The Association Between Vitamin D Status and Recurrent Wheezing

Objective

To investigate association between vitamin D status and recurrent wheezing in infants.

Methods

Thirty infants with recurrent wheezing and 45 healthy, similar aged infants without any history of acute or chronic illness were included in the study. The clinical features of infants were recorded and serum 25-hydroxyvitamin D [25(OH)D] levels were measured. Data analysis was performed using SPSS 13 package program.

Results

The mean value of 25 (OH) D vitamin levels were 22.1?±?8.9 IU/L and 18.8?±?11 IU/L for the control and recurrent attack group respectively. Seventy-three percent of subjects with recurrent wheezing had vitamin D levels in the deficient range (<20 ng/ml) and 48.9 % had vitamin D levels under?<?20 ng/ml in the control group. The percentage of insufficient vitamin D levels (<30 ng/ml) were 90 and 77.8 for the patient and control group respectively. Eight patients had extremely deficient vitamin D (<10 ng/ml) levels. There was no statistical significance between the groups in terms of the distribution of 25 (OH)D level.

Conclusions

The present study did not demonstrate significant association between vitamin D status and recurrent wheezing in the infants.     

Subclinical hypovitaminosis D among exclusively breastfed young infants

OBJECTIVE: To determine Vitamin D status of mother-newborn diads at birth and of their exclusively breastfed (EBF) infants at 3 months. DESIGN: Longitudinal study. METHODS: Exclusively breastfed infants born at term with birth weight > 2.5 kg to normal, healthy mothers followed till 3 months. Serum calcium, phosphorous, heat labile alkaline phosphatase (HLAP) and 25(OH)D estimated in 42 mother / cord blood diads and in 35 (EBF) infants followed up at 3 months. Twenty five (OH)D < 15 ng/mL was considered low and 15 to 25 ng/mL low to normal. RESULTS: Ca, P, HLAP were significantly higher in cord blood (P < 0.001) but mean 25 (OH)D, 19.36 ng/mL was comparable to maternal level of 22.9 ng/mL (r = 0.82, P < 0.001). At 3 months only HLAP was significantly higher compared to cord blood. Higher 25 (OH)D at 3 months correlated with higher 25 (OH)D values in cord blood (r = +0.616, P < 0.001) as well as higher antenatal maternal levels (r = + 0.552, P < 0.001). Serum 25 (OH)D values < 25 ng/mL was observed in 50 % mothers, 62 % cord blood specimens and 80 % infants at 3 months. CONCLUSIONS: Subnormal maternal vitamin D status is associated with vitamin D deficiency in newborns and persists in exclusively breastfed infants.     

25-hydroxyvitamin D and calcium levels in maternal, cord and infant serum in relation to maternal vitamin D intake

The plasma levels of 25-hydroxyvitamin D (25-OHD), total calcium, phosphorus and proteins were measured in 40 healthy mothers and their infants at the time of delivery during the months of December and January. Calcium, phosphorus and proteins were again measured in the plasma of the infants on the fourth day of life. Vitamin D intake of the mothers during their last 3 months of pregnancy were estimated by interviews. The mean (+/-SE) plasma levels of 25-OHD was 9.0 +/- 0.9 ng/ml in the mothers and 5.05 +/- 0.4 ng/ml in cords. There was a significant correlation between mother and cord plasma levels (r = 0.75, p less than or equal to 0.001). The concentration gradient of 25-OHD plasma levels between mother and cord is higher at high 25-OHD maternal concentrations. This suggests that the placenta plays a regulating role in the 25-OHD transfer between mother and foetus. The 4-day-old infants from mothers having a suboptimal vitamin D intake (less than 150 IU/day) have a lower mean serum plasma level than infants born from mothers with a vitamin D intake of more than 500 IU/day.     

