Plasma 25-hydroxyvitamin D3 Research Articles

Plasma 25-hydroxyvitamin D3, folate and vitamin B12 biomarkers among international colorectal cancer patients: a pilot study.

Vitamin D and folate are associated with decreased colorectal cancer risk and their association with colorectal cancer prognosis is under investigation. We assessed the levels of plasma 25-hydroxyvitamin D3 (25(OH)D3), folate and vitamin B12 in an international pilot study in order to determine variability of these biomarkers based on geographical location. Plasma 25(OH)D3, folate and vitamin B12 concentrations were measured in 149 invasive, newly diagnosed colorectal cancer cases from Heidelberg (Germany), Seattle (WA, USA), and Tampa (FL, USA) and in ninety-one age- and sex-matched controls. Their associations with potential predictors were assessed using multivariate linear regression analyses. Plasma 25(OH)D3, folate and vitamin B12 concentrations differed by location. Other predictors were season for 25(OH)D3 and tumour stage (vitamin B12). Season-corrected average 25(OH)D3 concentrations were higher in Heidelberg (31·7ng/ml; range 11·0-83·0 ng/ml) than in Seattle (23·3ng/ml; range 4·0-80·0 ng/ml) and Tampa (21·1ng/ml; range 4·6-51·6 ng/ml). In Heidelberg, a strong seasonal variation was observed. Folate (11·1ng/ml) and vitamin B12 (395pg/ml) concentrations in Heidelberg were lower than those in Seattle (25·3ng/ml and 740pg/ml, respectively) and Tampa (23·8ng/ml and 522pg/ml, respectively). Differences in plasma 25(OH)D3 and folate concentrations between Heidelberg and the US sites were observed, probably reflecting variation in outdoor activities and sun-avoidance behaviour during summer as well as in folic acid fortification and supplement use. Intra-site differences at each study location were greater than between-location variability, suggesting that individual health behaviours play a significant role. Nevertheless, the intra-site differences we observed may be due to chance because of the limited sample size. Our pilot study illustrates the value of an international cohort in studying colorectal cancer prognosis to discern geographical differences in a broad range of exposures.

Plasma 25-hydroxyvitamin D3 concentrations in Hermann's tortoises (Testudo hermanni) exposed to natural sunlight and two artificial ultraviolet radiation sources

Objective-To determine the effect of various UVB radiation sources on plasma 25-hydroxyvitamin D(3) concentrations in Hermann's tortoises (Testudo hermanni). Animals-18 healthy Hermann's tortoises. Procedures-Tortoises were exposed to sunlight in an outdoor enclosure located in the natural geographic range of Hermann's tortoises (n = 6 tortoises) or a self-ballasted mercury-vapor lamp (6) or fluorescent UVB-emitting lamp (6) in an indoor enclosure for 35 days. Plasma samples were obtained from each tortoise on the first (day 0) and last (day 35) days of the study, and concentrations of 25-hydroxyvitamin D(3) were determined. Amount of UVB radiation in enclosures was measured. Results-Mean ± SD plasma 25-hydroxyvitamin D(3) concentrations for tortoises exposed to the mercury-vapor and fluorescent lamps were significantly lower on day 35 (155.69 ± 80.71 nmol/L and 134.42 ± 51.42 nmol/L, respectively) than they were on day 0 (368.02 ± 119.34 nmol/L and 313.69 ± 109.54 nmol/L, respectively). Mean ± SD plasma 25-hydroxyvitamin D(3) concentration for tortoises exposed to sunlight did not differ significantly between days 0 (387.74 ± 114.56 nmol/L) and 35 (411.51 ± 189.75 nmol/L). Mean day 35 plasma 25-hydroxyvitamin D(3) concentration was significantly higher for tortoises exposed to sunlight versus those exposed to mercury-vapor or fluorescent lamps. Sunlight provided significantly more UVB radiation than did the mercury-vapor or fluorescent lamps. Conclusions and Clinical Relevance-Plasma 25-hydroxyvitamin D(3) concentrations differed between tortoises exposed to sunlight and those exposed to artificial UVB sources. Exposure to sunlight at a latitude similar to that of the natural geographic range is recommended for healthy and calcium-deficient tortoises.

