older age group (3·6 (1·2-10·6)) and living in the richest quintile (3·7 (1·1-12·5)) were found to be significantly associated with vitamin D insufficiency.

CONCLUSIONS

The study demonstrates a significant burden of vitamin D insufficiency and deficiency in both underweight and normal-weight children <2 years of age from an urban slum of Bangladesh. Identification of risk factors may help in mitigating the important burden in such children.

CYP2R1 mutations causing vitamin D-deficiency rickets

CYP2R1 is the principal hepatic 25-hydroxylase responsible for the hydroxylation of parent vitamin D to 25-hydroxyvitamin D [25(OH)D]. Serum concentrations of 25(OH)D reflect vitamin D status, because 25(OH)D is the major circulating metabolite of vitamin D. The 1α-hydroxylation of 25(OH)D in the kidney by CYP27B1 generates the fully active vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25(OH)₂D). The human CYP2R1 gene, located at 11p15.2, has five exons, coding for an enzyme with 501 amino acids. In Cyp2r1-/- knockout mice, serum 25(OH)D levels were reduced by more than 50% compared wild-type mice. Genetic polymorphisms of CYP2R1 account for some of the individual variability of circulating 25(OH)D values in the population. We review the evidence that inactivating mutations in CYP2R1 can lead to a novel form of vitamin D-deficiency rickets resulting from impaired 25-hydroxylation of vitamin D. We sequenced the promoter, exons and intron-exon flanking regions of the CYP2R1 gene in members of 12 Nigerian families with rickets in more than one family member. We found missense mutations (L99P and K242N) in affected members of 2 of 12 families. The L99P mutation had previously been reported as a homozygous defect in an unrelated child of Nigerian origin with rickets. In silico analyses predicted impaired CYP2R1 folding or reduced interaction with substrate vitamin D by L99P and K242N mutations, respectively. In vitro studies of the mutant CYP2R1 proteins in HEK293 cells confirmed normal expression levels but completely absent or markedly reduced 25-hydroxylase activity by the L99P and K242N mutations, respectively. Heterozygous subjects had more moderate biochemical and clinical features of vitamin D deficiency than homozygous subjects. After an oral bolus dose of 50,000 IU of vitamin D₂ or vitamin D₃, heterozygous subjects had lower increases in serum 25(OH)D than control subjects, and homozygous subjects had minimal increases, supporting a semidominant inheritance of these mutations. No CYP2R1 mutations were found in 27 Nigerian children with sporadic rickets, a cohort of 50 unrelated Nigerian subjects, or in 628 unrelated subjects in the 1000 Genomes Project. We conclude that mutations in CYP2R1 are responsible for an atypical form of vitamin D-deficiency rickets, which has been classified as vitamin D dependent rickets type 1B (VDDR1B, MIM 600081).

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 relationship of maternal bone density with nutritional rickets in Nigerian children

Factors that affect maternal bone mineral density may be related to the risk of nutritional rickets in their offspring. Our aim was to determine the relationship between maternal areal bone mineral density (aBMD) and rickets in Nigerian children. Using a case-control design, we measured forearm aBMD in 56 and 135 mothers of children with and without nutritional rickets, respectively. Active rickets was confirmed or excluded in all children radiographically. Using logistic regression, we assessed the association of maternal aBMD, adjusted for parity, pregnancy and lactation status, duration of most recent completed lactation, age of menarche, height, body mass index, and maternal age with nutritional rickets. The median (range) age of all mothers was 30years (17-47years), and parity was 4 (1-12). A total of 36 (19%) were pregnant and 55 (29%) were currently breast feeding. Mean (±SD) metaphyseal forearm aBMDs were 0.321±0.057 and 0.316±0.053g/cm² in mothers of children with and without rickets, respectively (P=0.60). Diaphyseal forearm aBMDs were 0.719±0.071 and 0.715±0.072g/cm², respectively (P=0.69). In an adjusted analysis, maternal forearm aBMD, bone mineral content and bone area at metaphyseal and diaphyseal sites were not associated with rickets in the child. In the adjusted analysis, rickets was associated with shorter duration of most recently completed lactation (aOR 0.91 for each additional month; 95% CI 0.83-0.99), older maternal age (aOR 1.07 for each additional year; 1.00-1.14), and less frequent maternal use of lead-containing eye cosmetics (aOR 0.20; 95% CI 0.05-0.64), without any difference in maternal blood lead levels. Maternal age, parity, age of menarche, height, and body mass index were not associated with having had a child with rickets in multivariate analysis. Nutritional rickets in Nigerian children was not associated with maternal forearm aBMD. Other unidentified maternal characteristics and practices likely contribute to the risk of rickets in Nigerian children.

