Vitamin D receptor polymorphism among rickets children in Mongolia

BACKGROUND

It was reported that 32% of children under five years old in Mongolia had symptoms of rickets. Vitamin D receptor (VDR) gene polymorphism has received attention in relation to bone metabolism. We therefore investigated whether VDR polymorphism is related to high prevalence of rickets in Mongolia and to bone properties in childhood.

METHODS

We conducted a case-control study in Ulaanbaatar involving 80 children aged 7-10 years with a history of rickets (cases) and 72 children with no history of rickets (controls). VDR polymorphism was assessed using BsmI, ApaI, and TaqI, and bone properties were determined by measuring age-standardized midtibial cortical speed of sound (TCSOS).

FINDINGS

Each allelic frequency was verified to satisfy the Hardy-Weinberg equilibrium in cases, controls, and the total sample. The VDR polymorphisms among cases (BB 3%, Bb 18%, bb 80%; AA 15%, Aa 38%, aa 47%; and TT 81 %, Tt 17%, tt 3%) did not differ significantly from those among controls (BB 1%, Bb 13%, bb 86%; AA 16%, Aa 46%, aa 38%; and TT 86%, Tt 13%, tt 1%). There were no significant differences in TCSOS according to the VDR genotype among either cases or controls.

CONCLUSIONS

The VDR polymorphism does not play a major role in the development of rickets in Mongolia and has no effect on TCSOS in childhood.

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.

Meat consumption reduces the risk of nutritional rickets and osteomalacia

Endogenous vitamin D deficiency (low serum 25(OH)D3) is a necessary but insufficient requirement for the genesis of vitamin D-deficiency rickets and osteomalacia. The magnitude of the independent contributions of dietary factors to rachitic and osteomalacic risk remains uncertain. We reanalysed two weighed dietary surveys of sixty-two cases of rickets and osteomalacia and 113 normal women and children. The independent associations of four dietary variables (vitamin D, Ca, fibre and meat intakes) and daylight outdoor exposure with rachitic and osteomalacic relative risk were estimated by multivariate logistic regression. Meat and fibre intakes showed significant negative and positive associations respectively with rachitic and osteomalacic relative risk (RR; zero meat intake: RR 29·8 (95 % CI 4·96, 181), P<0·001; fibre intake: RR 1·53 (95 % CI 1·01, 2·32), P+0·043). The negative association of meat intakes with rachitic and osteomalacic relative risk was curvilinear; relative risk did not fall further at meat intakes above 60 g daily. Daylight outdoor exposure showed a significant negative association with combined relative risk (RR 0·33 (95 % CI 0·17, 0·66), P<0·001). Operation of the meat and fibre risk factors was related to sex, age and dietary pattern (omnivore/lactovegetarian), mainly determined by religious affiliation. The mechanism by which meat reduces rachitic and osteomalacic risk is uncertain and appears independent of revised estimates of meat vitamin D content. The meat content of the omnivore Western diet may explain its high degree of protection against nutritional rickets and osteomalacia from infancy to old age in the presence of endogenous vitamin D deficiency.

Prevalence of vitamin D deficiency rickets in adolescent school girls in Western region, Saudi Arabia

OBJECTIVE

To determine the prevalence of vitamin D deficiency rickets among female adolescents and assess its relation to calcium intake and sun exposure.

METHODS

Four hundred and thirty-three school girls between 12-15 years old were selected randomly from different schools in Jeddah, between October 200--February 2004. We identified symptoms of rickets and determined the dietary habits and sun exposure habits, and laboratory investigations were also carried out.

RESULTS

It was found that, out of 433 cases, 350 (81%) had low vitamin D levels. Approximately 40% had very low levels of vitamin D and 61% were asymptomatic. Most of the symptoms were non specific. There was a positive correlation between low calcium in the diet and less sun exposure to low levels of vitamin D. Approximately 96% had normal serum phosphate, 89% had normal serum calcium, and 40% had normal serum alkaline phosphatase levels.

CONCLUSION

Vitamin D deficiency is common among adolescent females in Jeddah, Saudi Arabia. Cases are missed due to lack of symptoms in most cases and normal bone chemistry. Serum vitamin D level should be carried out in suspected cases. Health and nutritional education should be encouraged in schools. Focusing on the importance of adequate milk intake and sun exposure should be given a priority in any health education program.