Low serum 25-hydroxyvitamin D levels and bronchiolitis severity in Spanish infants

This cross-sectional study was performed to examine the prevalence of hypovitaminosis D in infants with acute bronchiolitis compared with control subjects and to evaluate the relationship between serum 25-hydroxyvitamin D (25(OH) D) and the severity of bronchiolitis. Serum 25(OH) D levels were measured by radioimmunoassay in 48 infants with acute bronchiolitis (2.5?±?2.0 months) and in 30 healthy infants (3.2?±?2.3 months). 25(OH) D levels (ng/ml) in children with acute bronchiolitis were significantly lower than in the control group (median 29.9 ng/ml (interquartile range (IQR) 21.4–37.5) versus median 38.2 ng/ml ((IQR 26.1–48.1), p?=?0.022), mainly in infants with moderate–severe bronchiolitis (median 29.8 ng/ml, IQR 19.2–35.9). The prevalence of hypovitaminosis D was remarkably greater among infants with bronchiolitis than in control subjects (52.1 versus 26.6 %). A significant inverse correlation was found between serum 25-hydroxyvitamin D levels and disease severity (rho?=??0.457, p?<?0.001). Conclusion: The prevalence of hypovitaminosis D is high in Spanish infants with bronchiolitis. The severity of acute bronchiolitis increases with a decline in serum 25 (OH) D level.     

Prospective study of vitamin D supplementation and rickets in China.

To determine whether amounts of vitamin D lower than recommended doses are effective in preventing rickets, 256 term infants from two northern and two southern cities in China were studied in a randomized trial of vitamin D supplementation (100, 200, or 400 IU/day) during the first 6 months of life. Cord blood and 6-month blood samples were collected and radiographs were obtained at 3 to 5 days and at 6 months of age. Cord serum 25-hydroxyvitamin D concentrations were lower in the north than in the south (5 vs 14 ng/ml (12.5 vs 35.0 nmol/L); p less than 0.01). Wrist ossification centers were less likely to be present at birth in the northern children than in the southern children (p = 0.009) and were more likely to be present in infants born in the fall who had higher cord serum concentrations of 25-hydroxyvitamin D (p = 0.04). Serum 25-hydroxyvitamin D concentrations were lower in northern children 6 months of age than in southern children (p = 0.005) and were higher with an increasing supplemental dosage of vitamin D (p less than 0.001), particularly in infants in the north. None of the infants had rickets at 6 months of age. Because of the low serum 25-hydroxyvitamin D concentrations, especially among infants in the north, it may be prudent to supplement the diet with vitamin D at a dose of 400 IU/day.     

How much vitamin D for neonates?

To assess the adequacy of different dosages of neonatal vitamin D, 25-hydroxyvitamin D serum concentrations were longitudinally monitored in 27 low-birth-weight and 25 full-term well infants from birth to 16 weeks after delivery. The infants were randomly assigned to receive either 10 micrograms/d (400 IU/d) or 20 micrograms/d (800 IU/d) of vitamin D or 0.85 or 1.5 micrograms/d of 25-hydroxyvitamin D3. In each infant who received 10 or 20 micrograms/d of vitamin D 25-hydroxyvitamin D, serum concentrations greater than 20 ng/mL were maintained, with some low-birth-weight infants reaching 60-ng/mL concentrations. Similarly, in the low-birth-weight infants receiving 1.5 and 0.85 micrograms/d of 25-hydroxyvitamin D3, serum 25-hydroxyvitamin D levels greater than 12 ng/mL were maintained. In the full-term infants who received 1.5 micrograms/d of 25-hydroxyvitamin D3, serum 25-hydroxyvitamin D concentrations of greater than 12 ng/mL were maintained, but in those who received 0.85 micrograms/d, serum 25-hydroxyvitamin D concentrations of 10 ng/mL could not be maintained. These vitamin D status data document that 10 micrograms (400 IU) of vitamin D represents a sufficient daily intake for both premature and full-term well infants. These data also indicate that while as little as 0.85 micrograms/d of 25-hydroxyvitamin D3 may facilitate vitamin D sufficiency in low-birth-weight neonates, it does not do so in full-term infants.     

