Higher Serum Vitamin Research Articles

HIGH PREVALENCE OF UNTREATED AND UNDERTREATED VITAMIN D DEFICIENCY AND INSUFFICIENCY IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE.

SUMMARYInflammatory bowel disease (IBD) patients with vitamin D deficiency show an increased risk of hospital admission, surgery, and loss of response to biologic therapy while high vitamin D levels are identified as a protective factor. Our goal was to investigate the prevalence of untreated and undertreated vitamin D deficiency and factors associated with vitamin D deficiency. In this cross-sectional study, we measured serum vitamin D in a random sample of Caucasian IBD patients. Vitamin D deficiency was defined as <50 nmol/L and insufficiency as 50-75 nmol/L. Supplementation was defined as taking 800-2000 IU vitamin D daily. Untreated patients were defined as not taking supplementation and undertreated group as receiving supplementation but showing vitamin D deficiency or insufficiency despite treatment. Our study included 185 IBD patients, i.e. 126 (68.1%) with Crohn’s disease (CD) and 59 (31.9%) with ulcerative colitis (UC). Overall, 108 (58.4%) patients had vitamin D deficiency and 60 (32.4%) patients vitamin D insufficiency. There were 16 (14.8%) and 11 (18.3%) treated patients in vitamin D deficiency and vitamin D insufficiency group, respectively. The rate of untreated patients was 81.7% (n=49) in vitamin D deficiency group and 85.2% (n=92) in vitamin D insufficiency group. Tumor necrosis factor alpha inhibitors were associated with higher serum vitamin D levels in CD and UC, and ileal involvement, ileal and ileocolonic resection with lower levels. In conclusion, not only is vitamin D deficiency common in IBD patients but the proportion of untreated and undertreated patients is considerably high. We suggest regular monitoring of vitamin D levels in IBD patients regardless of receiving vitamin D supplementation therapy.

Vitamin D-VDR Signaling Inhibits Wnt/β-Catenin-Mediated Melanoma Progression and Promotes Antitumor Immunity.

1α,25-Dihydroxyvitamin D3 signals via the vitamin D receptor (VDR). Higher serum vitamin D is associated with thinner primary melanoma and better outcome, although a causal mechanism has not been established. As patients with melanoma commonly avoid sun exposure, and consequent vitamin D deficiency might worsen outcomes, we interrogated 703 primary melanoma transcriptomes to understand the role of vitamin D-VDR signaling and replicated the findings in The Cancer Genome Atlas metastases. VDR expression was independently protective for melanoma-related death in both primary and metastatic disease. High tumor VDR expression was associated with upregulation of pathways mediating antitumor immunity and corresponding with higher imputed immune cell scores and histologically detected tumor-infiltrating lymphocytes. High VDR-expressing tumors had downregulation of proliferative pathways, notably Wnt/β-catenin signaling. Deleterious low VDR levels resulted from promoter methylation and gene deletion in metastases. Vitamin D deficiency (<25 nmol/L ∼ 10 ng/mL) shortened survival in primary melanoma in a VDR-dependent manner. In vitro functional validation studies showed that elevated vitamin D-VDR signaling inhibited Wnt/β-catenin signaling genes. Murine melanoma cells overexpressing VDR produced fewer pulmonary metastases than controls in tail-vein metastasis assays. In summary, vitamin D-VDR signaling contributes to controlling pro-proliferative/immunosuppressive Wnt/β-catenin signaling in melanoma and this is associated with less metastatic disease and stronger host immune responses. This is evidence of a causal relationship between vitamin D-VDR signaling and melanoma survival, which should be explored as a therapeutic target in primary resistance to checkpoint blockade. SIGNIFICANCE: VDR expression could potentially be used as a biomarker to stratify patients with melanoma that may respond better to immunotherapy.