"The English disease" or "Asian rickets"? Medical responses to postcolonial immigration

Do the former colonizing powers, like their former colonies, have "postcolonial medicine," and if so, where does it take place, who practices it, and upon whom? How has British medicine in particular responded to the huge cultural shifts represented by the rise of the New Commonwealth and associated postcolonial immigration? I address these questions through a case study of the medical and political responses to vitamin D deficiency among Britain's South Asian communities since the 1960s. My research suggests that in these contexts, diet frequently became a proxy or shorthand for culture (and religion, and race), while disease justified pressure to assimilate.

Impact of dietary and lifestyle on vitamin D in healthy student girls aged 11-15 years

OBJECTIVE

To study daily intake of calcium, phosphorus and vitamin D, to determine the biochemical findings of rickets and the effect of sunlight exposure and vitamin D supplementation in school girls with hypovitaminosis D.

METHODS

A cross-sectional study was conducted on school girls aged 11-15 years selected randomly from various areas of Tehran, Iran. Dietary information and amount of sunlight exposure were estimated by a 7 day recalling method using self-reported questionnaire. Hypovitaminosis D defined as low serum 25-hydroxyvitamin D concentration with two or more others abnormal biochemical findings. Girls with hypovitaminoses D were randomly divided into two groups. The faces and hands of girls in group 1 were exposed to sunlight for one hour per day for twenty days, while those in group 2 were administered vitamin D capsules, 50,000 IU per day for the same period.

RESULTS

four-hundred fourteen girls evaluated, mean daily calcium intake, sunlight exposure and vitamin D acquirement were 360 mg, 10 minutes and 119 IU, respectively. Mean serum 25-hydroxyvitamin D concentration was 30 ng/ml among all girls whereas in 15 (3.63%) of 414 girls was 7.8 ng/ml. Abnormal biochemical findings in these girls included hypocalcemia (n=4), hypophosphatemia (n=5), raised serum alkaline phosphatase (n=13), and parathyroid hormone (n=15). After intervention, mean serum 25-hydroxyvitamin D concentration in sunlight exposure (n=8) and vitamin D (n=7) supplementation increased to 14.4+/-4 ng/ml and 23+/-4 ng/ml respectively. There was a significant difference between the two groups (p<0.05).

CONCLUSION

Vitamin D deficiency developed in rapid growth period of girls without clear clinical rickets in sunny temperate climate city in Iran which vitamin D supplementation improved biochemical findings better than sunlight exposure.

Coping strategies and nutritional health in rural Niger: recommendations for consumption of wild plant foods in the Sahel

People who live in food and water deficit regions of Sahelien West Africa employ various coping strategies as they attempt to meet their food and water needs. In this paper we discuss various coping strategies employed by rural Nigeriens living in the Tanout and Mirriya administrative regions of central Niger. In rural Niger people often harvest or buy wild plant foods to eat. Laboratory studies of the nutritional content of these plants indicate that there are benefits to eating wild plant foods. In this study we summarize the results of field research conducted during the summer of 2002 on the use of wild plant foods in three regions of rural central Niger. Comparing local use of various wild plant foods with major nutrition-related health problems including protein deficiency, essential fatty acid deficiency, iron deficiency and iron deficiency anemia, calcium deficiency rickets, and zinc deficiency, suggests potential recommendations for consumption of these plants. However, further research on the bioavailability of these nutrients is needed to confirm the potential benefits of these plants.

[Vitamin D treatment in childhood: an evidence based discussion]

Vitamin D treatment during childhood has been recommended in those younger than one. Evidence is not available to recommend this treatment in general population. Solar exposure is enough in most infants younger than 1 year, and this should be taken into account. Data showing optimal doses at this stage is not available to date. Our review suggests, solar exposure in Spain appears sufficient.

Vitamin D deficiency in pregnant New Zealand women

AIM

This aim of this study was to identify the prevalence of vitamin D deficiency in pregnant women of a Wellington general practice where 10 cases of childhood rickets had been diagnosed over the past 3 years.

METHODS

Ninety pregnant women were screened for vitamin D deficiency by measuring 25-hydroxy vitamin D by DiaSorin radioimmunoassay. Recruitment into the study was over a 12-month period. A second appointment was arranged for clinical review and drawing of blood for parathyroid hormone, adjusted calcium, and alkaline phosphatase.

