Diagnosis of rickets and reassessment of prevalence among rural children in northern China

Nutritional Rickets Among Children: A Retrospective Study from Saudi Arabia

Background

Nutritional rickets remains a significant concern in certain countries, with increasing prevalence attributed to factors such as limited sunlight exposure and undernourishment. This study aimed to identify the factors associated with rickets due to nutritional deficiency in children from Jazan Province, southwestern Saudi Arabia.

Methods

A retrospective cross-sectional study was conducted using descriptive data from medical records at a tertiary hospital in Jazan Province. Records of patients diagnosed with rickets between January 2010 and December 2020 were analyzed. Symptomatic rickets cases from pediatric clinics were included, and diagnoses were based on biochemical and clinical tests. Risk factors were assessed using patient medical records. Data were analyzed using percentages, mean, and standard deviation.

Results

The study included 84 patients with rickets (53 females and 31 males), primarily between 11-18 years old. The mean body mass index (BMI) of the participants was 21.21. The most common risk factor was nutritional deficiencies, including vitamin D deficiency or calcium deficiency, with 75 patients reporting a family history of vitamin D deficiency. The children had limited sunlight exposure and low levels of calcium and vitamin D. Malnutrition was identified as the highest risk factor for rickets in the study population.

Conclusion

Nutritional rickets appears to be prevalent in the Jazan Province, emphasizing the need for government organizations to address this preventable disease. Adequate sun exposure and recommended dietary vitamin D intake are crucial to prevent rickets, as this study detected inadequate levels of calcium and vitamin D in children. National studies are required to further identify risk factors and develop appropriate strategies.

Nutritional rickets and vitamin D deficiency: consequences and strategies for treatment and prevention

INTRODUCTION

Rickets is typically characterized by bone deformities due to defective bone mineralization and chondrocyte maturation in growing bones. However, infantile rickets often goes unrecognized, because the skeletal abnormalities are more subtle and often can only be detected radiologically. Nutritional rickets is a major public health concern in several regions worldwide. It is most commonly caused by vitamin D and/or calcium deficiency.

AREA COVERED

We provide an overview of historical perspective, epidemiology, and pathophysiology of nutritional rickets. Additionally, we outline diagnostic approaches and highlight challenges in radiographic diagnosis of rickets. Finally, we present strategies for prevention and treatment of rickets.

EXPERT OPINION

Despite the evidence from clinical databases that rickets is a rare disease, it is likely that rickets is clinically underdiagnosed as studies designed to screen healthy children for radiographic evidence of rickets reported surprisingly much higher prevalence. It has been reported that some of the radiologic features of rickets can be misinterpreted as fractures. To prevent nutritional rickets, most if not all infants and young children, should receive vitamin D from formulas and foods that are fortified with vitamin D or supplementation to achieve a serum 25-hydroxyvitamin D of at least 20 ng/mL as recommended by the Institute of Medicine. It has been recommended by the Endocrine Society that to achieve maximum bone health for children and adults, a serum concentration of 25-hydroxyvitamin D should be at least 30 ng/mL and preferably 40-60 ng/mL. Pregnant women who are unable to obtain an adequate amount of vitamin D from sunlight exposure and natural and fortified diets should take a vitamin D supplement of 1500-2000 IUs daily as recommended by the Endocrine Society since it has been demonstrated that 600 IUs daily will not maintain a circulating 25-hydroxyvitamin D of at least 20 ng/mL and most pregnant women. If lactating women take approximately 6400 IUs of vitamin D daily, they provide enough vitamin D in their milk to satisfy their infant's requirement thereby preventing 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.

How Much Does Serum 25(OH)D Improve by Vitamin D Supplement and Fortified Food in Children? A Systematic Review and Meta-Analysis

OBJECTIVES

This study was conducted to respond certain important questions regarding the efficacy of vitamin D fortification and supplementation in children using a meta-analytical approach.

METHODS

MEDLINE, PubMed, Embase, Cochrane Library, and Google Scholar were searched, and 2341 studies were found in a preliminary search. After screening of titles and abstracts, 31 studies were selected.

RESULTS

Significant raises in circulating 25-hydroxy vitamin D (25(OH)D) concentrations were observed in both groups that took vitamin D supplement (mean difference [MD] 28.7, 95% confidence interval [CI] 22.5-34.9) and vitamin D-fortified foods (MD 20.29, 95% CI 13.3-27.2). The meta-regression revealed a significant association between age of participants (B -1.4, 95% CI -2.8, -0.02, P = 0.047) and dose of vitamin D (B 0.007, 95% CI 0.003, 0.01, P < 0.001), with the effect on serum 25(OH)D concentrations. The analysis showed that serum 25(OH)D concentration increases by 0.7 nmol/L for every 100 IU of vitamin D intake after adjustment for age, baseline serum 25(OH)D and latitude which is far less than the reported amount in adults.

CONCLUSIONS

Altogether, these findings indicate that in a mass vitamin D fortification program, circulating 25(OH)D concentration response in children may be lower in children than in adults and vitamin D supplementation may still be needed in this subpopulation.

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.

Rickets in Children: An Update

Rickets refers to a deficient mineralization of the growth plate cartilage, predominantly affecting longer bones. Despite the fact that preventive measures are available, it is still a common disease worldwide; nutritional rickets, due to vitamin D deficiency or dietary calcium inadequate intake, remains the most common form. Medical history, physical examination, radiologic features and biochemical tests are essential for diagnosis. Although recent studies suggest hypophosphatemia as the leading alteration, rickets is classically divided into two categories: calcipenic rickets and phosphopenic rickets. Knowledge of this categorization and of respective clinical and laboratory features is essential for rapid diagnosis and correct management. The aim of this review is to analyze the epidemiological, pathogenetic, clinical, and therapeutic aspects of the different forms of rickets, describing the novelties on this “long-lived” disease.

Strontium in public drinking water and associated public health risks in Chinese cities

Due to the fact that strontium (Sr) is not involved in the scope of supervision of drinking water in China, the Sr concentration in public drinking water and its related health risks have been neglected for a long time. In this research, public drinking water samples were collected from 314 cities across the country to reveal the concentration and spatial distribution of Sr in public drinking water. In addition, the Monte Carlo method (a statistical simulation method) was applied to evaluate the Sr intake from drinking water and human health risks among different age groups and different regions. As shown in the results, the Sr was in the concentration range of 0.005-3.11 mg/L with a mean value of 0.360 mg/L. There were significant differences in the Sr concentration in different regions; in general, it was high in the north and low in the south. The Sr intakes of infants, children, teens, and adults from drinking water were 0.273, 0.503, 0.633, and 0.784 mg/day, respectively. There was a significant positive correlation between Sr concentration in drinking water and bone mineral density (BMD) in the elderly. Especially, the correlation coefficients (r) between Sr concentration and the BMD of the elderly whose age fell in the range of 60-70 years were 0.692 (male) and 0.483 (female). In addition, the Sr concentration in drinking water was positively correlated with the incidence of children's rickets (r = 0.411), while the Ca/Br ratio was negatively correlated with the incidence of children's rickets (r = - 0.410). According to the health risk assessment, among people of different ages, infants' hazard index (HI) value was the highest. The mean value and 95th percentile value were 0.066 and 0.247. Non-carcinogenic risk of Sr through drinking water among different people in different regions was less than 1, which meant no significant damage to human health. This study is the first time to systematically investigate Sr in public drinking water across the whole country. More importantly, the conclusions can be applied to risk control and management of public drinking water.