Association between the Level of Serum Vitamin B12 and Venous Thromboembolism in African American Population

Background Multiple risk factors have been linked to venous thromboembolism (VTE). It is well established that elevated level of homocysteine correlated with increased risk of VTE. Some studies showed that vitamin B12 deficiency may be the cause for homocysteinemia. Therefore, it is recommended by some groups that vitamin B12 should be supplemented in the patient with high homocysteine to prevent VTE. However, more recent study has shown that there is correlation between the high serum Vitamin B12 level and risk of VTE in cancer patients.[1] provoked VTE after orthopedic surgery was also shown to be associated with elevated vitamin B12 serum levels in elderly patients. The role of vitamin B12 in VTE patients is not fully understood. Our study is to see whether there is correlation between serum Vitamin B12 level and risk of VTE in general population. Methods 177 Patients admitted to Kingsbrook Jewish Medical Center between January 1st, 2015 to December 31st, 2018 with the diagnosis of VTE were identified. 95 cases had measured serum Vitamin B12 results within 3 months. 97 patients without any history of VTE who were seen in the hematology clinic during the same period time were used as control in this study. Demographic information and Vitamin B12 level were collected. T test and chi-square were used for statistical analysis. Results VTE patients had a median age of 70, which is significantly higher than the median age of 57 in the control group. The mean level of vitamin B12 in control group was 620 pg/mL, which was lower than the average vitamin B12 level (770 pg/mL, p=0.0344) in the VTE group. When we divided the patients into 3 groups based on Vitamin B12 level: Low B12 (&lt;250 pg/mL), Moderate B12 (250-800 pg/mL) and High B12 (&gt;800 pg/mL). We observed 41% of VTE patients have B12 level more than 800 pg/mL while only 20% of control patients have high B12 level (chi-square, p=0.006). Discussion Our study showed that vitamin B12 level is significantly elevated in patients diagnosed with VTE and more than 40% of those patients actually have vitamin b12 level more than 800 pg/mL. It is known that elevated vitamin B12 level is associated with inflammation and increased mortality.[2] An association between elevated B12 levels and cancer has been reported in several studies [3]. It is unclear elevated vitamin B12 levels predict undiagnosed cancer which is a known risk factor for VTE or vitamin B12 directly contribute hypercoagulation. Nevertheless, we should be cautious when supplementing vitamin B12 and the dosage may need to be titrated closely. More clinical studies are definitely warranted.

Hypervitaminosis B12 - a new marker and predictor of prognostically unfavorable diseases

A high serum vitamin B12 level (hypercobalaminemia) is a underestimated anomaly. Clinically, it can be paradoxically accompanied by signs of deficiency, which are related to defects in tissue uptake of vitamin B12. The increase in the level of serum cobalamin occurs mainly in serious diseases that require early diagnosis: hemoblastosis, liver and kidney diseases, etc. This review presents data on the metabolism of vitamin B12 and the potential significance of increasing its level as a marker for the early diagnosis of these diseases.

Vitamin D Intoxication in An Elderly: A Case Report

Vitamin D is a very common prescribed drug for numerous indications. Due to scarce knowledge and poor awareness of the various formulations, preparations and dosages of Vitamin D, there are many chances of prescription errors, medication errors, product use issue and undesirable adverse drug reactions. We hereby detail case of 70-year-old ex-army gentleman reported to us with a history of lethargy, confusion, reduced appetite and gait imbalance since few days with a history of knee replacement surgery 2 years back. Medical history was not of much relevance before it was revealed that he was getting cholecalciferol injection with a strength of 600000 IU once a week for few months. He was detected to have very high serum vitamin D level and hypercalcemia. He was started on intravenous fluids, diuretics and glucocorticoids. In a few days, after effective treatment, the patient was discharged in a recovering stage and advised to stop intake calcium and vitamin D in any form. At his last follow up, after a few months of discharge, he had totally recovered.

Is high levels of vitamin D a new risk factor for Peyronie's disease?

The aim of this study is to investigate whether serum vitamin D level predicts the risk of Peyronie's disease. Calcium and inflammatory cytokines play an important role during fibrocalcification of the plaques in Peyronie's Disease. TGF-β1 is one of the most fibrogenic cytokines. Increasing serum vitamin D levels is considered that induce expression of TGF-β1. Serum vitamin D levels and TGF-β1 are related with calcifications of some soft tissues in previous studies. One hundred and three Peyronie patients and 162 healthy volunteers were included in the study. In both groups, demographic data, medical history, physical examination and erectile capacity were recorded. Serum 25-hydroxyvitamin D, total cholesterol, low-density lipoprotein, high-density lipoprotein, triglyceride and testosterone levels were measured. The mean level of serum 25 (OH) D was significantly higher in men with Peyronie's disease compared with the controls (32.6±7.9ng/ml vs. 18.5±6.6ng/ml respectively. p<0.001). There is a relationship between Peyronie's disease and high serum vitamin D levels. Also, increased low-density lipoprotein and total cholesterol levels, diabetes mellitus, and cardiovascular diseases were associated with Peyronie's disease.