RESULTS

100% of women presenting to the general practice for antenatal care consented to the study. 87% of women had 25-hydroxy vitamin D levels below 50 nmol/L. 61.2% of women had a vitamin D level below 25 nmol/L consistent with severe vitamin D deficiency. 10 women had an elevated parathyroid hormone consistent with secondary hyperparathyroidism. Only 22% of our patients were veiled, and included a diverse ethnic population, including African, Maori, European, Middle Eastern, and Polynesian women.

CONCLUSIONS

Vitamin D deficiency is common in young pregnant women in this general practice, and it was not only confined to veiled women or women with dark skin. This highlights the magnitude of vitamin D deficiency in the pregnant population in a New Zealand setting; this vitamin D deficiency is responsible for the re-emergence of childhood rickets.

Resurrection of vitamin D deficiency and rickets

The epidemic scourge of rickets in the 19th century was caused by vitamin D deficiency due to inadequate sun exposure and resulted in growth retardation, muscle weakness, skeletal deformities, hypocalcemia, tetany, and seizures. The encouragement of sensible sun exposure and the fortification of milk with vitamin D resulted in almost complete eradication of the disease. Vitamin D (where D represents D2 or D3) is biologically inert and metabolized in the liver to 25-hydroxyvitamin D [25(OH)D], the major circulating form of vitamin D that is used to determine vitamin D status. 25(OH)D is activated in the kidneys to 1,25-dihydroxyvitamin D [1,25(OH)2D], which regulates calcium, phosphorus, and bone metabolism. Vitamin D deficiency has again become an epidemic in children, and rickets has become a global health issue. In addition to vitamin D deficiency, calcium deficiency and acquired and inherited disorders of vitamin D, calcium, and phosphorus metabolism cause rickets. This review summarizes the role of vitamin D in the prevention of rickets and its importance in the overall health and welfare of infants and children.

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.

Association of swaddling, rickets onset and bone properties in children in Ulaanbaatar, Mongolia

OBJECTIVES

To examine the influence of duration of completely or partially wrapped swaddling on rickets onset and bone properties in children of school age.

STUDY DESIGN

Case-control study.

METHODS

Subjects were 73 children aged 7-10 years with a history of rickets (cases) and 70 children with no history of rickets (controls) in Ulaanbaatar, Mongolia. The periods of completely and partially wrapped swaddling, rickets onset and age-standardized mid-tibial cortical speed of sound (TCSOS) were examined. The associations between swaddling duration and rickets onset and that between swaddling duration and TCSOS were analysed.

RESULTS

All except one control child were completely wrapped from the first month after birth. The durations of completely wrapped and partially wrapped swaddling were similar among cases (3.6 and 4.7 months) and controls (3.1 and 4.4 months) (P=0.42 and P=0.65, respectively). Standardized TCSOS values of cases and controls were -0.572 and -0.038, respectively (P=0.06). The duration of swaddling did not show associations with rickets onset and standardized TCSOS among both cases and controls. Standardized TCSOS of cases with skeletal deformities at examination (-1.467, n=18) was lower than that of cases without skeletal deformities (-0.280, n=55) (P<0.01) and controls (-0.038, n=69) (P<0.001).

CONCLUSIONS

The practice of swaddling itself neither influences rickets onset nor bone properties in school-aged children in Ulaanbaatar. Bone properties of school-aged children who had suffered from rickets and with skeletal deformities were poorer than those in children without skeletal deformities and children without a history of rickets. Prevention of persistent skeletal deformities among the children who have suffered from rickets is critical to promote healthy bone development in Mongolia.

The re-emerging burden of rickets: a decade of experience from Sydney

AIM

To define the demographics and clinical characteristics of cases presenting with nutritional rickets to paediatric centres in Sydney, Australia.

METHODS

Retrospective descriptive study of 126 cases seen from 1993 to 2003 with a diagnosis of vitamin D deficiency and/or confirmed rickets defined by long bone x ray changes.

RESULTS

A steady increase was seen in the number of cases per year, with a doubling of cases from 2002 to 2003. Median age of presentation was 15.1 months, with 25% presenting at less than 6 months of age. The most common presenting features were hypocalcaemic seizures (33%) and bowed legs (22%). Males presented at a younger age, with a lower weight SDS, and more often with seizures. The caseload was almost exclusively from recently immigrated children or first generation offspring of immigrant parents, with the region of origin predominantly the Indian subcontinent (37%), Africa (33%), and the Middle East (11%). Seventy nine per cent of the cases were born in Australia. Eleven cases (all aged <7 months) presented atypically with hyperphosphataemia.