1 alpha,25(OH)2D3 inhibits not only Th1 but also Th2 differentiation in human cord blood T cells

Human naive CD4+ T helper (Th) and CD8+ cytotoxic (Tc) T cells, which only produce IL-2, may differentiate into Th1/Tc1- or Th2/Tc2-like lymphocytes, characterized by their cytokine production profile. 1 alpha,25-dihydroxyvitamin D3 (1 alpha, 25(OH)2D3) has been reported to inhibit Th1/Tc1-related, but increase Th2/Tc2-associated cytokines in T cells from adults. In industrialized countries, vitamin D supplementation for prevention of rickets is initiated within the first days of life and continued throughout the entire first year. Epidemiologic studies suggest an association of vitamin D exposure in newborns with the incidence of allergic diseases in later life. This study addresses the effects of 1 alpha, 25(OH)2D3 on Th1/Tc1 versus Th2/Tc2 differentiation in long term cell cultures of (naive) cord blood T lymphocytes. Our results show that in CD4+ as well as CD8+ cord blood cells, 1 alpha, 25(OH)2D3 inhibits not only IL-12-generated IFN-gamma production, but also suppresses IL-4 and IL-13 expression induced by IL-4. Thus, in cord blood 1 alpha, 25(OH)2D3 induces a T cell population without predominance of Th2 related cytokines.     

Status of vitamin D in children with sickle cell disease living in Madrid, Spain

Patients with sickle cell disease have vitamin D deficiency and poor bone health which makes them prone to have an increased risk of fractures and osteoporosis in adulthood. We performed a prospective, cross-sectional study in children diagnosed with sickle cell disease living in Madrid, Spain. The purpose of this study was to evaluate the status of vitamin D of these children. Patients 0?C16?years old were enrolled between 2008 and 2011. We studied demographics, calcium metabolism, and bone health, especially by measuring levels of 25-hydroxyvitamin D (25(OH)D), during different seasons of the year, and bone densitometry (beyond 4?years of age). Seventy-eight children were included in the study. Mean age was 4.8?±?4.3?years, and mean serum 25(OH)D level was 21.50?±?13.14?ng/ml, with no differences in 25(OH)D levels within different seasons. Fifty-six percent of children had levels of 25(OH) vitamin D of <20?ng/ml, whereas 79 and 18?% of them had levels of <30 and <11?ng/ml, respectively. Secondary hyperparathyroidism was observed in 25?% of children. Densitometry was performed in 33 children, and an abnormal z-score was seen in 15.2?% of them with no correlation with levels of 25(OH)D. Conclusions: Vitamin D deficiency is highly prevalent in children with sickle cell disease, who are residing in Madrid, Spain, and it is detected at a young age. We propose that early intervention may increase the possibility of an adequate bone density later in life.     

早产儿维生素D两种补充方案的疗效对比：前瞻性随机对照研究

目的 探讨不同维生素D补充方案对出生胎龄 < 34周早产儿生后第28天维生素D营养状况的影响。方法 将59例2018年10月至2019年10月出生胎龄 < 34周的住院早产儿随机分为肌注组（n=30）和口服组（n=29）。肌注组单次肌内注射维生素D₃注射液（10 000 IU/kg）,口服组口服维生素D₃滴剂（900 IU/d）,持续25 d。采集两组患儿生后48 h内（维生素D₃补充前）及第28天静脉血,检测血清25-羟维生素D[25(OH) D]水平。结果 生后48 h内,59例早产儿维生素D缺乏（≤15 ng/mL）率为78%;两组血清25(OH) D水平及维生素D缺乏率比较差异无统计学意义（P > 0.05）。生后第28天,肌注组血清25(OH) D水平显著高于口服组（P < 0.05）,肌注组维生素D缺乏率显著低于口服组（P < 0.05）,且无维生素D过量或中毒病例。结论 单次肌内注射10 000 IU/kg维生素D₃可显著提升出生胎龄 < 34周早产儿生后第28天血清25(OH) D水平,且能安全并有效地降低维生素D缺乏率。     