Study on the relationship between serum vitamin D and the risk of type 2 diabetes in Harbin residents

Objective: To analyze the relationship between serum vitamin D level and the risk of type 2 diabetes in Harbin residents. Methods: On April 2010, 24 communities in 7 districts of Harbin were selected as research sites using multi-stage stratified cluster random sampling method. A total of 9 734 residents aged 20-74 years was investigated using general questionnaire survey, dietary survey and biochemical indicators test and followed up from January 2015 to July 2016. A total of 4 721 subjects with serum vitamin D were included in the study. According to the quartile of baseline serum vitamin D, the subjects were divided into four groups, from Q1 to Q4 group. The multivariate logistic regression model was used to analyze the relationship between serum vitamin D and the risk of type 2 diabetes. A mediation analysis model was used to analyze the mediating role of insulin resistance in this risk relationship. Results: At the time of follow-up, 432 patients with type 2 diabetes were screened. The median (P(25), P(75)) age of the diabetic group and the non-diabetic group were 54 (49, 61) and 51 (43, 57) years, respectively, and males accounted for 40.5% (175 cases) and 35.5% (1 513 cases), respectively. The median (P(25), P(75)) serum vitamin D was 16.0 (13.5, 18.5) and 17.4 (14.3, 20.5) ng/ml, respectively. After relevant confounders and insulin resistance index (HOMA-IR) were adjusted, compared to the serum vitamin D level Q(1) group, the risk of diabetes was reduced by 40% in the Q(3) group with RR (95%CI) about 0.60 (0.44-0.82), while the risk of diabetes was reduced by 59% in Q(4) group with RR (95%CI) about 0.41 (0.29-0.57). Through mediation analysis, the Gutt index mediating effect representing peripheral insulin resistance was 53.8%, and the mediating effect of HOMA-IR representing hepatic insulin resistance was 6.6%. Conclusion: The risk of type 2 diabetes is low in Harbin residents with higher serum vitamin D level. Insulin resistance has a mediating effect on the relationship of vitamin D and the risk of type 2 diabetes.

793-P: Serum Vitamin C Level Is Associated with Low Mortality Dependent on Metabolic Syndrome and Periodontitis Status

Background: Both metabolic syndrome and severe periodontitis have been linked to higher all-cause mortality. Additionally, a bidirectional relationship exists between metabolic syndrome and periodontitis. Vitamin C is a potent antioxidant radical scavenger and serum vitamin C level may have modifying effects on mortality rate. Methods: We analyzed subjects from the NHANES III cohort, aged &amp;gt;= 40 years old who have received oral examination (n=10165). The NHANES III periodontal measurements included periodontal probing depth (PPD), gingival recession and bleeding on probing (BOP). Clinical attachment loss (CAL) was calculated as the sum of the recession and PPD. We used the linked mortality-follow-up data through December 31, 2015 for these NHANES III participants and identified 5320 deaths. Leading causes of death were stratified by metabolic syndrome and mean CAL status. Results: Subjects with metabolic syndrome (MS) and periodontitis (PD) are associated with higher mortality rates in this cohort (Table 1, Chi-square P values &amp;lt; 1e-10). High serum Vitamin C level is associated with low mortality rate in mid-risk population including subjects with MS but no PD and subjects with PD but no MS (Table 2). In contrast, the association is not observed in either high-risk (with both MS and PD) nor low-risk subjects (no MS no PD). Disclosure P. Tsou: None. C. Wu: None.

Influence Of Vitamin D Status On The Post-exercise Hepcidin And Interleukin-6 Response In Trained Athletes

