Rickets in the Middle East: role of environment and genetic predisposition

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

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

Serum 25-hydroxyvitamin D threshold and risk of rickets in young children: a systematic review and individual participant data meta-analysis to inform the development of dietary requirements for vitamin D

PURPOSE

The objective of this systematic review was to determine a minimum serum 25-hydroxyvitamin D (25OHD) threshold based on the risk of having rickets in young children. This work was commissioned by the WHO and FAO within the framework of the update of the vitamin D requirements for children 0-3 years old.

METHODS

A systematic search of Embase was conducted to identify studies involving children below  4 years of age with serum 25OHD levels and radiologically confirmed rickets, without any restriction related to the geographical location or language. Study-level and individual participant data (IPD)-level random effects multi-level meta-analyses were conducted. The odds, sensitivity and specificity for rickets at different serum 25OHD thresholds were calculated for all children as well as for children with adequate calcium intakes only.

RESULTS

A total of 120 studies with 5412 participants were included. At the study-level, children with rickets had a mean serum 25OHD of 23 nmol/L (95% CI 19-27). At the IPD level, children with rickets had a median and mean serum 25OHD of 23 and 29 nmol/L, respectively. More than half (55%) of the children with rickets had serum 25OHD below 25 nmol/L, 62% below 30 nmol/L, and 79% below 40 nmol/L. Analysis of odds, sensitivities and specificities for nutritional rickets at different serum 25OHD thresholds suggested a minimal risk threshold of around 28 nmol/L for children with adequate calcium intakes and 40 nmol/L for children with low calcium intakes.

CONCLUSION

This systematic review and IPD meta-analysis suggests that from a public health perspective and to inform the development of dietary requirements for vitamin D, a minimum serum 25OHD threshold of around 28 nmol/L and above would represent a low risk of nutritional rickets for the majority of children with an adequate calcium intake.

Treatment of vitamin D deficiency in children

INTRODUCTION

Vitamin D deficiency affects from 10% to 50% in various pediatric population groups and causes life-threatening hypocalcemia in infants, crippling rickets in infants and children, and increased risk of subsequent adult metabolic and neurologic problems.

AREAS COVERED

An English language literature search of PubMed was performed since 1940 as were the authors' personal literature collections. References identified in the reviewed literature are considered.

DIAGNOSIS

The diagnosis of vitamin D deficiency is based on serum 25-hydroxyvitamin D levels. Clinical features of rickets include bone deformities and elevated alkaline phosphatase. Most children and adolescents who are biochemically vitamin D deficient do not have specific symptoms or signs of deficiency.

PREVENTION

Prevention of vitamin D deficiency is via exposure to sunshine, food and beverage fortification, and dietary supplementation.

TREATMENT

Effective treatment of vitamin D deficiency is via oral or injectable administration of vitamin D. Dosing and duration of vitamin D therapy have been described for healthy children and for children with underlying medical conditions, but recommendations vary.

EXPERT OPINION

Further investigation is needed to determine long-term non-skeletal effects of childhood vitamin D deficiency, benefits of supplementation in asymptomatic individuals with biochemical vitamin D deficiency, and appropriate screening for vitamin D deficiency in asymptomatic children and adolescents.

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

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

Mahfouz N, Abushady MM, El-Alameey IR. Relation of Serum Micronutrients to Growth and Nutritional Habits of School-Aged Children in Egypt

Proper growth of children depends on several micronutrients. A fundamental role of Zinc and vitamins as A, B12 and D is crucial to prevent a failure to thrive. To study the relationship between Egyptian school aged children growth, nutritional habits and micronutrients deficiencies. Materials and methods: A case control research involved 60 school aged children (age ranged from 6 to 12 years). Group 1 (malnourished) compared with group II (apparently healthy children of matched peers). Serum concentrations of Zinc, Copper, and vitamins as A, B12, and D were measured using ELISA kits. Compared to controls, the cases showed significantly lower serum concentrations of Zinc, vitamin A, B12, and D (P<0.000 in all), while serum concentration of Copper was significantly higher. In the patient's group, serum vitamin B12, and Zinc concentrations showed significant positive correlation with height for age z- score, while serum Copper concentration showed significant negative correlation with BMI for age z- score. Serum Zinc, vitamin B12, and D concentrations were significantly correlated positively with serum vitamin A. Multiple logistic regression showed statistically significant association of high serum Copper and weekly consumption of sweetened beverages among the studied patients (P < 0.01). Vitamins and Zinc deficiencies showed high prevalence among the school children. Serum vitamin B12 and Zinc concentrations showed significant positive correlation with height. The significant association between high serum Copper and sugary beverages among the studied patients may be due to contained preservatives.

The genetic and epigenetic contributions to the development of nutritional rickets

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

Differential diagnosis of metabolic disease in a commingled sample from 19th century Hisban, Jordan

OBJECTIVE

This research attempts a differential diagnosis of skeletal lesions in a commingled sample from Hisban, Jordan, focusing on non-adults in the assemblage.

MATERIALS

2,883 well-preserved skeletal elements and 9 relatively complete skulls representing an MNI of 32 non-adults (<18 years old).

METHODS

All skeletal elements were observed macroscopically and pathophysiological processes underlying any lesions or other anomalies were assessed, followed by a comparative approach to rule out potential diagnoses.

RESULTS

The skeletal lesions observed were caused by inflammation due to chronic hemorrhaging, marrow hyperplasia due to an increase in hemopoiesis, rapid bone growth, and the impact of biomechanical strain on poorly mineralized elements. Rickets, scurvy, and acquired anemias best fit this pattern of lesions, although inflammation from other sources such as trauma or infection could not be definitively ruled out.

CONCLUSIONS

The in utero and postnatal environments at Hisban were conducive to the development of vitamin C and D deficiencies from birth until 2 years of age. The analysis of commingled remains requires an ontological shift in the importance of the individual to the population in paleopathology.

SIGNIFICANCE

This investigation demonstrates the efficacy of a combined biological and comparative approach in differential diagnosis in complicated commingled collections. In addition, it emphasizes the importance of the mother-infant dyad in understanding metabolic disease.

LIMITATIONS

Histological and radiographic analyses were not included in this diagnostic study due to COVID-19 travel restrictions.

SUGGESTIONS FOR FURTHER RESEARCH

Isotopic analysis to investigate childhood diet and histological and radiographic analyses to assess survival of deficiencies.

Vitamin D Receptor (VDR) Allelic Variants Correlating with Response to Vitamin D3 Supplementation in Breast Cancer Survivors

We investigated how vitamin D receptor (VDR) allelic variants affect breast cancer survivors' responses to vitamin D3 supplementation to increase circulating 25-hydroxy vitamin D (25(OH)D) levels. Two hundred and fourteen patients who were diagnosed with breast cancer at least 6 mo, prior to the study and had completed all treatment regimens were assigned to consume 4000 IU of vitamin D3 daily for 12 weeks. Linear and multinomial logistic regression analyses were used to analyze the association of VDR single nucleotide polymorphism (SNPs) with changes in circulating 25(OH)D. The TaqI and BsmI VDR sequence variants modified the effect of vitamin D3 treatment on the plasma 25(OH)D changes (P value = 0.008 for TaqI and P value = 0.0005 for BsmI). Patients with the bb [Q4 vs. Q1 odds ratio(OR) 8.04, 95% confidence interval (CI) 1.55-41.57] and tt [Q4 vs. Q1 OR 4.64 95%CI 1.02-21.02] genotype of BsmI and TaqI had larger increases in plasma 25(OH)D levels compared to those with BB and TT genotype respectively after adjustment for potential confounders. Haplotype analyses suggested the existence of specific combination of alleles that might be associated with circulating 25(OH)D changes. VDR allelic variants modulate vitamin D3 supplementation to increase plasma 25(OH) levels in breast cancer survivors.

