A major health problem facing immigrant children: nutritional rickets.

OBJECTIVES: Nutritional rickets (NR) is still an important problem and one which increasing influxes of immigrants are further exacerbating. This study evaluated cases of mostly immigrant children followed up with diagnoses of NR in our pediatric endocrinology clinic. METHODS: Details of 20 cases diagnosed with NR between 2017 and 2020 were retrieved from file records. RESULTS: Twenty (11 male) cases were included in the study. Three (15%) were Turkish nationals and the others (85%) were immigrants. Hypocalcemia and hypophosphatemia were detected in 17 and 13, respectively. Alkaline phosphatase (ALP) values were normal in two cases, while ALP and parathyroid hormone (PTH) values were elevated in all other cases, and PTH levels were very high (473.64 ± 197.05 pg/mL). 25-hydroxyvitamin D levels were below 20 ng/mL in all cases. Patients with NR received high-dose long-term vitamin D or stoss therapy. Six patients failed to attend long-term follow-up, while PTH and ALP levels and clinical findings improved at long-term follow-up in the other 14 cases. CONCLUSIONS: The elevated PTH levels suggest only the most severe cases of NR presented to our clinic. Clinically evident NR is therefore only the tip of the iceberg, and the true burden of subclinical rickets and osteomalacia remains unidentified. Public health policies should therefore focus on universal vitamin D supplementation and adequate dietary calcium provision, their integration into child surveillance programs, adequate advice and support to ensure normal nutrition, exposure to sunlight, and informing families of the increased risk not only for resident populations but also for refugee and immigrant children.

Alkaline phosphatase in pediatric patients with genu varum caused by vitamin D-deficient rickets.

An elevated serum alkaline phosphatase (ALP) level is one of the markers for the presence of rickets in children, but it is also associated with bone formation. However, its role in diagnosing genu varum in pediatric patients with vitamin D-deficient rickets is still unknown. To clarify the role of the serum ALP level in assessing the severity of genu varum, we retrospectively investigated this issue statistically using data on rickets such as serum intact parathyroid hormone (iPTH), 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, ALP, the level of creatinine as the percentage of the median according to age (%Cr), and the metaphyseal diaphyseal angle (MDA) in the lower extremities as an index of the severity of genu varum. A multiple regression analysis revealed that log ALP and %Cr values were negatively associated with MDA values. The former association was also confirmed by a linear mixed model, while iPTH was positively associated with MDA by path model analysis. To elucidate the association of ALP with MDA in the presence of iPTH, we investigated three-dimensional figures by neural network analysis. This indicated the presence of a biphasic association of ALP with MDA: the first phase increases while the second decreases MDA. The latter phenomenon is considered to be associated with the increase in bone formation due to the mechanical stress loaded on the lower extremities. These findings are important and informative for pediatricians to understand the significance of the serum ALP level in pediatric patients with genu varum caused by vitamin D deficiency.

Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health.