Knowledge, Attitude and Practice about Vitamin D among Pregnant Women at a Municipality of Bhaktapur

Introduction:

Almost a billion people in the world are affected by Vitamin D deficiency. During pregnancy, the deficiency of Vitamin D can manifest as gestational diabetes, pre-eclampsia, preterm birth, or miscarriage in the early stages of pregnancy. The objective of this study was to assess the knowledge, attitude and practice and importance of Vitamin D among pregnant women via focus group.

Methods:

A qualitative study was carried out at Changu Narayan Municipality, Duwakot ward no. two, Bhaktapur district from November to December 2019 after approval from Institutional Review Committee of Kathmandu Medical College (Ref. 181020192). Participants were selected via the Female Community Health Volunteer's pregnant women list by purposive sampling method. Focus group discussion was conducted among pregnant women. The interview questions were open-ended and the data were analyzed using thematic analysis.

Results:

Study participants showed limited knowledge on vitamin D. Few participants had information regarding sun exposure for vitamin D. But many participants had negative attitudes towards sun exposure and lack of knowledge on sun exposure requirements. The participants have a huge knowledge gap between Vitamin D and its importance in pregnancy.

Conclusions:

Increasing awareness of the importance of Vitamin D among pregnant women is required.

Serum biomarkers of the calcium-deficient rats identified by metabolomics based on UPLC/Q-TOF MS/MS

BACKGROUND

We previously identified the urinary biomarkers to diagnose calcium deficiency and nutritional rickets by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS). To find biomarkers of calcium deficiency and further confirm these biomarkers in serum, we performed serum metabolomics analysis of calcium-deficient rats.

METHODS

A calcium-deficient rat model was established with a low-calcium diet for 12 weeks. Serum metabolomics based UPLC/Q-TOF MS/MS and multivariate statistical analysis was performed to identify the alterations in metabolites associated with calcium deficiency in rats.

RESULTS

Bone mineral density, serum parathyroid hormone and alkaline phosphatase were significantly decreased in the low-calcium diet group (LCG) compared to the normal calcium diet group (NCG). Serum metabolic-profiling analysis could definitively distinguish between the LCG and NCG and identified 24 calcium-deficient biomarkers. Three metabolites (indoxyl sulfate, phosphate, and taurine) of the 24 biomarkers were found in our previous urinary metabolomics study of rats with a calcium deficiency and nutritional rickets. The areas under the curve (AUCs) of these three biomarkers were greater than 0.8, and the combination of any two biomarkers was higher than 0.95.

CONCLUSION

Dietary calcium deficiency induced the alterations of metabolites in the serum of rats, and the three identified biomarkers had relatively high diagnostic values for calcium deficiency in rats.

Vitamin D status in preschool children: should vitamin D supplementation, preventing vitamin D deficiency be continued in children over 2 years?

BACKGROUND

The aim of this study was to determine the prevalence of vitamin D deficiency among preschool children in rural and urban areas of Northern Iran and need for continuing vitamin D supplementation after 2 years of age.

METHOD

A sample of 406 children aged 30-72 months was selected from health centres. Serum levels of 25-hydroxyvitamin D (25OHD), demographic data, anthropometric characteristics and total body surface area, were evaluated.

RESULTS

Subnormal vitamin D levels were found in 68.94% (269) of children. In multiple logistic regression models, season (P = 0.001) and residency (P = 0.006) were significantly correlated with vitamin D deficiency. Multiple linear regression analysis revealed that age (β = -0.18, P < 0.001), body mass index (β = -1.1, P < 0.001) and sun exposure (β = 0.4, P < 0.001) were significantly associated with 25OHD level.

CONCLUSION

Owing to the high prevalence of subnormal vitamin D levels in preschool children, it is recommended that vitamin D deficiency prevention programs are continued in this age group.

Global consensus on nutritional rickets: Implications for Australia

In 2016, a global consensus on the prevention, diagnosis and management of nutritional rickets was published. The bone and mineral working group of the Australasian Paediatric Endocrine Group provides a summary and highlights differences to previous Australian and New Zealand (ANZ) guidelines on vitamin D deficiency and their implications for clinicians. Key points are: (i) The International Consensus document is focused on nutritional rickets, whereas the ANZ guidelines were focused on vitamin D deficiency. (ii) Definitions for the interpretation of 25-hydroxy vitamin D (25OHD) levels do not differ between statements. (iii) The global consensus recommends that routine 25OHD screening should not be performed in healthy children and recommendations for vitamin D supplementation are not based solely on 25OHD levels. The Australasian Paediatric Endocrine Group bone and mineral working group supports that screening for vitamin D deficiency should be restricted to populations at risk. (iv) Recommendations from the global consensus for vitamin D dosages for the therapy of nutritional rickets (diagnosed based on history, physical examination, biochemical testing and a confirmation by X-rays) are higher than in ANZ publications. (v) The global consensus recommends the implementation of public health strategies such as universal supplementation with vitamin D from birth to 1 year of age and food fortification. We conclude that updated global recommendations for therapy of nutritional rickets complement previously published position statements for Australia and New Zealand. Screening, management and the implementation of public health strategies need to be further explored for Australia.

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.

An epidemiology survey of vitamin D deficiency and its influencing factors

BACKGROUND

There is growing evidence that vitamin D is related to the development of a variety of diseases. The current study was performed to investigate the status of serum vitamin D distribution among adult Chinese people and reveal the influence of gender, age, seasonality and residential regions on serum vitamin D levels.

METHOD

This cross-sectional study included 14,302 participants aged from 18 years old to 65 years old from six major cities in China. The basic demographic information and the levels of serum vitamin D (25(OH)D) and vitamin D₃ (25(OH)D₃) were collected from Jan 2, 2014 to Dec 25, 2017.

RESULT

The prevalence of 25(OH)D₃ concentration <30ng/mL reached up to 83%, in which the rate of vitamin D insufficiency (20-29ng/mL) was 32.7%, and vitamin D deficiency (10-19ng/mL) accounted for 41.9%, and vitamin D severe shortage (<10ng/mL) accounted for 8.4%. Women were more likely to have vitamin D₃ deficiency and lower serum vitamin D₃ concentration than men (both p<0.001). The mean concentration of serum 25(OH)D and 25(OH)D₃ in summer and autumn were higher than that in spring and winter (p<0.001), and the mean concentration of serum 25(OH)D in people from Southern China was higher than that in people from other regions (p<0.001). Although the mean concentrations of serum 25(OH)D and 25(OH)D₃ were both increased by age, the percentage of patients with serum 25(OH)D₃ insufficiency was also increased.

CONCLUSION

Serum vitamin D deficiency is very common in adults in China. The level of serum vitamin D may be associated with age, sex, seasonality and residential regions.

Stoss therapy using fortified biscuit for vitamin D-deficient children: a novel treatment

BACKGROUND

To evaluate the efficacy of stoss therapy using fortified biscuit for vitamin D-deficient children.

METHODS

A total of 108 children aged 30-72 months with vitamin D deficiency were studied in a randomized single-blind clinical trial. The deficient children were assigned to three groups, namely, vitamin D-fortified biscuit (BG), capsule vitamin D (CG), and ampoule vitamin D (AG). Capsules and biscuits containing 50,000 IU of cholecalciferol were consumed twice per week for 3 consecutive weeks. Ampoules with 300,000 IU of cholecalciferol were injected intramuscularly in a single dose. Three weeks after treatment, serum 25(OH)D concentrations were measured, and the three groups were compared.