PURPOSE: Iron deficiency and reduced iron status have potential negative performance implications for athletes, particularly endurance runners. Hepcidin has a key role in iron homeostasis and is known to be influenced by interleukin (IL)-6. Emerging research from clinical populations indicates that vitamin D supplementation can reduce both circulating hepcidin and IL-6 levels hence could improve iron availability and increase performance. Exercise is known to increase both IL-6 and hepcidin levels, but the influence of vitamin D status on this response is unknown. METHODS: Twenty trained participants (24 ± 4 years; 184.3 ± 6.5 cm; 79.8 ± 7.5 kg; 55.7 ± 6.5 mL/min/kg) divided into 3 activity groups (endurance runners n=6; resistance trained n=6; team sports n=8) gave informed consent to take part in this study. Following an overnight fast, participants completed a sub-maximal and graded treadmill test to volitional exhaustion. Venous blood samples were collected pre, post, 1 h and 3 h post-exercise. Blood was analysed for serum total 25-hydroxy vitamin D at pre-exercise only; plasma hepcidin-25, plasma IL-6 and serum iron concentrations were assessed at all time points. RESULTS: Pre-exercise vitamin D values were similar between groups (90.2 ± 32.5 nM, p=0.563). Hepcidin increased significantly after exercise (F(1.1, 18.4)=36.81 p<0.001) with values peaking at 3 h post-exercise (pre 17.13 ± 12.15 ng/mL; 3 h post-exercise 38.44 ± 23.92 ng/mL). Both iron and IL-6 concentration increased significantly in response to exercise (F(1.9, 32.2)=44.1 p<0.001 and F(2.1, 36.4)=18.92 p<0.001, respectively). No significant interactions or group differences were found for hepcidin (p=0.121 and p=0.409), iron (p=0.529 and p=0.297) or IL-6 (p=0.709 and p=0.175). There was a significant negative correlation between peak hepcidin and relative VO2peak (rho=-0.468 p=0.038). There was a trend for a negative relationship between vitamin D values and % change in hepcidin from pre-exercise to 3 h post-exercise (r=-0.431 p=0.058) and a trend for a positive relationship between vitamin D and peak IL-6 values (r=0.410 p=0.072). CONCLUSIONS: Higher serum Vitamin D levels have the potential to reduce the post-exercise hepcidin response and therefore could have positive implications on athletes’ post-exercise iron status.

Canadian newcomer children's bone health and vitamin D status.

Adequate calcium intake and supply of vitamin D during childhood play important roles in ensuring adequate bone mass gain to achieve optimal peak bone mass. The Healthy Immigrant Children study employed a mixed-method cross-sectional study design to characterize the health and nutritional status of 300 immigrant and refugee children aged 3-13 years who had been in Canada for less than 5 years. This paper presents bone mineral content and vitamin D status data along with qualitative data that deepen the understanding of newcomer bone health status. A significantly higher percentage of refugee children (72.3%) had insufficient (<50 nmol/L) or deficient (<30 nmol/L) serum vitamin D compared with immigrants (53.2%). Vitamin D deficiency was most common among ethnic minority girls. Newcomer children with higher intakes of vitamin D, younger newcomer children, and those from western Europe or the United States had higher serum vitamin D levels. Immigrants had significantly higher mean total body bone mineral content compared with refugees. Total body fat, serum vitamin D, calcium intake, height, height by calcium intake, total body fat by calcium intake, and total body fat by height predicted total body bone mineral content levels. Vitamin D deficiency among newcomer children may be related to lack of knowledge regarding children's vitamin D requirements in the Canadian environment, dietary habits established in country of origin, low income that limits healthy dietary choices, and lifestyle habits that limit exposure to sunlight. Results suggest a need to screen newcomer children and pregnant women for vitamin D deficiency and support early intervention.

High levels of PIWI-interacting RNAs are present in the small RNA landscape of prostate epithelium from vitamin D clinical trial specimens.

BackgroundVitamin D, a hormone that acts through the nuclear vitamin D receptor (VDR), upregulates antitumorigenic microRNA in prostate epithelium. This may contribute to the lower levels of aggressive prostate cancer (PCa) observed in patients with high serum vitamin D. The small noncoding RNA (ncRNA) landscape includes many other RNA species that remain uncharacterized in prostate epithelium and their potential regulation by vitamin D is unknown.MethodsLaser capture microdissection (LCM) followed by small‐RNA sequencing was used to identify ncRNAs in the prostate epithelium of tissues from a vitamin D‐supplementation trial. VDR chromatin immunoprecipitation‐sequencing was performed to identify vitamin D genomic targets in primary prostate epithelial cells.ResultsIsolation of epithelium by LCM increased sample homogeneity and captured more diversity in ncRNA species compared with publicly available small‐RNA sequencing data from benign whole prostate. An abundance of PIWI‐interacting RNAs (piRNAs) was detected in normal prostate epithelium. The obligate binding partners of piRNAs, PIWI‐like (PIWIL) proteins, were also detected in prostate epithelium. High prostatic vitamin D levels were associated with increased expression of piRNAs. VDR binding sites were located near several ncRNA biogenesis genes and genes regulating translation and differentiation.ConclusionsBenign prostate epithelium expresses both piRNA and PIWIL proteins, suggesting that these small ncRNA may serve an unknown function in the prostate. Vitamin D may increase the expression of prostatic piRNAs. VDR binding sites in primary prostate epithelial cells are consistent with its reported antitumorigenic functions and a role in ncRNA biogenesis.