Prevalence and Predictors of Vitamin D Inadequacy: A Sample of 2,547 Patients in a Mediterranean Country

Background The aim of this retrospective study was to identify prevalence and risk factors for vitamin D inadequacy in a sunny Mediterranean country. Methods Results of 2,547 patients aged 19 to >60 years were included in this study. Data were derived from the laboratory database at Rafik Hariri University Hospital, Beirut, Lebanon, over a period of two years (2016-2017). Data included patient's age, gender, date of test, and vitamin D level. Females were questioned through phone call for marital status, parity, and veiling. Results The prevalence of vitamin D inadequacy was 83.5% overall, 86.4% in males, and 82.3% in females. At a cut-off of 20 ng/mL, vitamin D deficiency affected 63% of the studied population. A significant association was observed between vitamin D and age. The highest prevalence (71.2%) was found in females in the age group of 19-39 years, while no significant correlation with age was observed in males. Vitamin D levels were lower in veiled women (mean 25(OH)D = 17.9 ng/mL) compared to non-veiled women, although this difference was not significant. In addition, vitamin D inadequacy does not show a significant association with gender, parity, marital status, and season of the year. Conclusion The high prevalence of vitamin D inadequacy in our study in both males and females of all age groups calls for urgent actions at the national level to increase awareness in the population and to prevent the serious complications of vitamin D deficiency in all patients, especially those who are at a high risk.

Diagnosis and management of X-linked hypophosphatemia in children and adolescent in the Gulf Cooperation Council countries

INTRODUCTION

X-linked hypophosphatemia (XLH) is a rare inherited cause of hypophosphatemic rickets and osteomalacia. It is caused by mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX). This results in increased plasma fibroblast growth factor-23 (FGF23), which leads to loss of renal sodium-phosphate co-transporter expression leading to chronic renal phosphate excretion. It also leads to low serum 1,25-dihydroxyvitamin D (1,25(OH)₂D), resulting in impaired intestinal phosphate absorption. Chronic hypophosphatemia in XLH leads to impaired endochondral mineralization of the growth plates of long bones with bony deformities. XLH in children and adolescents also causes impaired growth, myopathy, bone pain, and dental abscesses. XLH is the most frequent inherited cause of phosphopenic rickets/osteomalacia. Hypophosphatemia is also found in calcipenic rickets/osteomalacia as a result of secondary hyperparathyroidism. Thus, chronic hypophosphatemia is a common etiologic factor in all types of rickets.

RESULTS

There is considerable overlap between symptoms and signs of phosphopenic and calcipenic rickets/osteomalacia. Wrong diagnosis leads to inappropriate treatment of rickets/osteomalacia. Nutritional rickets and osteomalacia are common in the Gulf Cooperation Council countries which include Saudi Arabia, United Arab Emirates, Kuwait, Qatar, Bahrain, and Oman. Due to high levels of consanguinity in the region, genetic causes of phosphopenic and calcipenic rickets/osteomalacia are also common.

CONCLUSION

This guideline was developed to provide an approach to the diagnosis of XLH, especially where there is no family history of the disease, and that other related conditions are not mistaken for XLH. We also guide the medical management of XLH with conventional treatment and with burosumab, a recombinant human IgG1 monoclonal antibody to FGF23.

Absence of vitamin D deficiency among common outdoor workers in Delhi

BACKGROUND

There is reservation about accepting the notion of widespread vitamin D deficiency (VDD) in sunny countries because information base is largely urban indoors, and the cut-off serum 25(OH)D > 75.0 nmol/L to define sufficiency is perceived as high.

OBJECTIVE

We assessed the vitamin D status of subjects engaged in six types of outdoor jobs with freedom to seek shade, when needed.

DESIGN

Descriptive observational study.

SUBJECTS AND METHODS

A total of 573 outdoors, (hawkers, n = 144; auto-rickshaw drivers, n = 113; manual rickshaw pullers, n = 49; fuel-station attendants, n = 84; gardeners, n = 96; traffic police personnel, n = 87) were assessed for serum 25(OH)D, iPTH and total calcium during summer and winter. Bank employees were indoor controls (n = 72). Serum 25(OH)D was defined as sufficient if ≥50.0 nmol/L and deficient when <30.0 nmol/L, as per 'Institute of Medicine'.

RESULTS

Mean serum 25(OH)D of 573 outdoors was 44.8 ± 19.6 nmol/L and showed a physiological inverse relation with iPTH (P < 0.001). 77.5% of the outdoors did not have VDD. Hawkers, gardeners, fuel-station attendants and rickshaw pullers had sufficient or near sufficient serum 25(OH)D. The mean serum 25(OH)D (30.6 ± 23.2 nmol/L) of indoors though lower by 12.7 nmol/L than outdoors was above the cut-off of VDD. Proportions with supranormal iPTH were comparable between outdoors and indoors (14.0% vs 20.8%). Despite winter dip, the mean serum 25(OH)D (31.2 ± 14.3 nmol/l) of outdoors was not deficient.

CONCLUSIONS

Vitamin D deficiency is not universal. Most urban outdoor workers do not have VDD.

Rickets severity predicts clinical outcomes in children with X-linked hypophosphatemia: Utility of the radiographic Rickets Severity Score

The Rickets Severity Score (RSS) was used to evaluate X-linked hypophosphatemic rickets (XLH), a genetic disorder mediated by increased circulating FGF23. The reliability of the RSS was assessed using data from a randomized, phase 2 clinical trial that evaluated the effects of burosumab, a fully human anti-FGF23 monoclonal antibody, in 52 children with XLH ages 5 to 12 years. Bilateral knee and wrist radiographs were obtained at baseline, week 40, and week 64. We evaluated the relationships of the RSS to the Radiographic Global Impression of Change (RGI-C), serum alkaline phosphatase (ALP), height Z-score, 6-minute walk test (6MWT) percent predicted, and the Pediatric Orthopedic Society of North America Pediatric Outcomes Data Collection Instrument (POSNA-PODCI). The RSS showed moderate-to-substantial inter-rater reliability (weighted kappa, 0.45-0.65; Pearson correlation coefficient (r), 0.83-0.89) and substantial intra-rater reliability (weighted Kappa, 0.66; r = 0.91). Baseline RSS correlated with serum ALP (r = 0.47). Baseline RSS identified two subgroups (higher [RSS ≥1.5] and lower RSS [RSS <1.5]) that discriminated between subjects with greater and lesser rachitic disease. Higher RSS was associated with more severe clinical features, including impaired growth (Z-score, -2.12 vs -1.44) and walking ability (6MWT percent predicted, 77% vs 86%), more severe self-reported pain (29.9 [more severe] vs 45.3 [less severe]) and less physical function (29.6 [more severe] vs 40.9 [less severe]). During burosumab treatment, greater reductions in RSS corresponded to higher RGI-C global scores (r = -0.65). Improvements in RSS correlated with decreased serum ALP (r = 0.47). These results show the reliability of the RSS in XLH, and demonstrate that higher RSS values are associated with greater biochemical, clinical, and functional impairments in children with XLH.