RESULTS

Each method of treatment could increase the mean serum 25(OH)D concentration to optimal level. Serum 25(OH)D concentrations ≥100 ng/mL were observed in six children, including four from AG and two from CG (P = 0.09). The comparison of the mean serum 25(OH)D concentrations after treatment showed between ampoule and capsule (P = 0.3) and capsule and biscuit (P = 0.62) were insignificant; however, the ampoule and biscuit groups differed significantly (P = 0.012).

CONCLUSION

Stoss therapy using fortified biscuit may be an effective way to improve compliance in children who cannot take capsules without adverse effects and may also be recommended for prevention purposes.

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.

Hypocalcaemic and hypophosphatemic rickets

Rickets refers to deficient mineralization at the growth plate and is usually associated with abnormal serum calcium and/or phosphate. There are several subtypes of rickets, including hypophosphatemic rickets (vitamin-D-resistant rickets secondary to renal phosphate wasting), vitamin D-dependent rickets (defects of vitamin D metabolism) and nutritional rickets (caused by dietary deficiency of vitamin D, and/or calcium, and/or phosphate). Most rickets manifest as bone deformities, bone pain, and impaired growth velocity. Diagnosis of rickets is established through the medical history, physical examination, biochemical tests and radiographs. It is of crucial importance to determine the cause of rickets, including the molecular characterization in case of vitamin D resistant rickets, and initiate rapidly the appropriate therapy. In this review, we describe the different causes and therapies of genetic and nutritional rickets, supported by the recent progress in genetics and development of novel molecules such as anti-FGF23 antibody.

Vitamin D Levels in Malnourished Children under 5 Years in a Tertiary Care Center at Muhimbili National Hospital, Dar es Salaam, Tanzania-A Cross-sectional Study

Objective

: To evaluate vitamin D levels/deficiency among malnourished children <5 years admitted at a tertiary care center, the Muhimbili National Hospital, Dar es Salaam, Tanzania. Children with malnutrition may have co-existing vitamin D deficiency (VDD), which may be severe.

Methods

: Serum vitamin D and alkaline phosphatase were evaluated, and X-ray of the wrist was carried out on 134 children.

Results

: VDD was found in 41 of 134 children (30.6%). The mean vitamin D level was 74.8 nmol/l. The mean alkaline phosphatase level was 176.6 U/l. Sixty-four (48%) children were found to have severe stunting, of whom 20 (31.2%) were vitamin D deficient. Marasmic children had higher odds of VDD compared with other forms of malnutrition.

Conclusion

: The high prevalence of VDD in malnourished children underlines the need for active surveillance and aggressive management.

Rickets: Historical, Epidemiological, Pathophysiological, and Pathological Perspectives

Rickets was a common metabolic disease of bone a century ago in Europe, North America, and East Asia (mainly due to vitamin D deficiency) but was largely eradicated in growing children by use of cod liver oil and the introduction of vitamin D fortification of milk in the 1930s in the United States. Vitamin D deficiency (VDD) remains the most common form of metabolic bone disease that is entirely preventable and treatable. Historically, rickets has appeared in sporadic epidemics and, despite the introduction of numerous preventive strategies, VDD has remained a global health problem amongst children. Moreover, developed countries such as Canada, Australia, the United Kingdom, and the United States have not been exempt from this. The radiological and histological features of rickets are both distinctive and characteristic and they reflect the underlying pathophysiological issue of decreased mineralization of bone as a result of VDD. The radiological features include 1) metaphyseal cupping and fraying, 2) poor mineralization of epiphyseal centers, 3) irregular and widened epiphyseal plates, 4) increased distance between the end of shaft and epiphyseal center, 5) cortical spurs at right angles to the metaphysis, 6) coarse trabeculation, and 7) periosteal reactions. Fractures may also be evident. The histological features of rickets reflect the failure of cartilage to mineralize and undergo resorption. This results in 1) disordered proliferation of chondrocytes in the hypertrophic zone secondary to a lack of apoptosis, 2) loss of the columnar arrangement of chondrocytes that results in thickening and disorganization of the hypertrophic zone, 3) tongue-like projections of cartilage that extend into the spongiosa, 4) irregularity of the limit between the proliferative and hypertrophic zones, and 5) penetration of blood vessels into the hypertrophic zone. The case of a premature 3-month-old female infant, born in the winter months in the arctic region of Canada who died from a lobar pneumonia with an incidental finding of radiological and pathological evidence of rickets, is presented. The case is used to review the entity of rickets from historical, pathophysiological, radiological, and histological perspectives.

Nutrient Status of Vitamin D among Chinese Children

Background: Vitamin D deficiency is considered to be a public health problem. However, the nutrient status of vitamin D in Chinese children is unclear. The aim of this study was to describe the vitamin D status among children aged under 18 years in southeast China. Methods: Children who visited the Huzhou Maternal and Child Care Hospital from January 2012 to August 2015 were included in this large cross-sectional study. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured by electrochemiluminescence immunoassay. Vitamin D status was defined as deficiency (25(OH)D < 20 ng/mL), insufficiency (25(OH)D: 20–29 ng/mL) and sufficiency (25(OH)D ≥ 30 ng/mL). The association between relevant variables and vitamin D status was analyzed by a using generalized estimated equation model and a multivariate regression model. Results: 13,997 children aged under 18 years were included. Of these, 23.3% children suffered from low vitamin D status (deficiency and insufficiency), while 76.7% had a sufficient vitamin D status. The prevalence of low vitamin D status was 29.7% in winter and 23.4% in spring, which was higher than that in summer (21.4%) and autumn (19.9%). Clinical visiting children (32.1%) suffered more from low vitamin D than health examination children (17.6%). Additionally, age and season were independently and significantly associated with 25(OH)D concentrations, respectively. Conclusions: The deficiency and insufficiency status of vitamin D was very common among newborns and children aged one to 17 years. This indicates that more sunshine and vitamin D–fortified foods are necessary among Chinese children.

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.

Screening for nutritional rickets in a community

Concern has been expressed about the rising incidence of nutritional rickets with its associated long-term sequelae in children globally. In order to address the condition worldwide, it is imperative that accurate figures of its incidence are available particularly in at-risk communities. In order to obtain these figures, various screening tools and diagnostic criteria have been used with no standardization of methodologies, resulting in varying prevalences which may under- or over-estimate the prevalence depending of the techniques used. This review discusses the advantages and disadvantages of various screening tests used to diagnose rickets in communities. Clinical signs characteristic of rachitic deformities have been used extensively, but are likely to over-estimate the prevalence and are dependent on the clinical skills of the observer. Biochemical tests such as alkaline phosphatase and 25-hydroxyvitamin D have also been proposed. There is no consensus on the usefulness of alkaline phosphatase as a screening tool, while there is general agreement that the measurement of vitamin D status is unhelpful in screening for rickets. Finally, the confirmation of the presence of active rickets in suspected infants and children is dependent on radiographic findings, although these may be less helpful in adolescents whose growth plates might be closed or nearly so. In order to obtain uniformity in screening for rickets globally, the is a need for consensus among public health specialists, paediatric endocrinologists and those interested in paediatric bone disease as to the best methods to be employed to determine the prevalence of rickets, particularly in communities with limited resources.

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.