Plasma 25-Hydroxyvitamin D3 and Bladder Cancer Risk According to Tumor Stage and FGFR3 Status: A Mechanism-Based Epidemiological Study

Previous evidence suggests that 25-hydroxyvitamin D(3) [25(OH)D(3)] protects against several cancers. However, little is known regarding urothelial bladder cancer (UBC). We analyzed the association between plasma 25(OH)D(3) and overall risk of UBC, as well as according to stage and FGFR3 molecular subphenotypes. Plasma concentrations of 25(OH)D(3) in 1125 cases with UBC and 1028 control subjects were determined by a chemiluminescence immunoassay. FGFR3 mutational status and expression in tumor tissue were assessed. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression adjusting for potential confounders. Analyses were further stratified by tumor invasiveness and grade, FGFR3 expression, and smoking status. Cell proliferation was measured in human UBC cell lines cultured with 1α,25-dihydroxyvitamin D(3). A statistically significantly increased risk of UBC was observed among subjects presenting the lowest concentrations of 25(OH)D(3) (OR(adj) = 1.83; 95% CI = 1.19 to 2.82; P = .006), showing a dose-response effect (P (trend) = .004). The association was stronger for patients with muscle-invasive tumors, especially among low-FGFR3 expressers (OR(adj) = 5.94; 95% CI = 1.72 to 20.45; P = .005). The biological plausibility of these associations is supported by the fact that, in vitro, 1α,25-dihydroxyvitamin D(3) upregulates FGFR3 expression in UBC cell lines with low levels of wild-type FGFR3. These findings support a role of vitamin D in the pathogenesis of UBC and show that 25(OH)D(3) levels are associated with FGFR3 expression in the tumor. Because FGFR3 mutation and overexpression are markers of better outcome, our findings suggest that individuals with low levels of plasma 25(OH)D(3) may be at high risk of more aggressive forms of UBC.

The association between plasma 25-hydroxyvitamin D3 concentrations, C-reactive protein levels, and coronary artery atherosclerosis in postmenopausal monkeys

The aim of this study was to identify the potential relationships between plasma 25-hydroxyvitamin D(3) (25OHD(3)), C-reactive protein (CRP), coronary artery atherosclerosis (CAA), and coronary artery remodeling in monkeys consuming atherogenic diets. Female cynomolgus monkeys (n = 74) were fed a casein-lactalbumin (C/L)-based, moderately atherogenic diet for 12 months. They then consumed either a soy-based (n = 35) or C/L-based (n = 39) diet for 32 months. CRP concentrations were then determined, and monkeys underwent surgical menopause. Each diet group was then rerandomized to receive soy (n = 36) or C/L (n = 38). After 32 postmenopausal months, 25OHD(3), CRP, CAA, and coronary artery remodeling were determined. All monkeys received a woman's equivalent of 1,000 IU/day of vitamin D(3) and 1,200 mg/day of calcium throughout the study. The premenopausal and postmenopausal dietary protein sources had no effect on postmenopausal 25OHD(3) concentrations (P = 0.6). Across treatment groups, there was a statistically significant inverse relationship between 25OHD(3) concentrations and CRP at necropsy (r = -0.35, P = 0.003). A significant inverse correlation between 25OHD(3) concentration and the change in CRP from premenopause to postmenopause was observed (r = -0.32, P = 0.007). The significant associations identified between plasma 25OHD(3) and CRP remained after controlling for postmenopausal diet. Those monkeys with a greater increase in CRP also had significantly more CAA and less ability to maintain normal lumens by remodeling. Higher plasma concentrations of 25OHD(3) were associated with lower CRP. Lower CRP was associated with less coronary atherosclerosis and improved coronary artery remodeling. These findings suggest that 25OHD(3) concentrations are associated with an anti-inflammatory state and may support an association between oral vitamin D3 and cardioprotection.