BACKGROUND: Vitamin D deficiency is common worldwide, contributing to nutritional rickets and osteomalacia which have a major impact on health, growth, and development of infants, children and adolescents. Vitamin D levels are low in breast milk and exclusively breastfed infants are at risk of vitamin D insufficiency or deficiency. OBJECTIVES: To determine the effect of vitamin D supplementation given to infants, or lactating mothers, on vitamin D deficiency, bone density and growth in healthy term breastfed infants. SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to 29 May 2020 supplemented by searches of clinical trials databases, conference proceedings, and citations. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs in breastfeeding mother-infant pairs comparing vitamin D supplementation given to infants or lactating mothers compared to placebo or no intervention, or sunlight, or that compare vitamin D supplementation of infants to supplementation of mothers. DATA COLLECTION AND ANALYSIS: Two review authors assessed trial eligibility and risk of bias and independently extracted data. We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: We included 19 studies with 2837 mother-infant pairs assessing vitamin D given to infants (nine studies), to lactating mothers (eight studies), and to infants versus lactating mothers (six studies). No studies compared vitamin D given to infants versus periods of infant sun exposure. Vitamin D supplementation given to infants: vitamin D at 400 IU/day may increase 25-OH vitamin D levels (MD 22.63 nmol/L, 95% CI 17.05 to 28.21; participants = 334; studies = 6; low-certainty) and may reduce the incidence of vitamin D insufficiency (25-OH vitamin D < 50 nmol/L) (RR 0.57, 95% CI 0.41 to 0.80; participants = 274; studies = 4; low-certainty). However, there was insufficient evidence to determine if vitamin D given to the infant reduces the risk of vitamin D deficiency (25-OH vitamin D < 30 nmol/L) up till six months of age (RR 0.41, 95% CI 0.16 to 1.05; participants = 122; studies = 2), affects bone mineral content (BMC), or the incidence of biochemical or radiological rickets (all very-low certainty). We are uncertain about adverse effects including hypercalcaemia. There were no studies of higher doses of infant vitamin D (> 400 IU/day) compared to placebo. Vitamin D supplementation given to lactating mothers: vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels (MD 24.60 nmol/L, 95% CI 21.59 to 27.60; participants = 597; studies = 7; low-certainty), may reduce the incidences of vitamin D insufficiency (RR 0.47, 95% CI 0.39 to 0.57; participants = 512; studies = 5; low-certainty), vitamin D deficiency (RR 0.15, 95% CI 0.09 to 0.24; participants = 512; studies = 5; low-certainty) and biochemical rickets (RR 0.06, 95% CI 0.01 to 0.44; participants = 229; studies = 2; low-certainty). The two studies that reported biochemical rickets used maternal dosages of oral D3 60,000 IU/day for 10 days and oral D3 60,000 IU postpartum and at 6, 10, and 14 weeks. However, infant BMC was not reported and there was insufficient evidence to determine if maternal supplementation has an effect on radiological rickets (RR 0.76, 95% CI 0.18 to 3.31; participants = 536; studies = 3; very low-certainty). All studies of maternal supplementation enrolled populations at high risk of vitamin D deficiency. We are uncertain of the effects of maternal supplementation on infant growth and adverse effects including hypercalcaemia. Vitamin D supplementation given to infants compared with supplementation given to lactating mothers: infant vitamin D supplementation compared to lactating mother supplementation may increase infant 25-OH vitamin D levels (MD 14.35 nmol/L, 95% CI 9.64 to 19.06; participants = 269; studies = 4; low-certainty). Infant vitamin D supplementation may reduce the incidence of vitamin D insufficiency (RR 0.61, 95% CI 0.40 to 0.94; participants = 334; studies = 4) and may reduce vitamin D deficiency (RR 0.35, 95% CI 0.17 to 0.72; participants = 334; studies = 4) but the evidence is very uncertain. Infant BMC and radiological rickets were not reported and there was insufficient evidence to determine if maternal supplementation has an effect on infant biochemical rickets. All studies enrolled patient populations at high risk of vitamin D deficiency. Studies compared an infant dose of vitamin D 400 IU/day with varying maternal vitamin D doses from 400 IU/day to > 4000 IU/day. We are uncertain about adverse effects including hypercalcaemia. AUTHORS' CONCLUSIONS: For breastfed infants, vitamin D supplementation 400 IU/day for up to six months increases 25-OH vitamin D levels and reduces vitamin D insufficiency, but there was insufficient evidence to assess its effect on vitamin D deficiency and bone health. For higher-risk infants who are breastfeeding, maternal vitamin D supplementation reduces vitamin D insufficiency and vitamin D deficiency, but there was insufficient evidence to determine an effect on bone health. In populations at higher risk of vitamin D deficiency, vitamin D supplementation of infants led to greater increases in infant 25-OH vitamin D levels, reductions in vitamin D insufficiency and vitamin D deficiency compared to supplementation of lactating mothers. However, the evidence is very uncertain for markers of bone health. Maternal higher dose supplementation (≥ 4000 IU/day) produced similar infant 25-OH vitamin D levels as infant supplementation of 400 IU/day. The certainty of evidence was graded as low to very low for all outcomes.

Vitamin D in Preterm and Full-Term Infants.