Food insecurity and malnutrition in Chinese elementary school students

It has been shown that food insecurity is associated with poor diet quality and unfavourable health outcomes. However, little is known about the potential effects of food insecurity on the overall malnutrition status among children. In this study, we investigated the prevalence of food insecurity among 1583 elementary school students, aged 6-14 years, living in Chinese rural areas and examined its association with four malnutrition signs, including rickets sequelae, anaemia, stunting and wasting. Information on food security was collected via questionnaires. Rickets sequelae were assessed by an experienced paediatrician during the interview. Anaemia was determined by the WHO Hb thresholds adjusted by the local altitude. Weight and height were measured during the interview. Stunting and wasting were then evaluated according to WHO child growth standards (2007). We examined the association between food insecurity and the number of malnutrition signs (total number = 4), and the likelihood of having severe malnutrition (presence of 3+ signs), after adjusting for potential confounders, such as age, social-economic status and dietary intakes. During the previous 12 months, the overall prevalence of food insecurity was 6.1% in the entire studied population and 16.3% in participants with severe malnutrition. Participants with food insecurity had a slightly higher number of malnutrition signs (1.14 v. 0.96; P=0.043) relative to those who were food secure, after adjusting for potential confounders. Food insecurity was also associated with increased likelihood of having severe malnutrition (adjusted OR 3.08; 95% CI 1.47, 6.46; P=0.003). In conclusion, food insecurity is significantly associated with malnutrition among Chinese children in this community.

Prevalence of rickets-like bone deformities in rural Gambian children

The aim of this study was to estimate the burden of childhood rickets-like bone deformity in a rural region of West Africa where rickets has been reported in association with a low calcium intake. A population-based survey of children aged 0.5-17.9 years living in the province of West Kiang, The Gambia was conducted in 2007. 6221 children, 92% of those recorded in a recent census, were screened for physical signs of rickets by a trained survey team with clinical referral of suspected cases. Several objective measures were tested as potential screening tools. The prevalence of bone deformity in children <18.0 years was 3.3%. The prevalence was greater in males (M = 4.3%, F = 2.3%, p < 0.001) and in children <5.0 years (5.7%, M = 8.3%, F = 2.9%). Knock-knee was more common (58%) than bow-leg (31%) or windswept deformity (9%). Of the 196 examined clinically, 36 were confirmed to have a deformity outside normal variation (47% knock-knee, 53% bow-leg), resulting in more conservative prevalence estimates of bone deformity: 0.6% for children <18.0 years (M = 0.9%, F = 0.2%), 1.5% for children < 5.0 years (M = 2.3%, F = 0.6%). Three of these children (9% of those with clinically-confirmed deformity, 0.05% of those screened) had active rickets on X-ray at the time of medical examination. This emphasises the difficulties in comparing prevalence estimates of rickets-like bone deformities from population surveys and clinic-based studies. Interpopliteal distance showed promise as an objective screening measure for bow-leg deformity. In conclusion, this population survey in a rural region of West Africa with a low calcium diet has demonstrated a significant burden of rickets-like bone deformity, whether based on physical signs under survey conditions or after clinical examination, especially in boys < 5.0 years.

Biomarkers identified by urinary metabonomics for noninvasive diagnosis of nutritional rickets

Nutritional rickets is a worldwide public health problem; however, the current diagnostic methods retain shortcomings for accurate diagnosis of nutritional rickets. To identify urinary biomarkers associated with nutritional rickets and establish a noninvasive diagnosis method, urinary metabonomics analysis by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis were employed to investigate the metabolic alterations associated with nutritional rickets in 200 children with or without nutritional rickets. The pathophysiological changes and pathogenesis of nutritional rickets were illustrated by the identified biomarkers. By urinary metabolic profiling, 31 biomarkers of nutritional rickets were identified and five candidate biomarkers for clinical diagnosis were screened and identified by quantitative analysis and receiver operating curve analysis. Urinary levels of five candidate biomarkers were measured using mass spectrometry or commercial kits. In the validation step, the combination of phosphate and sebacic acid was able to give a noninvasive and accurate diagnostic with high sensitivity (94.0%) and specificity (71.2%). Furthermore, on the basis of the pathway analysis of biomarkers, our urinary metabonomics analysis gives new insight into the pathogenesis and pathophysiology of nutritional rickets.

Vitamin D3 dose requirement to raise 25-hydroxyvitamin D to desirable levels in adolescents: results from a randomized controlled trial

Several organizations issued recommendations on desirable serum 25-hydroxy vitamin D [25(OH)D] levels and doses of vitamin D needed to achieve them. Trials allowing the formulation of evidence-based recommendations in adolescents are scarce. We investigated the ability of two doses of vitamin D3 in achieving recommended vitamin D levels in this age group. Post hoc analyses on data from a 1-year double-blind trial that randomized 336 Lebanese adolescents, aged 13 ± 2 years, to placebo, vitamin D3 at 200 IU/day (low dose), or 2000 IU/day (high dose). Serum 25(OH)D level and proportions of children achieving levels ≥ 20 ng/mL and 30 ng/mL were determined. At baseline, mean 25(OH)D was 15 ± 7 ng/mL, 16.4 ± 7 ng/mL in boys, and 14 ± 8 ng/mL in girls, p=0.003, with a level ≥ 20 ng/mL in 18% and ≥ 30 ng/mL in 5% of subjects. At 1 year, mean levels were 18.6 ± 6.6 ng/mL in the low-dose group, 17.1 ± 6 ng/mL in girls, and 20.2 ± 7 ng/mL in boys, p=0.01, and 36.3 ± 22.3 ng/mL in the high-dose group, with no sex differences. 25(OH)D increased to ≥ 20 ng/mL in 34% of children in the low-dose and 96% in the high-dose group, being higher in boys in the low-dose arm only; it remained ≥ 30 ng/mL in 4% of children in the low-dose arm but increased to 64% in the high-dose arm. Baseline 25(OH)D level, body mass index (BMI), and vitamin D dose assigned were the most significant predictors for reaching a 25(OH)D level ≥ 20 ng/mL and 30 ng/mL. A daily dose of 2000 IU raised 25(OH)D level ≥ 20 ng/mL in 96% of adolescents (98% boys versus 93% girls). Dose-response studies are needed to determine in a definitive manner the daily allowance of vitamin D for Middle Eastern adolescents with a similar profile.

Relationship between polymorphisms in vitamin D metabolism-related genes and the risk of rickets in Han Chinese children

Background

Vitamin D deficiency rickets is common in China. Genetic factors may play an important role in the susceptibility to rickets. Our study aimed to identify the relationship between three vitamin D-related genes (group specific component [GC], cytochrome P450, family 2, subfamily R, polypeptide 1 (CYP2R1), and 7-dehydrocholesterol reductase/nicotinamide-adenine dinucleotide synthetase 1 (DHCR7/NADSYN1) and rickets in Han Chinese children from northeastern China.

Methods

A total of 506 Han children from northeastern China were enrolled in the current study. Twelve SNPs in three candidate genes were genotyped using the SNaPshot assay. Linear regression was used to examine the effect of 12 single-nucleotide polymorphisms (SNPs) on the risk of rickets.

Results

In our case–control cohort, six alleles of the 12 SNPs conferred a significantly increased risk of rickets in GC (rs4588 C, P = 0.003, OR: 0.583, 95% CI: 0.412-0.836; rs222020 C, P = 0.009, OR: 1.526, 95% CI: 1.117-2.0985; rs2282679 A, P = 0.010, OR: 0.636, 95% CI: 0.449-0.900; and rs2298849 C, P = 0.001, OR: 1.709, 95% CI: 1.250-2.338) and in CYP2R1 (rs10741657 G, P = 0.019, OR: 1.467, 95% CI: 1.070-2.011; and rs2060793 G, P = 0.023, OR: 0.689, 95% CI: 0.502-0.944). The results remained significant after adjustment for sex and body mass index. We further analyzed the effect of genotypes under three different genetic models. After using Bonferroni’s method for multiple corrections, rs4588, rs2282679, and rs2298849 of the GC gene were significantly associated with rickets under the dominant (P =0.003 for rs4588, P =0.024 for rs2282679, and P =0.005 for rs2298849) and additive models (P = 0.006 for rs4588, P = 0.024 for rs2282679, and P = 0.005 for rs2298849). Haplotype analysis showed that the CAT haplotype of the GC gene (P = 0.005) and the GAA haplotype of the CYP2R1 gene (P = 0.026) were associated with susceptibility to rickets.

