Median 25OHD Concentration Research Articles

Failure of national antenatal vitamin D supplementation programme puts dark skinned infants at highest risk: A newborn bloodspot screening study

To determine the prevalence of vitamin D deficiency on dried blood spots (DBS) obtained at newborn blood spot screening (NBS) and thereby test the efficacy of the UK national antenatal supplementation programme in an increasingly ethnically diverse English population. To evaluate the seasonal and ethnic variation in neonatal plasma 25 hydoxyvitamin D (25OHD) and its determinants. Three thousand random DBS samples received at a single regional newborn screening laboratory (52°N) over two one-week periods, one in winter (February 2019) and one in summer (August 2019), were collected. Data was collected from NBS cards on birth weight, gestational age, maternal age, ethnicity, and post code which was replaced with index of multiple deprivation (IMD). 25OHD concentrations were measured on 6mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry adjusted to equivalent plasma values. 25OHD variation with season was assessed using Mann-Whitney U test and ethnic groups compared using Kruskal-Wallis test. Linear regression was used to assess the determinants of 25OHD concentrations. 25OHD measurements were available in 2999 (1580 males) subjects [1499 winter-born and 1500 summer-born]. The majority were white British (59.1%) and born at term (mean±SD gestational age of 38.8±1.8 weeks) with a mean (±SD) birth weight of 3306 (±565) grams. The overall prevalence of vitamin D deficiency [25OHD<30nmol/L (12μg/L)] was 35.7% (n=1070) and insufficiency [30-50nmol/L (12-20μg/L)] 33.7% (n=1010). The median (IQR) 25OHD concentration was significantly lower in the winter-born compared to summer-born [29.1 (19.8, 40.6) vs 49.2 (34.3, 64.8) nmol/L respectively; p<0.001]. Across both seasons, when compared to white British babies (41.6nmol/L), the median 25OHD concentrations were significantly lower in babies of black (30.3nmol/L; p<0.001), Asian (31.3nmol/L; p<0.001), any other mixed (32.9nmol/L; p<0.001), mixed white and black (33.7nmol/L; p<0.05) and any other white (37.7nmol/L; p<0.05) ethnicity. The proportion of deficiency was also higher in babies of Asian (48%), black (47%) and mixed ethnicity (38-44%) compared to any other white (34%) or white British (30%) ethnicity. Season of birth, ethnicity, gestation and maternal age accounted for almost 24% of the variation in 25OHD concentrations. The current UK antenatal supplementation programme fails to protect newborns from vitamin D deficiency, especially those from minority ethnic groups who are at high risk of vitamin D deficiency. Nearly 70% of all newborns and 85% of winter-borns had 25OHD concentrations below 50nmol/L (20μg/L). Almost 50% of babies of Black or Asian origin were deficient at birth, which explains their high risk of hypocalcaemic complications and rickets if left unsupplemented. Our findings call for an immediate review of the delivery of antenatal and infant vitamin D supplementation programmes and implementation of food fortification in the long term.

Association between serum 25-hydroxyvitamin D concentration and severity of first-diagnosed bullous pemphigoid in older adults

BackgroundHigher vitamin D status has been associated with symptom improvement and decreased risk of various autoimmune disorders. Our objective was to determine whether higher serum 25-hydroxyvitamin D (25OHD) concentration correlated with less severe first-diagnosed bullous pemphigoid (BP) in older inpatients. MethodsThis cross-sectional study was performed from November 2012 to February 2014 among 30 consecutive older inpatients (21 women; mean ± SD, 83 ± 7 years; all Caucasian) with a de novo diagnosis of active BP recruited in the Department of Dermatology of Angers University Hospital, France. The severity of BP was graded clinically on the basis of i) the number of bullae during the first three days of hospitalization (grade 0–4, worse), and ii) the extent of the lesions (grade 0–5, worse). ResultsSixteen participants had ≤ 5 bullae at the time of diagnosis, 8 had 6–20 bullae, 3 had 20–50 bullae, and 3 had >50 bullae. The lesions were spread over 5 cutaneous areas in 5 participants (17%). The median 25OHD concentration was 23 [IQR, 16–42] nmol/L. Serum 25OHD concentration was inversely correlated with the bullae grade (ρ = − 0.38, p = 0.04) and the lesion extension grade (ρ = − 0.50, p = 0.005). ConclusionsHigher serum 25OHD concentration correlated with less severe BP prior to initiation of treatment among our sample of older inpatients. This result suggests that vitamin D may be involved in the pathophysiology of BP and could serve as prognostic biomarker of BP.

