Vitamin D deficiency rickets in breast-fed infants presenting with hypocalcaemic seizures

Relationship between vitamin D deficiency and neonatal hypocalcemia: a meta-analysis

We aimed to explore the associations of neonatal hypocalcemia with neonatal vitamin D deficiency and maternal vitamin D deficiency. A comprehensive systematic literature search using PubMed and web of science was performed for relevant articles from inception to February 17th, 2023. We used odds ratio (OR) and 95 % confidence interval (CI) as effect sizes for our meta-analysis. Publication bias was evaluated using funnel plot, Begg's test, and Egger regression test. All the statistical analyses were performed using Stata 14.0. A total of 11 studies were included and analyzed, including 452 newborns with hypocalcemia and 2,599 newborns with normal serum calcium level. Our research results revealed that vitamin D deficiency in newborns may be related to the higher prevalence of hypocalcemia (OR: 2.87, 95 % CI: 1.17-7.04). In addition, maternal vitamin D deficiency might also be a risk factor for neonatal hypocalcemia (OR: 7.83, 95 % CI: 3.62-16.92). There was a significant correlation between vitamin D deficiency and neonatal hypocalcemia.This meta-analysis indicates that newborns with vitamin D deficiency have a higher risk of hypocalcemia, and maternal vitamin D level play a crucial role in this association. Vitamin D supplementation may have a positive effect in reducing the prevalence of neonatal hypocalcemia.

Vitamin D Deficiency Prevalence in Late Neonatal Hypocalcemia: A Multicenter Study

OBJECTIVE

Late neonatal hypocalcemia (LNH) is a common metabolic problem associated with hypoparathyroidism, high phosphate intake and vitamin D deficiency, often presenting with seizures. In this cross-sectional study, we aimed to evaluate the role of vitamin D deficiency in LNH in Turkey and to describe the characteristics of affected newborns.

METHODS

Conducted with a cross-sectional design and with the participation of 61 neonatal centers from December 2015 to December 2016, the study included term neonates with LNH (n=96) and their mothers (n=93). Data were registered on the FAVOR Web Registry System. Serum samples of newborns and mothers were analyzed for calcium, phosphate, magnesium, albumin, alkaline phosphatase, intact parathyroid hormone (iPTH) and 25 hydroxyvitamin D [25(OH)D] levels.

RESULTS

The median (range) onset time of hypocalcemia was 5.0 (4.0-8.0) days of age, with a male preponderance (60.4%). The median (range) serum 25(OH)D levels of the neonates and their mothers were 6.3 (4.1-9.05) and 5.2 (4.7-8.8) ng/mL, respectively. The prevalence of vitamin D deficiency (<12 ng/mL) was high in both the neonates (86.5%) and mothers (93%). Serum 25(OH)D levels of the infants and mothers showed a strong correlation (p<0.001). While the majority (93.7%) of the neonates had normal/high phosphorus levels, iPTH levels were low or inappropriately normal in 54.2% of the patients.

CONCLUSION

Vitamin D deficiency prevalence was found to be high in LNH. Efforts to provide vitamin D supplementation during pregnancy should be encouraged. Evaluation of vitamin D status should be included in the workup of LNH.

Vitamin D, rickets and child abuse: controversies and evidence

Suboptimal vitamin D status is a global health issue that affects children and adults worldwide. The prevalence of vitamin D deficiency and insufficiency has been well documented in the pediatric population in the United States. Although vitamin D deficiency is common, radiographic findings are uncommon and can be subtle. Additionally, because of the high prevalence of pediatric vitamin D insufficiency, it is commonly identified in young children with fractures. However, the majority of pediatric fractures are caused by trauma to healthy bones. Some, especially in infants and toddlers, are caused by non-accidental trauma. A small percentage is related to medical disease, including those associated with disorders of collagen, disorders of mineralization, and non-fracture mimics. Despite the scientific evidence, among disorders of mineralization, non-rachitic disorders of vitamin D have become a popular non-scientific theory to explain the fractures identified in abused children. Although infants and young children with rickets can fracture bones, the vast majority of fractures identified in abused infants are not caused by bone disease. Here we present a review of the literature on bone disease in the setting of accidental and non-accidental trauma. This context can help physicians remain vigilant about identifying vulnerable young children whose injuries are caused by non-accidental trauma.