Vitamin D Status in South Asian Populations - Risks and Opportunities

Human body acquires a significant amount of vitamin D by cutaneous synthesis under the action of sunlight and less is supplied through nutritional sources. Diversified sociocultural and economic determinants have been identified that limit the dietary intake of vitamin D and enough distribution of sunlight to maintain optimal levels of 25-hydroxyvitamin D (25(OH)D). Consequently, the world has witnessed a high prevalence of hypovitaminosis D in resource-limited South Asian countries. The purpose of this review is to provide a South Asian perspective of vitamin D status, critically examining India, Pakistan, Bangladesh, and Sri Lanka, and to shed light on potential determinants (latitude and season, sunshine exposure habits, age, gender, and genetic factors) leading to hypovitaminosis D among a variety of population groups. Literature search was carried out using bibliographic databases "PubMed," "Google Scholar," and "ScienceDirect.com." Serum 25(OH)D level, 20-50 nmol/L, was mainly taken as vitamin D deficiency, and determinants of low serum 25(OH)D concentration of the population under study were also considered. The review concludes that vitamin D deficiency is highly prevalent among South Asian populations and global efforts are needed to overcome hypovitaminosis in the region. In addition, dietary diversification, supplementation and fortification of foods with vitamin D, adequate exposure to sunlight, and consumption of animal foods were suggested as viable approaches to maintain 25(OH)D levels for optimal health.

Calcium Deficiency in Bangladesh: Burden and Proposed Solutions for the First 1000 Days

BACKGROUND

Bangladesh incurs among the highest prevalence of stunting and micronutrient deficiencies in the world, despite efforts against diarrheal disease, respiratory infections, and protein-energy malnutrition which have led to substantial and continuous reductions in child mortality over the past 35 years. Although programs have generally paid more attention to other micronutrients, the local importance of calcium to health has been less recognized.

OBJECTIVE

To synthesize available information on calcium deficiency in Bangladesh in order to inform the design of an effective national calcium program.

METHODS

We searched 3 online databases and a multitude of survey reports to conduct a narrative review of calcium epidemiology in Bangladesh, including population intake, determinants and consequences of deficiency, and tested interventions, with particular reference to young children and women of childbearing age. This was supplemented with secondary analysis of a national household survey in order to map the relative extent of calcium adequacy among different demographics.

RESULTS

Intake of calcium is low in the general population of Bangladesh, with potentially serious and persistent effects on public health. These effects are especially pertinent to young children and reproductive-age women, by virtue of increased physiologic needs, disproportionately poor access to dietary calcium sources, and a confluence of other local determinants of calcium status in these groups.

CONCLUSION

A tablet supplementation program for pregnant women is an appealing approach for the reduction in preeclampsia and preterm birth. Further research is warranted to address the comparative benefit of different promising approaches in children for the prevention of rickets.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial

Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p < 0.001). Daily calcium intakes of 1000 mg or 2000 mg produced more rapid radiographic healing of rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research.

Preventing Rickets in Locally Appropriate Ways: A Case Report from North China

A rickets prevention program was carried out in Shanxi Province, China using locally appropriate methods. At the end of two and one-half years, the prevalence of rickets was 18% lower in program townships (56%) than in a control township that had no rickets prevention program (74%). Maternal awareness of how to prevent rickets was higher in program townships (43%) than in the control township (28%). However, the actual effect of maternal awareness on the prevention of rickets was negligible. In conclusion, this rickets prevention program was effective at reducing the prevalence of rickets. It appears the program was effective because of the presence of concerned program workers regularly visiting mothers and their infants, and using locally appropriate methods, but neither the vitamin supplements used nor the kind of rickets prevention education provided the mothers was shown to be positively correlated.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describe the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Medical Hydrogeology of Asian Deltas: Status of Groundwater Toxicants and Nutrients, and Implications for Human Health

Drinking water, a fluid primarily for human hydration, is also a source of mineral nutrients. Groundwater, a drinking water source for more than 70% of inhabitants living in Asian deltas, has received much attention because of its naturally occurring arsenic, but the linkage of arsenic toxicity with other water constituents has not been studied. In addition, although nutrients are generally provided by food, in under developed rural settings, where people subsist on low nutrient diets, drinking-water-nutrients may supply quantities critical to human health thereby preventing diseases. Here, we show, using augmented datasets from three Asian deltas (Bengal, Mekong, and Red River), that the chemical content of groundwater is so substantial that in some areas individuals obtain up to 50% or more of the recommended daily intake (RDI) of some nutrients (e.g., calcium, magnesium, iron) from just two litres of drinking water. We also show some indications of a spatial association of groundwater nutrients and health outcome using demographic health data from Bangladesh. We therefore suggest that an understanding of the association of non-communicable disease and poor nutrition cannot be developed, particularly in areas with high levels of dissolved solids in water sources, without considering the contribution of drinking water to nutrient and mineral supply.

The Interrelationships between Lactose Intolerance and the Modern Dairy Industry: Global Perspectives in Evolutional and Historical Backgrounds

Humans learned to exploit ruminants as a source of milk about 10,000 years ago. Since then, the use of domesticated ruminants as a source of milk and dairy products has expanded until today when the dairy industry has become one of the largest sectors in the modern food industry, including the spread at the present time to countries such as China and Japan. This review analyzes the reasons for this expansion and flourishing. As reviewed in detail, milk has numerous nutritional advantages, most important being almost an irreplaceable source of dietary calcium, hence justifying the effort required to increase its consumption. On the other hand, widespread lactose intolerance among the adult population is a considerable drawback to dairy-based foods consumption. Over the centuries, three factors allowed humans to overcome limitations imposed by lactose intolerance: (i) mutations, which occurred in particular populations, most notably in the north European Celtic societies and African nomads, in which carriers of the lactose intolerance gene converted from being lactose intolerant to lactose tolerant; (ii) the ability to develop low-lactose products such as cheese and yogurt; and (iii) colon microbiome adaptation, which allow lactose intolerant individuals to overcome its intolerance. However, in a few examples in the last decade, modern dairy products, such as the popular and widespread bio-cultured yogurts, were suspected to be unsuitable for lactose intolerant peoples. In addition, the use of lactose and milk-derived products containing lactose in non-dairy products has become widespread. For these reasons, it is concluded that it might be important and helpful to label food that may contain lactose because such information will allow lactose intolerant groups to control lactose intake within the physiological limitations of ~12 g per a single meal.

