Rickets today--children still need milk and sunshine

Serum 25-hydroxyvitamin D requirements to prevent nutritional rickets in Nigerian children on a low-calcium diet-a multivariable reanalysis

BACKGROUND

Nutritional rickets is believed to result from the interaction of inadequate serum 25-hydroxyvitamin D [25(OH)D] concentration and dietary calcium intake, but this interaction has not been confirmed in children with rickets. Determining the vitamin D requirements to prevent nutritional rickets has been thwarted by inconsistent case definition, inadequate adjustment for calcium intake and other confounders, and 25(OH)D assay variability.

OBJECTIVES

To model the 25(OH)D concentration associated with nutritional rickets in calcium-deprived Nigerian children, adjusted for confounding factors, and develop a general approach to define vitamin D status while accounting for calcium intake.

METHODS

Logistic regression was used to model the association of serum 25(OH)D with having rickets adjusted for calcium intake in a reanalysis of a case-control study in Nigerian children. The matching variables age, sex, weight-for-age z score, and 4 additional significant variables were selected [religion, age began walking, phosphorus intake, and the 25(OH)D × calcium intake interaction] using a rigorous 7-step algorithm.

RESULTS

Cases had significantly (P < 0.0001) lower mean ± SD 25(OH)D than controls (33 ± 13 compared with 51 ± 16 nmol/L, respectively), whereas cases and controls had similarly (P = 0.81) low mean dietary calcium intakes (216 ± 88 and 213 ± 95 mg/d, respectively). There was a significant interaction between 25(OH)D and calcium intake [coefficient (95% CI): -0.0006 (-0.0009, -0.0002)]. Accordingly, as calcium intake increased from 130 to 300 mg/d, the adjusted odds of having rickets decreased dramatically with increasing 25(OH)D such that at 200 mg/d, the adjusted odds of having rickets at 47.5 nmol/L was 0.80, whereas it was 0.2 at 62.5 nmol/L. Moreover, at a calcium intake of 300 mg/d, the adjusted odds was 0.16 at a 25(OH)D concentration of 47.5 nmol/L and 0.02 at 62.5 nmol/L.

CONCLUSIONS

The vitamin D requirement to prevent nutritional rickets varies inversely with calcium intake and vice versa. Also, application of multivariable modeling is essential in defining vitamin D requirements.

Vitamin D levels in newborns and association with neonatal hypocalcemia

OBJECTIVE

Vitamin D has many important functions in our body. Especially in intrauterine and early infancy periods, Vitamin D plays a major role in bone development, growth, and the maturation of tissues such as lung and brain. Fetus is dependent on the mother in terms of Vitamin D and maternal Vitamin D deficiency results in a Vitamin D deficient newborn. The purpose of this study was to determine the levels of Vitamin D in newborns and to investigate the association between Vitamin D status of the baby and neonatal hypocalcemia.

METHOD

Vitamin D, calcium, and parathyroid hormone levels of 750 infants, born between 1 January 2014 and 30 June 2015 and followed in Ondokuz Mayıs University Neonatal Intensive Care Unit were analyzed retrospectively. Blood levels of Vitamin D were checked within 3 days after birth. A 25(OH)D3 level of <10 ng/ml indicated severe, levels between 10 and 20 ng/ml, which indicated moderate and levels between 20 and 30 ng/ml indicated mild Vitamin D deficiency. Serum calcium levels below 8 mg/dl in term infants and below 7 mg/dl in preterm infants were accepted as hypocalcemia. Hypocalcemia that developed within the first week after birth was defined as early, while hypocalcemia after one week were defined as late hypocalcemia.

RESULTS

A total of 44% of the infants in the study were girls, while 56% were boys; 38% were term and 62% were preterm. Average 25(OH)D3 level of all infants was 11.4 ± 10.2 (0-153) ng/ml. Only 30 (4%) infants had normal (>30 ng/ml) 25(OH)D3 levels; 68 (9%) had mild, 234 (31%) had moderate and 418 (56%) had severe vitamin D deficiency. No correlation was found between Vitamin D levels and gender, mother's age, gestational week or birth weight. In 79 (17.2%) preterms, neonatal hypocalcemia was observed. Vitamin D levels of the premature infants who had early neonatal hypocalcemia were statistically significantly lower when compared with those who did not have early neonatal hypocalcemia (p = .02). No significant difference was found between the Vitamin D levels of the term infants who had early neonatal hypocalcemia and those who did not (p= .29). No significant difference was found between the Vitamin D levels of the infants who had late neonatal hypocalcemia and those who did not (in preterm p = .27; in term p = .29).