The importance of vitamin D in maternal and child health: a global perspective

Vitamin D and calcium are important nutrients for skeletal growth and bone health. Children and pregnant women are particularly vulnerable to 25-hydroxy vitamin D deficiency (VDD). VDD, with or without dietary calcium deficiency, can lead to nutritional rickets (NR), osteomalacia, and disturbances in calcium homeostasis. Multiple studies have linked VDD to adverse health outcomes in both children and pregnant women that extend beyond bone health. VDD remains an important global public health concern, and an important differentiation must be made between the impact of VDD on children and adults. Reports of increased incidence of NR continue to emerge. NR is an entirely preventable condition, which could be eradicated in infants and children worldwide with adequate vitamin D and calcium supplementation. The desire and necessity to put in place systems for preventing this potentially devastating pediatric disease should not elicit dispute. VDD and NR are global public health issues that require a collaborative, multi-level approach for the implementation of feasible preventative strategies. This review highlights the history, risk factors, and controversies related to VDD during pregnancy and childhood with a particular focus on global NR prevention.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

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

EVIDENCE

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

PROCESS

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

RESULTS

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

CONCLUSION

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

Calcium to phosphorus ratio, essential elements and vitamin D content of infant foods in the UK: Possible implications for bone health

Adequate intake of calcium and phosphorus in the appropriate ratio of 1-2:1 (Ca:P), in addition to magnesium and vitamin D, is vital for bone health and development of infants. In this feasibility study, the ratio of Ca:P in conjunction with vitamin D and other essential elements (Cu, Fe, K, Mg, Na, and Zn) in a range of commercial infant food products in the UK was investigated. The elemental analysis was carried out using inductively coupled plasma optical emission spectrometry, and vitamin D levels were determined using an enzyme-linked immunosorbent assay. The quantitative data were further evaluated, based on a standardised menu, to measure the total daily intake of an infant aged 7-12 months against the Reference Nutrient Intake. The results from the study show that the Ca:P ratio of the infant's total dietary intake was within the recommended range at 1.49:1. However, the level of intake for each of the nutrients analyzed, with the exception of sodium, was found to be above the Reference Nutrient Intake, which warrants further investigation in relation to both micronutrient interactions and in situations where the intake of fortified infant formula milk is compromised. Finally, as the study is the first to include consumption of infant snack products, the level of total calorie intake was also calculated in order to assess the total daily estimated energy intake; the results indicate that energy intakes exceed recommendations by 42%, which may have implications for obesity.

Is breast best? Is early solid feeding harmful?

The health benefits of breastfeeding for babies and mothers have long been recognised and it is now globally recommended that it be continued exclusively for six months. Although there are few controlled trials to support this recommendation, the most important advantage is less morbidity from gastrointestinal infection in developing countries. There is also evidence that respiratory tract infections and atopic dermatitis is reduced, and the maternal risk of breast cancer decreases, particularly with a longer duration of breastfeeding and a high parity. There is little to suggest that exclusive breastfeeding for six months adversely affects infant growth, nutritional status or infant feeding skills, but more studies are needed. Equally, there is no evidence that introduction of solids from 17 weeks is harmful in developed countries. However, in the UK breastfeeding prevalence is low and solids are introduced early for the majority of infants and much can be done to positively encourage and support all mothers to continue breastfeeding for a longer period.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

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

EVIDENCE

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

PROCESS

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

RESULTS

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

CONCLUSION

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

Complications of vitamin D deficiency from the foetus to the infant: One cause, one prevention, but who's responsibility?

Calcium and phosphorus represent building material for bones. The supplier of these bone minerals is the hormone calcitriol, which originates from vitamin D, itself made by sunshine in human skin. Requirement for bone minerals is highest during phases of rapid growth, and no one grows faster than the foetus and the infant, making them particularly vulnerable. Deprivation of calcium, whether through low calcium intake or low vitamin D, leads to serious health consequences throughout life, such as hypocalcaemic seizures, dilated cardiomyopathy, skeletal myopathy, congenital and infantile rickets, and osteomalacia. These 5 conditions are often summarised as 'symptomatic vitamin D deficiency', are fully reversible but also fully preventable. However, the increasing prevalence of rickets and osteomalacia, and the deaths from hypocalcaemic cardiomyopathy, demand action from global health care providers. Clarification of medical and parental responsibilities is a prerequisite to deliver successful prevention programmes. The foetus and infant have the human right to be protected against harm, and vitamin D supplementation has the same public health priority as vaccinations.

