High prevalence of moderately severe vitamin D deficiency in preterm infants

Background: The recommended dose of vitamin D supplementation of preterm infants is based on data from populations in which severe vitamin D deficiency is uncommon and may be inadequate for infants in high risk population. However, data on vitamin D status of preterm infants in high‐risk populations, such as Middle Eastern countries is scarce. Methods: This study investigates the vitamin D status of Arab mothers and their preterm infants. Maternal serum and cord blood 25(OH)D, calcium (Ca), phosphorus (P) and alkaline phosphate (ALP) were measured at delivery. Serum 25(OH)D was measured by HPLC while the other biochemical parameters were measured by standard autoanalyzer. Results: Thirty‐four preterm infants were studied. The mean gestational age was 31.4 weeks and birth weight was 1667 g. The median serum 25(OH)D of 17.0 nmol/L in 28 mothers and 14.5 nmol/L in 34 cord blood samples were low. The median maternal and cord blood Ca, P and ALP levels were within normal range. Fifteen (44%) of the infants had moderately severe vitamin D deficiency (serum 25 (OH)D levels <12.5 nmol/L). The median serum 25(OH)D levels of mothers who had reportedly taken prenatal vitamin D supplementation and those who had not were similar (17.3 vs 16.3) nmol/L. The mean serum 25(OH)D levels among preterm infants in this study were low when compared to levels in Caucasians preterm infants on which the current vitamin D recommendations are based. Conclusion: The high prevalence of moderately severe vitamin D deficiency in Arab preterm infants provides a justification to investigate vitamin D requirement of preterm infants in this and other high‐risk populations.     

High prevalence of vitamin D deficiency in newborn infants of high-risk mothers

Objective

To determine the prevalence of vitamin D deficiency in newborn infants of mothers at risk of vitamin D deficiency because of dark skin or the wearing of concealing clothes (such as a veil) compared with a group presumed not to be at risk. A second aim was to correlate these newborn infants'' vitamin D concentrations with biochemical parameters of vitamin D metabolism and bone turnover at birth.

Design

A prospective study conducted between April 2004 and February 2006 including women delivering during this period and their newborn infants.

Setting

The outpatient clinic of the obstetrics department, Sint Franciscus Gasthuis, Rotterdam, the Netherlands.

Patients

Eighty seven newborn infants of healthy mothers with either dark skin and/or concealing clothing (risk group) or light skin (control group).

Results

We found a significant difference in the prevalence of vitamin D deficiency (25‐hydroxyvitamin D₃ <25 nmol/l) between newborn infants of mothers at risk and those of mothers in the control group (63.3% vs 15.8%; p<0.001). Mean alkaline phosphatase concentrations were significantly higher in the at risk group.

Conclusions

Newborn infants of mothers with dark skin or wearing concealing clothes are at great risk of vitamin D deficiency at birth. The clinical implications are unknown. Further research is necessary to determine the long‐term consequences of maternal and neonatal vitamin D deficiency so that guidelines on vitamin D supplementation during pregnancy can be issued.     

High prevalence of vitamin D deficiency in newborn infants of high-risk mothers.

OBJECTIVE: To determine the prevalence of vitamin D deficiency in newborn infants of mothers at risk of vitamin D deficiency because of dark skin or the wearing of concealing clothes (such as a veil) compared with a group presumed not to be at risk. A second aim was to correlate these newborn infants' vitamin D concentrations with biochemical parameters of vitamin D metabolism and bone turnover at birth. DESIGN: A prospective study conducted between April 2004 and February 2006 including women delivering during this period and their newborn infants. SETTING: The outpatient clinic of the obstetrics department, Sint Franciscus Gasthuis, Rotterdam, the Netherlands. PATIENTS: Eighty seven newborn infants of healthy mothers with either dark skin and/or concealing clothing (risk group) or light skin (control group). RESULTS: We found a significant difference in the prevalence of vitamin D deficiency (25-hydroxyvitamin D(3) <25 nmol/l) between newborn infants of mothers at risk and those of mothers in the control group (63.3% vs 15.8%; p<0.001). Mean alkaline phosphatase concentrations were significantly higher in the at risk group. CONCLUSIONS: Newborn infants of mothers with dark skin or wearing concealing clothes are at great risk of vitamin D deficiency at birth. The clinical implications are unknown. Further research is necessary to determine the long-term consequences of maternal and neonatal vitamin D deficiency so that guidelines on vitamin D supplementation during pregnancy can be issued.     