VITAMIN D METABOLISM IN PRETERM INFANTS

ABSTRACT. In order to evaluate after birth the changes in circulating vitamin D metabolite levels in preterm babies supplemented with vitamin D (2100 I. U./d), the serum concentration of 25-hydroxyvitamin D [25-OHD] and 1 α,25-dihydroxy vitamin D [1, 25(OH)₂D] were measured in 22 infants (31 to 35 weeks of gestation) from birth up to 96 hours of age. Compared to cord blood levels, serum calcium decreased significantly during the first 24 hours of life ( p <0.005) and remained low until day 4. Serum immunoreactive parathyroid hormone (iPTH) levels increased from birth to 24 hours and then plateaued. The 25-OHD levels at birth were 27.5±2.5 nmol/l and increased to 67.5±12.5 nmol/l ( p <0.005) during the four days of the study. During the same period, the 1, 25(OH)₂D serum levels increased steadily from 84<7 to 343<105 pmol/l ( p <0.005). At all times, there was a positive correlation between 25-OHD levels and those of 1, 25(OH)₂D. Our data demonstrate that in preterm infants after 31 weeks of gestation, absorption and activation of vitamin D is present as soon as 24 hours after birth and that early neonatal hypocalcemia is unlikely to be caused by an impairment of either PTH secretion or vitamin D activation.     

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.     

The plasma levels of 25-hydroxyvitamin D in patients with various liver diseases and the response of 25-hydroxyvitamin D to vitamin D treatment.

The mean plasma levels of 25-hydroxyvitamin D (25-OH-D) were measured before and after the administration of 2000 units of daily oral vitamin D2 for a period of 2 weeks in 9 normal infants and children, 7 infants with neonatal hepatitis and persistent neonatal hepatitis, and 4 infants with congenital biliary atresia. The mean plasma level of 25-OH-D increased significantly from 19.5 +/- 3.7 (S.E.) ng/ml to 34.0 +/- 6.8 (S.E.) ng/ml after administration of vitamin D2 in controls (p less than 0.05). The mean plasma level of 25-OH-D also increased from 8.0 +/- 2.1 (S.E.) ng/ml to 22.1 +/- 2.6 (S.E.) ng/ml after vitamin D treatment in hepatitis group (p less than 0.05). In patients with congenital biliary atresia, vitamin D treatment did not affect eh plasma levels of 25-OH-D.     

0~7岁儿童25羟维生素D和骨密度的关系研究

目的 评价 0~7 岁儿童维生素 D（VitD）营养状况及与骨密度的关系。方法 选择生长发育门诊因“生长发育缓慢、夜惊、多汗、烦躁不安”等就诊的儿童 6 838 人,采用化学发光法法测定血清 25 羟VitD [25-（OH）D] 水平,并同时应用定量超声仪进行骨密度检测。结果 研究对象血清 25-（OH）D 的水平为34±14 ng/mL,定量超声骨密度 Z 值为 -0.49±0.54。随着年龄增长,25-（OH）D 和骨密度水平逐渐降低,且 VitD缺乏、不足及骨密度不足的检出率逐渐增加（PPP结论 学龄前期和学龄期儿童 VitD 不足和缺乏的现象较婴幼儿更严重。在一定范围内 VitD 水平和骨密度可能有关。     

Vitamin D Status of term exclusively breastfed infants and their mothers from India

Objectives: (i) To measure 25‐OH vitamin D levels in term infants at 10 weeks and 6 months and to correlate with maternal vitamin D levels at 10‐week postpartum (ii) To evaluate infants at 6 months for rickets. Patients and methods: A total of 179 exclusively breastfed infant–mother pairs 96 appropriate‐for‐gestational age (Group 1) and 83 small‐ for‐ gestational age infants (Group 2) recruited at 10 weeks. At 6 months, 52 in group 1 and 45 in group 2 were evaluated. Venous blood sample were collected at 10 weeks and 6 months in infants and at 10 weeks in mothers for calcium, phosphorus, alkaline phosphatase and 25‐OH vitamin D estimation. Results: Mean 25‐OH vitamin D levels of infants (n = 97) were 11.55 ± 7.17 ng/mL at 10 weeks and 16.96 ± 13.33 ng/mL at 6 months (p < 0.001). Mean vitamin D levels of infants in group 1 and group 2 did not differ at recruitment and 6 months (p > 0.05)). Maternal vitamin D levels in group 1 and group 2 were 8.89 ± 5.97 and 9.87 ± 6.44 ng/mL, respectively (p = 0.44). Significant correlation was observed between 25‐OH vitamin D of infants and mothers (p < 0.05). At 10 weeks, 55.67% infants, 70% mothers and at 6 months, 44.33% infants had vitamin D < 11 ng/mL. At 6 months, 16.49% infants developed rickets. Conclusions: Exclusively breastfed infants and their mothers are Vitamin D deficient, hence the need to improve vitamin D status.     