Relationship of Vitamin D Levels with HbA1c and Fructosamine in Korean Type 2 Diabetic Patients

Objectives Although previous studies reported an association of serum vitamin D with glycated hemoglobin (HbA1c) and fructosamine, the relationships remain unclear. Therefore, this study aims to identify the relationships of serum vitamin D with HbA1c and fructosamine independent of parathyroid hormone (PTH) in Korean type 2 diabetic patients. Methods Total 227 adults (male 112 and female 115) who treated for type 2 diabetes in a general hospital participated in this study. The serum vitamin D, HbA1c, fructosamine and fasting blood glucose (FBG) were measured in participants who met the detailed inclusion criteria. The level of serum vitamin D was defined as follows; deficient: <10.0 ng/mL, insufficient: 10.0-19.9 ng/mL, optimal: ≥20.0 ng/m. Results In the analysis of covariance, after adjusted for other covariates including PTH, the means (standard error, SE) values of HbA1c became lower with higher serum vitamin D level (deficiency: 7.8 [0.2]%, insufficient: 7.5 [0.1]%, optimal: 7.2 [0.1]%, p=0.015). Also, after adjusted for other covariates including PTH, the mean (SE) values of fructosamine became lower with higher serum vitamin D level (deficiency: 357.1 [13.1] μmol/L, insufficient: 344.5 [4.9] μmol/L, optimal: 313.3 [6.4] μmol/L, p=0.001). However, the mean values of FBG were not significantly associated with the serum vitamin D level. Conclusions There were significant associations of vitamin D with HbA1c and fructosamine independent of PTH, but there was no association of vitamin D with FBG in Korean type 2 diabetic patients. Key words: Diabetes mellitus, Vitamin D, Glycated hemoglobin A, Fructosamine, Parathyroid hormone

Vitamin D status and its correlates in Saudi male population

BackgroundVitamin-D deficiency is a universal health problem caused primarily by inadequate exposure to sunlight. This study aimed to assess the vitamin D status and investigate the factors affecting vitamin D distribution among Saudi males.MethodsA cross-sectional study was conducted at the King Saud University Medical City from December 2015 to August 2016. Saudi males attending the outpatient primary health care clinics were invited to participate in the study. Data were collected on the current and past health status along with biochemical investigations for total 25-hydroxyvitamin D (25OHD), blood sugar, and cholesterol.ResultsMajority of the participants (76.1%) had vitamin D deficiency. Blood sugar level, age, and cholesterol level were the most significant factors associated with vitamin D status. The highest percentage of deficiency was observed in the youngest age group (30-40 years). With increasing age, the percentage of deficiency decreased significantly. Those with normal blood sugar and cholesterol level had higher serum vitamin D levels compared to those with diabetes and hypercholesterolemia.ConclusionsVitamin D deficiency is still endemic in Saudi Arabia, particularly among younger males and those with diabetes and hypercholesterolemia. Vitamin D screening, supplementations, and vitamin D-fortified foods should be provided especially for these groups.

The Role of Vitamin D in Implant Success

Vitamin D is a multifunctional hormone that is mostly produced in the skin following exposure to ultraviolet B sunlight. It coordinates the physiological functions by controlling calcium and phosphate metabolism, promotes growth, and induces necessary remodeling of the bones and teeth. As known high serum vitamin D levels have beneficial effects on oral health and that exposure to safe sunlight can reduce the risk of periodontal disease and thus affect implant success. In order to prove this hypothesis, we conducted a detailed literature review. In the literature review, 3 clinical studies and 2 case reports of implant and vitamin D were found. Although vitamin D is highly correlated with bone metabolism, and expected a very close relationship with implant success, a large number of experimental studies and few clinical studies unfortunately showed contradictory results and no direct studies showing vitamin D and implant success were found. Therefore, it is necessary to demonstrate the existence or absence of this relationship by conducting much broader studies.

The latitude-dependent autoimmune disease risk genes ZMIZ1 and IRF8 regulate mononuclear phagocytic cell differentiation in response to vitamin D.