Radiographic changes in nutritional ricket hips in children in response to treatment

PURPOSE

To review radiographic changes in the proximal femurs of children of different ages during the course of treatment for nutritional rickets.

METHODS

Pelvic radiographs of 161 children aged ≤ 13 years with nutritional rickets were retrospectively reviewed. Patients were treated with dietary counselling and vitamin D and calcium supplementation. Patients were followed up at week 3 and thereafter at a 2-month interval until ulnar convexity was achieved. Sequential radiographs of the hips in children of different ages were reviewed for each growth plate in terms of (1) the direction of growth, (2) active areas, (3) contribution of growth, and (4) the structure of the epiphysis. Radiographs were superimposed for comparison by matching the triradiate cartilage and the ischial portion of the obturator foramen.

RESULTS

The direction of growth of the growth plates was from the physeal plate that is the longitudinal growth plate of the neck (LGP), the femoral neck isthmus (FNI), and the trochanteric growth plate (TGP) to the diaphyseal region, and from the perichondrium to the ossification centre in the proximal femoral epiphysis. Before the age of one year, the growth zone of the proximal femur was homogenous, with no differentiation between the LGP, FNI, and TGP. By the age of 2 years, the differentiation was more clearly established; the FNI was usually smaller than the TGP and LGP. By the age of 3 years, the FNI became prominent and the TGP remained small. By the age of 4 years, the ossification centre of the greater trochanter appeared, and the LGP extended medially as a medial overhang (MOH). During the children's growth, the LGP, FNI, or TGP remained active to a variable extent and were distinct until the age of 6 years. Gradually, the periphery of the LGP became less active than the centre of the LGP and gave rise to the 'eye sign'. The MOH generally ceased to be active beyond the age 9 years. By the age of 12 years, the TGP and FNI were minimally active and only the centre of the LGP remained active.

CONCLUSION

The mineralisation process of healing rickets provides a useful biological marker for patterns of growth. Knowledge of the quantitative contribution of various growth plates of the proximal femur in childhood may increase the understanding of the pathomechanism of hip deformations.

Vitamin D/dietary calcium deficiency rickets and pseudo-vitamin D deficiency rickets

This review describes the pathogenesis, clinical presentation and biochemical perturbations found in privational (nutritional) rickets and pseudo-vitamin D deficiency rickets (PDDR), an autosomal recessive condition with loss of function mutations in CYP27B1. It may seem strange to combine a discussion on privational rickets and PDDR as a single topic, but privational rickets and PDDR present with similar clinical signs and symptoms and with similar perturbations in bone and mineral metabolism. Of interest is the characteristic lack of features of rickets at birth in infants with PDDR, a finding which has also been reported in infants born to vitamin D-deficient mothers. This highlights the independence of the fetus and neonate from the need for vitamin D to maintain calcium homeostasis during this period. The variable roles of vitamin D deficiency and dietary calcium deficiency in the pathogenesis of privational rickets are discussed and the associated alterations in vitamin D metabolism highlighted. Although PDDR is a rare autosomal recessive disorder, results of long-term follow-up are now available on the effect of treatment with calcitriol, and these are discussed. Areas of uncertainty, such as should affected mothers breastfeed their infants, are emphasized.

Nutritional rickets around the world

Nutritional rickets is a major public health problem in many countries of the world. The disease is characterized by deformities of the long bones, enlargement of the wrists and costochondral junctions, hypotonia and, in infants, craniotabes and delayed fontanelle closure. Predominantly caused by severe vitamin D deficiency, rickets can also be associated with hypocalcemic seizures and cardiac failure. First presentation is typically at 6-24 months of age, although hypocalcemia may be evident in younger infants. In many affluent industrialized countries, the prevalence of rickets in the general population diminished after the introduction of clean-air legislation and dietary supplementation. However, in such countries, vitamin-D deficiency rickets has re-emerged in recent years, particularly among groups with limited exposure to UVB-containing sunshine. Infants at risk of rickets tend to be those whose mothers had poor vitamin D status during pregnancy and those exclusively breast-fed for a prolonged period with little skin exposure to UVB. In other countries of the world, the prevalence of rickets can be high, even in regions with abundant year-round UVB-containing sunshine. In general, this is also due to vitamin D deficiency related to limited sun exposure. However, reports from Africa and Asia suggest that there may be other etiological factors involved. Studies in South Africa, Nigeria, The Gambia and Bangladesh have identified rickets in children, typically 3-5 years old at first presentation, in whom plasma 25-hydroxyvitamin D concentrations are higher than those characteristic of primary vitamin D deficiency. Calcium deficiency has been implicated, and in some, but not all, disturbances of phosphate metabolism, renal compromise and iron deficiency may also be involved. Continuing studies of the etiology of nutritional rickets will provide evidence to underpin guidelines for the prevention and treatment of rickets world-wide. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Awareness regarding the importance of calcium and vitamin D among the undergraduate pharmacy students in Bangladesh

Background

Calcium and vitamin D are two important micronutrients required for maintaining proper bone health. Previous works intended to determine the status of these micronutrients in local population have reported that the people in Bangladesh are at high risk of calcium insufficiency and hypovitaminosis D related health complications. Lack of awareness and insufficient knowledge of the essentiality of these two nutrients are assumed to cause this problem in Bangladesh. The present study was designed and conducted to establish a basic understanding on the level of gap of knowledge and awareness among pharmacy students at undergraduate level in Bangladesh.

