Association Of Plasma 25-hydroxyvitamin Research Articles

Associations of Plasma 25-Hydroxy Vitamin D and Dietary Vitamin D Intake with Insulin Resistance in Healthy Japanese Women.

We investigated the associations of plasma 25-hydroxy vitamin D (25(OH)D) concentration and the dietary intake of vitamin D with insulin resistance in Japanese women. Study participants were 406 Japanese women attended a health examination. They were not taking hormones or medications for diabetes and had no history of cancer, ischemic heart disease, or stroke. Information regarding medical history and lifestyle factors was obtained by a self-administered questionnaire, while hours of sun exposure were determined through interviews. Dietary intake of vitamin D was evaluated using a validated food frequency questionnaire. Fasting plasma glucose and insulin concentrations were measured, and insulin resistance (HOMA-IR) scores were calculated based on homeostasis model assessment. Women with vitamin D deficiency (25(OH)D<20 ng/mL) had significantly higher fasting plasma insulin concentration and HOMA-IR than did the other women. Plasma 25(OH)D concentration was significantly and inversely associated with fasting plasma insulin level and HOMA-IR after controlling for age, season, menopausal status, BMI, smoking status, alcohol intake, physical exercise, and intakes of fat and calcium. Dietary vitamin D intake was not associated with HOMA-IR concentration after adjusting for these covariates and hours of sun exposure. Although significant inverse association between plasma 25(OH)D concentration and HOMA-IR was observed in women with a low BMI, low fat intake, or a high calcium intake, the interaction terms were not statistically significant. Data suggest that plasma vitamin D, but not dietary vitamin D, is inversely associated with fasting plasma insulin concentration and HOMA-IR in non-diabetic Japanese women.

Vitamin D status and leukocyte telomere length in middle childhood.

Short telomere length is associated with chronic diseases and decreased lifespan. Vitamin D and its binding protein (DBP) may maintain telomeres through anti-inflammatory actions, yet the role of vitamin D on telomere length is uncertain, especially in children. We assessed the cross-sectional associations of plasma 25-hydroxy vitamin D (25(OH)D) and DBP with leukocyte telomere length (LTL) in a group of 447 children ages 5-12 years from the Bogotá School Children Cohort. We compared the distribution of age-standardized LTL (z-score) between 25(OH)D categories and between DBP quartiles overall and by sex. Overall, 25(OH)D was not significantly associated with LTL. Nonetheless, among boys, 25(OH)D < 50 nmol/L was related to an adjusted 0.36 shorter LTL z-score (95% CI: -0.71, -0.01; P = 0.046) compared with 25(OH)D ≥ 75 nmol/L. There was no association among girls. DBP was not significantly related to LTL. Intervention studies are warranted to determine whether increasing vitamin D status enhances telomere length.

Immune Response in Vitamin D Deficient Metastatic Colorectal Cancer Patients: A Player That Should Be Considered for Targeted Vitamin D Supplementation.

Simple SummaryIn this study, we investigated the role of vitamin D levels and the impact on immune response in patients with mCRC and propose a vitamin D cut-off level. Among several hematological, biochemical and immunological variables, we identified the neutrophils-to-lymphocytes ratio, CD4+ T lymphocytes and B lymphocytes as being closely related to vitamin D status with an impact on survival.Background: Vitamin D deficiency is a poor prognostic factor in metastatic colorectal cancer (mCRC); however, targeted supplementation trials have so far yielded limited results. We investigated clinical-laboratory parameters influencing vitamin D deficiency, with a particular focus on immune response, and the effect on survival. These parameters could help optimize targeted supplementation therapy. Methods: Association of plasma 25-hydroxyvitamin D (25(OH])D) with overall survival (OS) was assessed with the Hazard Ratio Smoothed Curve with Restricted Cubic Splines (HRSC-RCS) and maximally selected rank statistics (MSRS) in mCRC patients who underwent first-line chemotherapy. Several hematobiochemical variables were evaluated as predictors of vitamin D deficiency by means of Least Absolute Shrinkage and Selection Operator (LASSO) analysis. In a patient subset, peripheral lymphocyte subpopulations were also analyzed. Results: One hundred thirty-three mCRC patients were included. The median(m) baseline 25(OH)D was 10.8 ng/mL (range 3–53.4). HRSC-RCS revealed a linear association between 25(OH)D and OS. MSRS found 10 ng/mL as the optimal 25(OH)D cut-off. The median OS for 25(OH)D < 10 (n = 60) vs. > 10 ng/mL (n = 73) was 12.3 and 24.5 months, respectively (p = 0.002). The LASSO analysis identified high neutrophil-to-lymphocyte ratio (NLR > 3.5) as the strongest predictor of vitamin D deficiency (Odds Ratio 3.35, p 0.0009). Moreover, patients with low 25(OH)D levels (< 10 ng/mL) and high NLR (>3.5) had the shortest survival and patients with 25(OH)D >10 ng/mL and NLR <3.5 had the longest: mOS 8.1 and 28.1 months, respectively, HR 3.40 (1.76–6.59), p 0.0004. Besides the significant difference in NLR between 25(OH)D < and > 10 ng/mL patients (mNLR 3.6 vs. 2.9, p 0.03), the lymphocyte subpopulation analysis revealed that vitamin D deficiency was associated with high T- CD4+ (p = 0.04) and low B (p = 0.03) lymphocyte frequency. Conclusions: NLR is a powerful predictor of Vitamin D deficiency and can further help in stratifying prognosis. Vitamin D deficiency was associated with significant variations in peripheral immune cells. We hypothesize that integrated targeted interventions to both vitamin D and immune system would improve the prognosis of mCRC patients.

