Presentation of vitamin D deficiency

AIMS

To describe the various ways in which vitamin D deficiency presents in children in selected districts of London and to identify which factors, if any, determine the mode of presentation.

METHODS

Retrospective review of patients presenting to Newham General, Royal London, Great Ormond Street, and King's College Hospitals between 1996 and 2001 with either hypocalcaemia or rickets caused by vitamin D deficiency. Children with plasma 25-hydroxyvitamin D levels <25 nmol/l (10 ng/ml) were considered to have vitamin D deficiency.

RESULTS

Sixty five children, mostly from Black or Asian ethnic minority groups, were identified, 29 of whom had hypocalcaemic symptoms. Seventeen of these had no radiological evidence of rickets. The remainder (48 children) had radiological evidence of rickets with or without clinical signs. Symptoms and signs reverted to normal in all cases with vitamin D supplementation. All children who presented with symptomatic hypocalcaemia were aged either <3 or >10 years. There was a strong correlation between age at presentation and population growth velocity reference data.

CONCLUSIONS

Rickets remains a problem in the UK especially in "at risk" ethnic minority groups. Symptomatic hypocalcaemia is an important, but under-recognised presenting feature. Growth rate is likely to be an important factor in determining the mode of presentation. Unexplained hypocalcaemia should be attributed to vitamin D deficiency in "at risk" ethnic minority groups until proved otherwise.

Vitamin D and bone health in early life

Prolonged vitamin D deficiency resulting in rickets is seen mainly during rapid growth. A distinct age distribution has been observed in the Copenhagen area where all registered hospital cases of rickets were either infants and toddlers or adolescents from immigrant families. Growth retardation was only present in the infant and toddler group. A state of deficiency occurs months before rickets is obvious on physical examination. Growth failure, lethargy and irritability may be early signs of vitamin D deficiency. Mothers with low vitamin D status give birth to children with low vitamin D status and increased risk of rickets. Reports showing increasing rates of rickets due to insufficient sunlight exposure and inadequate vitamin D intake are cause for serious concern. Many countries (including the USA from 2003) recommend vitamin D supplementation during infancy to avoid rickets resulting from the low vitamin D content of human milk. Without fortification only certain foods such as fatty fish contain more than low amounts of vitamin D, and many children will depend entirely on sun exposure to obtain sufficient vitamin D. The skin has a high capacity to synthesize vitamin D, but if sun exposure is low vitamin D production is insufficient, especially in dark-skinned infants. The use of serum 25-hydroxyvitamin D to evaluate vitamin D status before development of rickets would be helpful; however, there is no agreement on cut-off levels for deficiency and insufficiency. Furthermore, it is not known how marginal vitamin D insufficiency affects children's bones in the long term.

Le rachitisme symptomatique de l’adolescent

Although systematic vitamin D supplementation in adolescents remains debated, rickets is nevertheless a well recognized pathology in this age group. Adolescence is an at-risk period because of rapid growth, insufficient calcium intake and/or vitamin D status. Surveys have shown that calcium intake is insufficient (< 1000 mg a day) in 45% of boys and 71% of girls and that vitamin D status is deficient (25-OH-D < 10 ng/ml). The aims of the study carried out by the Calcium Group of the Société Française de Pédiatrie, were to evaluate the frequency of rickets, and to define the criteria for the adolescent population at risk. Forty-one adolescents with rickets were hospitalized between 1985 and 2000. Most of the cases were from the Northern France: 20 from Paris and suburbs, eight from the North-West, four from the North, four from the North-East; five were from the Center of France. The mean age was 13 years and two months for the 28 girls, and 14 years and four months for the 13 boys. Eighty per cent of the adolescents were from immigrant families (33/41): 15 were from sub-Saharan Africa, ten from North Africa, six from Pakistan and two from Turkey. Two thirds of the adolescents were hospitalized in the 2nd quarter of the year. Some adolescents suffered from lower limb pain, 16 had deformations of lower limbs, particularly genu valgum, associated with pain; seven others had either muscle spasms (4), tetany (3). Serum calcium level was low (average 1.84 mmol/l: [1.1-2.5]), and serum 25-OH D level was extremely low. Radiographic characteristics observed were metaphyseal strips on the knees, with condensed edges at times, with the presence of bone demineralization. The treatment combined calcium and vitamin D, and was often administered intravenously when a hypocalcemia was detected. Rickets is not frequent in adolescents, but nonetheless this pathology is not exceptional, and the number of cases is probably under-estimated. Rickets affects immigrant adolescents in particular but nevertheless could also present a certain risk period for the general population.