Vitamin D in pregnancy at high latitude in Scotland

The aims of the present study were to determine compliance with current advice on vitamin D and to assess the influence of season, dietary intake, supplement use and deprivation on vitamin D status in pregnant mothers and newborns in the north of Scotland where sunlight exposure is low. Pregnant women (n 1205) and their singleton newborns were studied in the Aberdeen Maternity Hospital (latitude 57°N) between 2000 and 2006. Plasma 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 were measured at 19 weeks of gestation in mothers and at delivery in newborns. During pregnancy, 21·0 (95 % CI 18·5, 23·5) % of women took vitamin D supplements. The median intake was 5 μg/d and only 0·6 (95 % CI 0·1, 1·0) % took the recommended 10 μg/d. Supplement use, adjusted for season, dietary intake and deprivation, significantly increased maternal 25-hydroxyvitamin D (25(OH)D) by 10·5 (95 % CI 5·7, 15·2) nmol/l (P< 0·001); however, there was no significant effect on cord 25(OH)D (1·4 (95 % CI - 1·8, 4·5) nmol/l). The biggest influence on both maternal and cord 25(OH)D was season of birth (P< 0·001). Compared with the least deprived women (top three deciles), the most deprived pregnancies (bottom three deciles) were characterised by a significantly lower seasonally adjusted 25(OH)D ( - 11·6 (95 % CI - 7·5, - 15·7) nmol/l in the mother and - 5·8 (95 % CI - 2·3, - 9·4) nmol/l in the cord), and a lower level of supplement use (10 (95 % CI 4, 17) v. 23 (95 % CI 20, 26) %). More should be done to promote vitamin D supplement use in pregnancy but the critical importance of endogenous vitamin D synthesis, and known adaptations of fat metabolism specific to pregnancy, suggest that safe sun advice may be a useful additional strategy, even at high latitude.

Is vitamin D status a predictor glycaemic regulation and cardiac complication in type 2 diabetes mellitus patients?

ObjectiveTo evaluate vitamin D as a predictor of glycaemic regulation in type 2 diabetes mellitus patients. Research design and methodsIn observational study 171 type 2 diabetic patients who are followed for median (range) of 10.15 (3–18) years. Mean±SD age was 56±10. Plasma 25-hydroxyvitamin D3 levels were determined by high-performance liquid chromatography/tandem mass spectrometry on baseline samples. Vitamin D deficiency was defined as a 25-OHD level of less than 20ng/ml. Vitamin D levels between 20 and 30ng/ml are termed ‘insufficient’. Vitamin D levels greater than 30ng/ml are termed ‘optimal’. Results125 patients have vitamin D deficiency, 14 patients have insufficient and the others have optimal. Vitamin D levels were not associated with sex, age, BMI, HDL, LDL, kreatinin, hypertension and smoking. But vitamin D deficiency patients had more longer duration (p=0.011), more higher uric acid (p=0.021), fasting glucose (p=0.037), postprandial glucose (p=0.001) and HbA1c (p=0.026). ConclusionsIn our study type 2 diabetic patients have 73% of vitamin D deficiency. Vitamin D deficiency predicts higher fasting and postprandial blood glucose and diabetes disregulation. Type 2 DM patients and low 25-OH vitamin D levels could increased cardiovascular disease directly or indirectly (low HDL and high uric acid in 25-OH vitamin D <20ng/ml). Whether vitamin D substitution improves prognosis remains to be investigated.

Effect of vitamin D3 supplementation on the pharmacokinetics of digoxin – a pilot study