CONCLUSIONS

Although lack of Vitamin D is preventable and curable, it is an important health problem for newborns in Turkey. In our study, 56% of the infants were found to have severe lack of Vitamin D and lack of Vitamin D was found to be associated with early neonatal hypocalcemia in preterm newborns. However, long-term effects of lack of Vitamin D in infancy are not fully known. In order to be able to prevent neonatal Vitamin D deficiency, 1200 IU/day vitamin D was supplemented to mothers from the 12th gestational week to 6th month of the birth, which was put into effect by the Ministry of Health in 2011, and should be applied by all health workers.

Rickets: Historical, Epidemiological, Pathophysiological, and Pathological Perspectives

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

Preventing Rickets in Locally Appropriate Ways: A Case Report from North China

A rickets prevention program was carried out in Shanxi Province, China using locally appropriate methods. At the end of two and one-half years, the prevalence of rickets was 18% lower in program townships (56%) than in a control township that had no rickets prevention program (74%). Maternal awareness of how to prevent rickets was higher in program townships (43%) than in the control township (28%). However, the actual effect of maternal awareness on the prevention of rickets was negligible. In conclusion, this rickets prevention program was effective at reducing the prevalence of rickets. It appears the program was effective because of the presence of concerned program workers regularly visiting mothers and their infants, and using locally appropriate methods, but neither the vitamin supplements used nor the kind of rickets prevention education provided the mothers was shown to be positively correlated.

Sources of vitamin D and calcium in the diets of preschool children in the UK and the theoretical effect of food fortification

BACKGROUND

Dietary intakes of vitamin D are very low in the UK. Dietary calcium is also necessary to promote bone health. The fortification of foods with vitamin D could be a safe and effective way of increasing intake.

METHODS

Diets of preschool children, 755 at 18 months and 3.5 years, from the Avon Longitudinal Study of Parents and Children were assessed using dietary records completed by parents. Energy, vitamin D and calcium intakes were calculated. Multinomial logistic regression was used to estimate the odds ratio for being in the highest/lowest quartile of intake. Intakes were recalculated to test different fortification regimes.

RESULTS

Vitamin D intakes were low; all children were below the UK and US dietary recommendations. Calcium intakes decreased between the two ages as a result of reduced milk consumption. Children in the lowest quartile for vitamin D intake at 18 months were twice as likely to remain in that quartile at 3.5 years (odds ratio = 2.35; 95% confidence interval = 1.56-3.55). The majority of foods provide no vitamin D with fat spreads and milk as the main sources. The contribution from breakfast cereals increased, from 6% to 12%, as a result of the increased consumption of fortified cereals. Dairy foods provided the highest contribution to calcium at 18 months but were less important at 3.5 years. Theoretical intakes from different fortification regimens suggest that milk fortified at 2 μg 100 g(-1) vitamin D would provide most children with adequate but not excessive intakes.

CONCLUSIONS

Dietary vitamin D intakes were very low and calcium intakes were mostly adequate. Fortification of milk with vitamin D could be a good way to boost intakes.

The Interrelationships between Lactose Intolerance and the Modern Dairy Industry: Global Perspectives in Evolutional and Historical Backgrounds

Humans learned to exploit ruminants as a source of milk about 10,000 years ago. Since then, the use of domesticated ruminants as a source of milk and dairy products has expanded until today when the dairy industry has become one of the largest sectors in the modern food industry, including the spread at the present time to countries such as China and Japan. This review analyzes the reasons for this expansion and flourishing. As reviewed in detail, milk has numerous nutritional advantages, most important being almost an irreplaceable source of dietary calcium, hence justifying the effort required to increase its consumption. On the other hand, widespread lactose intolerance among the adult population is a considerable drawback to dairy-based foods consumption. Over the centuries, three factors allowed humans to overcome limitations imposed by lactose intolerance: (i) mutations, which occurred in particular populations, most notably in the north European Celtic societies and African nomads, in which carriers of the lactose intolerance gene converted from being lactose intolerant to lactose tolerant; (ii) the ability to develop low-lactose products such as cheese and yogurt; and (iii) colon microbiome adaptation, which allow lactose intolerant individuals to overcome its intolerance. However, in a few examples in the last decade, modern dairy products, such as the popular and widespread bio-cultured yogurts, were suspected to be unsuitable for lactose intolerant peoples. In addition, the use of lactose and milk-derived products containing lactose in non-dairy products has become widespread. For these reasons, it is concluded that it might be important and helpful to label food that may contain lactose because such information will allow lactose intolerant groups to control lactose intake within the physiological limitations of ~12 g per a single meal.