Findings

A total of 713 students of Bachelor of Pharmacy course participated in the study. The students were asked about basic idea related to calcium and vitamin D and the disorders due to their deficiency, name of common foods containing calcium and vitamin D, their perception regarding the essentiality of the said nutrients etc. It was found that most of the students were familiar with the importance of calcium (98.9%) and vitamin D (99.3%) in bone health. 82.2% students know about the term osteoporosis. Unfortunately, 10.7% and 18.8% students failed to mention at least one food that is rich in calcium and vitamin D, respectively. Most of the students got familiar about the nutrients from their teachers (48.9%) and textbooks (32.8%).

Conclusion

Being a student of pharmacy, the students should have more comprehensive knowledge about calcium and vitamin D. The present study indicates that the pharmacy students have lack of knowledge about calcium and vitamin D and thus it can be clearly predicted that the condition of general people may be worse.

Management of nutritional rickets in Indian children: a randomized controlled trial

INTRODUCTION

Rickets is usually attributed to vitamin D deficiency. However, recent studies have implicated dietary calcium deficiency in its etiology. Information on relative efficacy of calcium, vitamin D or both together in healing of rickets is limited.

OBJECTIVE

To study effect of treatment with calcium, vitamin D or a combination of these two on healing of nutritional rickets in young children.

DESIGN

Randomized controlled trial.

METHODS

Sixty-seven cases of nutritional rickets in the age group of 6 months to 5 years were randomly allocated to receive vitamin D (600 000 IU single intramuscular dose), calcium (75 mg/kg/day elemental calcium orally) or a combination of the above two for a period of 12 weeks. The demographic parameters, nutritional status, dietary calcium and phytate intake were assessed for all. Radiographs (wrist and knee) and biochemical parameters (serum calcium, inorganic phosphate, alkaline phosphatase, 25-hydroxycholecalciferol and parathyroid hormone) were evaluated at baseline, 6 and 12 weeks for evidence of healing.

RESULTS

Mean dietary intake of calcium in all cases was low (204 ± 129 mg/day). Mean serum 25-hydroxycholecalciferol D level was 15.9 ± 12.4 ng/ml, and 82.1% of patients had serum vitamin D levels <20 ng/ml, indicative of vitamin D deficiency. After 6 and 12 weeks of treatment, radiological and biochemical evidence of healing rickets was observed in all treatment groups, albeit to a variable extent. The combined end point of normal serum alkaline phosphatase and complete radiological healing at 12 weeks was observed in 50% subjects on combination therapy as compared with 15.7% subjects on vitamin D alone and 11.7% on calcium alone.

CONCLUSIONS

Children with rickets had a low serum vitamin D level and a low dietary calcium intake. The best therapeutic response was seen with a combination of vitamin D and calcium than either of them given alone.

TRIAL REGISTRATION NUMBER

CTRI/2010/091/000448.

Very low adequacy of micronutrient intakes by young children and women in rural Bangladesh is primarily explained by low food intake and limited diversity

Documentation of micronutrient intake inadequacies among developing country populations is important for planning interventions to control micronutrient deficiencies. The objective of this study was to quantify micronutrient intakes by young children and their primary female caregivers in rural Bangladesh. We measured 24-h dietary intakes on 2 nonconsecutive days in a representative sample of 480 children (ages 24-48 mo) and women in 2 subdistricts of northern Bangladesh by using 12-h weighed food records and subsequent 12-h recall in homes. We calculated the probability of adequacy (PA) of usual intakes of 11 micronutrients and an overall mean PA, and evaluated dietary diversity by counting the total number of 9 food groups consumed. The overall adequacy of micronutrient intakes was compared to dietary diversity scores using correlation and multivariate regression analyses. The overall mean prevalence of adequacy of micronutrient intakes for children was 43% and for women was 26%. For children, the prevalence of adequate intakes for each of the 11 micronutrients ranged from a mean of 0 for calcium to 95% for vitamin B-6 and was <50% for iron, calcium, riboflavin, folate, and vitamin B-12. For women, mean or median adequacy was <50% for all nutrients except vitamin B-6 and niacin and was <1% for calcium, vitamin A, riboflavin, folate, and vitamin B-12. The mean PA (MPA) was correlated with energy intake and dietary diversity, and multivariate models including these variables explained 71-76% of the variance in MPA. The degree of micronutrient inadequacy among young children and women in rural Bangladesh is alarming and is primarily explained by diets low in energy and little diversity of foods.