Vitamin D is necessary for the active (transcellular) absorption of calcium and for skeletal health. Inadequate vitamin D in infants leads to increased risks of poor bone mineralization and ultimately rickets. Rickets is uncommon in full-term infants with a much higher risk in very premature infants. However, the primary cause of rickets in premature infants is a deficiency of calcium and phosphorus, not vitamin D. Available research, as well as most guidelines, recommend an intake of 400 IU daily of vitamin D as adequate for bone health in preterm and full-term infants. Higher doses have not been consistently shown to have specific clinical benefits for healthy infants. There are no strong data to support either routine testing of serum 25-hydroxyvitamin D or targeting high serum 25-hydroxyvitamin D levels (e.g., 30 ng/mL) in healthy preterm or full-term infants. Vitamin D is commonly provided to infants via drops for breastfed babies or via infant formula, although alternative dosing approaches exist for breastfed infants, which some families may prefer. These include the use of drops placed on the mother's breast, dissolvable doses, and high maternal doses (approximately 6,400 IU daily). Infant formula contains vitamin D, and most infants will reach an intake from formula of about 400 IU daily within the first 2 months of life if they are consuming routine cow milk-based formula. Although vitamin D toxicity is very uncommon, caution should be used to avoid extremely concentrated high doses found in some commercially available drops. Infants with liver or kidney disease may need special attention to vitamin D intake and status. Further research is needed to define the role of vitamin D in non-bone health outcomes of infants and to identify methods to enhance compliance with current recommendations for vitamin D intake in infants.

C-Terminal Fibroblast Growth Factor-23 Levels in Non-Nutritional Hypophosphatemic Rickets.

Fibroblast growth factor-23 (FGF23) is central to phosphate homeostasis. The author examined if blood levels of FGF23 allow discrimination of classic hypophosphatemic rickets from other causes of non-nutritional rickets with hypophosphatemia. Forty-two children (median age: 102 mo) with non-nutritional rickets and hypophosphatemia were clinically classified as having distal renal tubular acidosis (RTA, n = 12), Fanconi syndrome (n = 8), classic hypophosphatemic rickets (n = 11), vitamin D dependent rickets (n = 7) and Dent disease (n = 4). Median blood FGF23 (measured by C-terminal ELISA) concentrations were similar in all groups (P = 0.24). These levels did not correlate with phosphate, tubular maximum for phosphate, calcium, 25-hydroxyvitamin D, creatinine, and parathormone levels. Patients with distal RTA showed variable degree of proximal tubular dysfunction that resolved following alkali supplements. Blood FGF23 levels did not satisfactorily differentiate classic hypophosphatemic rickets from other causes of hypophosphatemic rickets.

Nutritional rickets among children admitted with severe pneumonia at Mulago hospital, Uganda: a cross-sectional study.

BACKGROUND: There's abundant sunshine in the tropics but severe rickets is still observed. Nutritional rickets is associated with an increased risk of acute lower respiratory infections. Pneumonia is the leading cause of death in the under 5 -year old children with the highest burden in developing countries. Both Pneumonia and rickets are common in the developing countries and may affect clinical presentation and outcome. This study aimed to determine the prevalence and associated factors of nutritional rickets in children admitted with severe pneumonia. METHODS: This was a cross-sectional study of children aged 2-59 months presenting with severe pneumonia at an emergency unit. We enrolled 221 children between February and June 2012 after consent. A pre-coded questionnaire was used to collect data on socio-demographic, nutritional and past medical history. Physical exam was done for signs of rickets and anthropometric measurements. Serum calcium, phosphorus, and alkaline phosphatase (ALP) were assessed. Children with any physical signs of rickets or biochemical rickets (ALP > 400 IU); had a wrist x-ray done. Nutritional rickets was defined as the presence of radiological changes of cupping or fraying and/ or metaphyseal thickening. Severe pneumonia was defined using the WHO criteria. Statistical analysis was performed using the Stata 10 statistical package. P- value < 0.05 was significant. RESULTS: The prevalence of nutritional rickets among children with severe pneumonia is 9.5%. However, 14.5% had raised ALP (biochemical rickets). The factors independently associated with rickets was an elevated alkaline phosphatase; p-value < 0.001, or 32.95 95% CI (10.54-102.93). Other factors like breastfeeding, big family size, birth order were not significantly associated with rickets. Low serum calcium was detected in 22 (9.9%) of the 221 participants. Overall few children with rickets had typical clinical features of rickets on physical examination. CONCLUSION: Rickets is a common problem in our setting despite ample sunshine. Clinicians should actively assess children for rickets in this setting and screen for rickets in those children at high risk even without clinical features.

Nutritional rickets in Taiwanese children: Experiences at a single center.