Congenital rickets due to vitamin D deficiency in the mothers

BACKGROUND & AIMS

We wished to review all published reports of congenital rickets to identify the causes and characteristics.

METHODS

25 cases were identified in 19 published reports in which there was radiological and/or histological evidence of rickets in the first two weeks after birth. Cases of rickets associated with maternal renal failure were excluded as were infants born at less than 32 weeks gestation.

RESULTS

There was evidence of maternal deficiency in 24 of these cases. In 16 cases the diagnosis of the rickets led to the identification of symptomatic osteomalacia in the mothers. Of the 12 mothers who had assays for serum 25-hydroxyvitamin D (25OHD) 11 had values less than 10 ng/mL. Presentations in the infants included craniotabes, wide skull sutures, rachitic rosaries, enlargement of the wrists, tetany and convulsions. In two cases rickets had been suspected from antenatal X-rays. In five cases fractures were found at the time of initial presentation. Of the 16 infants with serum calcium assays 15 had values lower than 8.8 mg/dL. Of 13 infants who had serum alkaline phosphatase assays 12 had abnormally high levels. Of the seven infants in whom serum 25OHD was measured before treatment, all had values less than 10 ng/mL.

CONCLUSIONS

These reports provide strong support for the view that maternal deficiency leads to overt bone disease from before birth. Maternal deficiency probably also leads to impairment of bone quality in postnatal life. The importance of ensuring adequate vitamin D nutrition in pregnancy is emphasised.

Maternal vitamin D status in pregnancy and offspring bone development: the unmet needs of vitamin D era

Data from animal and human studies implicate maternal vitamin D deficiency during pregnancy as a significant risk factor for several adverse outcomes affecting maternal, fetal, and child health. The possible associations of maternal vitamin D status and offspring bone development comprise a significant public health issue. Evidence from randomized trials regarding maternal vitamin D supplementation for optimization of offspring bone mass is lacking. In the same field, data from observational studies suggest that vitamin D supplementation is not indicated. Conversely, supplementation studies provided evidence that vitamin D has beneficial effects on neonatal calcium homeostasis. Nevertheless, a series of issues, such as technical difficulties of current vitamin D assays and functional interplay among vitamin D analytes, prohibit arrival at safe conclusions. Future studies would benefit from adoption of a gold standard assay, which would unravel the functions of vitamin D analytes. This narrative review summarizes and discusses data from both observational and supplementation studies regarding maternal vitamin D status during pregnancy and offspring bone development.

Clinical, biochemical, and radiological manifestations of vitamin D deficiency in newborns presented with hypocalcemia

INTRODUCTION

The Clinical and radiological manifestations of newborns with severe VDD have not been studied well.

MATERIALS AND METHODS

We studied the clinical, biochemical, and radiological manifestations of 10 full-term (FT) newborns (6: M, 4: F) infant presented to with symptomatic hypocalcemia (seizure) secondary to vitamin D deficiency (VDD) during the first 10 days of life are described. All were exclusively breastfed since birth. All their mothers have low 25 hydroxy vitamin D (25OHD) level <10 ng/mL and were not taking vitamin supplements during pregnancy.

RESULTS

FT newborns with hypocalcemia secondary to VDD presented with generalized convulsions (10/10) and craniotabes (8/10), but none had rachitic chest rosaries or joint broadening. Cranial ultrasonographic evaluation was normal. Serum 25OHD concentrations were low in these newborns (13.2 ± 3.8 ng/mL) and their mothers (8.1 ± 1.5 ng/mL). A total of 60% of them had increased parathormone (PTH) concentrations (>60 ng/mL) and 60% had decreased magnesium (Mg) concentrations (<0.7 mmol/L). Their alkaline phosphatase (ALP) concentrations were significantly higher than normal newborns. All other laboratory results (liver function tests, urea and electrolytes, C reactive protein, lumbar puncture, blood culture, and lactate) were normal. In all patients, seizures ceased within 2 days of starting treatment with alphacalcidol and calcium. Radiological manifestations included metaphyseal band of relative lucency (osteopenia), just under the line of provisional calcification, within distal radius (7/10), femur (4/10), and tibia (3/10), mild cupping and haziness of distal radius (2/10).