Conclusions

This case–control study confirmed the strong effect of GC and CYP2R1 loci on rickets in Han children from northeastern China.

Prevalence of classic signs and symptoms of rickets and vitamin D deficiency in Mongolian children and women

In order to assess the current nutrition status of Mongolian population, including rickets and vitamin D deficiency of children and women, the Fourth National Nutrition Cross-Sectional Survey was conducted in 21 aimags (provinces) of 4 economic regions of the country and capital city Ulaanbaatar in 2010. Children of age under five years, and non-pregnant women of reproductive age were used as subjects for assessing rickets and vitamin D deficiency. A total of 400 households were randomly selected from each of 4 economic regions and Ulaanbaatar city. Clinical examinations were performed on 706 children of age under five years. Interviews were used to assess vitamin D supplement use. The serum level of 25-hydroxyvitamin D was measured in 524 children aged 6-59 months and in 867 women of reproductive age. This survey found that 21.8% of children had vitamin D deficiency, 20.6% had low vitamin D reserve, and 30.0% of women had vitamin D deficiency and 22.2% had low vitamin D reserve. The prevalence of vitamin D deficiency in children (35.0%, 95% CI, 24.7-47.0) and women (54.9%, 95% CI 45.5-64.0) in the Eastern Region was (35.0%, 95% CI, 24.7-47.0) significantly higher than in the Western, Khangai, Central Regions, and Ulaanbaatar. Further it was found that 27.4% of children under-two years had received vitamin D supplementation. The proportion of children, who did not receive vitamin D supplementation had a higher prevalence of vitamin D deficiency than that of the children of the Eastern Region. None of the women who were involved in this survey had received vitamin D supplementation; 10.2% of them had delivered in the past 12 months, and 22.5% were breastfeeding. The prevalence of classic signs and symptoms of rickets were commonly reported among children of age under five, and skeletal abnormalities more commonly reported in children aged 12-47 months. In conclusion, there is a high prevalence of classic signs and symptoms of rickets in children of age under five years. Vitamin D supplementation in adequate doses for the prevention and treatment of rickets in children is insufficient. Thus, a trial survey is needed to assess the safe and effective doses of vitamin D supplementation necessary for the maintenance of normal serum 25-hydroxyvitamin D concentrations in Mongolian children, and women. In addition, a vitamin D food fortification program is required. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Hypovitaminosis D and mild hypocalcaemia are highly prevalent among young Vietnamese children and women and related to low dietary intake

Introduction

In many developing countries including Vietnam, data are lacking on vitamin D and calcium deficiencies whereas those deficiencies can play an important role in the development of bone health and possibly non-communicable diseases. The purpose of this study was to determine the overall prevalence of vitamin D and calcium deficiencies in women and young children and their nutritional related risk factors.

Methods

A cross-sectional study conducted among 595 women of reproductive age and 532 children <5 years from 19 provinces of Vietnam. For each individual, data concerning daily diet, socioeconomic group, anthropometric status were obtained, and plasma concentrations of calcium and vitamin D were measured.

Results

The prevalence of hypovitaminosis D status was very high, with the prevalence of vitamin D deficiency (25(OH)D<30 nmol/L) and insufficiency (25(OH)D between 30–49.9 nmol/L) being 17% and 40% in women and 21% and 37% in children, respectively. Using more liberal cut-off of 75 nmol/L, approximately 90% of the women and children were classified as having hypovitaminosis D. Overweight/obese women had a 2 times lower risk (OR = 0.46, [0.24–0.90]) for vitamin D deficiency than non-overweight and non-obese women. No participant had severe calcium deficiency but moderate and mild hypocalcaemia (plasma calcium concentrations between 1.15-0.9 mmol/L for mild deficiency and between 0.9-0.8 mmol/L for moderate deficiency) affected respectively 14% and 83% of the women with 97% of the children having mild hypocalcaemia. Women and children consumed about 1% of the Institute of Medicine (IOM) recommended nutrient intake (RNI) for vitamin D and less than 43% of the RNI for calcium.

Conclusion

Our study suggests that calcium and vitamin D deficiencies represent a major public health concern in Vietnam. Thus, actions to improve the vitamin D and calcium status of the Vietnamese population should be considered.

Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis

BACKGROUND

Calcium deficiency is a global public-health problem. Although the initial stage of calcium deficiency can lead to metabolic alterations or potential pathological changes, calcium deficiency is difficult to diagnose accurately. Moreover, the details of the molecular mechanism of calcium deficiency remain somewhat elusive. To accurately assess and provide appropriate nutritional intervention, we carried out a global analysis of metabolic alterations in response to calcium deficiency.

METHODS

The metabolic alterations associated with calcium deficiency were first investigated in a rat model, using urinary metabonomics based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis. Correlations between dietary calcium intake and the biomarkers identified from the rat model were further analyzed to confirm the potential application of these biomarkers in humans.

RESULTS

Urinary metabolic-profiling analysis could preliminarily distinguish between calcium-deficient and non-deficient rats after a 2-week low-calcium diet. We established an integrated metabonomics strategy for identifying reliable biomarkers of calcium deficiency using a time-course analysis of discriminating metabolites in a low-calcium diet experiment, repeating the low-calcium diet experiment and performing a calcium-supplement experiment. In total, 27 biomarkers were identified, including glycine, oxoglutaric acid, pyrophosphoric acid, sebacic acid, pseudouridine, indoxyl sulfate, taurine, and phenylacetylglycine. The integrated urinary metabonomics analysis, which combined biomarkers with regular trends of change (types A, B, and C), could accurately assess calcium-deficient rats at different stages and clarify the dynamic pathophysiological changes and molecular mechanism of calcium deficiency in detail. Significant correlations between calcium intake and two biomarkers, pseudouridine (Pearson correlation, r = 0.53, P = 0.0001) and citrate (Pearson correlation, r = -0.43, P = 0.001), were further confirmed in 70 women.

CONCLUSIONS

To our knowledge, this is the first report of reliable biomarkers of calcium deficiency, which were identified using an integrated strategy. The identified biomarkers give new insights into the pathophysiological changes and molecular mechanisms of calcium deficiency. The correlations between calcium intake and two of the biomarkers provide a rationale or potential for further assessment and elucidation of the metabolic responses of calcium deficiency in humans.