BACKGROUND/PURPOSE: The number of children with nutritional rickets in Taiwan has increased over the last decade. The aim of this study was to present our experiences in the management of patients with this condition. PATIENTS AND METHODS: From 2011 to 2016, 10 children (3 boys and 7 girls) with nutritional rickets were enrolled in this study. Their clinical and biochemical data were analyzed. RESULTS: The median age of the 10 patients was 21 months (range, 12-25 months). The predisposing factors included exclusive breastfeeding, dietary restriction, and limited outdoor activities. The most common presentations were unsteady gait and bowlegs, and two patients had hypocalcemic seizures. All patients had elevated alkaline phosphatase levels (median, 1008 U/L; range, 484-2051 U/L), elevated serum intact parathyroid hormone levels (median, 333.8 pg/mL; range, 130-817 pg/mL), and hypophosphatemia (median, 3.0 mg/dL; range, 2.4-3.9 mg/dL). The median serum 25-hydroxyvitamin D level was 7.44 ng/mL (range, 1.44-9.82 ng/mL). After vitamin D supplementation was initiated, serum phosphorus levels normalized within 1 month, and serum intact parathyroid hormone levels returned to the normal range within 2 months. Six of the 10 patients had serum alkaline phosphatase levels close to the normal range within 3 months. All 10 patients exhibited complete bone healing within 6 months of vitamin D treatment. CONCLUSION: Nutritional rickets is not as rare in Taiwan as previously thought. When physicians encounter infants or toddlers with typical bone deformities or hypocalcemic seizures, a high index of suspicion and a detailed nutritional history are important for early diagnosis and treatment.

Milk vitamin D in relation to the 'adequate intake' for 0-6-month-old infants: a study in lactating women with different cultural backgrounds, living at different latitudes.

Breast-fed infants are susceptible to vitamin D deficiency rickets. The current vitamin D 'adequate intake' (AI) for 0-6-month-old infants is 10 µg/d, corresponding with a human milk antirachitic activity (ARA) of 513 IU/l. We were particularly interested to see whether milk ARA of mothers with lifetime abundant sunlight exposure reaches the AI. We measured milk ARA of lactating mothers with different cultural backgrounds, living at different latitudes. Mature milk was derived from 181 lactating women in the Netherlands, Curaçao, Vietnam, Malaysia and Tanzania. Milk ARA and plasma 25-hydroxyvitamin D (25(OH)D) were analysed by liquid-chromatography-MS/MS; milk fatty acids were analysed by GC-flame ionisation detector (FID). None of the mothers reached the milk vitamin D AI. Milk ARA (n; median; range) were as follows: Netherlands (n 9; 46 IU/l; 3-51), Curaçao (n 10; 31 IU/l; 5-113), Vietnam: Halong Bay (n 20; 58 IU/l; 23-110), Phu Tho (n 22; 28 IU/l; 1-62), Tien Giang (n 20; 63 IU/l; 26-247), Ho-Chi-Minh-City (n 18; 49 IU/l; 24-116), Hanoi (n 21; 37 IU/l; 11-118), Malaysia-Kuala Lumpur (n 20; 14 IU/l; 1-46) and Tanzania-Ukerewe (n 21; 77 IU/l; 12-232) and Maasai (n 20; 88 IU/l; 43-189). We collected blood samples of these lactating women in Curaçao, Vietnam and from Tanzania-Ukerewe, and found that 33·3 % had plasma 25(OH)D levels between 80 and 249·9 nmol/l, 47·3 % between 50 and 79·9 nmol/l and 19·4 % between 25 and 49·9 nmol/l. Milk ARA correlated positively with maternal plasma 25(OH)D (range 27-132 nmol/l, r 0·40) and milk EPA+DHA (0·1-3·1 g%, r 0·20), and negatively with latitude (2°S-53°N, r -0·21). Milk ARA of mothers with lifetime abundant sunlight exposure is not even close to the vitamin D AI for 0-6-month-old infants. Our data may point at the importance of adequate fetal vitamin D stores.

Oral Supplementation of Parturient Mothers with Vitamin D and Its Effect on 25OHD Status of Exclusively Breastfed Infants at 6 Months of Age: A Double-Blind Randomized Placebo Controlled Trial.