CONCLUSIONS

This large case series shows that a significant and increasing caseload of vitamin D deficiency remains, even in a developed country with high sunlight hours. Cases mirror recent immigration trends. Since birth or residence in Australia does not appear to be protective, screening of at risk immigrant families should be implemented through public health policies.

The Chakaria food system study: household-level, case-control study to identify risk factor for rickets in Bangladesh

OBJECTIVE

A comprehensive, multiround survey of local food systems in a rickets-endemic area of Bangladesh was conducted to identify household-level risk factors for rickets.

DESIGN

A household-level, case-control study was conducted in a rickets-endemic area, Chakaria, with planned comparisons between households with one or more rachitic child and neighboring households with no affected children.

SETTING

A rickets-endemic area of southeastern Bangladesh, Chakaria.

SUBJECTS AND METHODS

An interview-based survey was conducted in six villages in Chakaria with 199 households with at least one child showing physical signs consistent with rickets and 281 households with no affected children.

RESULTS

Households with rachitic children in Chakaria had more children, more pregnant or lactating women, and fewer adults than unaffected households in that community. Affected households tended to rely on farming for their livelihood and tended to have less economic activity as indicated by less outstanding debt than their neighbors. Households with rickets were at significantly greater risk of pneumonia than were other households. Calcium undernutrition was severe and widespread in Chakaria due to a food system that offered very little of the element in accessible forms. Household diets were based on cereals and starchy vegetables. Rice and fish constituted the major source of calcium for most households, although dairy products, when used, were very important calcium sources, particularly for young children. In fact, the use of dairy products was the only household choice that led to substantial increases in the calcium intakes of children, and households that used dairy products tended to show increased calcium intakes for all of their members.

CONCLUSIONS

The risk of a Chakarian household having a child with rickets appeared to be related to its economic status. Although this might be expected to be manifest as limitations in food access and/or use, rickets households failed to show a dietary pattern associated with rickets. Calcium undernutrition was prevalent and, thus, would appear to be a predisposing factor for rickets; however, calcium undernutrition was prevalent in Chakarian households with and without rickets. Therefore, it is probable that another precipitating factor(s) play a role(s) in the etiology of rickets in Chakaria.

A systematic review of nutritional rickets in Ethiopia: status and prospects

BACKGROUND

Nutritional rickets contributes to the high burden of illness and death among Ethiopian children below 5 years of age. Lack of adequate information appears to have negatively influenced the impact of prevention and treatment programs.

OBJECTIVES

The objective of this systematic review is to review existing body of knowledge about nutritional rickets in Ethiopia and develop recommendations that will guide development of strategies for effective interventions and research.

METHODS

Published and unpublished information on nutritional rickets in Ethiopia was collected systematically. The information was critically reviewed and discussed in the context of regional and global situation.

RESULTS

The major cause of nutritional rickets in Ethiopian children is lack of exposure to sunshine and/or inadequate intake of vitamin D. Lack of awareness and traditional beliefs are major causes for not exposing infants to sunshine. The disease is associated with poor socioeconomic status, low birth weight, protein-energy malnutrition and common childhood infections. Severe form of rickets is commonly seen at about 18 months of age. Rickets predisposes Ethiopian children to pneumonia. Diagnostic criteria used in most studies include two or more clinical signs and a characteristic radiological or biochemical abnormality. There are critical gaps in our knowledge about the epidemiology, ecology, and potentially effective interventions to prevent and treat rickets in Ethiopian children.

CONCLUSION

Most of the studies on nutritional rickets in Ethiopia have been conducted in hospital settings. There is a need for well designed epidemiological and ecological studies. The biologic basis for the striking association between PEM and active rickets seen in Ethiopia needs to be determined The role of calcium deficiency, the part played by genetic factors, the nature of the association between the duration of breastfeeding and rickets, and the role of complimentary feeds in Ethiopian children need to be explored. Studies are required to determine the amount of sunshine required to prevent rickets in Ethiopian infants. Studies are required to establish criteria for the diagnosis of clinical and sub clinical rickets, particularly in malnourished children. Prevention programs need to be pursued consistently and systematically and treatment options, including the single massive dose of vitamin D, need to be re-evaluated and optimal mode of treatment determined.