Relationships between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in 0-6 year old children

The relationship between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in young children remains unclear. In addition, consensus has not been reached with regard to the concentration of 25(OH)D to define vitamin D deficiency for infants and children. In the present study, 203 children 0-6 years old were recruited in Shanghai, China. The concentrations of serum 25(OH)D, weight, length, and quantitative ultrasound bone mineral density (BMD) of left mid-tibia were determined. Low BMD was defined as <20th percentile of given age and sex. Low 25(OH)D was defined as 25(OH)D<20 ng/ml. The results showed that median serum 25(OH)D level was 19.0 ng/ml, and 58.6% had a serum 25(OH)D below 20 ng/ml. After adjusting for potential confounders, a linear relationship between serum 25(OH)D and BMD was observed. Serum 25(OH)D was positively associated with BMD (ß=323.3, 95% CI=201.0-445.7, p<0.001), and low 25(OH)D (<20 ng/ml) had a high risk for low BMD (OR=5.5, 95% CI=2.5-12). In addition, there is a nonlinear relationship between 25(OH)D and low BMD, and a threshold for 25(OH)D of 20 ng/ml existed for low BMD. The prevalence of low BMD was 47.1% in the group of 25(OH)D<20 ng/ml, much higher than 16.7% in the group of 25(OH)D ≥ 20 ng/ml (p<0.05). The results suggested that quantitative ultrasound BMD could be an indicator for vitamin D status in young children, and also provided further evidence to define vitamin D deficiency for infants and children.

The Study in Vitamin D Concentration in the Blood for Infants with High Level of Alkaline Phosphatase

<sec><title>Objectives</title> Nowadays most infants on exclusively breast feeding have vitamin D deficiency due to the increase of breast feeding. However, domestic research lacks appropriate materials. Therefore, we researched practical clinical aspects of vitamin D deficiency related to breast milk feeding for infants who have a high amount of alkaline phosphatase (&gt; 500 IU/L). </sec><sec><title>Methods</title> The subjects of the study were 31 infants with high alkaline phosphatase level. We tested with 25-hydroxycholecalciferol (25-OHD₃), parathyroid hormone, calcium, ionized calcium, phosphorus in their blood and with a wrist x-ray. Then, we divided them into two groups of breast feeding and formula feeding and compared the results. </sec><sec><title>Results</title> Eighteen infants (58%) out of 31 infants that have high alkaline phosphatase were vitamin D insufficiency or deficiency, and 16 (100%) breast feeding infants of them showed vitamin D deficiency or insufficiency. However, only 2 (13%) of 15 formula feeding infants were at insufficiency. There was a correlation between alkaline phosphatase and 25-OHD₃ concentration in multiple regression analysis, but no correlation in other variables was found in group of breast milk feeding infants. There was neither correlation between vitamin D concentration and alkaline phosphatase nor other correlated variables in the group of formula milk feeding infants. </sec><sec><title>Conclusions</title> In this study, there was a high probability of vitamin D deficiency in the breast feeding infants with a high alkaline phosphatase level. Therefore, it is considered to be worth utilizing alkaline phosphatase as a screening test for vitamin D deficiency or rickets for breast feeding infants. </sec>

Prevalence and risk factors for vitamin D deficiency in children with iron deficiency anemia

PURPOSE

The increasing prevalence of breast feeding has led to concerns about vitamin D deficiency (VDD) and iron deficiency anemia (IDA) in children. We evaluated the prevalence of VDD in a population of Korean children with IDA and assessed the risk factors for VDD in these children.

METHODS

A total of 79 children who were diagnosed with IDA were prospectively surveyed from April 2010 to March 2011. Data were collected by questionnaire, medical assessment, and laboratory tests, including measurement of 25-hydroxyvitamin D (25OHD), hemoglobin, and wrist radiography.

RESULTS

The median age was 22 months and 30% of the subjects were female. Over a half of subjects (58%) had subnormal vitamin D level (25OHD<30 ng/mL), and VDD (25OHD<20 ng/mL) was present in 39% of children. There was no difference in serum hemoglobin level between IDA patients with VDD and those without VDD. Most subjects (89%) were currently or had recently been breastfed and almost all subjects (97%) who had VDD received breastfeeding. Children with VDD were more likely to be younger than 2 years, to have been breastfed, and to have been tested in winter or spring. Multivariable analysis indicated seasonal variation was a significant independent risk factor for VDD in our IDA patients.

CONCLUSION

Our results demonstrated that VDD has a high prevalence in Korean children with IDA. Primary care physicians should be aware of the possibility of VDD in children with IDA and should supplement the vitamin D as well as iron.

Heightened attention to supplementation is needed to improve the vitamin D status of breastfeeding mothers and infants when sunshine exposure is restricted

Although exclusively breastfed infants are at increased risk of vitamin D (vit D) deficiency if vit D supplementation is lacking and sun exposure is limited, assessment of both risk factors in the first year of life is lacking. We evaluated the contribution of vit D intake and sunlight exposure to vit D status in 120 healthy, breastfeeding mother-infant dyads, who were followed up for 1 year. Vitamin D intake and skin sunlight exposure were evaluated using questionnaires. Serum 25-hydroxyvitamin D, parathyroid hormone (PTH) and alkaline phosphatase levels were determined post-natally in mothers at 4 weeks and in infants at 4, 26 and 52 weeks. Vitamin D supplementation was low (<20%) and sunlight exposure was common (93%) in study infants. At 4 weeks, 17% of mothers were vit D deficient (<50 nmol L(-1)) and 49% were insufficient (50-<75 nmol L(-1)), while 18% of infants were severely vit D deficient (<25 nmol L(-1)) and 77% were deficient (<50 nmol L(-1)). At 26 weeks, winter/spring birth season and shorter duration of months of exclusive breastfeeding were protective of vit D deficiency in infants. Vitamin D deficiency in infants decreased to 12% at 52 weeks with sunlight exposure. Serum PTH levels were significantly higher in severely vit D deficient than sufficient infants. Vitamin D deficiency was widespread in early post-partum breastfeeding mothers and infants, and declined to one in eight infants at 52 weeks due mostly to sunshine exposure. When sunlight exposure is limited or restricted, intensified vit D supplementation of breastfeeding mothers and infants is needed to improve vit D status.

High prevalence of vitamin D deficiency among children aged 1 month to 16 years in Hangzhou, China

BACKGROUND

Recent studies have suggested that vitamin D deficiency in children is widespread. But the vitamin D status of Chinese children is seldom investigated. The objective of the present study was to survey the serum levels of 25-hydroxyvitamin D [25(OH)D] in more than 6,000 children aged 1 month to 16 years in Hangzhou (latitude: 30°N), the capital of Zhejiang Province, southeast China.

METHODS

The children aged 1 month to 16 years who came to the child health care department of our hospital, the children's hospital affiliated to Zhejiang university school of medicine, for health examination were taken blood for 25(OH) D measurement. Serum 25(OH) D levels were determined by direct enzyme-linked immunosorbent assay and categorized as < 25, < 50, and < 75 nmol/L.

RESULTS

A total of 6,008 children aged 1 month to 16 years participated in this cross-sectional study. All the subjects were divided into subgroups according to their age: 0-1y, 2-5y, 6-11y and 12-16y representing infancy, preschool, school age and adolescence stages respectively. The highest mean level of serum 25(OH)D was found in the 0-1y stage (99 nmol/L) and the lowest one was found in 12-16y stage (52 nmol/L). Accordingly, the prevalence of serum 25(OH)D levels of < 75 nmol/L and < 50 nmol/L were at the lowest among infants (33.6% and 5.4% respectively) and rose to the highest among adolescents (89.6% and 46.4% respectively). The mean levels of serum 25(OH)D and the prevalence of vitamin D deficiency changed according to seasons. In winter and spring, more than 50% of school age children and adolescents had a 25(OH)D level at < 50 nmol/L. If the threshold is changed to < 75 nmol/L, all of the adolescents (100%) had low 25(OH)D levels in winter and 93.7% school age children as well.

CONCLUSIONS

The prevalence of vitamin D deficiency and insufficiency among children in Hangzhou Zhejiang province is high, especially among children aged 6-16 years. We suggest that the recommendation for vitamin D supplementation in Chinese children should be extended to adolescence.