BACKGROUND: Exclusively breastfed infants are at increased risk of vitamin D deficiency and many lactating mothers have been found deficient in 25OHD stores. OBJECTIVE: To compare serum vitamin D levels in exclusively breastfed infants at 6 months of age with or without oral supplementation of 600,000 IU of vitamin D3 to mothers in early postpartum period. METHODS: Exclusively breastfeeding term parturient mothers were randomized 24-48 hours following delivery to receive either 600,000 IU of vitamin D3 (Cholecalciferol) over 10 days in a dose of 60,000 IU/day or placebo. 25OHD levels were measured by Radio Immuno Assay method at recruitment and after 6 months in all mothers and their infants. Urinary calcium and creatinine ratio was measured to monitor adverse effects of vitamin D3 in both mothers and infants at 14 weeks and 6 months of age. X-ray of both wrists in anteroposterior view and serum alkaline phosphatase of infants were done in both groups at 6 months of age to look for evidence of rickets. RESULTS: Maternal profile was similar in intervention (A) and control (B) groups. Mothers' serum 25OHD levels at recruitment were also similar being 16.2 ± 9.3 ng/mL in group A and 14.1 ± 7.1 ng/mL in group B. After 6 months, 25OHD levels were 40.3 ± 21.6 and 22.9 ± 20.1 ng/mL in group A and group B mothers (p ≤ 0.00), respectively. The serum 25OHD levels in cord blood were 9.9 ± 5.7 and 8.9 ± 5.1 ng/mL, respectively, in infants born to mothers in intervention and control groups (p = 0.433). At 6 months of age, the serum 25OHD levels significantly (p < 0.00) raised to 29.1 ± 14.6 ng/mL in infants of group A compared to those of group B (15.7 ± 17.7 ng/mL). Four infants developed radiological rickets at 6 months of age, two infants each in intervention group and study group. As against 10 infants in the control group (16.94%), no infant in the study group had biochemical rickets. Urinary calcium and creatinine ratio in mothers and infants at 14 weeks and 6 months of age in both intervention and study group was within normal limits, indicating there was no adverse effects of oral administration of 600,000 IU of vitamin D3. CONCLUSION: Serum 25OHD levels of exclusively breastfed infants significantly rise at 6 months of age when their mothers are orally supplemented with 60,000 IU of vitamin D3 daily for 10 days in the early postpartum period in comparison to infants of vitamin D3 unsupplemented mothers.

No Severe Hypercalcemia with Daily Vitamin D3 Supplementation of up to 30 µg during the First Year of Life.

BACKGROUND: Vitamin D supplementation is widely recommended for infants, but the optimal dose remains unclear. High intake may result in hypercalcemia. METHODS: We evaluated the incidence of hypercalcemia during the first year of life in a cohort of 987 healthy children who received 10 or 30 µg of vitamin D3 supplementation daily. Ionized calcium (Ca-ion) was analyzed at 6 and 12 months, and serum 25-hydroxyvitamin D (25-OHD) and parathyroid hormone (PTH) concentration at 12 months. Severe hypercalcemia was defined as Ca-ion exceeding the reference limit (1.16-1.39 mmol/L) by 10%. RESULTS: No severe hypercalcemia occurred. Mild hypercalcemia (1.40-1.52 mmol/L) was present at 6 months in 28% and at 12 months in 2% of infants. At 12 months, 25-OHD ranged between 23 and 241 nmol/L (median 97), and PTH was between undetectable and 104 pg/mL (median 24) and was below the reference range (11.5-78.4 pg/mL) in 11%. 25-OHD and Ca-ion correlated positively (r = 0.149), and 25-OHD was slightly higher in the 12 infants with mild hypercalcemia (median 97 vs. 110 nmol/L, p = 0.046). CONCLUSIONS: Vitamin D3 supplementation of 10 or 30 µg did not cause severe hypercalcemia. Mild hypercalcemia was more prevalent at 6 months than at 12 months, and was associated weakly with 25-OHD at 12 months.

Effect of intramuscular cholecalciferol megadose in children with nutritional rickets.