DISCUSSION

Newborns with VDD had significantly lower serum calcium, ALP and PTH and higher phosphate concentrations, compared to older infants with VDD rickets. In newborns with VDD, serum calcium levels were correlated significantly with 25OHD (r = 0.597, P < 0.001), Mg concentrations (r = 0.436, P < 0.001) and negatively with ALP concentrations (r = -0.451, P < 0.001). Serum PTH concentrations were correlated significantly with serum Mg (r = 0.78, P < 0.0001) but not with serum calcium (r = -0.103, P = 0.3) or 25OHD (r = -0.03, P = 0.7) concentrations.

CONCLUSION

The clinical, biochemical, and radiological manifestations of VDD in newborns indicate that they are less adapted to VDD compared to older infants. VD supplementation for mothers and newborns should be considered to avoid short-term complications of VDD in the neonatal period and on the growing infants especially in countries with high prevalence of VDD.

Awareness of vitamin D deficiency among at-risk patients

BACKGROUND

Vitamin D deficiency is a significant problem for a growing proportion of the UK population. Individuals with dark or covered skin are at particularly high risk due to ethno-cultural, environmental and genetic factors. We assessed the level of awareness of vitamin D deficiency among at-risk patients in order to identify groups most in need of education.

FINDINGS

A cross-sectional survey using a piloted questionnaire was conducted among consecutive at-risk patients without a diagnosis of Vitamin D deficiency arriving at a large inner city general practice in the North West of England over a five day period. The survey was completed by 221 patients. The mean age was 35 years. 28% of them (n = 61) had never heard about vitamin D. Older patients (p = 0.003) were less likely to have heard about vitamin D. 54% of participants were unaware of the commonest symptoms of vitamin D deficiency. 34% did not expose their skin other than their face in the last one year, and 11% did not include vitamin D rich foods in their diet.

CONCLUSION

The majority of at-risk patients are aware of vitamin D; nevertheless, there is a significant lack of knowledge among older people, who have higher morbidity. A programme of targeted education of the at-risk population is recommended.

Vitamin requirements for term infants: considerations for infant formulae

OBJECTIVE

To provide the informed health professional with an up to date evaluation of the current thinking regarding requirements for vitamins in infant feeds. ESTABLISHING CRITERIA FOR ADEQUACY: Vitamin adequacy in the neonate is currently defined in terms of circulating levels of a vitamin or of the activity of a vitamin dependent enzyme in the erythrocytes. Although these measurements have their value there is a need to develop biochemical, physiological or clinical markers of well defined specific function. For some vitamins there is a risk of deleterious effects of very high intakes: risk of toxicity needs to be taken into consideration when making recommendations for inclusion in infant formulae. BREAST MILK AS THE 'GOLD STANDARD': Breast milk concentrations of vitamins have been used as the criteria of adequate intake by neonates. This may not always be justified. Greater consideration needs to be given to differences in bioavailability of vitamins from breast milk compared with formula feeds, of the influence of season, and of stage of lactation, on the stated composition.

EXPERIMENTAL APPROACHES

Animal studies have provided limited information regarding effects of different levels of intakes on current status indices in the neonatal period. There are few reports of randomized controlled studies into the effects of different levels of vitamins and these rely heavily on biochemical criteria of adequacy.

RECENT DEVELOPMENTS

The inclusion of beta-carotene into formula feeds for premature babies is an issue of current interest. What is the justification for this? Are there potential benefits for the term infant? Riboflavin deficiency in the period around weaning may affect the normal structural and functional development of the gastrointestinal tract; some of these effects may be permanent. RESEARCH TO BE DONE: A greater understanding of the absorption and metabolism of vitamins during infancy is required in order to help establish dietary requirements. The relative bioavailability of vitamins in human milk and formulae needs to be investigated. Criteria for vitamin adequacy should be extended to include measures of function. Information regarding the conversion factor from tryptophan to niacin in infancy would allow us to set niacin requirements with greater confidence. There is a particular lack of information about concentrations of biotin and pantothenic acid in breast milk and the relative biochemical status of infants receiving breast milk and formulae. Benefits of including beta-carotene into infant formulae need to be evaluated. The role of individual micronutrients in the structural and functional development of the gastrointestinal tract should be explored.