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°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.Severe vitamin D deficiency (VDD) causes rickets in infants and children, and osteomalacia in adolescents and adults due to decreased bone mineralisation.¹ VDD in pregnancy is associated with restricted fetal and infant growth,^2,3 and predisposes to neonatal VDD and hypocalcaemia.⁴ Vitamin D status in childhood and adolescence may play a role in the prevention of osteoporosis.⁵ Adequate status may reduce the adult risk of diabetes, ischaemic heart disease, hypertension and tuberculosis.⁶In Melbourne, nutritional rickets was documented during the 1960s; 70% of the affected children were migrants of Mediterranean origin.⁷ More recently, VDD has been documented in veiled or dark skinned pregnant women,⁸ and in immigrant infants from different backgrounds presenting with rickets.⁹In the absence of supplementation, skin pigmentation and exposure to solar ultraviolet B (UVB) irradiation determine serum levels of 25‐hydroxyvitamin D (25‐OHD) through endogenous production.¹ Adults and adolescents living in climates with reduced UVB exposure are at increased risk of VDD,^10,11 particularly those individuals with dark skin,¹² with reduced sun exposure¹³ or wearing covering clothing for socio‐cultural reasons.¹⁴ Knowledge of the risk factors in specific populations is important in preventing VDD in pregnant women and infants,⁸ and may also contribute to the prevention of osteoporosis.¹⁵The increased rates of VDD in adult East African immigrants living in Melbourne, Australia¹⁶ suggested that their immigrant offspring are also at risk of VDD. We aimed to prospectively assess the prevalence, severity, pattern of and risk factors for VDD in these children. Malnutrition, iron and vitamin A deficiency are prevalent in African children,¹⁷ and VDD is associated with underweight¹⁸ and with iron deficiency anaemia.¹⁹ We aimed to determine if VDD was part of a broader nutritional problem in these children.     

Prevalence of vitamin D insufficiency in obese children and adolescents

OBJECTIVE: Recent studies have shown a broad prevalence of vitamin D deficiency in adults. Serum 25-hydroxyvitamin D (25-OHD) levels were reported to be inversely related to body mass index (BMI) and body fat content and correlated directly with hypertension, degree of insulin resistance and progression to diabetes mellitus. We sought to determine the prevalence of vitamin D insufficiency and markers of metabolic syndrome in an obese pediatric population. METHODS: Charts of 217 obese (weight >95th percentile for age and sex) children (118 females, 99 males; mean BMI 32.2 +/- 6.4 kg/m2; mean age 12.9 2 5.5; age range 7-18 years) who had received a standard physical examination at the pediatric endocrine clinic of the Infants and Children's Hospital of Brooklyn at Maimonides, Brooklyn, NY, were retrospectively analyzed. Data obtained included age, sex, weight, BMI, height and systolic and diastolic blood pressure. The routine bloodwork panel for obesity at our pediatric endocrine facility includes fasting 25-OHD, total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), triglycerides, ALT, AST, thyroid stimulating hormone (TSH), total T4, and insulin and glucose. Insulin sensitivity as calculated by quantitative insulin-sensitivity check index (QUICKI = 1/[log(I0) + log(G0)], where I0 is fasting insulin and G0 is fasting glucose) was computed following the visit. RESULTS: Overall, 55.2% of patients were vitamin D insufficient (25-OHD <20 ng/ml). Severely low vitamin D levels (25-OHD < or =10 ng/ml) were seen in 21.6% of 217 patients, which represents almost half of the insufficient group. In the 25-OHD <20 ng/ml group age, BMI, and SBP were significantly higher than in the 25-OHD 220 ng/ml group, while QUICKI (<0.35 is consistent with insulin resistance) was borderline low in the <20 ng/ml group. HDL-C was significantly lower in the 25-OHD < or =10 ng/ml group. The 25-OHD levels correlated negatively with BMI and positively with HDL-C. No other findings were significant. CONCLUSION: More than half of the obese children had vitamin D levels <20 ng/ml with equal gender distribution. Vitamin D insufficiency was associated with increased age, BMI, and SBP, and decreased HDL-C.     