Spatial distribution of calcium in food, water and soil and its possible influence on rickets disease in Northern Nigeria

Since the 1990s, children of the Gbagyi tribe in Northern Nigeria have been suffering severe rickets with an incidence of up to 40% in the children's generation. The disease seems to be prevalent in an area of approximately 100 km(2) south-east of Kaduna. According to broad medical studies in that area, there is no evidence for a genetic disposition but for a nutritional cause of the disease. A lack of calcium was found in blood and was calculated to originate from diet. We therefore checked parent material, soil, maize cobs (Zea mays) and drinking water for their specific Ca contents from a region with rickets problem (study area A) and compared the results to Ca amounts in similar samples from a region where rickets is unknown among the Gbagyi population (study area B). It thereby became apparent that there are no differences in mineralogical composition of the parent material between the study areas, but that Ca contents in soil, maize cobs and drinking water are 47.6%, 26.6%, respectively, 79.1% lower in study area A compared to study area B. This result suggests that there may indeed be a nutritionally and/or environmentally influence on rickets disease. Nevertheless, further research on this topic is required.

The role of vitamin D in pregnancy and lactation: insights from animal models and clinical studies

Maternal adaptations during pregnancy and lactation appear to provide calcium to fetus and neonate without relying on vitamin D or calcitriol. Consequently, the blood calcium, calciotropic hormones, and skeleton appear normal at birth in the offspring of mothers who are severely vitamin D deficient or who lack calcitriol or its receptor. It remains unclear whether skeletal or extraskeletal problems will develop postnatally from exposure to vitamin D deficiency in utero. During the neonatal period, calcitriol-stimulated intestinal calcium absorption becomes the dominant mechanism of calcium delivery. The vitamin D-deficient neonate is at risk to develop hypocalcemia, rickets, and possibly extraskeletal disorders (e.g., type 1 diabetes). Breastfed babies are at higher risk of vitamin D deficiency because normally little vitamin D or 25-hydroxyvitamin D passes into breast milk. Dosing recommendations during pregnancy and lactation should ensure that the baby is born vitamin D sufficient and maintained that way during infancy and beyond.

Calcium and bone metabolism disorders during pregnancy and lactation

Pregnancy and lactation cause a substantial increase in demand for calcium that is met by different maternal adaptations within each period. Intestinal calcium absorption more than doubles during pregnancy, whereas the maternal skeleton resorbs to provide most of the calcium content of breast milk during lactation. These maternal adaptations also affect the presentation, diagnosis, and management of disorders of calcium and bone metabolism. Although some women may experience fragility fractures as a consequence of pregnancy or lactation, for most women, parity and lactation do not affect the long-term risks of low bone density, osteoporosis, or fracture.

Association between calcium in cord blood and newborn size in Bangladesh

Ca status in the uterus during pregnancy has been suggested to affect fetal growth and size at birth. In Bangladesh, low Ca levels in pregnant women and low birth weight in infants are common. The present study explored the association between Ca levels in cord blood and newborn size at birth (birth weight and birth length) in Bangladesh. Samples and data included 223 women with live-born singleton deliveries in rural Bangladesh. Newborn weight and length were measured at birth. From cord blood obtained at delivery, Ca, 25-hydroxy vitamin D, bone-specific alkaline phosphatase and intact parathyroid hormone levels were determined. An association between size at birth and Ca levels in cord blood was found (birth weight, P = 0.022; birth length, P = 0.001). Associations between Ca and newborn size were further analysed using multivariate regression analyses. After adjusting for several covariates of characteristics in mothers and newborns (gestational weeks at birth, sex of newborn, socio-economic status, maternal height, BMI, age and season at birth), birth length still exhibited a significant relationship with Ca levels in cord blood (birth length, P = 0.030). The present study indicates that Ca status in cord blood might be associated with the birth length of newborns. Ca levels during gestation may affect fetal growth.

Vitamin D insufficiency

Vitamin D deficiency, which classically manifests as bone disease (either rickets or osteomalacia), is characterized by impaired bone mineralization. More recently, the term vitamin D insufficiency has been used to describe low levels of serum 25-hydroxyvitamin D that may be associated with other disease outcomes. Reliance on a single cutoff value to define vitamin D deficiency or insufficiency is problematic because of the wide individual variability of the functional effects of vitamin D and interaction with calcium intakes. In adults, vitamin D supplementation reduces the risk of fractures and falls. The evidence for other purported beneficial effects of vitamin D is primarily based on observational studies. We selected studies with the strongest level of evidence for clinical decision making related to vitamin D and health outcomes from our personal libraries of the vitamin D literature and from a search of the PubMed database using the term vitamin D in combination with the following terms related to the potential nonskeletal benefits of vitamin D: mortality, cardiovascular, diabetes mellitus, cancer, multiple sclerosis, allergy, asthma, infection, depression, psychiatric, and pain. Conclusive demonstration of these benefits awaits the outcome of controlled clinical trials.

Hyperparathyroidism and malnutrition with severe vitamin D deficiency

BACKGROUND

Vitamin D deficiency and its associated problems are common in developing Asian countries and countries of the Middle East. Various factors, including poor nutritional status and other compounding factors such as dietary, cultural, ethnic, and environmental factors, play a major role in contributing to the poor calcium and vitamin D homeostasis. Vitamin D deficiency is thought to exacerbate signs and symptoms of hyperparathyroidism (HPT). In this overview, we present evidence of the impact of vitamin D and calcium deficiency on primary HPT (PHPT).