Vitamin D deficiency rickets and allegations of non-accidental injury

Vitamin D deficiency rickets has long been recognized as a cause of fractures and fracture-like appearances in young children. Often seen in the early 20th century, rickets has recently been regarded as uncommon; the radiological appearances, familiar to previous generations, may not be recognized for what they are. This article reports four children with unexplained fractures initially attributed confidently to non-accidental injury. In each case, the later evidence of vitamin D deficiency led to a reconsideration of that diagnosis.

CONCLUSION

It is important to be aware of this bone disorder in the differential diagnosis of fractures, to investigate appropriately and to recognize that the radiological appearances may be misleading. A mistaken diagnosis of abuse does real harm, not least to the child itself.

Vitamin D nutritional status of exclusively breast fed infants and their mothers

BACKGROUND

Vitamin D nutrition has a profound effect on the development of an infant. Vitamin D status of mothers and their infants are closely correlated. While hypovitaminosis D has emerged as a significant public health problem across all age groups, there is limited information of this condition in lactating mothers and their breast fed infants.

AIM

To evaluate the vitamin D status of lactating mothers and their breast fed infants.

SUBJECTS AND METHODS

180 healthy lactating mothers and exclusively breast fed infants, 2-24 weeks old, were recruited for the study. The mother-infant pairs underwent concurrent clinical, biochemical and hormonal evaluation for calcium-vitamin D-PTH axis.

RESULTS

The mean serum 25(OH)D values in lactating mothers was 27.2 +/- 14.6 nmol/l (10.9 +/- 5.8 ng/ml), while that of their infants was 28.9 +/- 20.8 nmol/l (11.6 +/- 8.3 ng/ml). Serum 25(OH)D levels <25 nmol/l (10 ng/ml) were found in 47.8% of the mothers and 43.2% of the infants. Among these, elevated PTH levels (>54 pg/ml) were seen in 59.3% of the mothers and 69.6% of the infants. A highly significant negative correlation was found between serum 25(OH)D and PTH in mothers (r = -0.480, p = 0.01) and their infants (r = -0.431, p = 0.01). A strong positive correlation was seen of 25(OH)D levels in mother-infant pairs (r = 0.324, p = 0.001).

CONCLUSIONS

A high prevalence of vitamin D deficiency was found in lactating mothers and their exclusively breast fed infants. Infants born to mothers with hypovitaminosis D had 3.8 times higher risk of developing hypovitaminosis D as compared to those born to mothers with normal vitamin D levels.

Vitamin D: a growing perspective

Vitamin D deficiency has been widely reported in all age groups in recent years. Rickets has never been eradicated in developed countries, and it most commonly affects children from recent immigrant groups. There is much evidence that current vitamin D guidelines for the neonatal period, 5-10 microg (200-400 IU)/day, prevent rickets at the typical calcium intakes in developed countries. The annual incidence of vitamin D-deficiency rickets in developed countries ranges between 2.9 and 7.5 cases per 100,000 children. The prevalence of vitamin D deficiency in mothers and their neonates is remarkable, and the results of one study suggest that third-trimester 25-hydroxyvitamin D (25(OH)D) is associated with fetal bone mineral accrual that may affect prepubertal bone mass accumulation. Beyond infancy, the evidence indicates that 5 microg (200 IU)/day of vitamin D has little effect on vitamin D status as measured by the serum 25(OH)D concentration. Two randomized clinical trials show that higher vitamin D intake improves one-year gain in bone density in adolescent girls. The functions of vitamin D extend beyond bone to include immune system regulation and anti-proliferative effects on cells. Early life vitamin D inadequacy is implicated in the risk of bone disease, autoimmune disease, and certain cancers later in life; however, long-term interventional studies do not exist to validate the widespread implementation of greater vitamin D consumption. Here we review the available data concerning vitamin D status and health effects of vitamin D in pregnancy through to and including adolescence.