The frequency of vitamin D insufficiency in healthy female adolescents

Aim: To establish the frequency and causes of vitamin D insufficiency in healthy female adolescents in Izmir, Turkey. Methods: 64 adolescents from a low‐ (Ikinci Inönü) and a high‐ (Ilica) socio‐economic settlement were included. Parents’ monthly income was classified as low, middle and high. The blood samples were drawn at the end of the summer and winter periods. Results: Vitamin D insufficiency percentages for the end‐of‐winter period were 59.4% in Ikinci Inönü and 15.6% in Ilica, and for the end of summer 25% and 15.6%, respectively. Calcidiol levels of cases from Ikinci Inönü were found to be lower compared with the levels of cases from Ilica (34±15 vs 59±24 nmol/l for end of winter, p= 0.000; 51±22 vs 65±28 nmol/l for end of summer, p= 0.03). Calcidiol levels of cases whose parental monthly income was low and whose mothers were illiterate were significantly lower than the others (48±18 vs 65±29 nmol/l for end of summer, p= 0.01; 33±16 vs 56±23 nmol/l for end of winter, p= 0.000; 45±13 vs 64±29 nmol/l for end of summer, p= 0.007; 36±17 vs 51±25 nmol/l for end of winter, p= 0.02; respectively). Conclusion: Vitamin D insufficiency was frequent, especially in the end‐of‐winter period. Basic risk factors were low socio‐economic status, illiteracy of mothers and low calcium intake.     

Prevalence of vitamin D deficiency among healthy adolescents

BACKGROUND: Although vitamin D deficiency has been documented as a frequent problem in studies of young adults, elderly persons, and children in other countries, there are limited data on the prevalence of this nutritional deficiency among healthy US teenagers. OBJECTIVE: To determine the prevalence of vitamin D deficiency in healthy adolescents presenting for primary care. DESIGN: A cross-sectional clinic-based sample. SETTING: An urban hospital in Boston. PARTICIPANTS: Three hundred seven adolescents recruited at an annual physical examination to undergo a blood test and nutritional and activity assessments. MAIN OUTCOME MEASURES: Serum levels of 25-hydroxyvitamin D (25OHD) and parathyroid hormone, anthropometric data, nutritional intake, and weekly physical activity and lifestyle variables that were potential risk factors for hypovitaminosis D. RESULTS: Seventy-four patients (24.1%) were vitamin D deficient (serum 25OHD level, 相似文献   

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.     

Varying role of vitamin D deficiency in the etiology of rickets in young children vs. adolescents in northern India

The relative importance of calcium vs. vitamin D deficiency in the etiology of nutritional rickets in the tropics may be different in children compared with adolescents. We studied calcium intake, sun exposure, serum alkaline phosphatase, and 25 hydroxyvitamin D in 24 children and 16 adolescents with rickets/osteomalacia. The values were compared with those obtained in control subjects (34 children and 19 adolescents). We found that young children with rickets had lower calcium intake compared with controls (285 +/- 113 vs. 404 +/- 149 mg/day, p < 0.01), but similar sun exposure (55 +/- 28 vs. 56 +/- 23 min x m2/day) and 25 hydroxyvitamin D (49 +/- 38 vs. 61 +/- 36 nmol/l). Sixteen of 24 children with rickets had 25 hydroxyvitamin D above the rachitic range (> 25 nmol/l), in contrast to one of 16 adolescents. Adolescent patients had low calcium intake vs. controls (305 +/- 196 vs. 762 +/- 183 mg, p < 0.001), and lower sunshine exposure (16 +/- 15 vs. 27 +/- 17 min x m2/day, p < 0.01) and serum 25 hydroxyvitamin D (12.6 +/- 7.1 vs. 46 +/- 45.4 nmol/l, p < 0.001). The odds ratio for developing rickets with a daily calcium intake below 300 mg was 4.8 (95 per cent CI, 1.9 - 12.4, p = 0.001). Subjects with rickets were randomized to receive 1 g calcium daily, with or without vitamin D. Children showed complete healing in 3 months, whether they received calcium alone or with vitamin D. Adolescents showed no response to calcium alone, but had complete healing with calcium and vitamin D in 3-9 months (mean 5.3 months). Thus deficient calcium intake is universal among children and adolescents with rickets/osteomalacia. Inadequate sun exposure and vitamin D deficiency are important in the etiology of adolescent osteomalacia.     