Emerging evidence from preclinical, clinical and epidemiological studies suggests that vitamin D3 plays vital roles in several diseases in addition to bone disorders. According to new medical evidence, it is being recommended that vitamin D3 intake to be increased for maximal benefits in human health. However, it is necessary to consider potential side effects of increased intake of vitamin D3. Vitamin D3 exerts its actions through the vitamin D receptor, which is known to be an important regulator of P-glycoprotein (P-gp). As P-gp plays a significant role in limiting drug bioavailability, we undertook a study to compare single-dose digoxin (a P-gp substrate) pharmacokinetics in eight healthy male subjects before and after vitamin D3 supplementation (1000 IU per day). The geometric mean ratios for AUC(0-3h), AUC(0-48h) and C(max) were 1.06 (90% CI 0.92, 1.21) and 1.02 (90% CI 0.97, 1.08) and 1.03 (95% CI 0.86, 1.24), respectively. The median for digoxin T(max) was 0.75 h before and after vitamin D3 ingestion. The mean plasma 25-hydroxyvitamin D3 (25(OH)D3) levels remained constant after the intake of vitamin D3 (15.4 ± 3.7 and 14.4 ± 3.6 ng/mL, respectively), while there was a modest but statistically significant increase in plasma calcium levels, from 9.32-9.68 mg/dL (P = 0.0277). These results suggest that vitamin D3 supplementation (1000 IU per day) in human volunteers does not produce a P-gp-mediated drug interaction with orally administered digoxin.

Vitamin D Levels and Mortality in Type 2 Diabetes

OBJECTIVETo evaluate vitamin D as a predictor of all-cause and cardiovascular mortality and risk of progression to micro- or macroalbuminuria in type 2 diabetic patients.RESEARCH DESIGN AND METHODSIn a longitudinal observational follow-up study, 289 type 2 diabetic patients with normoalbuminuria (n = 172), microalbuminuria (n = 73), and macroalbuminuria (n = 44) at baseline were followed for a median (range) of 15.0 (0.2–23) years. Mean ± SD age was 54 ± 9 years. Plasma 25-hydroxyvitamin D3 levels were determined by high-performance liquid chromatography/tandem mass spectrometry on baseline samples. Severe vitamin D deficiency was defined as the lower 10th percentile (<13.9 nmol/l).RESULTSMedian (range) vitamin D level was 35.7 (5–136.7) nmol/l. Vitamin D levels were not associated with age, sex, estimated glomerular filtration rate, urinary albumin excretion rate (UAER), or A1C at baseline, but low levels were weakly associated with elevated systolic blood pressure (R = 0.13, P = 0.03). During follow-up, 196 (68%) patients died. All-cause mortality was increased in patients with severe vitamin D deficiency (hazard ratio 1.96 [95% CI 1.29–2.98]). The association persisted after adjustment for UAER, A1C, diabetes duration, and conventional cardiovascular risk factors (2.03 [1.31–3.13]). Severe vitamin D deficiency was associated with increased cardiovascular mortality (1.95 [1.11–3.44]), and the association persisted after adjustment (1.90 [1.15–3.10]). Severe vitamin D deficiency at baseline did not predict progression to micro- or macroalbuminuria.CONCLUSIONSIn type 2 diabetic patients, severe vitamin D deficiency predicts increased risk of all-cause and cardiovascular mortality, independent of UAER and conventional cardiovascular risk factors. Whether vitamin D substitution improves prognosis remains to be investigated.

Effects of vegetable feed ingredients on bone health in Atlantic salmon

Summary The aim of the present study was to examine if dietary inclusion of vegetable lipids (VL) and proteins (VP) influenced markers of bone health in Atlantic salmon. Triplicate groups were fed one of four different diets; 100% fish protein (FP) and fish lipids (FL) (FPFL), 80% VP and 35% VL (80VP35VL), 40% VP and 70% VL (40VP70VL), or 80% VP and 70% VL (80VP70VL) for 12 months on-growth in sea water. Fish were analyzed for vertebral bone mineralization (mineral content, as % of bone dry weight), vertebral deformities (radiology), vertebral bone mRNA expression of factors involved in mineralization (bone gla protein, bgp) and growth regulation (igf-I and growth hormone receptor), as well as plasma vitamin D metabolites. The fish grew from 0.35 to 4 kg during the experimental period. At the end of the experiment, significantly lower prevalence of fish with one or more deformed vertebrae was observed in the 80VP70VL group (11%) compared to the other groups (33–43%). There was a significant higher relative expression of igf-I mRNA in vertebral bone of fish fed the 80VP70VL diet compared to control fish (FPFL), while the other genes studied were unaffected. Elevated plasma 25-hydroxyvitamin D3 recorded in the marine feed group is discussed as a predictor for later development of bone deformities. In conclusion, the present study shows that high inclusion levels of vegetable lipids and proteins may have a positive effect on bone health in Atlantic salmon postsmolts.