Evolutionary Perspective in Rickets and Vitamin D

Modern lifestyle limits our exposure to sunlight, which photosynthesizes vitamin D in the skin, and the incidence of nutritional rickets has been resurging. Vitamin D is one of the first hormones; it is photosynthesized in all organism from the phytoplankton to mammals. A selective sweep of the promoter of the vitamin D receptor (VDR) happened as soon as Homo sapiens migrated out of Africa; it co-adapted with skin color genes to provide adaptation to latitudes and the levels of exposure to ultraviolet (UV)B radiation along the route out of Africa. Exposure to UVB radiation balances the need for vitamin D photosynthesis and degradation of folic acid by UVB radiation. Skin color follows a latitude distribution: the darkest populations dwell in the tropical belt; and the fair-skinned populations inhabit the northern countries. Due to their greater need for calcium during their reproductive life, the skin color of women is lighter- than that of men. Vitamin D is essential for mineral homeostasis and has a wide variety of non-skeletal functions, of which the most important for natural selection is a regulatory function in the innate immune system. In the human fossil record, vitamin D deficiency coincided with bone tuberculosis. About 6,000 years ago, a diet which included cow's milk provided Neolithic humans with twice as much calcium and was more alkaline than that of its Paleolithic predecessors. Adiposity is negatively associated with the vitamin D status and obese individuals require 2-3 times more vitamin D than non-obese individuals to normalize circulating 25OHD levels. In an era of an obesity epidemic, we need more research to determine whether adiposity should be considered when determining the dietary requirements for vitamin D and calcium and the optimal serum 25OHD levels.

Knowledge, attitude and practice of health care practitioners in Saudi Arabia, with regard to prevention of vitamin D deficiency in infancy

Objectives:

To understand the knowledge, attitude, and practice of healthcare practitioners in Saudi Arabia, with regard to vitamin D supplementation.

Methods:

A cross-sectional survey was conducted among healthcare practitioners in the Tabuk region of Saudi Arabia between January 2015 and December 2016. A questionnaire assessing knowledge, attitude and practice with regard to prevention of vitamin D deficiency was distributed to 100 healthcare practitioners.

Results:

There was a good understanding of the importance of vitamin D deficiency; and overall practices were good. The average knowledge score was 4.75/8 (range 2-7), largely due to 85% of recipients identifying sun exposure between 6-7 am as the optimal time. There was a lack of understanding also, that as little as 10 minutes exposure is of benefit.

Conclusion:

This study highlights the need for distribution of the recommendations for vitamin D supplementation in KSA, as widely as possible. This study suggests that healthcare practitioners understand the importance of correction of vitamin D deficiency. Deficiencies in knowledge with regard to sun exposure were identified. Dissemination of this information is, therefore, likely to impact significantly on the practice of a receptive clinical population.

Prevalence and Trends of Vitamin D Deficiency among Iranian Adults: A Longitudinal Study from 2001-2013

Vitamin D deficiency/insufficiency is currently considered to be a re-emerging public health problem globally. This study was designed to determine the prevalence of vitamin D deficiency and insufficiency and to investigate its trend from 2001 to 2013 in a longitudinal study of Iranian adults. This study was part of a population-based, longitudinal ongoing study of Iranian healthy adults aged 35 y and older at baseline. Serum vitamin D level was assessed in a sub-sample of 370 subjects, who were apparently healthy at the time of recruitment in 2001 and were free from MetS, in three phases (2001, 2007 and 2013) during the 12-y study period. Adjusted prevalence and trend of vitamin D deficiency were calculated. Mean serum vitamin D levels increased over the time of the study (52.12, 54.27 and 62.28 nmol/L, respectively) and the prevalence of vitamin D deficiency decreased (30.5, 27.0 and 24.4, respectively). However, the prevalence of vitamin D insufficiency did not change over this time period. The risk of vitamin D deficiency decreased significantly in 2007 [OR: 0.73 (95% CI: 0.53, 0.99)] and 2013 [OR: 0.50 (95% CI: 0.36, 0.70)] compared to the baseline. The present study demonstrated some improvement in serum vitamin D levels, while the prevalence of vitamin D inadequacy was still high. Considering the possible health consequences of vitamin D deficiency, there is an urgent need for developing population-wide strategies, such as supplementation and fortification, to prevent or control vitamin D deficiency.

Vitamin D status in prepubertal children with isolated idiopathic growth hormone deficiency: effect of growth hormone therapy

Few studies, and with controversial results, analyzed vitamin D status in children before and after growth hormone (GH) treatment. Thus, we aimed to assess vitamin D status in prepubertal children with idiopathic growth hormone deficiency (GHD), and to evaluate the effect of GHD and GH treatment on vitamin D levels. Fifty prepubertal children with isolated GHD were compared with 50 controls. All were subjected to history, anthropometric assessment and measurement of 25 hydroxyvitamin D (25(OH)D), serum calcium, phosphorous, alkaline phosphatase and parathyroid hormone (PTH) at diagnosis and 1 year after GH therapy. Serum 25(OH)D levels <30 ng/mL and 20 ng/mL were defined as vitamin D insufficiency and deficiency, respectively. 25(OH)D was lower in cases than controls. Forty per cent of children with GHD were 25(OH)D insufficient and 44% deficient, while 16% were sufficient at baseline. There was a positive correlation between 25(OH)D and peak GH levels. Peak GH was a significant predictor of 25(OH)D levels. After 1 year of GH therapy, 25(OH)D increased (18.42±5.41 vs 34.5±10.1 ng/mL; P<0.001). Overall, 22% of cases remained insufficient and 24% deficient, with an increase in prevalence of children with normal levels (54%; P<0.001). 25(OH) correlated negatively with PTH (r=-0.71, P=0.01). In conclusion, hypovitaminosis D is prevalent in children with GHD and significantly improved 1 year after GH therapy. 25(OH)D should be assessed in children with GHD at diagnosis and during follow-up.

Using data from a multi-hospital clinical network to explore prevalence of pediatric rickets in Kenya

Background: Nutritional rickets is a public health concern in developing countries despite tropical climates and a re-emerging issue in developed countries. In this study, we reviewed pediatric admission data from the Clinical Information Network (CIN) to help determine hospital and region based prevalence of rickets in three regions of Kenya (Central Kenya, Western Kenya and Nairobi County). We also examine the association of rickets with other diagnosis, such as malnutrition and pneumonia, and study the effect of rickets on regional hospital stays.

Methods: We analyzed discharge records for children aged 1 month to 5 years from county (formerly district) hospitals in the CIN, with admissions from February 1 ^st 2014 to February 28 ^th 2015. The strength of the association between rickets and key demographic factors, as well as with malnutrition and pneumonia, was assessed using odds ratios. The Fisher exact test was used to test the significance of the estimated odd ratios. Kaplan-Meier curves were used to analyze length of hospital stays.

Results: There was a marked difference in prevalence across the three regions, with Nairobi having the highest number of cases of rickets at a proportion of 4.01%, followed by Central Region at 0.92%. Out of 9756 admissions in the Western Region, there was only one diagnosis of rickets. Malnutrition was associated with rickets; this association varied regionally. Pneumonia was found to be associated with rickets in Central Kenya. Children diagnosed with rickets had longer hospital stays, even when cases of malnutrition and pneumonia were excluded in the analysis.

Conclusion: There was marked regional variation in hospital based prevalence of rickets, but in some regions it is a common clinical diagnosis suggesting the need for targeted public health interventions. Factors such as maternal and child nutrition, urbanization and cultural practices might explain these differences.