High prevalence of asymptomatic vitamin D and iron deficiency in East African immigrant children and adolescents living in a temperate climate

OBJECTIVES

Vitamin D deficiency (VDD) is common in immigrant children with increased skin pigmentation living in higher latitudes. We assessed the pattern of and risk factors for VDD in immigrant East African children living in Melbourne (latitude 37 degrees 49' South).

STUDY DESIGN

A prospective survey of 232 East African children attending a clinic in Melbourne. Data were collected by questionnaire, medical assessment and laboratory tests.

RESULTS

Low 25-hydroxyvitamin D (25-OHD) levels (<50 nmol/l) occurred in 87% of children, and VDD (25-OHD <25 nmol/l) in 44%. Risk factors included age <5 years, female gender, increased time in Australia, decreased daylight exposure and winter/spring season. Anaemia (20%), vitamin A deficiency (20%) and iron deficiency (19%) were also identified.

CONCLUSIONS

Asymptomatic VDD is common in East African immigrant children residing at a temperate latitude. Risk factors for VDD limit endogenous vitamin D production. Screening of immigrant children with increased skin pigmentation for VDD, anaemia, iron and vitamin A deficiency is appropriate. VDD in adolescent females identifies an increased risk of future infants with VDD.

Nutritional rickets around the world: causes and future directions

INTRODUCTION

Nutritional rickets has been described from at least 59 countries in the last 20 years. Its spectrum of causes differs in different regions of the world.

METHODS

We conducted a systematic review of articles on nutritional rickets from various geographical regions published in the last 20 years. We extracted information about the prevalence and causes of rickets.

RESULTS

Calcium deficiency is the major cause of rickets in Africa and some parts of tropical Asia, but is being recognised increasingly in other parts of the world. A resurgence of vitamin D deficiency has been observed in North America and Europe. Vitamin D-deficiency rickets usually presents in the 1st 18 months of life, whereas calcium deficiency typically presents after weaning and often after the 2nd year. Few studies of rickets in developing countries report values of 25(OH)D to permit distinguishing vitamin D from calcium deficiency.

CONCLUSIONS

Rickets exists along a spectrum ranging from isolated vitamin D deficiency to isolated calcium deficiency. Along the spectrum, it is likely that relative deficiencies of calcium and vitamin D interact with genetic and/or environmental factors to stimulate the development of rickets. Vitamin D supplementation alone might not prevent or treat rickets in populations with limited calcium intake.

Limited availability of nutritional vitamin D causing inappropriate treatment of vitamin D deficiency rickets with a response resembling pseudohypoparathyroidism type II in a Japanese patient

Vitamin D deficiency rickets occasionally resembles pseudohypoparathyroidism type II (PHP type II) with respect to the response to exogenous PTH in the presence of hypocalcemia. We encountered a Japanese patient with stage 2 vitamin D deficiency rickets, who had increased urinary cAMP excretion and no response of urinary phosphate or N-acetyl-beta-D-glucosaminidase excretion to exogenous PTH under normocalcemic and normophosphatemic conditions, after treatment with 1,25(OH)2 vitamin D3. This case shows that it is possible for a response mimicking that of PHP type II to occur when the serum calcidiol level is low due to causes other than hypocalcemia and secondary hyperparathyroidism. When the serum calcidiol level is low, the appropriate treatment should be cholecalciferol or ergocalciferol. However, because neither is commercially available as a useful formulation in Japan, physicians are forced to inappropriately use calcitriol or analogs.

Vitamin D deficiency rickets caused by improper lifestyle in Japanese children

BACKGROUND

Nutritional rickets is considered rare in developed countries. However, reports on vitamin D deficiency rickets caused by improper lifestyle have recently increased. The clinical and laboratory characteristics of patients with vitamin D deficiency rickets treated at Fukuoka Children's Hospital, Fukuoka, Japan, were evaluated to clarify current causes and ways to prevent this disease.

METHODS

Clinical records were reviewed, and obtained information and data were summarized.