Studies on rickets and osteomalacia in Bactrian camels (Camelus bactrianus)

Epidemiological studies have indicated incidences of 32.9% and 27.8% for rickets and osteomalacia, respectively, in Bactrian camels (Camelus bactrianus), but there is an increased incidence under drought conditions, sometimes reaching 75%. We have found that concentrations of phosphorus and copper in forage and soil samples in a drought affected area were significantly lower than in a control area or normal reference values (P < 0.01) ; the mean Ca:P ratio in the forages was 50:1. The phosphorus content of blood and hair from affected camels was significantly less than that in controls (P < 0.01) and concentrations of copper in the liver and kidney were significantly lower in affected camels than control animals (P < 0.01); the concentrations of triiodothyronine (T(3)), thyroxine (T(4)) and parathyroid hormone (PTH) in the serum from affected animals were significantly higher than those from healthy controls (P < 0.01); serum inorganic phosphorus and ceruloplasmin levels were lower than those in the controls (P < 0.01 or P < 0.05); the concentrations of serum alpha-globulin and beta-globulin were significantly higher in the affected camels than in the healthy controls (P < 0.01). The pathological changes seen in camels affected with rickets included porous, brittle, light, osteoporotic bones that were susceptible to fractures and had less resistance to cutting and sawing. Wrist joints were enlarged with an apparent bowing of the long bones in forelimb and with typical broadening of the epiphyses. In adult female camels, many enlarged scars were often seen in ribs indicating earlier fractures. The disease could be cured with supplementary bone meal, phosphate or mineral mixtures and in field investigations clinical signs disappeared within 15 days. Over the same period, the concentrations of phosphorus and alkaline phosphatase in blood returned to normal. The disease may be effectively prevented by use of mineral blocks (block salt licks) or dosing orally with copper, selenium and cobalt soluble glass boluses. We conclude that rickets and osteomalacia are mainly caused by phosphorus and copper deficiencies in the pasture.

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.

Postnatal evaluation of vitamin D and bone health in women who were vitamin D-deficient in pregnancy, and in their infants

OBJECTIVE

To determine the postnatal vitamin D status and bone health of women identified as vitamin D-deficient in pregnancy, and of their infants.

DESIGN AND PARTICIPANTS

Retrospective audit conducted between 27 August and 5 November 2003. The study included women delivering between August and October 2002 at the Royal Women's Hospital, Melbourne, who had had a 25-hydroxyvitamin D (25-[OH]D) level < 30 nmol/L in pregnancy, and their infants at age 4-10 months.

SETTING

The outpatient clinic at the Royal Children's Hospital, Melbourne.

MAIN OUTCOME MEASURES

Maternal and infant serum levels of vitamin D, total alkaline phosphatase (tALP), parathyroid hormone (PTH), calcium and phosphorus; x-ray results in children with clinical or laboratory findings suggestive of rickets.

RESULTS

Of 69 mother-infant pairs invited to participate, 47 (68%) attended. All 47 women had 25-(OH)D levels < 50 nmol/L, and 39 (83%) had levels < 30 nmol/L. Vitamin D supplements had been prescribed in pregnancy for 35 women (74%), and 19/35 reported having taken them as prescribed. None had continued to take supplements postnatally, but one had recently started taking them again. Among 45 infants from whom blood samples were successfully obtained, 18 (40%) had 25-(OH)D levels < 50 nmol/L, and 14 (31%) had levels < 30 nmol/L. Twelve of 16 breastfed infants had 25-(OH)D levels < 30 nmol/L, compared with 2/29 fed formula milk (P = 0.001).

CONCLUSIONS

Most mothers who had been vitamin D-deficient in pregnancy were also deficient postnatally, indicating that treatment offered, counselling and/or treatment compliance were inadequate. Their infants, especially if breastfed, were at high risk of vitamin D deficiency and increased bone formation. Breastfed infants of mothers at high risk of vitamin D deficiency should receive vitamin D supplements.

Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease

Most humans depend on sun exposure to satisfy their requirements for vitamin D. Solar ultraviolet B photons are absorbed by 7-dehydrocholesterol in the skin, leading to its transformation to previtamin D3, which is rapidly converted to vitamin D3. Season, latitude, time of day, skin pigmentation, aging, sunscreen use, and glass all influence the cutaneous production of vitamin D3. Once formed, vitamin D3 is metabolized in the liver to 25-hydroxyvitamin D3 and then in the kidney to its biologically active form, 1,25-dihydroxyvitamin D3. Vitamin D deficiency is an unrecognized epidemic among both children and adults in the United States. Vitamin D deficiency not only causes rickets among children but also precipitates and exacerbates osteoporosis among adults and causes the painful bone disease osteomalacia. Vitamin D deficiency has been associated with increased risks of deadly cancers, cardiovascular disease, multiple sclerosis, rheumatoid arthritis, and type 1 diabetes mellitus. Maintaining blood concentrations of 25-hydroxyvitamin D above 80 nmol/L (approximately 30 ng/mL) not only is important for maximizing intestinal calcium absorption but also may be important for providing the extrarenal 1alpha-hydroxylase that is present in most tissues to produce 1,25-dihydroxyvitamin D3. Although chronic excessive exposure to sunlight increases the risk of nonmelanoma skin cancer, the avoidance of all direct sun exposure increases the risk of vitamin D deficiency, which can have serious consequences. Monitoring serum 25-hydroxyvitamin D concentrations yearly should help reveal vitamin D deficiencies. Sensible sun exposure (usually 5-10 min of exposure of the arms and legs or the hands, arms, and face, 2 or 3 times per week) and increased dietary and supplemental vitamin D intakes are reasonable approaches to guarantee vitamin D sufficiency.

The frequency of nutritional rickets among hospitalized infants and its relation to respiratory diseases

This case control study was conducted to determine the frequency of nutritional rickets among hospitalized infants and to assess their relation to respiratory diseases. All infants between the age of 3 months and 2 years admitted to the pediatric ward of Queen Alia Military Hospital during the period February-October 2001 were examined and investigated to rule out nutritional rickets. Children admitted for the first time to hospital for acute illnesses were only included in the study. A special data collection sheet was designed for this study which includes information on the age, sex, causes of admission, family size, the rank of the child in the family, family monthly income, outdoor clothing habit of the mother, and the mode of feeding. Data were collected from the infant charts and/or by interviewing the child's mother or guardian. Clinical signs of rickets were also recorded, including rosary beads, craniotabes, wide anterior fontanel, delayed dentition, widening of epiphysis, bowing of the legs, and double malulous. Blood sample was collected for calcium, phosphorus, alkaline phosphatase, and hemoglobin level. Those infants with any clinical sign of rickets and/or abnormal chemical results had a wrist X-ray to confirm the diagnosis of rickets. The rachitic group (cases) was compared for statistical significance with the remaining non-rachitic infants (controls) for the data collected. Rachitic infants received intramuscular 600,000 IU of vitamin D; a follow-up wrist X-ray and blood sample for calcium, phosphorus and alkaline phosphatase was arranged 3 weeks later. Forty-seven infants (10.6 per cent) out of the 443 included in the study were found to have nutritional rickets. Forty (85.1 per cent) of the rachitic infants were admitted due to lower respiratory tract diseases compared with 30 per cent of the control group and the difference was statistically significant (p < 0.01). Duration of hospital stay in the rachitic infants was also significantly more prolonged than the non-rachitic control group (9.5 days vs. 7.4 days, p = 0.002). Rachitic infants were breastfed in 82.9 per cent, ranked second or more in the family in 87.2 per cent, and had mothers who wore head cover outdoors in 80.8 per cent compared with 60.8, 40.1, and 60.3 per cent, respectively, in the non-rachitic group (p < 0.01). High alkaline phosphatase, hypocalcemia, hypophosphatemia, and anemia was found in 100, 19, 50, and 78.7 per cent, respectively, in the rachitic group compared with 9.8, 2, 1.2, and 43.7 per cent, respectively, in the control group (p < 0.001). Nutritional rickets seems to be a common problem among infants in Jordan. Further studies at national level are needed to determine the prevalence of rickets in Jordan. Rachitic infants are commonly hospitalized due to lower respiratory tract infections, thus there is a high index of suspicion for rickets among hospitalized infants with lower respiratory tract diseases.