Vitamin D deficiency in patients with osteoarthritis undergoing total hip replacement

We measured the plasma 25-hydroxyvitamin D(3) (25(OH)D(3)) levels in 62 consecutive Caucasian patients undergoing total hip replacement for osteoarthritis. The patients were divided into two groups based on whether they were vitamin D sufficient or deficient. The groups were matched for age, gender and the American Society of Anaesthesiologists (ASA) grade. The prevalence of vitamin D deficiency in our patients was comparable with recent population-based studies performed in the United Kingdom. Patients with vitamin D deficiency had lower pre-operative Harris hip scores (Mann-Whitney test, p = 0.018) and were significantly less likely to attain an excellent outcome from total hip replacement (chi-squared test, p = 0.038). Vitamin D levels were found to positively correlate with both pre- and post-operative Harris hip scores. These results warrant further study of vitamin D deficiency in patients undergoing joint replacement as it is a risk factor for a suboptimal outcome which is relatively simple and cheap to correct.

Initial Periodontal Therapy Reduced Systemic and Local 25‐Hydroxy Vitamin D3 and Interleukin‐1β in Patients With Aggressive Periodontitis

25-hydroxy vitamin D(3) is the major circulating metabolite of vitamin D. Elevated plasma 25-hydroxy vitamin D(3) levels were verified to be associated with generalized aggressive periodontitis (GAgP). In the present study, the influence of initial periodontal therapy on systemic and local levels of 25-hydroxy vitamin D(3) and three related elements (osteocalcin and interleukin-1beta and -6) in patients with GAgP was investigated. Nineteen patients with GAgP were enrolled. All patients received initial periodontal therapy. Gingival crevicular fluid at two sites of each subject were obtained before therapy and 2 and 6 months after therapy. Plasma was obtained before and 2 months after therapy from 12 of 19 subjects. Systemic and local levels of 25-hydroxy vitamin D(3), osteocalcin, and interleukin-1beta and -6 before and after therapy were measured using radioimmunoassay or enzyme-linked immunosorbent assay kits and compared. The respective systemic 25-hydroxy vitamin D(3) and interleukin-1beta levels significantly dropped from baseline to 2 months after therapy (29.28 nmol/l versus 22.50 nmol/l, P = 0.001, and 6.71 ng/l versus 3.23 ng/l, P <0.001, respectively). The respective local 25-hydroxy vitamin D(3) and interleukin-1beta levels significantly decreased from baseline to 2 and 6 months after therapy (8,950 nmol/l versus 5,650 nmol/l versus 3,438 nmol/l, P <0.001, and 10,595 ng/l versus 5,495 ng/l versus 3,960 ng/l, P <0.001, respectively). Systemic and local 25-hydroxy vitamin D(3) concentrations were positively correlated at baseline (r = 0.877; P = 0.022), as was osteocalcin (r = 0.939; P = 0.005). 25-hydroxy vitamin D(3) and interleukin-1beta levels were systemically and locally reduced in patients with GAgP by initial periodontal therapy. 25-hydroxy vitamin D(3) might be involved in periodontal inflammation.

Abstract A107: Predicted vitamin D status and pancreatic cancer risk in two prospective cohort studies