Using data from a multi-hospital clinical network to explore prevalence of pediatric rickets in Kenya

Background: Nutritional rickets is a public health concern in developing countries despite tropical climates and a re-emerging issue in developed countries. In this study, we reviewed pediatric admission data from the Clinical Information Network (CIN) to help determine hospital and region based prevalence of rickets in three regions of Kenya (Central Kenya, Western Kenya and Nairobi County). We also examine the association of rickets with other diagnosis, such as malnutrition and pneumonia, and study the effect of rickets on regional hospital stays. Methods: We analyzed discharge records for children aged 1 month to 5 years from county (formerly district) hospitals in the CIN, with admissions from February 1st 2014 to February 28th 2015. The strength of the association between rickets and key demographic factors, as well as with malnutrition and pneumonia, was assessed using odds ratios. The Fisher exact test was used to test the significance of the estimated odd ratios. Kaplan-Meier curves were used to analyze length of hospital stays. Results: There was a marked difference in prevalence across the three regions, with Nairobi having the highest number of cases of rickets at a proportion of 4.01%, followed by Central Region at 0.92%. Out of 9756 admissions in the Western Region, there was only one diagnosis of rickets. Malnutrition was associated with rickets; this association varied regionally. Pneumonia was found to be associated with rickets in Central Kenya. Children diagnosed with rickets had longer hospital stays, even when cases of malnutrition and pneumonia were excluded in the analysis. Conclusion: There was marked regional variation in hospital based prevalence of rickets, but in some regions it is a common clinical diagnosis suggesting the need for targeted public health interventions. Factors such as maternal and child nutrition, urbanization and cultural practices might explain these differences.

Vitamin D deficiency causes rickets in an urban informal settlement in Kenya and is associated with malnutrition

The commonest cause of rickets worldwide is vitamin D deficiency, but studies from sub-Saharan Africa describe an endemic vitamin D-independent form that responds to dietary calcium enrichment. The extent to which calcium-deficiency rickets is the dominant form across sub-Saharan Africa and in other low-latitude areas is unknown. We aimed to characterise the clinical and biochemical features of young children with rickets in a densely populated urban informal settlement in Kenya. Because malnutrition may mask the clinical features of rickets, we also looked for biochemical indices of risk in children with varying degrees of acute malnutrition. Twenty one children with rickets, aged 3 to 24 months, were identified on the basis of clinical and radiologic features, along with 22 community controls, and 41 children with either severe or moderate acute malnutrition. Most children with rickets had wrist widening (100%) and rachitic rosary (90%), as opposed to lower limb features (19%). Developmental delay (52%), acute malnutrition (71%), and stunting (62%) were common. Compared to controls, there were no differences in calcium intake, but most (71%) had serum 25-hydroxyvitamin D levels below 30 nmol/L. These results suggest that rickets in young children in urban Kenya is usually driven by vitamin D deficiency, and vitamin D supplementation is likely to be required for full recovery. Wasting was associated with lower calcium (p = .001), phosphate (p < .001), 25-hydroxyvitamin D (p = .049), and 1,25-dihydroxyvitamin D (p = 0.022) levels, the clinical significance of which remain unclear.

Nutritional rickets around the world: an update

Worldwide, nutritional rickets continues to be an evolving problem with several causes. This paper provides an updated literature review characterising the prevalence, aetiology, pathophysiology and treatment of nutritional rickets worldwide. A systematic review of articles on nutritional rickets from various geographical regions was undertaken. For each region, key information was extracted, including prevalence, cause of rickets specific to the region, methods of confirming the diagnosis and current treatment and preventive measures. Calcium deficiency continues to be a major cause of rickets in Africa and Asia. Vitamin D deficiency rickets is perhaps increasing in the Americas, Europe and parts of the Middle East. There continues to be a distinct presentation of calcium-predominant versus vitamin D predominant rickets, although there are overlapping features. More careful diagnosis of rickets and reporting of 25-OHD concentrations has improved accurate knowledge of rickets prevalence and better delineated the cause. Nutritional rickets continues to be an evolving and multi-factorial problem worldwide. It is on a spectrum, ranging from isolated vitamin D deficiency to isolated calcium deficiency. Specific areas which require emphasis include a consistent community approach to screening and diagnosis, vitamin D supplementation of infants and at-risk children, prevention of maternal vitamin D deficiency and the provision of calcium in areas with low calcium diets.

Nutritional rickets: vitamin D, calcium, and the genetic make-up

BACKGROUND

The prevalence of vitamin D (vitD) deficiency presenting as rickets is increasing worldwide. Insufficient sun exposure, vitD administration, and/or calcium intake are the main causes. However, vitD system-related genes may also have a role.

METHODS

Prospective study: 109 rachitic children completed a 6-mo study period or until rachitic manifestations disappeared. Thirty children were selected as controls. Clinical and biochemical data were evaluated at baseline in patients and controls and biochemistry re-evaluated at radiological healing. Therapy was stratified in three different protocols. Fifty-four single-nucleotide polymorphisms (SNPs) of five vitD system genes (VDR, CP2R1, CYP27B1, CYP24A1, and GC) were genotyped and their association with clinical and biochemcial data was analyzed.

RESULTS

Therapy response was similar in terms of radiological healing although it was not so in terms of biochemical normalization. Only VDR gene (promoter, start-codon, and intronic genotypes) was rickets-associated in terms of serum 25-OH-D, calcium, radiological severity and time needed to heal. Eight patients with sufficient calcium intake and 25-OH-D levels carried a VDR genotype lacking minor allele homozygous genotypes at SNPs spread along the gene.

CONCLUSION

Although patients presented epidemiologic factors strongly contributing to rickets, genetic modulation affecting predisposition, severity, and clinical course is exerted, at least in part, by VDR gene polymorphic variation.

Prevalence of Vitamin D Deficiency and Calcium Homeostasis in Saudi Children

OBJECTIVE

Vitamin D deficiency (VDD) and vitamin D insufficiency (VDI) are significant health problems all over the world. The aim of this study was to determine the prevalence of VDD and VDI in children and adolescents residing in 8 provinces in the Kingdom of Saudi Arabia and to also investigate calcium homeostasis in these subjects.

METHODS

A cross-sectional study was conducted in 2110 participants aged between 6 and 15 years. Information on socio-demographic status, anthropometric measurements, knowledge about vitamin D, color of the skin, dietary intake, sun exposure experience, smoking, and physical activity were collected through a questionnaire given to the parents of all subjects. The subjects were divided into three groups as vitamin D deficient, vitamin D insufficient, and vitamin sufficient according to their blood level of vitamin D [VDD ≤25 nmol/L (25 hydroxy vitamin D), VDI >25-50 nmol/L, and VDS >50 nmol/L].

RESULTS

VDD was highly prevalent in this group of children. 95.3 of the subjects had either VDD (45.5%) or VDI (49.9%). The prevalence rate of VDD combined with VDI was higher in females (97.8%) compared to males (92.8%) (p<0.001). Only 1.6% had significant hypocalcaemia. Children with dark skin had lower concentrations of vitamin D and higher concentrations of parathormone. A positive correlation was observed between 25 hydroxy vitamin D level and serum calcium, inorganic phosphate, and alkaline phosphatase concentrations. onclusion: The results showed a high prevalence of VDD and VDI in Saudi children with significantly higher prevalence in girls. These findings necessitate the set-up of a national program for vitamin D supplementation and health education for this vulnerable group.

Incidence and Risk Factors of Rachitic Genu Varus in Preschool Children in a Paediatric Health Institute in Egypt as One of the Developing Countries

BACKGROUND

Rachitic genu varus is one of the common conditions among the Egyptian children, despite the shinning sun of Egypt all the year.

PURPOSE

The aim of the study was to estimate the incidence of rachitic genu varus among the Egyptian children, and to assess the risk factors contributing to it.