Evaluation of children with nutritional rickets

AIM

To evaluate the clinical findings, risk factors, therapy and outcome in 946 children with nutritional rickets.

PATIENTS AND METHODS

This retrospective study included a review of medical records of patients with nutritional rickets between March 2004 and 2009. Patients who displayed both the biochemical inclusion criteria and the clinical signs/symptoms or radiological signs of rickets were included in the study.

RESULTS

The present study included 946 patients aged between 4 months and 15 years. Distribution of the cases showed a density between December and May. The age at diagnosis, showed two peaks and most of the patients were in the age range 0-23 months and 12.0-15 years. In infants and young children, most of the patients had been admitted to the hospital due to infectious diseases. In older children, short stature and obesity were the most common complaints.

CONCLUSION

Children aged between 0-23 months and 12.0-15 years were under most risk for nutritional rickets, especially in winter and spring and vitamin D should be given to them as supplementation dose.

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.

Heritability and environmental factors affecting vitamin D status in rural Chinese adolescent twins

CONTEXT

Factors associated with the high prevalence of vitamin D deficiency in China are not well described, especially among Chinese adolescents.

OBJECTIVES

The aim of the study was to examine important environmental or sociodemographic factors influencing 25-hydroxyvitamin D [25(OH)D] levels and estimate its heritability.

DESIGN

A sample of 226 male and female adolescent twins aged 13-20 yr from a large prospective twin cohort of rural Chinese children and adolescents that has been followed for 6 yr were evaluated.

MAIN OUTCOME MEASURE(S)

Blood level of 25(OH)D was measured using tandem mass spectrometry methodology.

RESULTS

The overall mean (SD) 25(OH)D level was 18.0 (9.4) ng/ml, with wide variation by gender and season. In males (47.4% of subjects), the mean (SD) 25(OH)D level was 12.1 (4.2) ng/ml in non-summer and 27.4 (8.8) ng/ml in summer; in females, it was 10.1 (4.1) ng/ml in non-summer and 19.5 (6.3) ng/ml in summer. A multivariate model that included gender, age, season, physical activity, and student status demonstrated that male gender, summer season, and high physical activity significantly increased 25(OH)D levels. Summer season and male gender also significantly decreased the risk of being in the lowest 25(OH)D tertile. Overall, 68.9% of the variability in 25(OH)D level was attributable to additive genetic influence. Stratification by gender found that in males, 85.9% of the variability in 25(OH)D level was attributable to such influence, but in females, it was only 17%.

CONCLUSION

In this sample of rural Chinese adolescents, 25(OH)D level was influenced by gender, season, and physical activity level. There was a strong genetic influence on 25(OH)D level in males only.

Prevalence and risk factors of vitamin D deficiency rickets in Hokkaido, Japan

BACKGROUND

Resurgence of vitamin D deficiency rickets has been recognized worldwide. While many cases of this disease have been reported in Hokkaido, the northern island of Japan, no prevalence data is available. Here, we investigated the prevalence and risk factors of vitamin D deficiency rickets in Hokkaido.

METHODS

A specially designed questionnaire was sent to 84 major pediatric departments of hospitals in Hokkaido to collect information of the confirmed cases between July 1999 and June 2004.

RESULTS

Sixty-seven hospitals responded to the questionnaire. Of these, 20 hospitals reported 31 confirmed cases. All the patients were infants and toddlers, less than 4 years of age. The prevalence of cases in a recent year was estimated to be nine in 100,000 children under four years of age. Most of the 31 cases in our study were breast-fed. Eleven cases showed signs of malnutrition due to unbalanced diet or dietary restriction. Furthermore, the prevalence of cases was higher in the northeastern region than in the southwestern region. The number of cases increased gradually from the end of winter to spring.

CONCLUSIONS

This is the first report ascertaining the prevalence of vitamin D deficiency rickets in Hokkaido, Japan. Limited exposure to sunlight and inadequate diet in early childhood are key risk factors of this disease. Thus, it is crucial to introduce active recommendations for vitamin D supplementation based on age, residential area, and to advocate public awareness for preventing this disease.

Vitamin D deficiency in healthy children in a sunny country: associated factors

OBJECTIVE

The objective of the present study was to determine the factors associated with low concentrations of 25-hydroxy vitamin D (vitamin D deficiency) in healthy children in Qatar.

DESIGN

The survey was a cross-sectional study conducted at the Primary Health Care Clinics over the period from August 2007 to March 2008. Subjects The study was carried out among healthy Qatari nationals, male and female, aged below 16 years. A random sample of 650 healthy subjects who visited the Primary Health Care Centers for any reason other than acute or chronic disease were approached and 458 subjects gave consent; a response rate of 70.5%.

METHODS

Face-to-face interviews were based on a questionnaire that included variables such as socio-demographic information, assessment of non-dietary covariates, assessment of dietary intake, vitamin D intake, type of feeding, clinical manifestations and laboratory investigations. The subjects' health status was assessed by medical conditions, family history, body mass index, past or present clinical manifestations, 25-hydroxy vitamin D, calcium, alkaline phosphates, phosphorus, HbA1C, Parathyroid Hormone (PTH), magnesium and creatinine analysis.

RESULTS

The study revealed that vitamin D deficiency was highly prevalent in Qatari adolescents (11-16 years old; 61.6%), followed by the 5-10 year olds (28.9%) and those below 5 years old (9.5%). Vitamin D deficiency increased with age and there was a significant difference between vitamin D-deficient and normal children in their age groups (P =0.013). The body mass index was significantly lower in vitamin D-deficient children (19.6+/-3.6; P =0.019). A family history of vitamin D deficiency was more frequent in children with vitamin D deficiency (33.7%) than in normal children (24.5%). Most of the vitamin D-deficient children had no physical activity (60.6%) and no exposure to sunlight (57.5%). There was a significant difference between both groups in terms of family history of vitamin D deficiency, physical activity, exposure to sunlight and duration of time spent outside under the sun (P <0.05). The mean values of vitamin D serum concentration, calcium, alkaline phosphates, and phosphorus were very low in vitamin D-deficient children. Vitamin D-deficient children had a very poor diet for vitamin D (cod liver oil, 56.5%; milk fortified with vitamin D, 27.3%; fortified food, 24.1%; and seafood, 5.7%) compared with normal children. Fractures (P =0.006), delayed milestones (P =0.013), rickets (P =0.017) and gastroenteritis (P =0.020) were significantly higher in vitamin D-deficient children.

CONCLUSION

The study findings revealed that Qatari children are at high risk for vitamin D deficiency. Lack of exposure to sunlight, outdoor activities under the sun, and physical activity and vitamin D intake are the main associated factors for vitamin D deficiency in the young population of Qatar. Breast-fed infants need to take vitamin D supplements for a longer period.

Prevalence of vitamin D deficiency among healthy infants and toddlers

OBJECTIVES

To determine the prevalence of vitamin D deficiency and to examine whether 25-hydroxyvitamin D (25OHD) concentration varies as a function of skin pigmentation, season, sun exposure, breastfeeding, and vitamin D supplementation.

DESIGN

Cross-sectional sample.

SETTING

Urban primary care clinic.

PARTICIPANTS

Healthy infants and toddlers (N = 380) who were seen for a routine health visit.

OUTCOME MEASURES

Primary outcomes were serum 25OHD and parathyroid hormone levels; secondary measures included data on sun exposure, nutrition, skin pigmentation, and parental health habits. Wrist and knee radiographs were obtained for vitamin D-deficient participants.