Abstract Background: Experimental data indicate that vitamin D has anticancer properties. However, epidemiologic studies on vitamin D and pancreatic cancer risk have yielded inconsistent results. We previously developed a model to predict long-term plasma 25-hydroxyvitamin D3 [25(OH)D] levels from multiple determinants of vitamin D status (dietary and supplementary vitamin D, skin pigmentation, adiposity, geographic residence, and leisure-time physical activity as a surrogate of sunlight exposure). Here, we examine the association between predicted vitamin D status and pancreatic cancer risk in the Nurses' Health Study and Health Professionals Follow-up Study. Methods: We prospectively followed 118,597 participants in these two cohorts from 1986–2006. We calculated a 25(OH)D score from six predictors of vitamin D status for each individual using a multiple linear regression model and then examined the predicted 25(OH)D levels in relation to pancreatic cancer risk with Cox proportional hazards models. The multivariate models were adjusted for age, sex, race, height, smoking, and diabetes. Results: During 20 years of follow-up, we identified 575 incident pancreatic cancer cases. Higher 25(OH)D score was associated with a significant reduction in pancreatic cancer risk; compared with the lowest quintile, participants in the highest quintile of 25(OH)D score had an adjusted RR of 0.65 (95% CI, 0.50–0.86; P for trend = 0.001). The results remained unchanged after further adjusting for BMI and physical activity or after excluding the first 2 years of follow-up. This inverse association was also consistent across gender and strata of other covariates, including age, region, smoking, BMI, and physical activity. Conclusion: Higher 25(OH)D score was associated with a lower risk of pancreatic cancer in these two prospective cohort studies. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A107.

Short communication: The preruminant calf as a model for characterizing the effects of vitamin D status in the neonate

The objective of this study was to evaluate the feasibility of using the preruminant dairy calf as a model for evaluating effects of vitamin D status in the neonate. Because the newborn calf can be sustained during the first weeks of life solely on a fluid diet having a defined composition, has documented nutritional requirements, and is minimally affected by repeated samplings of peripheral blood, it has the potential to serve as a model for characterizing nutrient-specific effects on the growth and health of the neonate. Colostrum-fed Holstein bull calves (n=13) entered the trial at approximately 4 d of age. All calves were fed a custom-formulated milk replacer devoid of vitamin D. Plasma 25-hydroxyvitamin D3 concentrations in all calves were determined on a regular basis beginning at d 0. Using this information, low- and high-status groups of calves were established by subcutaneous administration of 25-hydroxyvitamin D3. To maintain targeted plasma 25-hydroxyvitamin D3 concentrations in low (<30 ng/mL) and high (>60 ng/mL) vitamin D–status calves, low-status calves (n=6) received a total of 8,600 IU (2,225 IU/wk) of vitamin D during the experimental period and high-status calves (n=7) received 54,000 IU (13,500 IU/wk). Concentrations of 25-hydroxyvitamin D3 in low-status calves averaged 27 ng/mL, compared with 78 ng/mL in high-status calves, and were less at all sampling times from d 7 to d 28. Concentrations of 1,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 were not correlated. Calcium, magnesium, and phosphorous concentrations were unaffected by 25-hydroxyvitamin D3 administration; however, plasma calcium and 1,25-dihydroxyvitamin D3 concentrations were correlated. Calcium and magnesium concentrations decreased with age but remained within normal ranges for dairy cattle. These results indicate that it is possible to predictably control vitamin D status over a 28-d period and suggest that the preruminant calf might be useful as a model for studying effects of vitamin D on growth, development, and immune function in the neonate.

Supplementing dairy steers and organically managed dairy cows with synthetic vitamin D3is unnecessary at pasture during exposure to summer sunlight

Use of synthetic feed additives, including synthetic vitamin D3 (D3) in the feed for cows and other ruminants, is not consistent with the international principles of organic farming. If dairy farmers wish to produce in accordance with the organic principles, production animals would be left with only their endogenous production of D3 from summer sunlight as a source of D3. To examine the impact of supplemental synthetic D3 from the feed on the D3 status of dairy cattle in organic production in Nordic countries, 20 high-yielding dairy cows and 30 dairy steers were divided into two groups: one supplemented with synthetic D3 in the feed and one not supplemented with synthetic D3. Vitamin D3 status of the animals was assessed by measuring the concentration of the liver-derived 25-hydroxyvitamin D3 (25OHD3) in plasma. Results showed that 25OHD3 concentration in plasma from dairy cattle as well as from steers decreased during winter for both supplemented and unsupplemented groups. Unsupplemented cows and steers had approximately 2 ng 25OHD3 per ml plasma during winter, whereas supplemented animals had between 10 (cows) and 30 (steers) ng/ml. During summer and autumn there was no additive effect of supplementing with synthetic D3 since unsupplemented and supplemented animals had the same D3 status at this time of year. In all cows summer concentrations of 25OHD3 were 20-25 ng/ml and in all steers 40-50 ng/ml plasma. The decrease in vitamin D3 status during winter indicates that cows and steers are able to store D3 only to a limited extent. The results also show that cows or steers fed supplemental D3 according to Swedish recommendation throughout the year are not able to maintain their summer value of 25OHD3 during winter.