Epidemiological, molecular and genetic studies have indicated that high serum vitamin D levels are associated with lower risk of several autoimmune diseases. The vitamin D receptor (VDR) binding sites in monocytes and dendritic cells (DCs) are more common in risk genes for diseases with latitude dependence than in risk genes for other diseases. The transcription factor genes Zinc finger MIZ domain-containing protein 1 (ZMIZ1) and interferon regulatory factor 8 (IRF8)-risk genes for many of these diseases-have VDR binding peaks co-incident with the risk single nucleotide polymorphisms (SNPs). We show these genes are responsive to vitamin D: ZMIZ1 expression increased and IRF8 expression decreased, and this response was affected by genotype in different cell subsets. The IL10/IL12 ratio in tolerogenic DCs increased with vitamin D. These data indicate that vitamin D regulation of ZMIZ1 and IRF8 in DCs and monocytes contribute to latitude-dependent autoimmune disease risk.

Vitamin D Decreases Beck Depression Inventory Score in Patients with Mild to Moderate Ulcerative Colitis: A Double-Blind Randomized Placebo-Controlled Trial

ABSTRACTThe prevalence of depression in inflammatory bowel disease (IBD) is significantly more than in controls. Some studies assessed the link between vitamin D and depression. The aim of this study was to assess the effect of vitamin D on Beck Depression Inventory (BDI) score in ulcerative colitis (UC) patients. In this double-blind randomized controlled trial, 90 mild to moderate UC patients were assigned to receive a single injection of 300,000 IU vitamin D3 or 1 ml normal saline as placebo. At baseline and 3 months later, measurements of BDI score and serum 25-OH-vitamin D3 were done. Data were compared by independent sample t test, Mann–Whitney U test, and analysis of covariance (ANCOVA). Baseline BDI scores were not statistically different between the two groups (p = .4); scores decreased in the vitamin D group after the intervention (p = .023). Further subgroup analysis regarding baseline serum vitamin D levels and adjusted for baseline BDIs revealed lowering effect of vitamin D on BDI scores only in subgroup with baseline serum vitamin D levels equal to or higher than 30 ng/ml (p < .001). In this study, there was a statistically significant reduction in BDI score in mild to moderate UC patients 3 months after 300,000 IU vitamin D3 injection. Subgroup analysis showed that patients with sufficient baseline vitamin D may benefit from supplementation more than vitamin D–deficient patients, which indicates that higher serum vitamin D levels may be needed for its antidepressant effect.

Vitamin D deficiency as a risk factor for thyroid cancer: A meta-analysis of case-control studies.

The association between vitamin D deficiency and thyroid cancer is controversial. Some studies have demonstrated that higher serum vitamin D levels might protect against thyroid cancer, whereas others have not, or have even indicated the opposite to be the case. The aim of this meta-analysis was to investigate the association between vitamin D deficicency and thyroid cancer and propose that vitamin D deficiency is a risk factor for thyroid cancer. This was a meta-analysis of 14 articles of the association between vitamin D deficiency and thyroid cancer. Databases including PubMed, Cochrane library, Sinomed, CNKI, Wanfang, and clinical trial register centers, were searched for case-control studies of vitamin D in thyroid cancer. Fourteen studies were included in this meta-analysis. A fixed-effect model was used to merge the standardized mean difference value of serum 25-hydroxyvitamin D levels. The pooled effect showed that the levels of serum 25-hydroxyvitamin D were lower in patients with thyroid cancer preoperatively than in the controls (-0.22; 95% confidence interval [CI], -0.36 to -0.09; P = 0.001). There was no difference after thyroid cancer patients underwent thyroidectomy (-0.19; 95% CI, -0.47 to 0.10; P = 0.21). A fixed-effect model was used to pool the odds ratio of thyroid cancer and vitamin D deficiency. It showed that the pooled odds ratio from six studies was 1.30 (95% CI, 1.00-1.69; P = 0.05). Subgroup analysis of 25-hydroxyvitamin D levels between different pathologic characteristics in patients with thyroid cancer was summarized, but no statistical differences were determined. Lower serum 25-hydroxyvitamin D levels were associated with increased risk for thyroid cancer. On the other hand, vitamin D deficiency may act as a risk factor for thyroid cancer.

Lactase persistence may explain the paradoxical findings of high vitamin D concentrations in Europeans living in areas of low UV-B irradiation.