PATIENTS AND METHODS

This prospective study recruited a total of 250 consecutive children, being 130 males and 120 females, with rachitic bow legs or genu varus, between 2 - 4 years of age, together with 250 controls of the same age group, out of a total number of 1900 children with other types of rickets, and other children's orthopaedic diseases, who presented to the National Institute of Neuromotor System in Egypt between September 2014 to September 2015. The cases and the controls were subjected to clinical, laboratory biochemical, and plain radiographic examinations. Their parents were subjected to epidemiological, maternal, and nutritional questionnaires.

RESULTS

The calculations revealed high incidence (13.1%) of rachitic genu varus. The risk factors were low socioeconomic status, insufficient family income, poor housing conditions, lack of exposure to sunlight due to cultural practices, sole breast feeding, and inadequate supplementation of vitamin D to the children and the pregnant women. The p value was <0.05.

CONCLUSION

Vitamin D deficiency rachitic genu varus is a multifactorial condition in Egypt. Raising the standard of living, level of education, housings, and dietary supplementation of vitamin D to the pregnant women and infants are the solution.

Efficacy and safety of pamidronate in children with vitamin D intoxication

BACKGROUND

Bisphosphonates are used in the treatment of vitamin D intoxication (VDI) after failure of conventional therapy including prednisolone. Safety concerns restrict the use of bisphosphonates from being used as first-line therapy for VDI in children. The aim of this study was to evaluate the efficacy and safety of pamidronate in comparison with prednisolone in children with VDI.

METHODS

We reviewed the hospital records of children consecutively diagnosed with VDI at two medical centers in a 15 year period.

RESULTS

The subjects consisted of 21 children (age, 0.3-4.2 years) who were treated with prednisolone and/or bisphosphonates. Pamidronate (n = 18) or alendronate (n = 3) was used in six patients after unsuccessful prednisolone treatment, and in 15 patients from baseline. Initial serum calcium and 25-hydroxyvitamin D were 16.1 ± 1.9 mg/dL and 493 ± 219 ng/mL, respectively. The median time to reach normocalcemia in the pamidronate, alendronate and prednisolone groups was 3 days (range, 2-12 days), 4 days (range, 3-6 days) and 17 days (range, 12-26 days), respectively (P = 0.013). The pamidronate group had a fivefold shorter hospital stay than the prednisolone group. Three patients initially treated with prednisolone developed nephrocalcinosis but this did not occur in any patient treated with bisphosphonates from baseline. Apart from transient fever and moderate hypophosphatemia, no side-effect of bisphosphonate treatment was observed.

CONCLUSIONS

Pamidronate is efficient and safe for the treatment of VDI in children. Pamidronate use significantly shortens the duration of treatment, and thereby may prevent the development of nephrocalcinosis. Instead of prednisolone, pamidronate should be used together with hydration and furosemide as the first-line therapy for VDI.

Vitamin D status in children and adolescents with autoimmune thyroiditis

BACKGROUND

Vitamin D deficiency is a global health problem. Its role as an immune modulator has been recently emphasized. There is increasing evidence for the significant role of vitamin D in reducing the incidence of autoimmune diseases. However, little is known about the status of vitamin D in children and adolescents with autoimmune thyroiditis (AIT).

OBJECTIVE

The goal of the present study was to assess vitamin D status in Egyptian children and adolescents with AIT and to explore its relation to biomarkers of autoimmunity and thyroid function.

DESIGN

A prevalence case-control study that included 56 children with AIT and 56 healthy, age- and sex-matched subjects that served as the control group. The following was done for all participants: thorough history, physical examination, thyroid ultrasound, measurement of thyroid-stimulating hormone (TSH), free thyroxin (FT4), anti-thyroid peroxidase antibodies (TPOAb), anti-thyroglobulin antibody (TgAb) and assessment of serum 25-hydroxy vitamin D (25OHD) level.

RESULTS

Overt hypothyroidism was detected in 42/56 while subclinical hypothyroidism was detected in 14/56 of the studied patients. Vitamin D deficiency rate was significantly higher in the AIT group compared to the control subjects (71.4 vs 21.4 %, P < 0.001). In AIT group, the mean level of 25OHD was significantly lower compared to the control group (16.2 ± 8.2 vs 33.9 ± 12.7 nmol/L, P < 0.001). The difference was more evident in patients with overt hypothyroidism than those with subclinical hypothyroidism (P < 0.01). There were significant negative correlations between serum 25OHD and age, duration of the disease, BMI, anti-TPOAb, anti-TGAb and TSH (P < 0.001 each). On the other hand, serum 25OHD correlated positively with FT4 levels. While 25OHD level was an independent risk factor for AIT, it failed to qualify as an independent risk for the progression of AIT to overt hypothyroidism after adjustment for other potential confounding factors; age, sex and BMI.

CONCLUSIONS

Low serum vitamin D is significantly associated with AIT in Egyptian children. However, vitamin D level is not an independent risk for the progression of AIT to overt hypothyroidism. BMI may have an influence on serum 25OHD levels.

Osteoporosis: An under-recognized public health problem

Over 200 million people suffer from osteoporosis worldwide, which occurs when bone tissues become structurally deteriorated and bone mass becomes fragile, resulting in an increased risk of fracture. This review aims to describe the underlying risk factors and provide guidance on changes in lifestyle for those at risk of developing osteoporosis. It highlights risk factors such as age, sex, genetic background, and other under lying illnesses (factors that are generally “non-modifiable”). Furthermore, it focuses on factors that are dependent on lifestyle and (local) habits (factors that are “modifiable”), such as diet, sunlight exposure, exercise, and medication. Clearly, osteoporosis is a multifactorial disease and multiple of these risk factors can occur simultaneously. Currently, the data available differ greatly between regions and some areas might be affected more seriously than others. This review suggests that this might be due to differing healthcare training systems and suboptimal awareness of osteoporosis. Importantly, osteoporosis and resulting bone fractures represent a significant economic burden for both individuals and the wider society. Therefore, improved awareness of the disease may influence personal habits, reduce suffering, and alleviate the burden on healthcare expenditure.

Predictors of Serum 25-Hydroxyvitamin D Concentrations among a Sample of Egyptian Schoolchildren

Objective. To assess the level of 25-hydroxyvitamin D status among a sample of Egyptian schoolchildren and to evaluate predictors of deficiency and insufficiency. Subjects and Methods. A cross-sectional study comprising 200 prepubescent schoolchildren aged from 9 to 11 years was performed. A questionnaire including frequency of midday sun exposure, milk intake, physical activity, and level of maternal education was taken. Body mass index (BMI) was calculated; serum 25-hydroxyvitamin D [25(OH)D], serum calcium, phosphorus, and parathyroid hormone were measured. Results. Vitamin D deficiency [serum 25(OH)D < 20 ng/mL] was detected in 11.5% of subjects while its insufficiency (serum 25(OH)D is between 20 and 29.9 ng/mL) was detected in 15%. Results revealed that obesity, low physical activity, low sun exposure, and low maternal education level are significant predictors of insufficiency, though female gender, low maternal education level, and low milk intake are significant predictors of deficiency. Lower serum phosphorus and higher serum parathyroid hormone were significantly associated with both deficiency and insufficiency (p < 0.05). Conclusion. Vitamin D deficiency and insufficiency are common among schoolchildren in Egypt. Food fortification, vitamin D supplementation, and increasing maternal awareness about the importance of physical activity and exposure of their children to ultraviolet light may help to overcome this problem.