Cross-sectional evaluation of the relationship between vitamin D status and supplement use across levels of kidney function in adults

ObjectivesThe objective of this study was to assess vitamin D status of US non-pregnant adults using a standardised assay across 15 mL/min/1.73 m2 increments of kidney function, report the use...

Association of vitamin D deficiency, season of the year, and latent tuberculosis infection among household contacts.

ObjectivesVitamin D (VD) enhances the immune response against Mycobacterium tuberculosis in vitro, and VD deficiency has been described in patients with active tuberculosis (TB). However, the role of hypovitaminosis D in the pathogenesis of early TB infection acquisition is unclear. We aimed to evaluate the association of VD deficiency, season of the year, and latent TB infection in household contacts (HHC), given that this is a potentially modifiable condition often related to nutritional deficiencies and lack of sun exposure.MethodsWe prospectively enrolled new pulmonary TB cases (n = 107) and their HHC (n = 144) over a 2-year period in Santiago, Chile. We compared plasma 25-hydroxycholecalciferol (25OHD) levels and examined the influence of season, ethnic background, living conditions, and country of origin.ResultsOver 77% of TB cases and 62.6% of HHC had VD deficiency (<20 ng/ml). Median 25OHD concentration was significantly lower in TB cases than in HHC (11.7 vs. 18.2 ng/ml, p<0.0001). Migrants HHC had lower 25OHD levels than non-migrants (14.6 vs. 19.0 ng/ml, p = 0.026), and a trend towards a higher burden of latent TB infection (52.9% vs. 35.2%, p = 0.066). Multivariate analysis found VD deficiency in HHC was strongly associated with being sampled in winter/spring (adOR 25.68, 95%CI 7.35–89.7), corresponding to the seasons with lowest solar radiation exposure. Spring enrollment–compared with other seasons–was the chief risk factor for latent TB infection in HHC (adOR 3.14, 95%CI 1.28–7.69).ConclusionsHypovitaminosis D was highly prevalent in TB cases and also in HHC. A marked seasonality was found for both VD levels and latent TB in HHC, with winter being the season with lowest VD levels and spring the season with the highest risk of latent TB infection.

Determinants of Neonatal Vitamin D Levels as Measured on Neonatal Dried Blood Spot Samples

Background: Vitamin D deficiency is linked to adverse childhood health outcomes, yet data on the distribution and quantifiable determinants of neonatal 25-hydroxyvitamin D₃ (25OHD) concentration, a vitamin D biomarker, are limited. Objective: Our aim was to identify determinants of neonatal 25OHD concentration, measured using neonatal dried blood spots (DBS). Methods: A total of 259 ethnically diverse children aged 0-16 years born in Victoria, Australia, were recruited. Data included maternal sun exposure, skin type, 25OHD concentration on stored neonatal DBS, and genotypes at the target genes. Associations were investigated using multiple linear regression models. Results: The median 25OHD concentration was 29.2 nmol/l (IQR 18.0-47.4). Measured 25OHD was <50 nmol/l in almost half of the neonatal sample. Ambient ultraviolet radiation (UVR) 6 weeks before birth was the strongest predictor of neonatal 25OHD, accounting for 23% of its variation. A further 10% was explained by infant genetic variants at GC (rs2282679), the gene encoding the vitamin D binding protein, and DHCR7 (rs12785878), a gene required for synthesis of 7-dehydrocholesterol, a precursor to 25OHD. DBS age explained 7%, and patterns of maternal sun exposure and clothing choices accounted for 4%. A child's skin colour was strongly associated with GC gene variants and not independent of these variants in predicting 25OHD. The final model explained 43% of the total variance in neonatal 25OHD concentration. Conclusion: Maternal lifestyle factors and infant genetic variants predict neonatal 25OHD levels; the importance of maternal UVR exposure in late pregnancy is highlighted.

Vitamin D Deficiency in Uygurs and Kazaks Is Associated with Polymorphisms in CYP2R1 and DHCR7/NADSYN1 Genes