Vitamin D has a critical role in skeletal health and maintaining serum calcium levels. Calcium is needed for a variety of cellular and metabolic processes in the body. Large amounts of vitamin D can be produced in the skin when exposed to UV-B radiation. It is therefore a paradox that in Europe, Caucasians living in higher latitude countries, such as Scandinavia and Iceland, have higher serum vitamin D compared with those living in lower latitude. In a recent study of adult-type lactase persistence (LP), it was shown that Caucasian of European descent, who carried the C-13910T LP allele, had higher levels of total serum 25-hydroxyvitamin D compared with those who were lactase non-persistent. This was attributed to higher consumption of dairy. We postulated that the distribution of the LP C-13910T allele in Caucasian populations may explain the vitamin D concentration pattern seen in Europe. Baseline mean total serum 25 hydroxyvitamin D concentration from a clinical trial of post-menopausal women with osteoporosis was correlated to published LP frequencies in European populations. In multiple regression analysis, mean total serum 25 hydroxyvitamin D concentrations in both winter and summer were in turn correlated to LP phenotype frequency (winter: r2 = 0.51, p < 0.05; summer: r2 = 0.4, p < 0.05). High frequency of LP in northern Europe may explain high mean total serum 25 hydroxyvitamin D concentrations despite low UV-B radiation exposure.

Vitamin D, the gut microbiome and inflammatory bowel disease.

Vitamin D has an important role in bone metabolism but recently has been recognized as an immunoregulator, and this has led to investigations on the effect of Vitamin D supplementation in various autoimmune diseases and its anti-inflammatory effects. There is some evidence that Vitamin D can regulate gastrointestinal inflammation. In addition, previous studies have shown that Vitamin D can affect the gut microbiome. The aim of this review is to evaluate the effect of Vitamin D on inflammatory processes, especially its relation to the inflammatory bowel disease (IBD) and gut microbiome. There is some evidence that Vitamin D can regulate gastrointestinal inflammation, with epidemiological studies showing that individuals with higher serum Vitamin D have a lower incidence of IBD, particularly Crohn's disease. Vitamin D changes transcription of cathelicidin and DEFB4 (defensin, beta 4) that can affect the gut microbiome. Several cell types of the immune system express Vitamin D receptor, and hence the use of Vitamin D in immune regulation has some potential. Furthermore, Vitamin D deficiency leads to dysbiosis of gut microbiome and reported to cause severe colitis. Vitamin D supplementation is low cost and available and can be a therapeutic option.

SERUM VITAMIN D AND AGE-RELATED MUSCLE LOSS IN AFRO-CARIBBEAN MEN: THE IMPORTANCE OF AGE AND DIABETIC STATUS

Prospective studies examining the potential association of vitamin D with age-related muscle loss have shown inconsistent results. To examine the association between baseline serum 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and prospective change in lean mass with aging in African ancestry population. We also determined if associations were modulated by age and diabetes mellitus (DM). Prospective observational cohort study. Data were collected from a random sub-sample of 574 men, participants of the Tobago Bone Health Study (TBHS). 574 Afro-Caribbean men, aged 43+ years (mean age: 59.1 ± 10.5), who were randomly selected as the participants in both the baseline and the follow-up visits. Baseline fasting serum 25(OH)D was measured using liquid chromatography mass spectrometry (LC-MS/MS), and and 1,25(OH)2D was measured using radioimmunosassay (RIA). Changes in dual-energy X-ray absorptiometry (DXA)-measured appendicular lean mass (ALM), and total body lean mass (TBLM) were measured over an average of 6.0 ± 0.5 years. The associations of 25(OH)D and 1,25(OH)2D with ALM and TBLM were assessed by multiple linear regression model after adjusting for potential confounders. When stratifying all men into two groups by age, greater baseline 25(OH)D and 1,25(OH)2D levels were associated with smaller losses of ALM and TBLM in older (age 60+ years) but not in younger (age 43 - 59 years) men. When stratifying by DM status, the associations of 25(OH)D and 1,25(OH)2D with declines in ALM and TBLM were statistically significant only in prediabetic, but not among normal glycemic or diabetic men. Higher endogenous vitamin D concentrations are associated with less lean mass loss with aging among older and prediabetic Afro-Caribbean men independent of potential confounders. Our findings raise a possibility that maintaining high serum vitamin D level might be important for musculoskeletal health in elderly and prediabetic African ancestry men.