Vitamin D Deficiency in Children and Adolescents in Bağcılar, İstanbul

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Vitamin D status and associated factors of deficiency among Jordanian children of preschool age

BACKGROUND/OBJECTIVES

Vitamin D deficiency in children remains a global concern. Although literature exists on the vitamin D status and its risk factors among children in the Middle East, findings have yielded mixed results, and large, representative community studies are lacking.

SUBJECTS/METHODS

In a nationally representative survey of 1077 Jordanian children of preschool age (12-59 months) in Spring 2010, we measured 25(OH)D3 concentrations by liquid chromatography-tandem mass spectrometry and calculated prevalence ratios for deficiency associated with various factors.

RESULTS

RESULTS showed 19.8% (95% confidence interval (CI): 16.4-23.3%) deficiency (<12 ng/ml) and 56.5% (95% CI: 52.0-61.0%) insufficiency (<20 ng/ml). In adjusted models, prevalence of deficiency was higher for females compared with males (prevalence ratio (PR)=1.74, 95% CI: 1.22-2.47, P=0.002) and lower for children 24-35 months of age (PR=0.64, 95% CI: 0.44-0.92, P=0.018) compared with children 12-23 months of age. In rural areas, there was no difference in prevalence of vitamin D deficiency between those whose mothers had/did not have vitamin D deficiency (P=0.312); however, in urban areas, prevalence of vitamin D deficiency was 3.18 times greater among those whose mothers were vitamin D deficient compared with those whose mothers were not deficient (P=0.000).

CONCLUSIONS

Vitamin D deficiency and insufficiency pose significant public health problems in Jordanian children with female children disproportionately affected. Strong associations between vitamin D status in children and urban residency and maternal vitamin D status suggest that the behaviors related to sun exposure in urban mothers likely also affect the sun exposure and thus vitamin D status of their children.

Serum 25 hydroxyvitamin D in employees of a Middle Eastern university hospital

BACKGROUND

The Middle East registers the highest rate of vitamin D deficiency worldwide. In Lebanon, previous studies looked at this deficiency in schoolchildren, university students, young adults and postmenopausal women. However, no previous study was performed in hospital workers. The objective of our study was to evaluate vitamin D status in a Beirut hospital center and to look at the potential factors influencing these measurements.

METHODS

This cross-sectional study was performed on hospital employees who came for a regular checkup at the primary health-care department. 25(OH)D measurements were performed using the Dia-Sorin chemiluminescent assay.

RESULTS

392 subjects (318 women and 74 men) were included in the study. The mean age of the participants was 41.02 ± 11.3 years. The mean 25(OH)D level was 15.61 ± 7.91 ng/ml, with no significant difference according to gender. There were no significant correlations between 25(OH)D and both BMI and age, but 25(OH)D was significantly associated with educational level (p = 0.03). There was a significant difference in 25(OH)D levels according to season (p < 0.001) and a significant association between 25(OH)D and the reported weekly hours of sun exposure (r = 0.1, p = 0.032), but not with the reported sunscreen use. Fish consumption was positively associated with 25(OH)D levels (p = 0.018), while milk, dairy product or egg consumption did not achieve any significant relationship. In a stepwise linear regression analysis, fish consumption and season were the only independent predictors of 25(OH)D levels (p = 0.007 and p = 0.0001 respectively).

CONCLUSION

Vitamin D deficiency is common among hospital workers. This finding reinforces the need for vitamin D supplementation in these high-risk populations.

Vitamin D status and its relationship with metabolic markers in persons with obesity and type 2 diabetes in the UAE: a cross-sectional study

AIM

To report vitamin D status and its impact on metabolic parameters in people in the United Arab Emirates with obesity and type 2 diabetes (T2D).

METHODOLOGY

This cross-sectional study included 309 individuals with obesity and T2D who were randomly selected based on study criteria. Serum concentrations of 25-hydroxy vitamin D (s-25(OH)D), calcium, phosphorus, parathyroid hormone, alkaline phosphatase, glycemic profile, and cardiometabolic parameters were assessed in fasting blood samples, and anthropometric measurements were recorded.

RESULTS

Vitamin D deficiency (s-25(OH)D < 50 nmol/L) was observed in 83.2% of the participants, with a mean s-25(OH)D of 33.8 ± 20.3 nmol/L. Serum 25(OH)D correlated negatively (P < 0.01) with body mass index, fat mass, waist circumference, parathyroid hormone, alkaline phosphatase, triglycerides, LDL-cholesterol, and apolipoprotein B and positively (P < 0.01) with age and calcium concentration. Waist circumference was the main predictor of s-25(OH)D status. There was no significant association between serum 25(OH)D and glycemic profile.

CONCLUSION

There is an overwhelming prevalence of vitamin D deficiency in our sample of the Emirati population with obesity and T2D. Association of s-25(OH)D with body mass index, waist circumference, fat mass, markers of calcium homeostasis and cardiometabolic parameters suggests a role of vitamin D in the development of cardiometabolic disease-related process.

Hypovitaminosis D in the Middle East and North Africa: Prevalence, risk factors and impact on outcomes

BACKGROUND

The Middle East and North Africa (MENA) region registers some of the highest rates of hypovitaminosis D worldwide.  

AIM

We systematically reviewed the prevalence of hypovitaminosis D, rickets and osteomalacia, their predictors and impact on major outcomes, in the region.

METHODS

Medline, Pubmed and Embase search engines, entering keywords and concepts, combined with individual countries of interest, were used. Search was limited years 2000-2012; and review articles were used for the period preceding year 2000.

RESULTS

Rickets and osteomalacia still occur in this sunny region. Hypovitaminosis D prevails, with rates varying 30-90%, considering a desirable serum 25 hydroxy-vitamin D [25(OH)D] of 20 ng/ml. Advancing age, female gender, multi-parity, clothing style, season, socio-economic status and urban living are recognized predictors of hypovitaminosis D in adults. Prolonged breastfeeding without vitamin D supplementation and low dietary calcium intake are the recognized risk factors for rickets and hypovitaminosis D in children.. Associations with pain score and disease activity in rheumatologic disorders, viral load and interleukins in hepatitis C, BMI, lipids and insulin sensitivity, blood pressure, heart failure and mortality are described. Sun exposure in adults decreased prevalence of metabolic syndrome in one study. Few randomized vitamin D trials revealed that the majority of mothers or children failed to achieve a desirable 25(OH)D level, even with doses by far exceeding current recommendations. A trial in adolescent girls reveals substantial bone and lean mass increments.

CONCLUSION

Hypovitaminosis D is prevalent in MENA. The lack of populations based studies, gaps in studies in infants, pre-pubertal children and pregnant women, hinder the development of region specific guidelines and constitute a major obstacle to impact this chronic and most often subclinical disease.

Dilated cardiomyopathy due to hypocalcaemic rickets: is it always a reversible condition?

Nutritional rickets is still occasionally found in high-income countries, especially in populations at risk, and induced hypocalcaemia is a rare but possible cause of dilated cardiomyopathy. Although rare, physicians need to consider nutritional rickets in the differential diagnosis of hypocalcaemia cardiac failure, especially in high-risk populations such as immigrants. Despite being a reversible condition, the prognosis depends on the severity and time of diagnosis. We report two cases of exclusively breastfed infants with congestive cardiac failure due to hypokinetic dilated cardiomyopathy who had completely different outcomes. This report supports the need for prevention of this deficiency and underlies the role of vitamin D supplementation.

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.

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'.