Circulating 25-Hydroxyvitamin D Levels and Survival in Patients With Colorectal Cancer

Higher plasma 25-hydroxyvitamin D(3) (25(OH)D) levels are associated with a decreased incidence of colorectal cancer, but the influence of plasma 25(OH)D on the outcome of patients with established colorectal cancer is unknown. We prospectively examined the association between prediagnosis 25(OH)D levels and mortality among 304 participants in the Nurses' Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) who were diagnosed with colorectal cancer from 1991 to 2002. Participants diagnosed within 2 years of blood collection were excluded. Patients were observed until death, June 2005 (NHS), or January 2005 (HPFS), whichever came first. The primary end point was overall mortality. Cox proportional hazards models were used to calculate hazard ratios (HR) adjusted for other risk factors for cancer survival. Higher plasma 25(OH)D levels were associated with a significant reduction in overall mortality (P for trend = .02). Compared with the lowest quartile, participants in the highest quartile had an adjusted HR of 0.52 (95% CI, 0.29 to 0.94) for overall mortality. A trend toward improved colorectal cancer-specific mortality was also seen (HR = 0.61; 95% CI, 0.31 to 1.19). The results remained unchanged after excluding patients diagnosed within 5 years of blood collection (P for trend = .04); the multivariate HR for overall mortality comparing extreme quartiles was 0.45 (95% CI, 0.19 to 1.09). Among patients with colorectal cancer, higher prediagnosis plasma 25(OH)D levels were associated with a significant improvement in overall survival. Further study of the vitamin D pathway and its influence on colorectal carcinogenesis and cancer progression is warranted.

Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata)

To determine whether corn snakes exposed to UVB radiation have increased plasma 25-hydroxyvitamin D3 concentrations, compared with control snakes. 12 corn snakes (Elaphe guttata). After an acclimation period in individual enclosures, a blood sample was collected from each snake for assessment of plasma 25-hydroxyvitamin D3 concentration. Six snakes were provided with no supplemental lighting, and 6 snakes were exposed to light from 2 full-spectrum coil bulbs. By use of a radiometer-photometer, the UVA and UVB radiation generated by the bulbs were measured in each light-treated enclosure at 3 positions at the basking surface and at 2.54 cm (1 inch) below each bulb surface; the arithmetic mean values for the 3 positions at the basking surface and each individual bulb surface were calculated immediately after the start of the study and at weekly intervals thereafter. At the end of the study (day 28), another blood sample was collected from each snake to determine plasma 25-hydroxyvitamin D3 concentration. Mean +/- SD plasma concentration of 25-hydroxyvitamin D3 in snakes that were provided with supplemental lighting (196 +/- 16.73 nmol/L) differed significantly from the value in control snakes (57.17 +/- 15.28 nmol/L). Mean exposure to UVA or UVB did not alter during the 4-week study period, although the amount of UVA recorded near the bulb surfaces did change significantly. These findings have provided important insight into the appropriate UV radiation requirements for corn snakes. Further investigation will be needed before exact husbandry requirements can be determined.