Phenotype presentation of hypophosphatemic rickets in adults

Hypophosphatemic rickets (HR) is a group of rare disorders caused by excessive renal phosphate wasting. The purpose of this cross-sectional study of 38 HR patients was to characterize the phenotype of adult HR patients. Moreover, skeletal and endodontic severity scores were defined to assess possible gender differences in disease severity in patients with genetically verified X-linked HR. Compared to normal reference data, i.e., z = 0, HR patients had significantly lower final height, with a mean difference in z-score of -1.9 (95% CI -2.4 to -1.4, P < 0.001). Compared to paired z-scores of final height, z-scores of leg length were significantly lower and those of sitting height were significantly higher (P < 0.001), resulting in disproportion as indicated by the significantly elevated sitting height ratio, mean difference in z-score of 2.6 (95% CI 2.1-3.1, P < 0.001). Z-scores of head circumference (median 1.4, range -0.4 to 5.5, P < 0.001) and z-scores of bone mineral density (BMD) of the lumbar spine (median 1.9, range -1.5 to 8.6, P < 0.001) were significantly elevated compared to normal reference data. The relative risk (RR) of fracture was reduced (RR = 0.34, 95% CI 0.20-0.57, P < 0.001). The skeletal severity score tended to be higher in males compared to females (P = 0.07), and no gender difference in endodontic severity was found. In conclusion, adult HR patients were characterized by short stature and were disproportioned. They had elevated BMD of the lumbar spine and a reduced risk of fractures. We found a tendency for males to be more severely affected than females.

Nutritional rickets: still a problem for the pediatric population

Rickets is a mineralization disorder of the growing bone. Nutritional rickets is still prevalent in many parts of the developing world and is re-emerging in developed countries. Although vitamin D deficiency plays a central role in the pathogenesis of this disease, calcium deficiency and genetic factors may also cause or contribute to the development of rickets. This review will focus on the classical form of nutritional rickets, in other words, vitamin D-deficiency rickets. The epidemiology, ethiopathogenesis, risk factors, clinical picture, diagnosis, treatment and prevention of nutritional rickets are reviewed.

Nutritional rickets and z scores for height in the United Arab Emirates: to D or not to D?

BACKGROUND

Vitamin D deficiency is still prevalent worldwide, including the Middle East. A cohort of patients with nutritional rickets was treated with vitamin D(2) (ergocalciferol) alone. After this intervention, patients were followed to document changes in z scores for height after treatment. The secondary aim was to determine the proportion of affected children who had vitamin D deficiency or calcium deficiency.

METHODS

Z score for height was calculated as the difference between the observed value and the median value, divided by the SD of the population. Z scores were compared in patients before and after treatment.

RESULTS

The improvement in z score after treatment was 0.86 +/- 0.95. The 95% confidence interval for the mean difference was 1.32-0.40 (t = 3.95, P < 0.001). With a diagnostic cut-off for 25 hydroxyvitamin D(3) (25D) deficiency of <25 nmol/L, only half were diagnosed with severe vitamin D deficiency. The remaining patients had presumable calcium deficiency. The alkaline phosphatase (ALP) was negatively correlated to z scores, implying that higher ALP concentrations predicted severe bone disease (lower z scores). The variables 25D and age were moderately and positively correlated (Pearson's r = 0.59, 95%CI: 0.15-0.84; P = 0.01), indicating that younger infants had the lowest 25D levels.

CONCLUSION

Vitamin D alone was efficient in resolving radiological and biochemical disturbances as well as improving z scores for height in a cohort of children with nutritional rickets, which included patients with 25D deficiency as well as calcium deficiency. The results support the hypothesis of the interplay and continuum of 25D deficiency and calcium deficiency in the pathogenesis of rickets.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Vitamin D-deficiency rickets among children in Canada

BACKGROUND

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

METHODS

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

RESULTS

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

INTERPRETATION

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

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

BACKGROUND

Rates of rickets from 15.9 to 26.7% have been reported in China.