Prevalence of low bone mass in postmenopausal Kuwaiti women residents in the largest province of Kuwait

We measured bone mineral density (BMD) in Kuwaiti women residents in the largest province of Kuwait state to highlight the BMD changes with each age, in particular when they reach the postmenopausal stage. Healthy Kuwaiti females between the ages of 10 and 89 years, who were residents in the largest province of Kuwait, were included in the study. After measurements of their height and weight, their bone mineral density of L2-L4 lumbar spine and femur (neck and total) was measured using dual-energy X-ray absorptiometry. Out of the studied 903 female subjects, 811 fulfilled the inclusion criteria. Their mean ± SEM age and body mass index (BMI) were respectively 47 ± 1 years and 30.8 ± 0.2 kg/m(2). Out of these 811 subjects, 454 were postmenopausal, and their age and BMI were 55.0 ± 0.3 years and 32.0 ± 0.3 kg/m(2), respectively. We have demonstrated that osteoporotic BMD of the spine and femur neck occurred in 20.2 and 12.5 % of postmenopausal Kuwaiti females, whereas osteopenic BMD of the spine and femur neck was observed at a frequency of 35.4 and 42.8 % of women, respectively. When the subjects were subdivided as per BMI, it was notable that overweight and obese had significantly higher BMD than normal weight postmenopausal women. BMD of the spine, femur neck, and femur total demonstrated significant positive correlations with body weight and BMI, whereas they demonstrated significant negative correlations with age. Low BMD of the femur neck and spine, reflected by the combination of osteopenia and osteoporosis, seemed to occur in more than half (55.3-55.6 %) of postmenopausal Kuwaiti women.

OBJECTIVES

Most of the studies on assessment of prevalence of low bone mass were focused in Caucasian population. Data on subjects of the Mediterranean area are limited. We measured bone mineral density (BMD) in Kuwaiti women residents in the largest province of Kuwait state to highlight the BMD changes with each age, in particular when they reach the postmenopausal stage.

SUBJECTS AND METHODS

Kuwaiti female subjects of different age groups between 10 and 89 years, who were residents in the largest province of Kuwait (Hawalli), were included in the study. They were included if they had been healthy over the last 12 months, had no past history of bone disease, and are not taking any prescription medication that may affect bone density. Their bone mineral density of L2-L4 lumbar spine and femur (neck and total) was measured using dual-energy X-ray absorptiometry.

RESULTS

Out of the studied 903 female subjects, 811 fulfilled the inclusion criteria and were included in the study. Their mean ± SEM age and body mass index (BMI) were respectively 47 ± 1 years and 30.8 ± 0.2 kg/m(2). Out of these 811 subjects, 454 were postmenopausal, and their age and BMI were 55.0 ± 0.3 years and 32.0 ± 0.3 kg/m(2), respectively. We have demonstrated that osteoporotic BMD of the spine and femur neck occurred in 20.2 and 12.5 % of postmenopausal Kuwaiti females, respectively, whereas osteopenic BMD of the spine and femur neck was observed at a frequency of 35.4 and 42.8 % of women. When subjects were subdivided as per BMI, it was notable that overweight and obese postmenopausal women had significantly higher BMD of lumbar spine, femur neck, and femur total than normal weight postmenopausal women. Bone mineral densities of the spine, femur neck, and femur total demonstrated significant positive correlations with body weight and BMI, whereas they demonstrated significant negative correlations with age.

CONCLUSION

Low BMD of the femur neck and spine, reflected by the combination of osteopenia and osteoporosis, seemed to occur in more than half (55.3-55.6 %) of postmenopausal Kuwaiti women residents at the largest province of Kuwait.

Low vitamin d and cardiovascular risk factors in males and females from a sunny, rich country

BACKGROUND

Low serum vitamin (vit) D levels are common even in sunny countries. We assessed the prevalence and relationship of low vit D with cardiovascular risk factors in Qatar.

METHODS

Data were collected retrospectively from January 2008 and November 2009. In patients who had low vi t D (< 30 ng/ml ) , demographic and clinical profiles were analyzed and compared in males and females.

RESULTS

The overall mean level of vit D among 547 patients was 14.4±11 ng/mL. Among the low vitamin D group, 56% were females (mean age 48±12) and 44% males (mean age 49.6±13). Severely low vit D levels (<10 ng/mL) were found in 231 (46%) patients with mean age of 46±12 years. Compared with females, males with low vitamin D were more likely to have diabetes mellitus (38 vs 22%, p=0.001), dyslipidemia (41 vs 29%, p=0.007), myocardial infarction (5.5 vs 1.5%, p=0.001) and angiographically documented coronary artery disease (CAD) (53 vs 17%, p=0.001). Multivariate logistic regression analysis showed that in the presence of low vit D, age and hypertension were independent predictors of CAD (OR 1.07;95% CI: 1.02-1.11) and OR 8.0; 95% CI: 1.67-39.82), respectively.

CONCLUSIONS

Our study supports the widespread prevalence of low vit D in sunny regions. Low vit D is associated with 3 times increase in the rate of MI among males. Hypertension increases the risk of CAD 8 times in the presence of low vit D regardless of gender.

Maternal vitamin D status: implications for the development of infantile nutritional rickets

The mother is the major source of circulating 25-OHD concentrations in the young infant. Thus maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. As a result, breastfed infants of mothers with vitamin D deficiency who are unsupplemented and who receive little sunlight exposure are at high risk of developing vitamin D deficiency or rickets. Despite food fortification policies in many countries and recommendations for vitamin D supplementation of at-risk groups, vitamin D deficiency and infantile rickets remain major public health challenges in many developed and developing countries. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and pregnant women in high risk communities with at least 600 IU; awareness needs to be developed among the public and medical practitioners of the urgent need to improve the vitamin D status of pregnant and lactating mothers and their infants. Further studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies also need to be conducted to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.

Genetic and environmental predictors of serum 25-hydroxyvitamin D concentrations among middle-aged and elderly Chinese in Singapore

Vitamin D is known for maintaining Ca homeostasis and bone structure, and may also decrease susceptibility to chronic and infectious diseases. However, data on vitamin D status and its predictors among Southeast Asian populations are limited. We evaluated the distribution and determinants (genetic and environmental) of serum 25-hydroxyvitamin D (25(OH)D) concentrations among 504 middle-aged and elderly participants (aged 45-74 years) in the Singapore Chinese Health Study. Data on dietary and other lifestyle factors were collected by trained interviewers. Serum 25(OH)D concentrations and genetic polymorphisms in vitamin D metabolism pathway enzymes (cytochrome P450 (CYP) 2R1, 3A4, 27B1, 24A1; vitamin D binding protein (also known as group-specific component, GC); and vitamin D receptor) were measured using stored biospecimens. Mean 25(OH)D concentration was 68·8 nmol/l. Serum 25(OH)D concentrations were positively associated with dietary vitamin D intake, and inversely associated with hours spent sitting at work. BMI was not associated with 25(OH)D concentrations. CYP2R1 rs10741657, rs12794714, rs1993116; CYP3A4 rs2242480; and GC rs4588, rs7041, rs16847015, rs2298849 were statistically significantly associated with 25(OH)D concentrations. Individuals with the Gc2-2 haplotype (rs4588AA/rs7041TT) had statistically significantly lower 25(OH)D concentrations compared to all other Gc haplotypes (P-trend < 0·001). The majority of participants (86 %) had 25(OH)D concentrations ≥ 50 nmol/l, which is consistent with the 2011 Institute of Medicine (US) recommendation for bone health, and 32 % had concentrations of ≥ 75 nmol/l that are thought to be required for broader health effects. Dietary vitamin D intake, hours spent indoors at work and genetic variation in CYP2R1, CYP3A4 and GC are significant predictors of 25(OH)D concentrations among Singapore Chinese.