Response element binding proteins and intracellular vitamin D binding proteins: novel regulators of vitamin D trafficking, action and metabolism

Using vitamin D-resistant New World primates as model of natural diversity for sterol/steroid action and metabolism, two families of novel intracellular vitamin D regulatory proteins have been discovered and their human homologs elucidated. The first family of proteins, heterogeneous nuclear ribonucleoproteins (hnRNPs), initially considered to function only as pre-mRNA-interacting proteins, have been demonstrated to be potent cis-acting, trans-dominant regulators of vitamin D hormone-driven gene transactivation. The second group of proteins bind 25-hydroxylated vitamin D metabolites. Their overexpression increases vitamin D receptor (VDR)-directed target gene expression. We found that these intracellular vitamin D binding proteins (IDBPs) are homologous to proteins in the heat shock protein-70 family. Our ongoing studies indicate directly or indirectly through a series of protein interactions that the IDBPs interact with hydroxylated vitamin D metabolites and facilitate their intracellular targeting.

Practices of vitamin D recommendation in Las Vegas, Nevada

Reports of vitamin D deficiency rickets, although rare in the United States, have increased over the past few years, including in children living in climates with abundant sunshine. The purpose of this study was to describe vitamin D recommendation practices among pediatric health care providers in Las Vegas, Nevada. Of the 155 providers surveyed, 52.3% did not recommend vitamin D for exclusively breastfed babies. Providers who were more likely to recommend supplementation were doctors of medicine, were female, specialized in pediatrics, were of Hispanic ethnicity, had previously practiced and trained in states less sunny than Nevada, had graduated from training 21 or more years previously, had taken histories of infants' sun exposure, and had clinical experience with cases of rickets. Providers demonstrated a knowledge deficitforquestions that dealt with preventive measures.

The need for animal source foods by Kenyan children

Food intake and dietary patterns in Kenyan households have been studied since the 1920s. Reports on breastfeeding, nutrient intake, micronutrient deficiencies and the impacts of malaria and intestinal parasites on nutritional status are reviewed. Diets are mainly cereal-based, with tubers and a variety of vegetables and fruits when available. White maize, sorghum and millet are high in phytate and fiber, which inhibit the absorption of micronutrients such as zinc and iron. Communities growing cash crops have little land for food crops. Although households may own cattle, goats and poultry, commonly these are not consumed. Adults in nomadic communities consume more meat than nonpastoralists. Lakeside and oceanside communities do not consume adequate amounts of fish. Poor households have a limited capacity to grow and purchase food, therefore they have more nutrient deficiencies. Early weaning to cereal porridge deprives the infant of protein and other nutrients from human milk. Other milk is consumed only in small amounts in sweetened tea. Older children eat adult diets, which are extremely bulky and hard to digest. Anemia is mainly due to iron deficiency, malaria and intestinal parasites. In general, Kenyan children have inadequate intakes of energy, fat and micronutrients such as calcium, zinc, iron, riboflavin and vitamins A and B-12. The multiple micronutrient deficiencies may contribute to early onset of stunting and poor child development, whereas lack of calcium together with vitamin D deficiency are responsible for the resurgence of rickets. There is an urgent need to increase the intake of animal source foods by Kenyan children.

Rickets among children of a coastal area of Bangladesh

Many children with rachitic deformities have been reported in southern coastal area of Bangladesh but the actual rate of prevalence was not known. A survey was conducted to determine the magnitude of rachitic problem among the children of Chakaria thana of Cox's Bazar district of Bangladesh. Nine hundred children between 1-15 years selected randomly from 30 villages of total 340 villages. Face to face interview of the parents was taken and the children were examined for evidences of rickets. Serum calcium, phosphorus, alkaline phosphatase (ALP) were estimated and radiology of limbs were done in all clinically suspected cases and in a control of every eighth child. Seventy eight children (8.7%) had physical features suggestive of rickets. Fifty eight (6.4%) children had 'clinical rickekts' (positive physical feature(s) but normal ALP and negative radiology), 12 (1.3%) children had 'biochemical rickets' (positive physical features and raised ALP but negative radiology) and 8 (0.9%) children had 'confirmed rickets' (positive physical features, raised ALP and positive radiology). Out of 78 children with rachitic feature(s), Pectus carinatum was found as the most common clinical feature in 26 (33.3%) children followed by genu valgum in 23 (29.4%) cases. Twenty two normal children (2.2%) had raised level of ALP (>300U/L). The prevalence of rickets is high in children of Chakaria and further study is needed to find out the exact aetiology of rickets in children there.