METHODS

We performed an evidence-based review of articles published in the English language between January 1960 and June 2008.

RESULTS

Level IV evidence suggests widespread calcium and vitamin D deficiency in developing countries (issue 1). Limited level IV evidence suggests malnutrition as a primary cause of calcium and vitamin D deficiency (issue 2). Level IV evidence suggests that calcium and vitamin deficiencies cause secondary HPT and possibly PHPT as well (issues 3 and 4). A literature search revealed only six studies that correlated vitamin D levels with clinical, biochemical, and pathologic features of PHPT (issue 5). These studies provide level IV evidence suggesting that vitamin D deficiency causes some specific clinical features of PHPT as well as exacerbating other features of the disease.

CONCLUSIONS

In the developing countries, which have severe vitamin D and calcium deficient population, PHPT patients present with advanced disease and particularly severe bone symptoms. There is presently only level IV evidence of vitamin D status affecting the clinical severity of PHPT.

Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets

Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH)D concentrations, and serum 1,25(OH)(2) D values are markedly elevated. Studies of Nigerian children with rickets demonstrated they have high fractional calcium absorption. A high-phytate diet was demonstrated to increase calcium absorption compared with the fasting state, and enzymatic dephytinization did not significantly improve calcium absorption. When given vitamin D, children with rickets have a marked increase in 1,25(OH)(2) D concentrations without any change in fractional calcium absorption. No positive relationship was found between fractional calcium absorption and serum 25(OH)D concentrations in children on low-calcium diets. More research is needed to understand the interaction between calcium and vitamin D and the role of vitamin D in calcium absorption.

Nutritional Rickets among Children in a Sun Rich Country

Objective. This study describes the magnitude and characteristics of nutritional rickets and associated risk factors among children in Qatar. Subjects. A consecutive sample of 730 healthy subjects who visited the primay health care clinics were approached and 540 (73.9%) subjects gave consent. Mehods. Nutritional rickets diagnosis was based on clinical radiologic and biochemical parameters and normalization of alkaline phosphatase level after 6 weeks course of daily vitamin D therapy. Results. The study revealed that 23.9% of the studied children had nutritional rickets. The mean ± SD age of those with rickets (3.76 years ± 1.51) was slightly higher than those without rickets (3.57 years ± 1.45). Family history of vitamin D deficiency (44.2%; P = .001) and diabetes mellitus (53.5%; P = .002) were significantly higher in rachitic children than in nonrachitic children. The children with rickets spent a significantly shorter average duration (26.86 minutes ± 19.94) under the sun than those without rickets (30.59 minutes ± 15.72; P < .001). A significantly larger proportion of rachitic children was afflicted with vitamin D deficiency (75.2% versus 62.2%; P < .001), secondary hypothyroidism (100% versus 7.5%; P = .009) and muscular weakness (56.6% versus 26.3%; P < .001). Conclusion. The most important risk factors were low vitamin D and calcium intakes, lack of exposure to sunlight, prolonged breast feeding without supplementation of vitamin D.

Hypovitaminosis D in developing countries-prevalence, risk factors and outcomes

Hypovitaminosis D is a prevalent disorder in developing countries. Clinical manifestations of hypovitaminosis D include musculoskeletal disorders, such as nonspecific muscle pain, poor muscle strength and low BMD, as well as nonmusculoskeletal disorders, such as an increased risk of respiratory infections, diabetes mellitus and possibly cardiovascular diseases. In developing countries, the prevalence of hypovitaminosis D varies widely by and within regions; prevalence ranges between 30-90%, according to the cut-off value used within specific regions, and is independent of latitude. A high prevalence of the disorder exists in China and Mongolia, especially in children, of whom up to 50% are reported to have serum 25-hydroxyvitamin D levels <12.5 nmol/l. Despite ample sunshine throughout the year, one-third to one-half of individuals living in Sub-Saharan Africa and the Middle East have serum 25-hydroxyvitamin D levels <25 nmol/l, according to studies published in the past decade. Hypovitaminosis D is also prevalent in children and the elderly living in Latin America. Risk factors for hypovitaminosis D in developing countries are similar to those reported in Western countries and include extremes of age, female sex, winter season, dark skin pigmentation, malnutrition, lack of sun exposure, a covered clothing style and obesity. Clinical trials to assess the effect of vitamin D supplementation on classical and nonclassical clinical outcomes in developing countries are needed.

Comparison of metabolism of vitamins D2 and D3 in children with nutritional rickets

