Association between vitamin D and hepatitis C virus infection: A meta-analysis

AIM:To evaluate the association between 25-hydroxyvitamin D[25(OH)D]and sustained virological response(SVR)in hepatitis C virus(HCV)infected individuals.METHODS:Relevant studies were identified by systematically searching MEDLINE databases up to March2012 and abstracts of the European and American Congress of Hepatology conducted in 2011.Studies must provide information on SVR and the levels of 25(OH)D3and/or 25(OH)D2[henceforth referred to as 25(OH)D]in sera samples from HCV infected individuals.The inclusion criteria were:clinical studies that included HCV infected patients aged older than 18 years regardless of HCV genotype or ethnic group;provided information on SVR rates;and were reported in the English languageas full papers.Due to the heterogeneity of studies in categorizing serum vitamin D levels,a cut-off value of30 ng/mL of serum 25(OH)D was used.Heterogeneity was assessed using I2statistics.The summary odds ratios with their corresponding 95%CI were calculated based on a random-effects model.RESULTS:Overall,11 studies(8 observational and 3interventional)involving 1575 individuals were included and 1117 HCV infected individuals(71%)showed low vitamin D levels.Most of the studies included monoinfected HCV individuals with the mean age ranging from 38 to 56 years.Four studies were conducted in human immunodeficiency virus/HCV infected individuals.Regarding vitamin D measurement,most of the studies employed radioimmunoassays(n=5)followed by chemiluminescence(n=4)and just one study employed high performance/pressure liquid chromatography(HPLC).Basal vitamin D levels varied from 17 to43 ng/mL in the studies selected,and most of the HCV infected individuals had genotype 1(1068/1575)with mean viral load varying from log 4.5-5.9 UI/mL.With regard to HCV treatment,most of the studies(n=8)included HCV individuals without previous treatment,where the pooled SVR rate was 46.4%.High rates of SVR were observed in HCV individuals with vitamin D levels above 30 ng/mL(OR=1.57;95%CI:1.12-2.2)and those supplemented with     

Complementary role of vitamin D deficiency and the interleukin-28B rs12979860 C/T polymorphism in predicting antiviral response in chronic hepatitis C

The widely accepted interleukin-28B (IL-28B) rs12979860 C/T polymorphism and the more recently proposed vitamin D serum concentration are two novel predictors of the response to antiviral treatment in chronic hepatitis C virus (HCV) infection. This study aimed to verify whether the IL-28B rs12979860 C/T polymorphism and pretreatment serum vitamin D levels have independent or complementary roles in predicting the rates of sustained viral response (SVR). The present study included 211 consecutive, treatment-na?ve chronic HCV patients who had their pretreatment serum 25-OH vitamin D level and IL-28B rs12979860 C/T genotype determined. Overall, SVR was achieved by 134/211 (63.5%) patients and by 47/110 (42.7%) patients infected with difficult-to-treat HCV genotypes. On multivariate analysis, SVR was predicted by the HCV genotype, the IL-28B rs12979860 C/T polymorphism, and gamma-glutamyl transpeptidase, HCV RNA, cholesterol, and 25-OH vitamin D serum levels, with an area under the receiver operating characteristic (ROC) curve of 0.827. When difficult-to-treat HCV genotypes were analyzed separately, the SVR was predicted by the IL-28B rs12979860 C/T polymorphism, viral load, and serum vitamin D level, with an area under the ROC curve of 0.836. Moreover, by categorizing these latter patients into four groups-C/C homozygotes with vitamin D levels >20 ng/mL (group A) or ≤20 ng/mL (group B) and C/T heterozygotes or T/T homozygotes with vitamin D levels >20 ng/mL (group C) or ≤20 ng/mL (group D)-a significant linear trend was observed, with SVR rates in the following descending order: group A, 18/21 (85.7%); group B, 6/11 (54.5%); group C, 14/38 (36.8%); and group D, 9/40 (22.5%) (P < 0.0001). CONCLUSION: Vitamin D serum levels are complementary to the IL-28B rs12979860 C/T polymorphism in enhancing the correct prediction of the SVR in treatment-na?ve chronic hepatitis C.     

Vitamin D deficiency and vitamin D therapy in chronic hepatitis C

Background. Vitamin D has immunomodulatory properties, exerts an anti-hepatitis C virus (HCV) effect in vitro and improves response to interferon-based therapy in patients with chronic hepatitis C (CHC). Low serum levels of 25(OH) vitamin D [25(OH)D] are frequently found in CHC patients and seem to be related to more advanced stages of liver fibrosis. The study aims to establish the incidence of vitamin D deficiency in Spanish patients with CHC, its possible relation with features of liver damage and with the IL28B gene polymorphism, and the immediate effect of vitamin D therapy on CHC-related analytical variables.Materials and methods. Baseline serum 25(OH)D levels were measured in 108 consecutive CHC patients (60 men, age 54.3 ± 10.5 yrs). Results of transient elastography and of IL28B rs12979860C/T genotype were available in 89 and 95 patients, respectively. Forty one patients with insufficient levels of 25(OH)D received vitamin D supplements and were re-evaluated thereafter.Results. Deficiency of vitamin D (< 20 µg/dL) and suboptimal levels (20–30 µg/mL) were detected in 36.1% and 40.9% of patients, respectively. No relationships were found between 25(OH)D levels and biochemical liver tests, fibrosis stage and IL28B genotype. Vitamin D therapy normalized 25(OH)D levels in all treated patients, but did not modify significantly HCV-RNA serum levels or biochemical tests.Conclusions. Vitamin D deficiency is common in Spanish patients with CHC but it is related neither to biochemical and virological variables nor with the fibrosis stage and IL28B polymorphism. Vitamin D therapy has no immediate effect on HCV-RNA serum levels.     