METHODS

Combining the methods of epidemiology and the behavioral sciences, this study investigated the prevalence of rickets in children in rural Shanxi Province, China. A total of 250 children age 12-24 months were examined physically for the presence of rickets, blood was drawn for laboratory analysis, and X-rays were taken of each child's wrists.

RESULTS

Vitamin D deficiency in the spring was found among 65.3% of children. Rickets diagnosis relying on clinical signs alone determined a rickets prevalence of 41.6%, declining to 17.0% in the fall after a summer of sun exposure (chi(2) = 8.356, P = 0.004). But an integrated diagnostic method exploiting clinical signs, X-ray and alkaline phosphatase levels found the prevalence of active rickets to be 3.7%. Furthermore, it was demonstrated that only five clinical signs reflect active rickets--wide wrists, frontal bossing, rachitic rosary, Harrison's sulcus, and bowed legs.

CONCLUSIONS

The prevalence of active rickets in young children in northern China is lower than previously reported. Even in poor countries, simple tests such as X-rays and alkaline phosphatase can be added to physical examination to more accurately diagnose active rickets.

Nutritional rickets: nature or nurture?

Rickets is a mineralization disorder of the growing bone. Nutritional rickets is still prevalent in many parts of the world. Although vitamin D deficiency plays a central role in the pathogenesis of this disease, calcium deficiency and genetic factors may also cause or contribute to the development of rickets. This review will focus on the classical form of nutritional rickets: vitamin D deficiency rickets. Epidemiology, ethiopathogenesis, risk factors, the current clinical picture, diagnosis, treatment and prevention of nutritional rickets will be reviewed.

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.

Vitamin D status of mothers and their neonates in Kuwait

BACKGROUND

There has been a resurgence of nutritional rickets in children in many developing countries and some of the developed countries. Children between 6 and 18 months old are commonly affected. In order to find out the association between vitamin D and rickets we studied the vitamin D status of the neonates and their mothers in Kuwait.

METHODS

Two hundred and fourteen full-term pregnant mothers and their neonates were selected from two hospitals in Kuwait. All mothers had normal vaginal delivery. On the day of delivery 2.5 mL of maternal blood and 2.5 mL of cord blood samples were withdrawn. Serum 25-hydroxyvitamin D (25OHD) was determined in duplicate by radioimmunoassay using an Incstar kit. Quality control analyses were done using several between and within run experiments.

RESULTS

A total of 128 mother-neonate pairs were selected from the Al-Adan hospital and 86 from the Maternity Hospital. The mean age and parity of the mothers were similar in both hospitals. The mean (+/- SD) 25OHD levels of the mothers and the neonates in the Adan hospital were 13.3 (6.5) ng/mL and 8.2 (6.5) ng/mL, respectively. The corresponding values in the Maternity Hospital were 17.6 (12.4) and 8.1 (7.3) ng/mL for the mothers and the neonate, respectively. Serum 25OHD of the mothers and their newborn infants were highly correlated (r = 0.790, P < 0.001).

CONCLUSIONS

Results demonstrate that 40% of the mothers and 60% of the neonates are vitamin D deficient on the day of delivery. The vitamin D of the mothers and neonates are highly correlated (r = 0.790, P < 0.001).

Variable presentations of rickets in children in the emergency department

Vitamin D-deficient rickets is uncommon but becoming more prevalent in the pediatric population likely related to increases in breast-feeding. It should be considered in many clinical situations. We present 3 cases of rickets presenting acutely to the emergency department. Their presentations included a fracture concerning for child abuse, tetany, and hypocalcemic seizures. In all cases, laboratory and radiographic evaluations were consistent with the diagnosis of nutritional rickets and their symptoms were related to rickets resolved with appropriate treatment. Although uncommon, vitamin D-deficient rickets should be considered in children with the above presentations.