Children with calcium-deficiency rickets may have increased vitamin D requirements and respond differently to vitamin D(2) and vitamin D(3). Our objective was to compare the metabolism of vitamins D(2) and D(3) in rachitic and control children. We administered an oral single dose of vitamin D(2) or D(3) of 1.25 mg to 49 Nigerian children--28 with active rickets and 21 healthy controls. The primary outcome measure was the incremental change in vitamin D metabolites. Baseline serum 25-hydroxyvitamin D [25(OH)D] concentrations ranged from 7 to 24 and 15 to 34 ng/mL in rachitic and control children, respectively (p < .001), whereas baseline 1,25-dihydroxyvitamin D [1,25(OH)(2)D] values (mean ± SD) were 224 ± 72 and 121 ± 34 pg/mL, respectively (p < .001), and baseline 24,25-dihydroxyvitamin D [24,25(OH)(2)D] values were 1.13 ± 0.59 and 4.03 ± 1.33 ng/mL, respectively (p < .001). The peak increment in 25(OH)D was on day 3 and was similar with vitamins D(2) and D(3) in children with rickets (29 ± 17 and 25 ± 11 ng/mL, respectively) and in control children (33 ± 13 and 31 ± 16 ng/mL, respectively). 1,25(OH)(2)D rose significantly (p < .001) and similarly (p = .18) on day 3 by 166 ± 80 and 209 ± 83 pg/mL after vitamin D(2) and D(3) administration, respectively, in children with rickets. By contrast, control children had no significant increase in 1,25(OH)(2)D (19 ± 28 and 16 ± 38 pg/mL after vitamin D(2) and D(3) administration, respectively). We conclude that in the short term, vitamins D(2) and D(3) similarly increase serum 25(OH)D concentrations in rachitic and healthy children. A marked increase in 1,25(OH)(2)D in response to vitamin D distinguishes children with putative dietary calcium-deficiency rickets from healthy children, consistent with increased vitamin D requirements in children with calcium-deficiency rickets. © 2010 American Society for Bone and Mineral Research.

Relationship between rickets and incomplete distal renal tubular acidosis in children

Background

In the Sub Saharan Africa Rickets has now been established to be due primarily to calcium deficiency and sometimes in combination with vitamin D deficiency. The main thrust of management is calcium supplementation with or without vitamin D. An observation was made that some children with nutritional rickets do not respond to this management modality. The recently reported high prevalence of Incomplete Distal Renal Tubular Acidosis (idRTA) in adults with osteoporosis as brought to fore the possibility of this being a possible cause of calcium wastage and therefore the poor response in these group of children with rickets.

Aim

To determine the prevalence of idRTA amongst a cohort of subjects with rickets

To show a relationship between rickets and incomplete distal renal acidosis

To determine the response of children with rickets and idRTA to addition of Shohl's solution to therapy

Methodology

Two separate cohorts of children with rickets performed the ammonium chloride loading test to detect those with incomplete renal tubular acidosis. Following identification for idRTA, Shohl's solution was added to therapy of calcium and vitamin D supplementation and their response compared to those without idRTA on calcium and vitamin D supplementation solely.

Results

50 children with rickets aged from two to six years of age and composed of 29 females and 21males were investigated. Incomplete renal tubular acidosis was found in 38% of them. Prevalence of idRTA was highest amongst those aged 3-6 years of age. Those with idRTA had worse limb deformities, biochemical and radiological parameters than those who hadn't. Rate of response on those with idRTA treated with Shohl's solution was at par with those without idRTA.

Conclusion

Incomplete idRTA exist amongst children with rickets and should be looked out for in severe rickets and older children. Treatment of idRTA will lead to optimal response and healing of rickets.

High prevalence of vitamin D and calcium deficiency among pregnant women and their newborns in Chengdu, China

BACKGROUND

Vitamin D and calcium deficiency is common in pregnant women and newborn infants. There are few data about the prevalence of hypovitaminosis D during pregnancy and infancy in China. We assessed vitamin D status of pregnant women and their neonates in Chengdu, Sichuan province, China.

METHODS

Maternal serum and cord blood levels of calcium, 25-hydroxyvitamin D [25(OH)D], alkaline phosphatase, and parathyroid hormone (PTH) were studied in 77 urban and rural mother-neonate pairs at term.

RESULTS

The mean level of maternal serum 25(OH)D was 35.95+/-19.7 nmol/L, and that of cord blood 25(OH)D was 40.98+/-18.89 nmol/L. The intake of calcium and vitamin D was uniformly low, although it was higher in urban (1010+/-450 mg/d, 237+/-169 IU/d) than in rural (320+/-210 mg/d, 62+/-66 IU/d) women. Maternal serum 25(OH)D was correlated positively with cord blood 25(OH)D (r=0.94, P<0.01).

CONCLUSIONS

There is a high prevalence of vitamin D and calcium insufficiency in pregnant women and neonates in Chengdu even when mothers are compliant with prenatal vitamin supplementation. Supplementation is needed to improve maternal and neonatal vitamin D and calcium nutrition.

Nutritional rickets: still a problem for the pediatric population

Rickets is a mineralization disorder of the growing bone. Nutritional rickets is still prevalent in many parts of the developing world and is re-emerging in developed countries. Although vitamin D deficiency plays a central role in the pathogenesis of this disease, calcium deficiency and genetic factors may also cause or contribute to the development of rickets. This review will focus on the classical form of nutritional rickets, in other words, vitamin D-deficiency rickets. The epidemiology, ethiopathogenesis, risk factors, clinical picture, diagnosis, treatment and prevention of nutritional rickets are reviewed.

Vitamin D deficiency in Turkish mothers and their neonates and in women of reproductive age

OBJECTIVE

Materno-fetal vitamin D deficiency (VDD) may occur in the early neonatal period. We aimed to evaluate the vitamin D (vitD) status and risk factors for VDD in healthy newborns and their mothers, and also in fertile women.