Rickets in the Dairy State

BACKGROUND

Nutritional vitamin D deficiency rickets occurs when children do not receive adequate vitamin D, which can be obtained from diet or manufactured in the skin when there is adequate sun exposure. A number of reports have described cases of vitamin D deficiency rickets in breastfed infants, but the public health significance of this problem in Wisconsin is unknown.

OBJECTIVES

Our objectives were to identify cases of vitamin D deficiency rickets in Wisconsin infants and to determine the percentage of these infants participating in the Wisconsin Women, Infant and Children (WIC) program.

METHODS

All cases of rickets due to nutritional vitamin D deficiency seen at Children's Hospital of Wisconsin or its associated outpatient clinics were identified by retrospective chart review. Data collected included date of birth, age at presentation, race, clinical presentation, diet history, history of vitamin supplementation, x-ray findings, and biochemical studies. The children with nutritional vitamin D deficiency rickets were cross-referenced with the Wisconsin WIC database.

RESULTS

Fifty-one definite cases of nutritional vitamin D deficiency rickets were identified. Skeletal deformities, failure to thrive, fractures, seizures, incidental lab finding, tetany, and refusal to walk were the most common reasons for identifying rickets. All of the children were breastfed and did not receive vitamin supplementation. The infants had a mean age of 13.6 months and 46 (90%) were African American. Thirty-seven out of 51 children (73%) were enrolled in the Wisconsin WIC program.

CONCLUSION

Vitamin D deficiency nutritional rickets is an important public health problem in Wisconsin. The Wisconsin WIC program may be an important site for intervention strategies.

Comparison of low and high dose of vitamin D treatment in nutritional vitamin D deficiency rickets

In this study, we compared three different therapy modes (150,000 IU, 300,000 IU, and 600,000 IU vitamin D p.o.) in infants with nutritional vitamin D deficiency rickets (VDR). Our purpose was to determine the most effective dosage of vitamin D with least side effects for treating VDR. The study included 56 patients, 3-36 months of age, with nutritional VDR and 20 age-matched control infants. In all infants, serum calcium, phosphorus, alkaline phosphatase, magnesium, serum 25-hydroxycholecalciferol, plasma intact parathormone levels and urinary Ca/creatine ratio were determined. Of 56 patients, 52 were able to be followed long-term. These patients were reexamined on the 3rd day, 7-10th day, and 25-30th day after treatment. On the 30th day post-treatment, we did not find any difference between the doses in the improvement of rickets. However, hypercalcemia was present in eight infants who had been administered 300,000 IU (two infants) and 600,000 IU (six infants) of vitamin D. In conclusion, our findings showed that 150,000 IU or 300,000 IU of vitamin D was adequate in the treatment of VDR, but 600,000 IU of vitamin D may carry the risk of hypercalcemia.

A comparison of breastfed children with nutritional rickets who present during and after the first year of life

This study compares the patient characteristics of breastfed children in Baltimore, Maryland from 1990 to 2000 diagnosed with nutritional rickets at 12 months or younger to those older than 12 months to gain a better understanding of nutritional and environmental factors. All 30 of the patients were African American. Patients 12 months or younger (n=15) compared to those older than 12 months (n=15) were more likely to be born during the summer and to present with seizures and hypocalcemia. We recommend vitamin D supplementation of all breastfed infants at an early age and that supplementation continue throughout the duration of breastfeeding.

Nutritional rickets with normal circulating 25-hydroxyvitamin D: a call for reexamining the role of dietary calcium intake in North American infants

The incidence of nutritional rickets appears to be increasing in North American infants and toddlers; it is widely assumed that this is due to vitamin D deficiency. Thus, records of 43 children with nutritional rickets from greater New Haven, Connecticut, from 1986-2002 were identified. The mean age of presentation was 20 months; 86% were of African-American, Hispanic, or Middle Eastern descent. More than 93% of children had been breastfed; however, 15% had received vitamin D supplementation. Eighty-six percent of those with food histories available were weaned to diets with minimal dairy content after nursing. Serum 25-hydroxyvitamin D was 20.9 +/- 11.5 ng/ml and was less than 15 ng/ml in only 22% of patients. Three representative case histories suggest that dietary calcium intake may play a contributory role in the development of disease; 1 case documents radiographic and biochemical resolution of rachitic abnormalities after calcium treatment, but no vitamin D therapy. Clinicians should be aware that low dietary calcium intake after weaning may result in the development of nutritional rickets, and that attention to calcium intake as well as that of vitamin D is important in the establishment of optimal dietary practices for North American infants and children.