BackgroundOur study is aimed to 1) clarify the vitamin D status in Uygur and Kazak ethnic populations and 2) elucidate the relationship between 14 SNPs (in 5 vitamin D-related genes) and vitamin D deficiency in these 2 ethnic populations.Material/MethodsA multistage-cluster sampling survey was carried out for residents with Uygur or Kazak ethnicity in Xinjiang, China. Anthropometric measurements were taken and the concentrations of 25OHD were measured. Fourteen common variants in VDR, GC, CYP2R1, CYP27B1, and DHCR7/NADSYN1 were genotyped by using multiple SNaPshot assay. Logistic regression analysis was performed to identify the possible risk factors for vitamin D deficiency, after adjusting for several environmental and biological factors. The pattern of SNP associations was distinct between Uygurs and Kazaks.ResultsAnthropometric measurements and the concentrations of 25OHD were obtained from 1873 participants (945 Uygur ethnic and 928 Kazak ethnic). The genotypes of 14 SNPs were measured for 300 Uygurs and 300 Kazaks. The median 25OHD concentration was as low as 10.4 ng/ml in Uygurs and 16.2ng/ml in Kazaks. In Uygurs, the prevalence of vitamin D deficiency, in-sufficiency, and sufficiency was 91.2%, 5.8%, and 3.0%, respectively. CYP2R1-rs10766197 was significantly associated with the presence of vitamin D deficiency in the Uygur ethnic population (P=0.019, OR=6.533, 95%C.I.: 361–31.357), while DHCR7/NADSYN1-rs12785878 was significantly associated with the presence of vitamin D deficiency in the Kazak ethnic population (P=0.011, OR=2.442, 95%C.I.: 1.224–4.873). Of 10 SNPs in VDR and GC genes, none was associated with vitamin D status in these 2 ethnic populations.ConclusionsVitamin D insufficiency is highly prevalent in Uygurs and Kazaks living in Xinjiang, China. Polymorphisms in CYP2R1-rs10766197 and DHCR7/NADSYN1-rs12785878 are associated with vitamin D deficiency in Uygur and Kazak ethnic populations.

Vitamin D status of schoolchildren in Northern Algeria, seasonal variations and determinants of vitamin D deficiency

There are no published data on the vitamin D status of children living in North Africa. In 435 healthy Algerian children 5-15 years old, we found that vitamin D insufficiency (serum 25-hydroxyvitamin D (25OHD) <50 nmol/L) was frequent, especially in winter. Low vitamin D status was associated with increased parathyroid hormone (PTH) and leg deformation As there are no published data on the vitamin D status of children living in North Africa, we evaluated the 25OHD concentration of healthy Algerian children at the end of summer and at the end of winter. As secondary objectives, we studied the various determinants of vitamin D status and the PTH-25OHD relationship in these subjects. Four hundred thirty-five children 5-15 years old were examined and had a blood sample in September 2010. Of them, 408 were sampled again in March 2011. Median 25OHD concentration in the whole group was 71.4 nmol/L in September and 52.9 nmol/L in March. In September, 58.4, 29.9, and 8.1% had a 25OHD concentration below 75, 50, and 30 nmol/L respectively. In March, these percentages increased to 65.2, 41.4, and 17.4% for the 75, 50, and 30 nmol/L threshold, respectively. In multivariate analysis, older age, darker skin phototype, low daily vitamin D and calcium intake, poor socioeconomic status, and short daily sun exposure remained significantly associated with a 25OHD <50 nmol/L at both visits. In 72 (16.6%) children, genu varum/valgum was present. Compared to the 363 children without leg deformation, they presented more frequently with the risk factors of vitamin D insufficiency. They also had lower 25OHD concentrations and higher PTH and tALP. Serum PTH and 25OHD concentrations were negatively and significantly correlated (r = -0.43; p < 0.001) without a 25OHD threshold above which PTH does not decrease anymore. Despite a sunny environment, vitamin D insufficiency is frequent in healthy Algerian children.

Vitamin D deficiency and changes in serum vitamin D levels with treatment among tuberculosis patients in South Korea

Vitamin D deficiency has been reported to be associated with the development of active tuberculosis (TB), but many discrepancies exist among studies. The aims of this study were to compare the frequency of vitamin D deficiency in a Korean population of TB patients and control subjects, and to monitor the changes in vitamin D levels during TB treatment. Patients with newly diagnosed TB were prospectively enrolled. In addition, healthy volunteers or patients with diseases other than TB were enrolled as controls. Baseline serum 25-hydroxyvitamin D (25-OHD) levels were measured in both groups and compared. In the TB patients, measurements of serum 25-OHD were repeated 1 month after the initiation of treatment and again after completion of treatment. In total, 116 patients with TB and 86 control subjects were recruited. The median 25-OHD concentration was not different in TB patients at diagnosis (13.9 ng/mL; interquartile range (IQR) 8.80-21.8) compared with control subjects (13.2 ng/mL; IQR 9.6-19.3) (P = 0.97). The frequency of vitamin D deficiency (≤ 10 ng/mL) was also not different in TB patients (36.2%) compared with controls (27.3%) (P = 0.21). In TB patients, the median 25-OHD concentration decreased significantly during treatment, to 12.5 ng/mL at 1 month and 11.0 ng/mL on completion of treatment (P = 0.01). Vitamin D levels do not appear to be associated with the development of TB in the Korean population. The median 25-OHD concentration decreased after treatment for TB.