25-hydroxy-vitamin-D in serum of newborns and infants during continuous oral vitamin D treatment (author's transl)

Using the Haddad modified method, 25-OH-D were measured in the blood of the umbilical cord of 29 infants and in peripheral serum after 6 weeks. 16 infants were given a daily dosage of 1000 I. E., 13 infants 500 I. E. vitamin D against rickets. Further they were fed with an adapted milk containing 400 I. E. vitamin D/1. The mean cord serum values were 13 and 15 ng/ml. After treatment with 1000 I. E., 25-OH-D values around 54 ng/ml were measured after 6 weeks and under 500 I. E. daily, values of 37 ng/ml, respectively. Treatment using a dosage of 500 I. E. vitamin D combined with feeding with vitamin D fortified milk seems adequate, to prevent vitamin D depletion.     

Bone mineral content, serum vitamin D metabolite concentrations, and ultraviolet B light exposure in infants fed human milk with and without vitamin D2 supplements

OBJECTIVE: To monitor ultraviolet B light exposure in human milk-fed infants both with and without supplemental vitamin D2, and to measure longitudinally the bone mineral content, growth, and serum concentrations of calcium, phosphorus, 25-hydroxyvitamin D3, 25-hydroxyvitamin D2, 1,25-dihydroxyvitamin D, and parathyroid hormone. DESIGN: Longitudinal, randomized, double-blind, placebo-controlled study of 6 months' duration. SETTING: Patients from private pediatric practice, Madison, Wisconsin. PATIENTS: Sequential sampling of 46 human milk-fed white infants; 24 received 400 IU/day of vitamin D2, and 22 received placebo. An additional 12 patients were followed who received standard infant formula. Eighty-three percent of patients completed a full 6 months of the study. MEASUREMENTS and RESULTS: Ultraviolet B light exposure and measurements of growth did not differ between groups. At 6 months, the human milk groups did not differ significantly in bone mineral content or serum concentrations of parathyroid hormone or 1,25-dihydroxyvitamin D, although total 25-hydroxyvitamin D values were significantly less in the unsupplemented human milk group (23.53 +/- 9.94 vs 36.96 +/- 11.86 ng/ml; p less than 0.01). However, 25-hydroxyvitamin D3 serum concentrations were significantly higher in the unsupplemented human milk-fed group compared with the supplemented group (21.77 +/- 9.73 vs 11.74 +/- 10.27 ng/ml, p less than 0.01) by 6 months of age. CONCLUSION: Unsupplemented, human milk-fed infants had no evidence of vitamin D deficiency during the first 6 months of life.     

Perinatal vitamin D metabolism. II. Serial 25-hydroxyvitamin D concentrations in sera of term and premature infants.

Serial concentration values of 25-hydroxyvitamin D (25-OHD) were determined in the sera of term, premature, and twin infants. In infants born at term with normal concentrations of 25-OHD in cord blood, serial concentrations of 25-OHD remained normal; in infants born at term with low concentrations of 25-OHD in cord blood, serial concentrations of 25-OHD increased. In premature infants with normal concentrations of 25-OHD in cord blood, serial concentrations of 25-OHD decreased; in premature infants with low values of 25-OHD in cord blood, serial concentrations of 25-OHD did not increase until a postconceptual age of 36 to 38 weeks. The concentrations of 25-OHD in the sera of twin infant pairs followed parallel courses. Oral and intravenous supplementation of vitamin D did not significantly increase the concentrations of 25-OHD in serum of premature infants. These findings suggest that a decreased rate of 25-hydroxylation of vitamin D may be a factor impairing homeostasis of 25-OHD in premature infants.     