Association of plasma 25-hydroxyvitamin D with physical performance in physically active children

Vitamin D is thought to regulate skeletal muscle function and boost physical performance. The aim of this study was to assess the relationship between vitamin D and physical performance in physically active children. This cross-sectional study included 125 children who practice football as a leisure activity. Plasma 25-hydroxyvitamin D (25-OHD) was assessed using a chemiluminescence immunoassay method. Vitamin D inadequacy was defined as 25-OHD < 20 ng/mL. Physical performance testing included measurements of muscle strength (maximal isometric contraction), jumping ability (vertical jump, standing broad jump, triple hop test), linear sprint (10 m and 20 m), and agility (9 × 4-m shuttle run). Plasma 25-OHD concentrations were positively correlated with muscle strength (r = 0.539; p < 0.001), vertical jump (r = 0.528; p < 0.001), and standing broad jump (r = 0.492; p < 0.001) but inversely correlated with sprint performance (r = -0.539; p < 0.001). In multivariate analysis models, plasma 25-OHD concentrations were associated with each physical performance parameter independently of age, maturity status, body mass index, fat mass, and protein and calcium intakes. In conclusion, a low plasma 25-OHD level was associated with decreased muscle strength, agility, and jumping and sprinting abilities in physically active children. Vitamin D inadequacy may limit exercise performance. Further research should verify whether correction of vitamin D deficiency enhances physical performance.

Prediagnostic Plasma 25-Hydroxyvitamin D and Pancreatic Cancer Survival.

Although vitamin D inhibits pancreatic cancer proliferation in laboratory models, the association of plasma 25-hydroxyvitamin D [25(OH)D] with patient survival is largely unexplored. We analyzed survival among 493 patients from five prospective US cohorts who were diagnosed with pancreatic cancer from 1984 to 2008. We estimated hazard ratios (HRs) for death by plasma level of 25(OH)D (insufficient, < 20 ng/mL; relative insufficiency, 20 to < 30 ng/mL; sufficient ≥ 30 ng/mL) by using Cox proportional hazards regression models adjusted for age, cohort, race and ethnicity, smoking, diagnosis year, stage, and blood collection month. We also evaluated 30 tagging single-nucleotide polymorphisms in the vitamin D receptor gene, requiring P < .002 (0.05 divided by 30 genotyped variants) for statistical significance. Mean prediagnostic plasma level of 25(OH)D was 24.6 ng/mL, and 165 patients (33%) were vitamin D insufficient. Compared with patients with insufficient levels, multivariable-adjusted HRs for death were 0.79 (95% CI, 0.48 to 1.29) for patients with relative insufficiency and 0.66 (95% CI, 0.49 to 0.90) for patients with sufficient levels (P trend = .01). These results were unchanged after further adjustment for body mass index and history of diabetes (P trend = .02). The association was strongest among patients with blood collected within 5 years of diagnosis, with an HR of 0.58 (95% CI, 0.35 to 0.98) comparing patients with sufficient to patients with insufficient 25(OH)D levels. No single-nucleotide polymorphism at the vitamin D receptor gene met our corrected significance threshold of P < .002; rs7299460 was most strongly associated with survival (HR per minor allele, 0.80; 95% CI, 0.68 to 0.95; P = .01). We observed longer overall survival in patients with pancreatic cancer who had sufficient prediagnostic plasma levels of 25(OH)D.

Bladder Cancer is Associated with Low Plasma 25-hydroxyvitamin D Concentrations in Tunisian Population

abstractLittle evidence suggests an impact of vitamin D on bladder cancer risk in Caucasians. This study aimed to investigate association of plasma 25-hydroxyvitamin D (25-OHD) with urothelial bladder cancer (UBC) risk in Tunisians. A case-control study included 250 patients with UBC and 250 healthy controls. Plasma 25-OHD was assessed by a competitive chemiluminescence immunoassay. Vitamin D deficiency and insufficiency were defined as 25-OHD <30 nmol/L and 30 to 49.99 nmol/L, respectively. Logistic regression models adjusting for gender, age, smoking status, duration of smoking, occupational exposure, and season were applied. Vitamin D deficiency (50.4% vs. 34.8%; P < 0.001) and insufficiency (40.4% vs. 26.8%; P < 0.001) were more frequent in patients than controls. Multivariate analysis showed that UBC is associated with vitamin D deficiency [odd-ratio (95% confidence interval), 3.71 (1.76–7.80); P = 0.001] and vitamin D insufficiency [2.65 (1.40–5.01); P = 0.003]. Other predictors of UBC were female gender, tobacco use, smoking duration, and occupational exposure. Plasma 25-OHD concentrations are low in Tunisian patients with UBC. These findings support experimental and epidemiological evidence of protective role of vitamin D against UBC but could not ascertain causal relationship. Further prospective studies and clinical trials are warranted to check causality.