BACKGROUND: The treatment practices for vitamin D deficiency rickets are highly variable. Though a single intramuscular (IM) megadose of vitamin D is economical, and ensures good compliance, it poses the risk of hypervitaminosis D. This observational study was conducted to assess the duration of effect and safety of single IM megadose of cholecalciferol in the treatment of vitamin D deficiency rickets. METHODS: Children younger than 14 years with rickets were enrolled. Baseline investigations included radiograph of wrists and estimation of serum calcium, phosphate, alkaline phosphatase (ALP), 25(OH) vitamin D and parathormone (PTH) levels. All children received a single IM megadose of vitamin D3. Biochemical parameters were re-evaluated at 1.5, 3 and 6 months after the megadose and the values were compared to the baseline. RESULTS: We enrolled 21 children, out of which nine remained under active follow-up till 6 months. Radiological evidence of rickets was present in all 21 children, 14 had hypocalcemia at the time of presentation. After IM cholecalciferol megadose, median 25 hydroxy vitamin D [25(OH)D] level remained significantly more than the baseline till 6 months after the megadose. At 1.5 months after the vitamin D megadose, three (30%) of the children were found to develop toxic levels of vitamin D (>150 ng/mL), although none had hypercalcemia or any clinical manifestation of vitamin D toxicity. At 3 months and 6 months after the megadose, 25(OH)D levels remained in the sufficient range (20-100 ng/mL) in seven out of the eight children who came for follow-up. CONCLUSIONS: A single IM megadose of vitamin D may be effective in significantly increasing the 25(OH)D levels for at least 6 months in children with rickets, but elevation of 25(OH)D to toxic range raises concern regarding its safety.

Vitamin D Status in South Asian Populations - Risks and Opportunities.

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

Incidence and characteristics of vitamin D deficiency rickets in New Zealand children: a New Zealand Paediatric Surveillance Unit study.

OBJECTIVE: To investigate the incidence and characteristics of vitamin D deficiency rickets in New Zealand (NZ). METHODS: Prospective surveillance among paediatricians of Vitamin D Deficiency Rickets was conducted by the New Zealand Paediatric Surveillance Unit (NZPSU) for 36 months, from July 2010 to June 2013, inclusive. Inclusion criteria were: children and adolescents <15 years of age with vitamin D deficiency rickets (defined by low serum 25-hydroxyvitamin D and elevated alkaline phosphatase levels, and/or radiological rickets). RESULTS: Fifty-eight children with confirmed vitamin D deficiency rickets were identified. Median age was 1.4 (range 0.3-11) years, 47% were male, and 95% of the children were born in NZ; however, the majority of the mothers (68%) were born outside NZ. Overall annual incidence of rickets in children aged <15 years was 2.2/100,000 (95%CI 1.4-3.5); with incidence in those <3 years being 10.5/100,000 (95%CI 6.7-16.6). Skeletal abnormalities, poor growth and motor delay were the most common presenting features, with hypocalcaemic convulsion in 16% of children. Key risk factors identified were: darker skin pigment, Indian and African ethnicity, age <3 years, exclusive breast feeding, and southern latitude, particularly when combined with season (winter/spring). Of the patients reported, none had received appropriate vitamin D supplementation. CONCLUSIONS: Vitamin D deficiency rickets remains a problem for NZ children. Key risk factors remain similar to those identified in the international literature. Preventative targeted vitamin D supplementation, as per existing national guidelines, was lacking in all cases reported. IMPLICATIONS: Vitamin D deficiency rickets is the most significant manifestation of vitamin D deficiency in growing children. To reduce the incidence of this disease among those at high risk, increasing awareness and implementation of current public health policies for targeted maternal, infant and child supplementation are required.

Rickets and vitamin D deficiency in Alaska native children.

BACKGROUND: Rickets and vitamin D deficiency appeared to increase in Alaskan children starting in the 1990s. We evaluated the epidemiology of rickets and vitamin D deficiency in Alaska native (AN) children in 2001-2010. METHODS: We analyzed 2001-2010 visits with rickets or vitamin D deficiency diagnosis for AN and American Indian children and the general US population aged <10 years. We conducted a case-control study of AN rickets/vitamin D deficient cases and age- and region-matched controls. RESULTS: In AN children, annual rickets-associated hospitalization rate (2.23/100,000 children/year) was higher than the general US rate (1.23; 95% CI 1.08-1.39). Rickets incidence increased with latitude. Rickets/vitamin D deficiency cases were more likely to have malnutrition (OR 38.1; 95% CI 4.9-294), had similar breast-feeding prevalence, and were less likely to have received vitamin D supplementation (OR 0.23; 95% CI 0.1-0.87) than controls. CONCLUSIONS: Our findings highlight the importance of latitude, malnutrition, and lack of vitamin D supplementation as risk factors for rickets.

Normal bone mass and normocalcemia in adulthood despite homozygous vitamin D receptor mutations.