RESULTS

Eight patients with vitamin D deficiency rickets (five boys and three girls) were treated during the past 10 years (January 1992 to December 2001). Two infants were referred to the hospital for hypocalcemia and convulsion, and six toddlers (1-2 years old) for bowlegs. One patient lacked exposure to sunlight, and six had an unbalanced diet. The cause of rickets could not be established in one patient. Anthropometric and laboratory data did not indicate malnutrition. Serum alkaline phosphatase was 2518.3 +/- 1401.7 IU/l, calcium was 8.2 +/- 2.6 mg/dL (including 4.7 mg/dL in one infant and 4.8 mg/dL in another), and phosphorus was 4.9 +/- 1.0 mg/dL. High sensitive parathyroid hormone was 1393.1 +/- 321.7 pg/mL (reference range, 180-560), 1,25-dihydroxyvitamin D was 86.0 +/- 61.5 pg/mL (reference range, 20-70), and 25-hydroxyvitamin D was 11.6 +/- 5.6 ng/mL (reference range, 10-30). The patients recovered with a change to a balanced diet, the promotion of weaning, and/or an increase in sunlight exposure.

CONCLUSION

Vitamin D deficiency rickets remains a common condition that is best managed by education and disease prevention.

Vitamin D deficiency in early infancy

We analyzed the characteristics of young infants diagnosed with vitamin D deficiency in early infancy at 2 medical centers in Turkey. In this retrospective, cross-sectional study, the clinical, biochemical, and radiographic findings of infants who were diagnosed with vitamin D deficiency at <3 mo of age between May 2001 and May 2003 were reviewed. A total of 42 infants (27 boys and 15 girls) were diagnosed with vitamin D deficiency in the first 3 mo of life during this 2-y period. The age of infants at diagnosis was 60 +/- 19 d (range 32-112 d). The majority (78.7%) presented with seizures. No skeletal deformities were detected clinically, and radiological findings were subtle. All infants had low serum calcium levels but serum phosphorous levels varied. Eight infants (19.0%) had low, 19 (45.3%) had normal, and 15 (35.7%) had elevated serum phosphorous levels. Serum 25-hydroxyvitamin D levels in those measured (29 infants and 15 mothers) were <37.5 nmol/L. Most infants (83%) were exclusively breast-fed without supplemental vitamin D, and none of the mothers were supplemented with vitamin D during pregnancy. All mothers had limited sunlight exposure and 33 of 42 mothers (78.6%) wore concealing clothing. The majority of young infants diagnosed with vitamin D deficiency present with seizures, have low dietary vitamin D intake, and mothers with poor vitamin D reserves. Evaluation of vitamin D status should be included into the workup of hypocalcemia in early infancy. Prevention of deficiency by supplementing pregnant women and infants who are exclusively breast-fed is essential.

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.

The investigation of hypocalcaemia and rickets

Our understanding of disorders that present with hypocalcaemia has advanced rapidly in the past decade. The molecular basis of many of these disorders and conditions associated with phosphate wasting has now been established. While many children will need specialist involvement, they often will present to general paediatricians, and appropriate investigations prior to intervention will enable early diagnosis. Not all children with hypocalcaemia and low or low normal parathyroid hormone levels have isolated hypoparathyroidism, and clinicians need to be aware of the potential for misdiagnosis. Outpatient departments and paediatric wards should have a readily accessible and comprehensive list of bloods that need to be taken when a child presents with hypocalcaemia or rickets.

Hypovitaminosis D and vitamin D deficiency in exclusively breast-feeding infants and their mothers in summer: a justification for vitamin D supplementation of breast-feeding infants

OBJECTIVE

To determine the prevalence of hypovitaminosis D in exclusively breast-feeding infants and their mothers in a community where maternal sunshine exposure is low.

STUDY DESIGN

Serum levels of calcium, phosphate, alkaline phosphatase, 25-hydroxy vitamin D (25-OHD), and intact parathyroid hormone were measured in 90 unsupplemented healthy term breast-feeding Arab/South Asian infants and their mothers in summer. Maternal dietary vitamin D intake was also estimated.

RESULTS

The median age of infants was 6 weeks. The median serum 25-OHD concentrations in mothers (8.6 ng/mL) and infants (4.6 ng/mL) were low, and 61% of the mothers and 82% of the 78 infants tested had hypovitaminosis D (serum 25-OHD <10 ng/mL). The infants with hypovitaminosis D had elevated serum alkaline phosphatase and a tendency to higher serum intact parathyroid hormone levels. The average daily maternal vitamin D intake from commercial milk was 88 IU.