High prevalence of vitamin D and calcium deficiency among pregnant women and their newborns in Chengdu,China

Background  

Vitamin D and calcium deficiency is common in pregnant women and newborn infants. There are few data about the prevalence of hypovitaminosis D during pregnancy and infancy in China. We assessed vitamin D status of pregnant women and their neonates in Chengdu, Sichuan province, China.     

Higher prevalence of vitamin D deficiency in mothers of rachitic than nonrachitic children

Vitamin D deficiency [serum 25-hydroxyvitamin D <25 nmol/L (<10 ng/mL)] was identified in 92% of rachitic Arab children and 97% of their mothers compared with 22% of nonrachitic children and 52% of their mothers. There was a positive correlation between maternal and child vitamin D levels. We conclude that mothers of rachitic children should be investigated and treated for vitamin D deficiency.     

Prevention of rickets and vitamin D deficiency in infants, children, and adolescents

Rickets in infants attributable to inadequate vitamin D intake and decreased exposure to sunlight continues to be reported in the United States. There are also concerns for vitamin D deficiency in older children and adolescents. Because there are limited natural dietary sources of vitamin D and adequate sunshine exposure for the cutaneous synthesis of vitamin D is not easily determined for a given individual and may increase the risk of skin cancer, the recommendations to ensure adequate vitamin D status have been revised to include all infants, including those who are exclusively breastfed and older children and adolescents. It is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of vitamin D beginning soon after birth. The current recommendation replaces the previous recommendation of a minimum daily intake of 200 IU/day of vitamin D supplementation beginning in the first 2 months after birth and continuing through adolescence. These revised guidelines for vitamin D intake for healthy infants, children, and adolescents are based on evidence from new clinical trials and the historical precedence of safely giving 400 IU of vitamin D per day in the pediatric and adolescent population. New evidence supports a potential role for vitamin D in maintaining innate immunity and preventing diseases such as diabetes and cancer. The new data may eventually refine what constitutes vitamin D sufficiency or deficiency.     

Presentation of vitamin D deficiency

Aims: To describe the various ways in which vitamin D deficiency presents in children in selected districts of London and to identify which factors, if any, determine the mode of presentation. Methods: Retrospective review of patients presenting to Newham General, Royal London, Great Ormond Street, and King''s College Hospitals between 1996 and 2001with either hypocalcaemia or rickets caused by vitamin D deficiency. Children with plasma 25-hydroxyvitamin D levels <25 nmol/l (10 ng/ml) were considered to have vitamin D deficiency. Results: Sixty five children, mostly from Black or Asian ethnic minority groups, were identified, 29 of whom had hypocalcaemic symptoms. Seventeen of these had no radiological evidence of rickets. The remainder (48 children) had radiological evidence of rickets with or without clinical signs. Symptoms and signs reverted to normal in all cases with vitamin D supplementation. All children who presented with symptomatic hypocalcaemia were aged either <3 or >10 years. There was a strong correlation between age at presentation and population growth velocity reference data. Conclusions: Rickets remains a problem in the UK especially in "at risk" ethnic minority groups. Symptomatic hypocalcaemia is an important, but under-recognised presenting feature. Growth rate is likely to be an important factor in determining the mode of presentation. Unexplained hypocalcaemia should be attributed to vitamin D deficiency in "at risk" ethnic minority groups until proved otherwise.