THE PLASMA LEVELS OF 25-HYDROXYVITAMIN D IN PATIENTS WITH VARIOUS LIVER DISEASES AND THE RESPONSE OF 25-HYDROXYVITAMIN D TO VITAMIN D TREATMENT

ABSTRACT. The mean plasma levels of 25-hydroxyvitamin D (25-OH-D) were measured before and after the administration of 2000 units of daily oral vitamin D₂ for a period of 2 weeks in 9 normal infants and children, 7 infants with neonatal hepatitis and persistent neonatal hepatitis, and 4 infants with congenital biliary atresia. The mean plasma level of 25-OH-D increased significantly from 19.5±3.7 (S.E.) ng/ml to 34.0±6.8 (S.E.) ng/ml after administration of vitamin D₂ in controls ( p <0.05). The mean plasma level of 25-OH-D also increased from 8.0±2.1 (S.E.) ng/ml to 22.1±2.6 (S.E.) ng/ml after vitamin D treatment in hepatitis group ( p <0.05). In patients with congenital biliary atresia, vitamin D treatment did not affect the plasma levels of 25-OH-D.     

Serum vitamin D metabolites in very low birth weight infants with and without rickets and fractures

Seventy-one very low birth weight (less than or equal to 1500 gm) infants were studied to determine the sequential changes in serum vitamin D metabolite concentrations between infants with and without radiographically documented rickets, fractures, or both (R/F). Usual intake of vitamin D included 20 IU/kg/day from parenteral nutrition or 400 IU/day supplementation with enteral feeding. Radiographs of both forearms and serum samples were obtained at 3, 6, 9, and 12 months. Twenty-two infants had R/F. At 3 months, significantly lower mean (+/- SEM) serum phosphorus levels (4.5 +/- 0.4 vs 6.1 +/- 0.2 mg/dl), higher 1,25-dihydroxyvitamin D (1,25-[OH]2D) concentrations (96 +/- 5 vs 77 +/- 4 pg/ml), and higher free 1,25-(OH)2D index (1,25-[OH]2D:vitamin D binding protein ratio; 5.2 +/- 0.3 x 10(5) vs 4.0 +/- 0.2 x 10(5] were found in the R/F group. These values returned to normal and were similar between groups on subsequent measurements. Serum calcium, magnesium, and 25-hydroxyvitamin D (25-OHD) concentrations were normal and similar between groups. In both groups, serum vitamin D binding concentrations increased initially but remained stable and normal beyond 6 months. We conclude that in very low birth weight infants with R/F, the vitamin D status (as indicated by serum 25-OHD concentrations) is normal, and that lowered serum phosphorus levels, higher serum 1,25-(OH)2D levels, and a higher free 1,25-(OH)2D index support the thesis that mineral deficiency (especially of phosphorus) may be important in the pathogenesis of R/F in small preterm infants.     

Vitamin D insufficiency common in newborns, children and pregnant women living in Newfoundland and Labrador, Canada

Vitamin D deficiency is associated with poor bone health, colorectal cancer, type 1 diabetes and multiple sclerosis. Two national health-related societies in Canada have made recommendations for vitamin D supplementation, yet little research has been reported on the vitamin D status of Canadians. Lifestyle changes, such as sunscreen use, spending less time outdoors and insufficient intake of vitamin D-containing foods as well as northern latitude, may be affecting human vitamin D status. A cross-sectional analysis of 25-hydroxyvitamin D [25-(OH)D] was conducted in pregnant women, newborns (umbilical cord blood) and children. Samples were analysed by liquid chromatography mass spectrometry. Published ranges for 25-(OH)D were used to determine vitamin D status. The prevalence of 25-(OH)D deficiency for the three groups studied revealed most concentrations in the 25-(OH)D deficiency or insufficiency ranges. There were significant differences in all groups studied between seasons, with the exception of maternal blood and female cord blood samples. 25-(OH)D insufficiency was common in all groups for winter and summer, more so in winter. 25-(OH)D insufficiency was common in the three groups studied. The Newfoundland and Labrador population may be at increased risk for vitamin D insufficiency because of factors such as northern latitude and lifestyle issues. Further research on the vitamin D status of this population is important, considering the potential adverse health-related outcomes and the recommendations on supplementation being made.