UNLABELLED: Adding to the debate around vitamin D's effects on skeletal health, we report the long-term follow-up of two patients with severe vitamin D receptor mutations, who had normal bone mass acquisition and normalization of calcemia around puberty, suggesting that vitamin D might not be essential for skeletal health in adulthood. INTRODUCTION: Vitamin D plays a pivotal role in calcium homeostasis, and the consequences of vitamin D insufficiency for skeletal health, as well as the importance of its supplementation, are a matter of great interest. Individuals bearing homozygous vitamin D receptor (VDR) defects present with severe hypocalcemic rickets in early infancy due to vitamin D resistance. METHODS: Here, we report the follow-up of two patients with hereditary vitamin D-resistant rickets (HVDRR), focusing on bone mass acquisition and evolution of calcemia. RESULTS: Patient 1 is a 30-year-old male bearing a homozygous p.Arg30* nonsense mutation in the VDR DNA-binding domain, who presented at 6 months. From 9 years of age, treatment requirement decreased progressively. Follow-up with DXA showed normal bone mass acquisition. In adulthood, he maintains normocalcemia without calcium supplementation and has no signs of bone fragility. Patient 2 is a 37-year-old female with milder HVDRR and alopecia due to a homozygous p.Gly319Val mutation in the VDR ligand-binding domain. Around puberty, hypercalciuria and kidney stones were detected, resulting in suspension of treatment. Follow-up with DXA revealed normal bone mass, and she maintained normocalcemia without supplementation during gestation and lactation. CONCLUSIONS: The long-term follow-up of HVDRR provides insights into the role of vitamin D in human calcium homeostasis and bone health. The normalization of calcemia and normal bone mass acquisition despite a permanently dysfunctional VDR suggest that vitamin D might not be essential for skeletal health in adulthood. Extrapolation of these findings may have implications in broader clinical settings, especially considering widespread vitamin D supplementation.

Two cases of rickets presenting with poor growth, hypotonia, and respiratory problems.

Rickets is a rare disease in developed countries. In children, it is a disease which affects growing bone. Depending on the severity, it can present with a wide variety of symptoms. Because it is such a rare disease in developed countries, symptoms suggesting rickets are often not easily recognized. This can cause a delay in diagnosing and treating rickets. Often unnecessary and sometimes invasive investigations are performed. First leading clues to rickets on physical examination are poor growth, especially length, thickening of wrists, bow legs, and craniotabes. At further examination, special attention should be paid to osteopenia and cupping and fraying at the metaphyses on X-rays. Laboratory results suggestive for rickets are elevated alkaline phosphatase and disturbances in calcium and phosphate homeostasis. In this report, we present two cases presenting with poor growth, severe pain, and respiratory problems secondary to calcipenic rickets.

Vitamin D and skeletal health in infancy and childhood.

During growth, severe vitamin D deficiency in childhood can result in symptomatic hypocalcaemia and rickets. Despite the suggestion from some studies of a secular increase in the incidence of rickets, this observation may be driven more by changes in population demographics than a true alteration to age, sex and ethnicity-specific incidence rates; indeed, rickets remains uncommon overall and is rarely seen in fair-skinned children. Additionally, the impact of less severe vitamin D deficiency and insufficiency has received much interest in recent years, and in this review, we consider the evidence relating vitamin D status to fracture risk and bone mineral density (BMD) in childhood and adolescence. We conclude that there is insufficient evidence to support the suggestion that low serum 25-hydroxyvitamin D [25(OH)D] increases childhood fracture risk. Overall, the relationship between 25(OH)D and BMD is inconsistent across studies and across skeletal sites within the same study; however, there is evidence to suggest that vitamin D supplementation in children with the lowest levels of 25(OH)D might improve BMD. High-quality randomised trials are now required to confirm this benefit.

300,000 IU or 600,000 IU of oral vitamin D3 for treatment of nutritional rickets: a randomized controlled trial.