Rickets

Rickets, once thought vanquished, is reappearing. In some less developed countries it hardly went away. This seminar reviews the effects of genes, stage of development, and environment on clinical expression of the disease. Rickets can be secondary to disorders of the gut, pancreas, liver, kidney, or metabolism; however, it is mostly due to nutrient deficiency and we concentrate on this form. Although calcium deficiency contributes in communities where little cows' milk is consumed, deficiency of vitamin D is the main cause. There are three major problems: the promotion of exclusive breastfeeding for long periods without vitamin D supplementation, particularly for babies whose mothers are vitamin D deficient; reduced opportunities for production of the vitamin in the skin because of female modesty and fear of skin cancer; and the high prevalence of rickets in immigrant groups in more temperate regions. A safety net of extra dietary vitamin D should be re-emphasised, not only for children but also for pregnant women. The reason why many immigrant children in temperate zones have vitamin D deficiency is unclear. We speculate that in addition to differences in genetic factors, sun exposure, and skin pigmentation, iron deficiency may affect vitamin D handling in the skin or gut or its intermediary metabolism.

Children with nutritional rickets referred to hospitals in Copenhagen during a 10-year period

AIM

To describe the prevalence of nutritional rickets among children admitted to three large paediatric departments in the Copenhagen area during a 10 y period.

METHODS

Retrospective analysis of cases identified from the diagnosis registers fulfilling the diagnostic criteria for nutritional rickets.

RESULTS

Forty cases were identified, distributed in two distinct age groups: 0.5-4 y (n = 31) and 9-15 y (n = 9). All cases were immigrants, of whom 95% were born in Denmark. The main symptoms in the younger age group were bowed legs and clumsy walk, and in the peripubertal group were painful joints. Two children had generalized convulsions. None of the cases had received vitamin D supplementation.

CONCLUSION

Nutritional rickets is still present among immigrants in Denmark, and it is likely that the prevalence of mild cases is high. Prevention through vitamin D supplementation is important, but requires a dedicated health education effort.

[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.

Fortification of orange juice with vitamin D: a novel approach for enhancing vitamin D nutritional health

BACKGROUND

Fortification of milk with vitamin D may not be adequate for satisfying the vitamin D requirement because of variability in vitamin D content after fortification and because many persons have milk allergy or lactose intolerance. Additional foods need to be fortified with vitamin D.

OBJECTIVE

We determined whether vitamin D, a fat-soluble vitamin, is bioavailable in orange juice and skim milk, 2 nonfat beverages.

DESIGN

On 3 separate occasions, 18 adults ingested 25 000 IU vitamin D(2) in 240 mL whole milk or skim milk or in 0.1 mL corn oil applied to toast. A separate, double-blind, randomized, controlled trial investigated whether the consumption of orange juice fortified with vitamin D(3) would increase serum 25-hydroxyvitamin D [25(OH)D] concentrations: 14 subjects ingested 240 mL orange juice fortified with 1000 IU vitamin D, and 12 subjects ingested a control orange juice daily for 12 wk.

RESULTS

Peak serum vitamin D(2) concentrations did not differ significantly after the ingestion of vitamin D(2) in whole milk, skim milk, or corn oil on toast. After subjects consumed orange juice fortified with 1000 IU vitamin D(3) daily for 12 wk, serum 25(OH)D(3) concentrations increased by 150%, and serum parathyroid hormone concentrations decreased by 25% compared with baseline; control subjects had a seasonal increase of 45% in 25(OH)D and no significant change in serum parathyroid hormone.

CONCLUSIONS

The fat content of milk does not affect vitamin D bioavailability. Vitamin D fortification at 1000 IU/240 mL orange juice for 12 wk safely increased 25(OH)D(3) concentrations in adults.

Vitamin D receptor polymorphisms and nutritional rickets in Nigerian children

Nutritional rickets is common in Nigeria where vitamin D deficiency is rare and dietary insufficiency of calcium is common. It occurs more commonly in siblings of affected children than of unaffected children. Postulating that vitamin D receptor (VDR) polymorphisms might relate to the susceptibility of some Nigerian children to develop rickets in the setting of low calcium intake, we compared the VDR genotypes, as determined by the presence or absence of Bsm I, Apa I, Taq I, and Fok I restriction enzyme cleavage sites, between 105 children with active nutritional rickets and 94 subjects representative of the community from which the rachitic children came. In the rickets group, the ff genotype was less common than in the community group, and the FF genotype was relatively increased (f allele frequency, 17% in rachitic children and 26% in the community group, p = 0.03). Neither individual allele frequencies for the other polymorphisms nor combinations of genotypes at different sites were different between the rachitic and community groups. Although it is not clear why a presumed better-functioning VDR variant (F allele) is associated with an increased risk of developing rickets, this study raises the possibility that VDR alleles might be important in determining an individual's susceptibility to developing rickets when faced with dietary calcium deficiency.