[Nutritional rickets in childhood: analysis of 62 cases]

BACKGROUND AND OBJECTIVE

Until recently, rickets secondary to vitamin D deficiency was considered a medical oddity rather than a clinical reality in Catalonia (Spain). However, recent data show a reemergence of the disease in the infancy.

PATIENTS AND METHOD

Retrospective clinical survey of epidemiologic and clinical features of infants and children (34 boys and 28 girls) diagnosed of nutritional rickets in pediatric departments of Catalonia (Spain) over the last 10 years.

RESULTS

Mean age (SD) at diagnosis was 9.9 (7) months (range: 3-36), 35.5% were under 6 months. Race distribution: blacks 61.3%, dark-skinned 36%; white 6.4%. Country of origin: Sub-Saharan Africa 59.7%, Morocco 33.9%, Catalonia 3.2%, Pakistan 1.6%. Seasonal distribution: 60% were diagnosed in autumn and winter. At diagnosis, 72% were following an exclusive milk diet (48% maternal milk alone) without vitamin D supplementation. Most common clinical presentation in infants under 6 months was: hypocalcemic tetany/seizures; in children aged 6-12 months: failure to thrive; and in children over 12 months: skeletal deformities. Weight and height expressed as z-score value at diagnosis was 0.67 and 0.91, respectively.

CONCLUSIONS

Nutritional rickets is a current reality in Catalonia and it mainly affects immigrant infants and children from Sub-Saharan Africa and Morocco, black or dark-skinned, fed with maternal milk alone, without vitamin D supplementation and with little sun exposure. Systematic, preventive supplementation with vitamin D is essential in these populations.

Assessment of nutritional rickets in Western Saudi Arabia

OBJECTIVE

To explore the role of radiological examination and certain biochemical values in diagnosis and assessing severity of nutritional rickets.

METHODS

Cases of symptomatic nutritional rickets (age range between 3-36 months) seen at King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia, during the period 1997-1999 were studied. Clinical examination by the author of the study, determination of calcium (Ca), phosphate (PO4), alkaline phosphates (ALP), hand and wrist x-rays, were performed for all cases.

RESULTS

Sixty cases of nutritional rickets were diagnosed within 2 years (incidence of 0.5%), 38.3% of the patients presented with swollen wrist and 28.3% with bowleg. The bone profile at time of diagnosis: Ca=2.33 +/- 0.23, PO4 = 1.47 +/- 0.40 and ALP = 925 +/- 418. Approximately 81.7% of the patients had normal Ca level, 18.3% had low serum PO4 level, 98.3% showed high value of ALP. X-ray studies indicated that, 58.3% of patients had active rickets, 35% had minimal changes, and 6.7% showed healed rickets. Among those having active rickets 20% had low PO4 level, 83% had normal Ca value, and 100% had high ALP. The mean value +/- SD of biochemical values in this group: Ca = 2.34 +/- 0.24, PO4 = 1.45 +/- 0.42, ALP = 1067 +/- 452. The later was significantly higher compared to other groups (P=0.004) but no significant differences were observed between mean values of other parameters.

CONCLUSION

Radiological examination and ALP remains essential to confirm clinical diagnosis of rickets and assessment of severity.

Rapid assessment of the prevalence of lower limb clinical rickets in Bangladesh

This study attempted to measure the prevalence of lower limb clinical rickets using a rapid assessment methodology in Cox's Bazaar, a coastal district of Bangladesh. The study populations were drawn from 28 random villages representing all seven 'thanas' (subdistricts) of the district. Data were collected on 25,891 children and young people aged 1-20 years in two phases. In the first phase, 30 trained, local, non-medical people listed 490 children suffering from visible signs of any physical disability. To achieve this, they demonstrated a multicolored poster showing the features of lower limb clinical rickets to key informants in the villages. In the second phase, two teams of medically trained people (physicians), each with one male and one female, validated the above cases for rickets. They verified and validated 278 cases in five thanas. Due to inclement weather and floods, they could not visit the other two thanas. Based on these data, the adjusted prevalence rates for lower limb clinical rickets were calculated to be 931 per 100,000 population (95% confidence intervals 795-1067). The prevalence was highest (1215) in children aged 1-4 years and lowest (498) amongst 17-20 year olds. Females had lower prevalence than males. Based on the study experience, a quick investigation using a similar methodology was performed in five other districts (Sunamganj, Noakhali, Bhola, Jessore and Gaibandha), and clinical signs of lower limb rickets were found in Sunamganj and Jessore. It thus indicates that rickets may be endemic, not only in Cox's Bazaar but also in some other parts of Bangladesh. The methodology used for this study was found to be rapid, simple, replicable and inexpensive.