CONCLUSIONS

Hypovitaminosis D is common in summer in exclusively breast-feeding infants and their mothers. The results provide justification for vitamin D supplementation of breast-feeding infants and mothers in the United Arab Emirates. Low vitamin D intake probably contributed to low maternal vitamin D status.

Risk factors for vitamin D deficiency in breast-fed newborns and their mothers

OBJECTIVES

Vitamin D plays a critically important role in the development, growth, and mineralization of the skeleton during its formative years, and performs an equally essential role in maintaining a healthy mineralized skeleton for adults of all ages. We evaluated the vitamin D status and risk factors for vitamin D deficiency in healthy breast-fed newborns and their nursing mothers.

METHODS

Serum 25-hydroxyvitamin D (25OHD), calcium, phosphorus, and alkaline phosphatase levels were measured in 54 newborns and their nursing mothers whose ages ranged from 18 to 38 y. The relation between serum 25OHD level and demographic factors was analyzed. Bone mineral density was measured in the mothers with a serum 25OHD level below 25 nmol/L to determine the extent of bone mineralization.

RESULTS

The mean serum 25OHD level in the 54 mothers was 29.11 +/- 10.47 nmol/L. Forty-six percent of the mothers had serum 25OHD levels below 25 nmol/L. The risk factors for low maternal serum 25OHD level were found in decreasing order of importance as follows: low socioeconomic class (odds ratio [OR] = 8.1, P = 0.000), being covered (OR = 4.3, P = 0.023), and low educational level (OR = 3.5, P = 0.033). The mean serum 25OHD level in the newborns was 18.62 +/- 8.00 nmol/L. Eighty percent of the newborns had serum 25OHD levels below 25 nmol/L. There was a significant correlation between the serum 25OHD levels of the newborns and their mothers (r = 0.63, P = 0.01). The most important risk factor for low serum 25OHD level in the newborn was a maternal 25OHD level below 25 nmol/L (OR = 15.2, P = 0.002), followed a covered mother (OR = 6.8, P = 0.011). Bone mineral densitometry showed osteopenia in 40% of the women with serum 25OHD levels below 25 nmol/L. All women were from a lower socioeconomic class and 80% were covered.

CONCLUSIONS

Vitamin D deficiency is still a common and serious health problem of women of reproductive age and their babies in developing countries at the outset of a new millennium.

Dietary calcium and mineral/vitamin supplementation: a controversial problem

There is a consensus that adequate calcium intake during bone development, and possibly in adulthood and senescence, helps to prevent bone resorption and osteoporosis. The uptake of dietary calcium should be sufficient to maintain both normal serum calcium concentrations and parathyroid hormone levels in the low normal range throughout the day, otherwise, increased bone resorption occurs. Calcium intake varies with race and with environmental and dietary conditions. Estimating the appropriate amount of calcium to be added to dietary sources for an optimal supplementation regimen is therefore difficult. Few intervention studies have evaluated the dose-effect relationship for calcium supplementation conclusively. The mechanisms regulating fractional calcium absorption as a function of intake suggest that very high daily doses are probably useless. They may be unsafe in the long term because of the risks of hypercalciuria and kidney stones, and of an imbalance in the ratio of calcium to magnesium. Concomitant supplementation with limited amounts of magnesium may reduce this risk and improve mineralization. Dietary intake is 500-600 mg/day in most studies, making 400 mg/day an appropriate supplementary dose for most premenopausal women (RDA 1000 mg/day). After the menopause and during lactation (RDA 1200-1500 mg/day), 800 mg/day is probably appropriate, particularly if low doses of vitamin D are taken concomitantly.

[Pathological phosphorus and calcium metabolism during pregnancy and breast feeding]

The occurrence of calcium and vitamin D deficiencies is enhanced during pregnancy and lactation. The presentation of parathyroid diseases is altered during gestation. A peculiar form of osteoporosis, pregnancy-associated osteoporosis, may be observed. Fetus and newborns suffer the consequences of all these disorders. The authors have reviewed the early detection and treatment of these diseases and emphasized their prevention.