Vitamin D Deficiency: This clandestine endemic disease is veiled no more

Recently, scientists have generated a strong body of evidence providing new information about the preventive effect of vitamin D on a broad range of disorders. This evidence suggests that vitamin D is much more than a nutrient needed for bone health; it is an essential hormone required for regulation of a large number of physiological functions. Sufficient concentration of serum 25-hydroxyvitamin D is essential for optimising human health. This article reviews the present state-of-the-art knowledge about vitamin D's status worldwide and refers to recent articles discussing some of the general background of vitamin D, including sources, benefits, deficiencies, and dietary requirements, especially in pregnancy. They offer evidence that vitamin D deficiency could be a major public health burden in many parts of the world, mostly because of sun deprivation. The article also discusses the debate about optimal concentration of circulating serum 25-hydroxyvitamin D, and explores different views on the amount of vitamin D supplementation required to achieve and maintain this concentration.

Diet, genetics, and disease: a focus on the middle East and north Africa region

The Middle East and North Africa (MENA) region suffers a drastic change from a traditional diet to an industrialized diet. This has led to an unparalleled increase in the prevalence of chronic diseases. This review discusses the role of nutritional genomics, or the dietary signature, in these dietary and disease changes in the MENA. The diet-genetics-disease relation is discussed in detail. Selected disease categories in the MENA are discussed starting with a review of their epidemiology in the different MENA countries, followed by an examination of the known genetic factors that have been reported in the disease discussed, whether inside or outside the MENA. Several diet-genetics-disease relationships in the MENA may be contributing to the increased prevalence of civilization disorders of metabolism and micronutrient deficiencies. Future research in the field of nutritional genomics in the MENA is needed to better define these relationships.

Differences in vitamin D status and calcium metabolism in Saudi Arabian boys and girls aged 6 to 18 years: effects of age, gender, extent of veiling and physical activity with concomitant implications for bone health

Objective

Few data exist looking at vitamin D status and bone health in school-aged boys and girls from Saudi Arabia. The present study aimed to determine the extent of poor vitamin D status in school boys and girls aged 6–18 years and to examine if there was any difference in status with age, physical activity and veiling and concomitant effects on bone.

Design

Cross-sectional study.

Setting

Jeddah, Kingdom of Saudi Arabia.

Subjects

A total of 150 boys (7–16 years) and 150 girls (6–18 years) from local schools were divided into age categories: 6–9 years (elementary school); 10–12 years (secondary school); 13–14 years (middle years); 15–18 years (high school).

Results

Vitamin D status was significantly lower in girls than boys in all age groups (P < 0·01), with the 15–18-year-old girls having the lowest level (22·0 (sd 9·4) nmol/l) in comparison to the 15–18-year-old boys (39·3 (sd 14·0) nmol/l) and the 6–9-year-old girls (41·2 (sd 9·3) nmol/l). Parathyroid hormone status was highest in the 15–18-year-old girls in comparison to boys of the same age. A total of 64 % of 15–18-year-old girls had 25-hydroxyvitamin D (25OHD) status <25 nmol/l in comparison to 31 % in the 13–14 years age category, 26 % in the 10–12 years category and 2·5 % in the 6–9 years category. No boys had 25OHD status <25 nmol/l. Fully veiled girls had lower 25OHD status than partly veiled or unveiled girls (P < 0·05). Low 25OHD and high parathyroid hormone was associated with lower bone mass in the 6–9 years and 13–14 years age groups (P < 0·05).

Conclusions

These data suggest significant hypovitaminosis D in older adolescent females, which is a cause for concern given that there is currently no public health policy for vitamin D in the Kingdom of Saudi Arabia.

Association of vitamin D-related gene polymorphisms with manifestation of vitamin D deficiency in children

The prevalence of vitamin D deficiency, presenting as hypocalcemic seizures or rickets in children, is increasing worldwide due to insufficient vitamin D intake and lack of exposure to sunshine. However, considering that relatively few children with low 25-hydroxyvitamin D [25(OH)D] levels manifest symptoms, it is possible that genetic factors may predispose individuals to vitamin D deficiency. Recent twin studies have reported that the level of serum of 25(OH)D is influenced by genetic factors. In addition, genome-wide association studies and candidate gene studies have revealed that several vitamin D-related genes, including VDR, GC, NADSYN1, CYP2R1, CYP24A1, CYP27B1, and C10orf88 contribute to variations in serum 25(OH)D levels. To investigate whether genetic predisposition contributes to vitamin D deficiency, we analyzed polymorphisms in vitamin D-related genes in 30 Japanese patients with vitamin D deficiency presenting at less than 4 years of age, along with 66 controls. A χ(2) test showed that the genotype frequencies of BsmI polymorphism in VDR and rs10898191 in NADSYN1 were significantly different between the two groups. The allele frequencies of BsmI, ApaI, TaqI in VDR, rs10898191 in NADSYN1, and rs705117 in GC were also significantly different. In particular, the frequency of the BAtS haplotype in VDR was significantly increased in the patient group relative to controls (p = 0.0014; odds ratio, 5.61; 95% confidence interval 1.92 - 16.40). Although this is a small study, our findings suggest that VDR, NADSYN1, and GC polymorphisms may be linked to the manifestation of vitamin D deficiency in Japanese children.

Vitamin D deficiency and prevention: Turkish experience

A nationwide 'vitamin D prophylaxis augmentation programme' initiated in 2005 in Turkey reduced the prevalence of rickets from 6% in 1998 to 0.1% in 2008 in children under 3 years of age. The programme included free distribution of vitamin D drops to all newborns and infants (0-12 months) visiting primary health stations throughout the country. Free disposal of vitamin D to infants is an effective strategy for preventing vitamin D-deficient rickets.

A common variant in the adiponectin gene and polycystic ovary syndrome risk

In this study, we explored whether polymorphisms in insulin receptor (INSR), adiponectin (ADIPOQ), parathyroid hormone (PTH), and vitamin D receptor (VDR) genes are associated with polycystic ovary syndrome (PCOS). A total of 362 subjects, including 181 women with PCOS and 181 controls were enrolled in this case-control study. Two SNPs (rs2059806 and rs1799817) in the INSR gene, two SNPs (rs2241766 and rs1501299) in the ADIPOQ gene, one SNP (rs6256) in the PTH gene, and one SNP (rs757343) in the VDR gene were analyzed using PCR-RFLP method. We observed no significant difference in genotype and allele frequencies between the women with PCOS and controls for the rs2059806, rs1799817, rs1501299, rs6256, and rs757343 polymorphisms either before or after adjustment for confounding factors including age and BMI. However, the ADIPOQ rs2241766 "TT" genotype compared with "TG and GG" genotypes was associated with a 1.93-fold increased risk for PCOS (P = 0.006, OR = 1.93, 95% CI = 1.20-3.11), and the differences remained significant after adjustment for age and BMI (P = 0.039, OR = 1.72, 95% CI = 1.03-2.86). Furthermore, the ADIPOQ rs2241766 "T" allele was significantly overrepresented in women with PCOS than controls (P = 0.006; OR = 1.80, 95% CI = 1.18-2.70), and the difference remained significant after Bonferroni correction. Our findings suggest that the ADIPOQ rs2241766 "TT" genotype is a marker of increased PCOS susceptibility. This study also indicates for the first time that there are no significant association between INSR rs2059806, PTH rs6256, and VDR rs757343 gene polymorphisms and PCOS risk. However, these data remain to be confirmed in larger studies and in other populations.