METHODS

Serum 25 hydroxyvitamin D3 (25(OH)D), calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) levels were measured in 70 mothers (study group) and their newborns, and in umbilical cord samples. 104 nonpregnant fertile women comprised the control group. Demographic factors such as education and clothing habits of the mother, number of pregnancies and month of delivery were recorded. A serum 25(OH)D level below 11 ng/ml was accepted as severe, 11-25 ng/ml as moderate VDD, and a value over 25 ng/ml as normal.

RESULTS

Severe VDD was found in 27% of the mothers, and moderate deficiency in 54.3%. Severe VDD was detected in 64.3% of the neonates, and moderate deficiency in 32.9%. Only 18.6% of the mothers and 2.9% of the neonates had normal vitD levels. In the control group, severe VDD was observed in 26.9%, and moderate deficiency in 45.2%. Only 27.8% of the controls had normal vitD levels. In the control group, the 25(OH)D levels of the women dressed in modern clothes were significantly higher than those of the women wearing traditional clothes. This difference was not observed in the study group because 75% of these 70 mothers wore modern clothes. Mothers giving birth during the summer months and their neonates had significantly higher serum 25(OH)D levels than those of the mothers giving birth during the winter months and their neonates.

CONCLUSION

The study has shown that in Turkey VDD is an important problem in women of reproductive age, in mothers and their neonates. The 25(OH)D levels obtained from the cord may serve as a guide in the determination of the high risk groups.

Pediatric vitamin D and calcium nutrition in developing countries

Over one billion humans have insufficient circulating levels of vitamin D, and dietary insufficiency of calcium is common in developing countries. Worldwide, nutritional rickets is considered to be the most common non-communicable disease of children. Rickets can be due either to primary deficiencies of vitamin D or calcium or to combined deficiencies of both elements. Vitamin D deficiency is also increasingly linked to non-skeletal complications. Even without laboratory and radiologic resources, the diagnosis of rickets is considered clinically when a child presents with limb deformities and has beaded ribs and widened wrists and ankles. Prevention is possible through increased sun exposure and dietary enhancement. Treatment of nutritional rickets involves provision of adequate vitamin D and calcium. Further research is needed to elucidate the precise epidemiology of vitamin D and calcium deficiencies in developing countries, to determine the roles of additional pathologic factors contributing to the development and morbidity of rickets, to improve affordable and feasible means of diagnosing rickets in resource-limited areas, to better target at-risk populations for preventive interventions, to identify accurate dosing and delivery of therapeutic interventions, and to evaluate the long-term consequences of vitamin D and calcium deficiencies in childhood.

Nutritional rickets and z scores for height in the United Arab Emirates: to D or not to D?

BACKGROUND

Vitamin D deficiency is still prevalent worldwide, including the Middle East. A cohort of patients with nutritional rickets was treated with vitamin D(2) (ergocalciferol) alone. After this intervention, patients were followed to document changes in z scores for height after treatment. The secondary aim was to determine the proportion of affected children who had vitamin D deficiency or calcium deficiency.

METHODS

Z score for height was calculated as the difference between the observed value and the median value, divided by the SD of the population. Z scores were compared in patients before and after treatment.

RESULTS

The improvement in z score after treatment was 0.86 +/- 0.95. The 95% confidence interval for the mean difference was 1.32-0.40 (t = 3.95, P < 0.001). With a diagnostic cut-off for 25 hydroxyvitamin D(3) (25D) deficiency of <25 nmol/L, only half were diagnosed with severe vitamin D deficiency. The remaining patients had presumable calcium deficiency. The alkaline phosphatase (ALP) was negatively correlated to z scores, implying that higher ALP concentrations predicted severe bone disease (lower z scores). The variables 25D and age were moderately and positively correlated (Pearson's r = 0.59, 95%CI: 0.15-0.84; P = 0.01), indicating that younger infants had the lowest 25D levels.

CONCLUSION

Vitamin D alone was efficient in resolving radiological and biochemical disturbances as well as improving z scores for height in a cohort of children with nutritional rickets, which included patients with 25D deficiency as well as calcium deficiency. The results support the hypothesis of the interplay and continuum of 25D deficiency and calcium deficiency in the pathogenesis of rickets.

Vitamin D across the lifecycle: physiology and biomarkers

The field of vitamin D public health research has a pressing need to define sensitive and specific predictors of vitamin D status that can be used to determine whether an individual or population has a supply of vitamin D that is sufficient to meet requirements. The aim of this review is to highlight the considerations needed when evaluating evidence of the relations between vitamin D biomarkers and functional or health outcomes across the life cycle. It draws attention to the importance of distinguishing between biomarkers of supply, function, and outcome and of considering the many factors that could influence interpretation, such as life stage, ethnicity, body mass index, liver and kidney function, and dietary calcium and phosphorus intake. The vitamin D biomarkers that have shown the most utility to date are the plasma concentration of 25-hydroxyvitamin D (supply), the plasma concentration of parathyroid hormone (function), and the presence or absence of rickets (outcome). However, a single biomarker of vitamin D status or threshold value is unlikely to be valid in all situations. The field therefore needs research to refine existing biomarkers or establish new indicators that take the many factors into account and to identify useful functional biomarkers of vitamin D status for infants, children, women of reproductive age, and specific ethnic groups. However, evidence using the biomarkers currently available shows that frank vitamin D deficiency is a major public health problem in many parts of the world that requires urgent attention.