Vitamin D deficiency is associated with severity of liver disease in HIV/HCV coinfected patients

To study the association of plasma 25-hydroxy vitamin D (25(OH)D) levels in HIV/HCV coinfected patients with severity of liver disease and virological response to hepatitis C virus (HCV) therapy with pegylated-interferon-alpha plus ribavirin (pegIFNα/RBV). A cross-sectional study in 174 HIV/HCV coinfected patients that underwent a liver biopsy previously to start HCV therapy and a retrospective study of 125 of them. Plasma 25(OH)D levels were quantified by enzyme immunoassay. Liver biopsies were evaluated by METAVIR score. A sustained virological response (SVR) was defined as an undetectable serum HCV viral load (<10IU/mL) up through 24 weeks after the end of HCV treatment. The median of plasma 25(OH)D level was 48nmol/L (p25th: 32.5; p75th: 56.1) and 27 (15.5%) had 25(OH)D deficiency (<25nmol/L). The percentage of 25(OH)D deficiency was higher in patients with significant fibrosis (F≥2) (92.6% vs. 57.1%; p=0.010) and moderate necroinflammatory activity grade (A≥2) (85.2% vs. 60%; p=0.043). However, adjusted logistic regression analyses showed that 25(OH)D deficiency was only associated with severity of liver disease [F≥2 (OR=8.47 (95% of confidence interval (CI)=1.88; 38.3); p=0.005) and A≥2 (OR=3.25 (95%CI=1.06; 10.1); p=0.040)]. Moreover, any significant relationship was found between 25(OH)D deficiency and SVR after HCV therapy. Plasma 25(OH)D deficiency was associated with liver disease severity in HIV/HCV coinfected patients, but it was not associated with HCV treatment failure.

63: Associations of plasma 25-hydroxyvitamin D levels with endothelial function and preeclampsia

Low level of vitamin D has been associated with increased risk of preeclampsia. However, the underlying mechanism remains unknown. We examined the associations between plasma levels of 25-hydroxyvitamin D [25(OH)D], markers of endothelial function, intercellular adhesion molecule (ICAM)-1 and vascular adhesion molecule (VCAM)-1 and the risk of preeclampsia.

Associations of Plasma 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Concentrations With Death and Progression to Maintenance Dialysis in Patients With Advanced Kidney Disease

Low vitamin D concentrations are prevalent in patients with chronic kidney disease (CKD). We investigated the relationship between plasma 25-hydroxyvitamin D (25[OH]D) or 1,25-dihydroxyvitamin D (1,25[OH](2)D) concentrations with death, cardiovascular events, and dialysis therapy initiation in patients with advanced CKD. The HOST (Homocysteinemia in Kidney and End Stage Renal Disease) Study was a randomized double-blind trial evaluating the effects of high doses of folic acid on death and long-term dialysis therapy initiation in patients with advanced CKD (stages 4 and 5 not yet on dialysis therapy). 25(OH)D and 1,25(OH)(2)D were measured in stored plasma samples obtained 3 months after trial initiation and evaluated at clinically defined cutoffs (<10, 10-30, and >30 ng/mL) and tertiles (<15, 15-22, and >22 pg/mL), respectively. Cox proportional hazard models were used to examine the association between vitamin D concentrations and clinical outcomes. 1,099 patients with advanced CKD from 36 Veteran Affairs Medical Centers. 25(OH)D and 1,25(OH)(2)D concentrations. Death, cardiovascular events, and time to initiation of long-term dialysis therapy. After a median follow-up of 2.9 years, 41% (n = 453) died, whereas 56% (n = 615) initiated dialysis therapy. Mean 25(OH)D and 1,25(OH)(2)D concentrations were 21 ± 10 ng/mL and 20 ± 11 pg/mL, respectively. After adjustment for potential confounders, the lowest tertile of 1,25(OH)(2)D was associated with death (HR, 1.33; 95% CI, 1.01-1.74) and initiation of long-term dialysis therapy (HR, 1.78; 95% CI, 1.40-2.26) compared with the highest tertile. The association with death and initiation of dialysis therapy was moderately attenuated after adjustment for plasma fibroblast growth factor 23 (FGF-23) concentrations (HRs of lower tertiles of 1.20 [95% CI, 0.91-1.58] and 1.56 [95% CI, 1.23-1.99], respectively, compared with highest tertile). There was no association between 25(OH)D concentrations and outcomes. Participants were mostly men. Low plasma 1,25(OH)(2)D concentrations are associated with death and initiation of long-term dialysis therapy in patients with advanced CKD. FGF-23 level may attentuate this relationship.