25-Hydroxyvitamin D3 affects vitamin D status similar to vitamin D3 in pigs – but the meat produced has a lower content of vitamin D

In food databases, the specific contents of vitamin D3 and 25-hydroxyvitamin D3 in food have been implemented in the last 10 years. No consensus has yet been established on the relative activity between the components. Therefore, the objective of the present study was to assess the relative activity of 25-hydroxyvitamin D3 compared to vitamin D3. The design was a parallel study in pigs (n 24), which from an age of 12 weeks until slaughter 11 weeks later were fed approximately 55 microg vitamin D/d, as vitamin D3, in a mixture of vitamin D3 and 25-hydroxyvitamin D3, or 25-hydroxyvitamin D3. The end-points measured were plasma 25-hydroxyvitamin D3, and in the liver and loin the content of vitamin D3 and 25-hydroxyvitamin D3. Vitamin D3 and 25-hydroxyvitamin D3 in the feed did not affect 25-hydroxyvitamin D3 in the plasma, liver or loin differently, while a significant effect was shown on vitamin D3 in the liver and loin (P < 0.001). 25-Hydroxyvitamin D3 in the plasma, liver and loin significantly correlates with the sum of vitamin D3 and 25-hydroxyvitamin D3 in the feed (P < 0.05). Therefore, 25-hydroxyvitamin D3 should be regarded as having the same activity as vitamin D3 in food databases. Sole use of 25-hydroxyvitamin D3 as a vitamin D source in pig feed will produce liver and meat with a negligible content of vitamin D3, while an increased content of vitamin D3 in the feed will produce liver and meat with increased content of both vitamin D3 and 25-hydroxyvitamin D3.

Vitamin D Supplementation and Cardiovascular Disease Risk

Many studies,1,2 but not all, have shown that low bone density is associated with increased cardiovascular disease (CVD) risk. Vitamin D deficiency is common in the elderly and is associated with osteoporosis; however, the association of endogenous 25-OH vitamin D (25-OH D) levels with CVD events is controversial.3,4 CVD rates are higher during winter seasons and at increased geographic latitudes where average serum vitamin D levels are lowest.5 Low 25-OH D levels have been found in stroke6 and heart failure patients.7 Moreover, 25-OH D deficiency is associated with hypertension, obesity,8 glucose intolerance,8 and the metabolic syndrome,9 which may be responsible, at least in part, for its association with increased CVD risk. Article p 846 Although vitamin D supplementation improves bone strength, elevated serum vitamin D levels may be associated with lower levels of vascular calcification. In subjects at moderately high risk for coronary heart disease, endogenous serum vitamin D levels were inversely correlated with the extent of coronary artery calcification as determined by cardiac computed tomography.10 Vitamin D also has intriguing antiinflammatory properties11 that have potential therapeutic benefit in several autoimmune diseases and allograft rejection. In 2 small clinical trials,12,13 vitamin D supplementation lowered C-reactive protein levels. Additionally, 1,25(OH)2D induces relaxation of vascular smooth muscle cells …

Plasma 25-hydroxyvitamin D 3 does not vary over the course of a malaria infection

Journal Article Plasma 25-hydroxyvitamin D3 does not vary over the course of a malaria infection Get access Katie Newens, Katie Newens Search for other works by this author on: Oxford Academic PubMed Google Scholar Suzanne Filteau, Suzanne Filteau Search for other works by this author on: Oxford Academic PubMed Google Scholar Andrew Tomkins Andrew Tomkins Search for other works by this author on: Oxford Academic PubMed Google Scholar Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 97, Issue 6, November-December 2003, Page 630, https://doi.org/10.1016/S0035-9203(03)80081-0 Published: 01 November 2003

Application of 4-(4-nitrophenyl)-1,2,4-triazoline-3,5-dione to analysis of 25-hydroxyvitamin D3 in human plasma by liquid chromatography/electron capture atmospheric pressure chemical ionization-mass spectrometry.

The utility of 4-(4-nitrophenyl)-1,2,4-triazoline-3,5-dione (NPTAD) as a derivatization reagent in the analysis of 25-hydroxyvitamin D3 [25(OH)D3] using liquid chromatography/electron capture atmospheric pressure chemical ionization-mass spectrometry (LC/ECAPCI-MS) was examined. The derivatives of 25(OH)D3 with NPTAD underwent electron capture in the APCI source in the negative-ion mode and provided 30-fold higher sensitivity compared to an intact compound. This derivatization-LC/ECAPCI-MS method was applied to a plasma 25-hydroxyvitamin D3 assay, and gave satisfactory results in sensitivity, specificity, measurable range and throughput of the analysis.