OBJECTIVE: To evaluate the non-inferiority of a lower therapeutic dose (300,000 IU) in comparison to standard dose (600,000) IU of Vitamin D for increasing serum 25(OH) D levels and achieving radiological recovery in nutritional rickets. DESIGN: Randomized, open-labeled, controlled trial. SETTING: Tertiary care hospital. PARTICIPANTS: 76 children (median age 12 mo) with clinical and radiologically confirmed rickets. INTERVENTION: Oral vitamin D3 as 300,000 IU (Group 1; n=38) or 600,000 IU (Group 2; n=38) in a single day. OUTCOME VARIABLES: Primary: Serum 25(OH)D, 12 weeks after administration of vitamin D3; Secondary: Radiological healing and serum parathormone at 12 weeks; and clinical and biochemical adverse effects. RESULTS: Serum 25(OH)D levels [geometric mean (95% CI)] increased significantly from baseline to 12 weeks after therapy in both the groups [Group 1: 7.58 (5.50­10.44) to 16.06 (12.71­ 20.29) ng/mL, P<0.001]; Group 2: 6.57 (4.66­9.25) to 17.60 (13.71­22.60, P<0.001]. The adjusted ratio of geometric mean serum 25(OH)D levels at 12 weeks between the groups (taking baseline value as co-variate) was 0.91 (95% CI: 0.65­1.29). Radiological healing occurred in all children by 12 weeks. Both groups demonstrated significant (P<0.05) and comparable fall in the serum parathormone and alkaline phosphatase levels at 12 weeks. Relative change [ratio of geometric mean (95% CI)] in serum PTH and alkaline phosphatase, 12 weeks after therapy, were 0.98 (0.7­1.47) and 0.92 (0.72­1.19), respectively. The serum 25(OH)D levels were deficient (<20 ng/mL) in 63% (38/60) children after 12 weeks of intervention [Group 1: 20/32 (62.5%); Group 2: 18/28 (64.3%)]. No major clinical adverse effects were noticed in any of the children. Hypercalcemia was documented in 2 children at 4 weeks (1 in each Group) and 3 children at 12 weeks (1 in Group 1 and 2 in Group 2). None of the participants had hypercalciuria or hypervitaminosis D. CONCLUSION: A dose of 300,000 IU of vitamin D3 is comparable to 600,000 IU, administered orally, over a single day, for treating rickets in under-five children although there is an unacceptably high risk of hypercalcemia in both groups. None of the regime is effective in normalization of vitamin D status in majority of patients, 3 months after administering the therapeutic dose.

A Randomized controlled trial on safety and efficacy of single intramuscular versus staggered oral dose of 600 000IU Vitamin D in treatment of nutritional rickets.

OBJECTIVE: Comparison of efficacy and safety of two different regimens of vitamin D-600 000 IU as a single intramuscular dose, and 60 000IU orally once a week for 10 weeks-in treatment of nutritional rickets. METHODS: Children with nutritional rickets (age: 0.5-5 years, n = 61) were randomized to receive either 60 000IU vitamin D orally once a week for 10 weeks or 600 000IU single intramuscular injection. Serum calcium, phosphate, alkaline phosphatase, urinary calcium/creatinine ratio, serum 25 hydroxy vitamin D and radiological score were compared at 12-week follow-up. RESULTS: No difference was found in efficacy of the two regimens on comparing biochemical and radiological parameters. Serum 25 hydroxy vitamin D >100 ng/ml was found in two children in the oral group and one child in the intramuscular group. No child developed hypercalcemia or hypercalciuria after starting treatment. CONCLUSION: Staggered oral and one-time intramuscular administrations of 600 000IU vitamin D are equally effective and safe in treatment of nutritional rickets.

Does vitamin D sufficiency equate to a single serum 25-hydroxyvitamin D level or are different levels required for non-skeletal diseases?

OBJECTIVE: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vitamin D status and the role of Vitamin D supplementation in the management of non-skeletal diseases. We outline reasons for anticipating different serum vitamin D levels are required for different diseases. METHOD: Review the literature for evidence of efficacy of supplementation and minimum effective 25-hydroxyvitamin D (25-OHD) levels in non-skeletal disease. RESULTS: Evidence of efficacy of vitamin supplementation is graded according to levels of evidence. Minimum effective serum 25-OHD levels are lower for skeletal disease, e.g., rickets (25 nmol/L), osteoporosis and fractures (50 nmol/L), than for premature mortality (75 nmol/L) or non-skeletal diseases, e.g., depression (75 nmol/L), diabetes and cardiovascular disease (80 nmol/L), falls and respiratory infections (95 nmol/L) and cancer (100 nmol/L). CONCLUSIONS: Evidence for the efficacy of vitamin D supplementation at serum 25-OHD levels ranging from 25 to 100 nmol/L has been obtained from trials with vitamin D interventions that change vitamin D status by increasing serum 25-OHD to a level consistent with sufficiency for that disease. This evidence supports the hypothesis that just as vitamin D metabolism is tissue dependent, so the serum levels of 25-OHD signifying deficiency or sufficiency are disease dependent.