Comparison of high performance liquid chromatography, radio immunoassay and electrochemiluminescence immunoassay for quantification of serum 25 hydroxy vitamin D

Objective To compare the performance of radioimmunoassay (RIA) with high-performance liquid chromatography (HPLC) and electrochemiluminescence (ECLIA) for the quantification of vitamin D (25OHD). Methods HPLC method for the determination of 25OHD in human biological samples was developed and compared in terms of accuracy and precision with a commercially available RIA assay. Performance of RIA assay with ECLIA technology for 25OHD analysis was further compared. Results Median 25OHD levels with HPLC vs. RIA were 50.1 nmol/L (IQ = 17.7–199.4 nmol/L) and 51.1 nmol/L (IQ = 12.5–187.2 nmol/L) respectively, whereas median 25OHD concentration with RIA vs. ECLIA was 32.4 nmol/L (9.98–199.7 nmol/L) and 29.9 nmol/L (4.9–214.6 nmol/L), respectively. Comparison data for HPLC vs. RIA showed RIA = − 1.13 + 1.01 (HPLC) (RMSE = 11.2 nmol/L) and for RIA vs. ECLIA revealed, ECLIA = 3.21 + 0.9 (RIA) (RMSE9.6 nmol/L). Conclusion Acceptable correlation was observed among HPLC and RIA and also with RIA and ECLIA in quantification of 25OHD.

Plasma concentrations of vitamin D metabolites before and during treatment of vitamin D deficiency rickets in children.

Plasma concentrations of 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D (1,25-(OH)2D), and 24,25-dihydroxyvitamin D (24,25-(OH)2D) were determined in 17 children with vitamin D deficiency rickets before therapy was started. Thirteen of them also had these tests repeated during treatment. The median 25-OHD concentration was at the lower limit of the reference range before, but increased distinctly within one week of treatment with 1 700-4 000 IU vitamin D per day (17 vs. 37 nmol/l, p less than 0.01). 24,25-(OH)2D was undetectable in twelve of the patients before therapy. Detectable concentrations were in the range of 1.7 to 3.5% of the corresponding 25-OHD levels throughout the study, and the two metabolites were closely correlated (r = 0.84, p less than 0.0005). The median 1,25-(OH)2D concentration was near the average of the reference range before, but increased to well above the upper limit of normal within one week of treatment (121 vs. 368 pmol/l, p less than 0.01). The levels were largely normal after 10 weeks of therapy, as were the plasma concentrations of calcium, phosphate, and alkaline phosphatase. Parathyroid activity, as judged by serum parathyroid hormone or urinary cyclic AMP concentrations, was stimulated in 11 of 12 children studied prior to treatment. It is concluded that there may be no clear-cut differences between normal nad rachitic values of the different vitamin D metabolites under practical clinical conditions. A low 25-OHD level combined with evidence of a stimulated parathyroid activity, and a rise of 1,25-(OH)2D levels to supernormal values following a few days of vitamin D therapy may be diagnostic clues.

Plasma concentrations of vitamin D metabolites in premature infants.

The plasma concentrations of 25-hydroxyvitamin D (OHD), 1,25-(OH)2D and 24,25-(OH)2D were determined in 28 healthy premature infants (median gestational age 33, range 28-36 wk; and median birth weight 1880, range 900-2350 g) during the first 5-10 wk of life, and in a reference group of 17 young adults. The infants received a vitamin D supplement of 500 IU/d and a diet low in calcium (Ca) and phosphorus (P) compared with that of corresponding intrauterine accretion rates. The median 25-OHD concentration increased from 11 (range 6-30) ng/ml at 1 d to 27 (range, 15-41) ng/ml by 5-10 wk of age (P less than 0.01). 1,25-(OH)2D concentrations at age 1 d were similar to the adult levels (median 37, range 8-64 versus 35, range 18-58 pg/ml), but increased significantly within 1 wk to 48 (26-156) pg/ml (P = 0.01), and between 1 and 3-4 wk of age to 104 (58-203) pg/ml (P less than 0.01). The levels at 5-10 wk were similar to the 3-4 wk value. 24,25-(OH)2D concentrations were persistently low compared with the adult levels (medians 0.4-0.5, range less than 0.3-2.1 versus 1.7, range 0.4-2.0 ng/ml, P less than 0.01). The relative concentrations, expressed as the ratio of 24,25-(OH)2D to 25-OHD, were comparable to those of the adults at birth, but decreased significantly within 2 wk. The data demonstrate that healthy premature infants can produce high plasma levels of 1,25-(OH)2D.