RESULTS

The prevalence of vitamin D deficiency (< or =20 ng/mL) was 12.1% (44 of 365 participants), and 146 participants (40.0%) had levels below an accepted optimal threshold (< or =30 ng/mL). The prevalence did not vary between infants and toddlers or by skin pigmentation. There was an inverse correlation between serum 25OHD and parathyroid hormone levels (infants: r = -0.27, P < .001; toddlers: r = -0.20, P = .02). In multivariable models, breastfeeding without supplementation among infants and lower milk intake among toddlers were significant predictors of vitamin D deficiency. In vitamin D-deficient participants, 3 participants (7.5%) exhibited rachitic changes on radiographs, whereas 13 (32.5%) had evidence of demineralization.

CONCLUSIONS

Suboptimal vitamin D status is common among otherwise healthy young children. Predictors of vitamin D status vary in infants vs toddlers, information that is important to consider in the care of these young patients. One-third of vitamin D-deficient participants exhibited demineralization, highlighting the deleterious skeletal effects of this condition.

Very high rates of vitamin D insufficiency in women of child-bearing age living in Beijing and Hong Kong

We aimed to describe the vitamin D status of young women living in two Chinese cities in the spring – Beijing in the north (latitude 39° north) and Hong Kong (latitude 22° north) in the south. We also examined the relationship between serum 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations to determine a threshold for serum 25-hydroxyvitamin D above which there is no further suppression of PTH. Finally, we examined whether dietary Ca intake influences this relationship. Non-pregnant women aged 18–40 years (n 441) were recruited between February and June. Fasting blood was collected and dietary intakes were assessed using 5 d food records. Mean serum 25-hydroxyvitamin D concentration was lower in Beijing than Hong Kong women (29 v. 34 nmol/l; P < 0·001). Vitamin D deficiency ( ≤  25 nmol/l) was indicated in 40 % of Beijing and 18 % of Hong Kong women, and over 90 % of women in both cities were insufficient ( ≤ 50 nmol/l). Mean Ca and vitamin D intakes were 478 mg/d and 2·0 μg/d, respectively. The relationship between 25-hydroxyvitamin D concentration and PTH was linear throughout the range with a slope of − 0·36 (different from 0; P < 0·001; R 0·26), with no apparent threshold. There was no influence of Ca intake on the relationship between 25-hydroxyvitamin D and PTH concentration. Vitamin D deficiency is common and insufficiency is very common in non-pregnant women in Hong Kong and Beijing during spring. Serum 25-hydroxyvitamin D was inversely associated with PTH with no apparent threshold. Strategies such as vitamin D fortification or supplementation may be required.

Doing the month: rickets and post-partum convalescence in rural China

OBJECTIVE

to analyse the health beliefs underlying the Chinese custom of 'doing the month', in particular mothers' perceptions of rickets.

DESIGN

a qualitative approach was used. Four focus group discussions were tape recorded. Translated transcripts were analysed and coded.

SETTING

Yuci District, rural Shanxi Province, China.

PARTICIPANTS

eighteen young mothers with children aged between 12 and 24 months, five grandmothers aged between 48 and 55 years, five township clinic maternal and child health workers, and seven traditional medicine doctors.

FINDINGS

Zuo yuezi (doing the month) is accepted by Chinese mothers as a time of respite and physical recovery. It is also burdensome to mothers, as cloistering indoors compromises both mother and baby's exposure to the sun, resulting in vitamin D deficiency and rickets.

KEY CONCLUSIONS

in order to reduce the rates of rickets in children, it is important to promote a more balanced and health-enhancing form of zuo yuezi that maintains necessary vitamin D status of both the mother and her baby. By understanding this custom, medical professionals caring for pregnant and post-partum Chinese women in Western countries will be able to better serve their health needs.

Severe Vitamin D-deficiency and the Health of North China Children

OBJECTIVES

To determine the health and nutritional status of rural Chinese children ages 12-24 months.

METHODS

This study used a cross-sectional design with a longitudinal component. Anthropometry and blood chemistry were measured on each child twice (n = 250). Caretaker knowledge and behaviors that relate to the child's health and diet were evaluated by interview.

RESULTS

Children were taken outdoors at an average age of 131.8 days. 65.3% of surveyed children had serum 25-OH-D levels less than 12 ng/ml in the spring. This declined to 2.8% in the fall. Mean blood lead levels were 15.7 +/- 11.0 microg/dl in the spring declining to 12.4 +/- 12.5 microg/dl in the fall (t = 6.47, P = 0.000). This still left 63.5 and 54.9% of the children with toxic blood lead levels in spring and fall. Rates of respiratory disease declined significantly from spring to fall. A summer outdoors remarkably improved vitamin D-deficiency and lead toxicity. However, nutritional status worsened as during the summer diet was unable to keep up with growth and increased nutritional demand. From spring to fall serum zinc declined from 0.77 +/- 0.19 to 0.66 +/- 0.21 microg/ml (t = 3.33, P = 0.001) and blood hemoglobin declined from 12.5 +/- 1.2 to 12.0 +/- 1.2 gm/dl (t = 4.07, P = 0.000).

CONCLUSIONS

Northern climate and cloistering of children creates a host of health risks for north China children. Vitamin D-deficiency, lead poisoning and respiratory disease are significantly worse during the winter months. These children need vitamin D supplementation during the winter and improved overall nutritional status during the summer to maintain ideal growth and development.

Vitamin D-deficiency rickets among children in Canada

BACKGROUND

Based on regional and anecdotal reports, there is concern that vitamin D-deficiency rickets is persistent in Canada despite guidelines for its prevention. We sought to determine the incidence and clinical characteristics of vitamin D-deficiency rickets among children living in Canada.

METHODS

A total of 2325 Canadian pediatricians were surveyed monthly from July 1, 2002, to June 30, 2004, through the Canadian Paediatric Surveillance Program to determine the incidence, geographic distribution and clinical profiles of confirmed cases of vitamin D-deficiency rickets. We calculated incidence rates based on the number of confirmed cases over the product of the length of the study period (2 years) and the estimates of the population by age group.

RESULTS

There were 104 confirmed cases of vitamin D- deficiency rickets during the study period. The overall annual incidence rate was 2.9 cases per 100,000. The incidence rates were highest among children residing in the the north (Yukon Territory, Northwest Territories and Nunavut). The mean age at diagnosis was 1.4 years (standard deviation [SD] 0.9, min-max 2 weeks-6.3 years). Sixty-eight children (65%) had lived in urban areas most of their lives, and 57 (55%) of the cases were identified in Ontario. Ninety-two (89%) of the children had intermediate or darker skin. Ninety-eight (94%) had been breast-fed, and 3 children (2.9%) had been fed standard infant formula. None of the breast-fed infants had received vitamin D supplementation according to current guidelines (400 IU/d). Maternal risk factors included limited sun exposure and a lack of vitamin D from diet or supplements during pregnancy and lactation. The majority of children showed clinically important morbidity at diagnosis, including hypocalcemic seizures (20 cases, 19%).

INTERPRETATION

Vitamin D-deficiency rickets is persistent in Canada, particularly among children who reside in the north and among infants with darker skin who are breast-fed without appropriate vitamin D supplementation. Since there were no reported cases of breast-fed children having received regular vitamin D (400 IU/d) from birth who developed rickets, the current guidelines for rickets prevention can be effective but are not being consistently implemented. The exception appears to be infants, including those fed standard infant formula, born to mothers with a profound vitamin D deficiency, in which case the current guidelines may not be adequate to rescue infants from the vitamin D-deficient state.