Prevalence of and factors associated with vitamin D deficiency in 4,793 Japanese patients with rheumatoid arthritis

To determine the prevalence of vitamin D deficiency and associations with clinical characteristics in Japanese patients with rheumatoid arthritis (RA), serum 25(OH)D levels, laboratory data, and clinical data were obtained from 4,793 patients with RA (4,075 women, 718 men, mean age 59.7 years) who participated in the Institute of Rheumatology Rheumatoid Arthritis observational cohort study in April and May of 2011. Serum vitamin D levels were evaluated using a radioimmunoassay. We defined vitamin D deficiency as <20 ng/mL and severe deficiency as <10 ng/mL. Associations of vitamin D deficiency with patient characteristics were examined using multivariate logistic regression. Among all patients, the mean (SD) serum 25(OH)D level was 16.9 ng/mL (6.1), and the prevalence of vitamin D deficiency and severe deficiency were 71.8 and 11.5 %, respectively. In multivariate analysis, female gender, younger age, high Japanese version of health assessment questionnaire (HAQ) disability score, low serum total protein levels, low serum total cholesterol levels, high serum alkaline phosphate (ALP) levels, and non-steroidal anti-inflammatory drug (NSAID) use were significantly associated with vitamin D deficiency (P?<?0.01). Vitamin D deficiency appears to be common in Japanese patients with RA, as previously reported for patients of other ethnicities. Female gender, younger age, high HAQ disability score, low serum levels of total protein and total cholesterol, high serum ALP levels, and NSAID use appear to be associated with vitamin D deficiency in Japanese patients with RA.     

Effect of Vitamin D Serum Levels and GC Gene Polymorphisms in Liver Fibrosis Due to Chronic Hepatitis C

Introduction and aimVitamin D has been associated with chronic liver diseases and low vitamin levels may contribute to progression of chronic hepatitis C. The aim of this study was to evaluate the influence of vitamin D serum levels and GC gene polymorphisms in the severity of liver fibrosis in patients with chronic hepatitis C genotype 1.Material and methodsCross-sectional study that enrolled 132 adult patients with chronic hepatitis C genotype 1 attended at the outpatient Clinic of Gastroenterology Division at Hospital de Clínicas de Porto Alegre. At the time of enrollment patients had a blood withdraw for serum 25(OH)D determination and genotypic analysis of rs7041 and rs4588 polymorphisms in GC gene. None/mild fibrosis was considered as METAVIR F0, F1 and F2 and severe fibrosis as METAVIR F3 and F4.ResultsMedian 25(OH)D levels in the sample were 19.9 ng/mL (P25-P75: 14.0-29.4). Fifty percent of patients presented vitamin D deficiency (< 20 ng/mL). In stepwise multiple linear regression the variables associated with 25(OH)D levels were blood withdrawn in Winter/spring season, the haplotypes AT/AT + AG/AT of rs7041 and rs4588 and female sex. For evaluation of severe fibrosis, variables associated in logistic regression were age, vitamin D severe deficiency (< 10 ng/mL), glucose levels, BMI and platelets count.ConclusionsVitamin D levels are associated with severity of liver fibrosis in chronic hepatitis C genotype 1 patients. Although the rs7041 and rs4588 GC polymorphisms are strong predictors of vitamin D levels, they do not play a direct role in liver fibrosis.     

Vitamin D deficiency and hepatitis viruses-associated liver diseases:a literature review

The secosteroid hormone vitamin D has, in addition to its effects in bone metabolism also functions in the modulation of immune responses against infectious agents and in inhibiting tumorigenesis. Thus, deficiency of vitamin D is associated with several malignancies, but also with a plethora of infectious diseases. Among other communicable diseases, vitamin D deficiency is involved in the pathogenesis of chronic liver diseases caused by hepatitis B and C viruses(HBV, HCV) and high prevalence of vitamin D deficiency with serum levels below 20 mg/mL in patients with HBV and HCV infection are found worldwide. Several studies have assessed the effects of vitamin D supplementation on the sustained virological response(SVR) to interferon(IFN) plus ribavirin(RBV) therapy in HBV and HCV infection. In these studies, inconsistent results were reported. This review addresses general aspects of vitamin D deficiency and, in particular, the significance of vitamin D hypovitaminosis in the outcome of HBVand HCV-related chronic liver diseases. Furthermore,current literature was reviewed in order to understand the effects of vitamin D supplementation in combination with IFN-based therapy on the virological response in HBV and HCV infected patients.     

基线维生素D与慢性丙型肝炎持久病毒学应答相关性的Meta分析

目的：探讨基线维生素D水平与HCV基因1、4型感染者对标准抗病毒治疗持久病毒学应答（SVR）的关系。方法检索数据库中有关基线维生素D水平与HCV基因1、4型慢性感染者接受抗病毒治疗后SVR相关性的文献,meta分析比较SVR组和非SVR组的基线维生素D水平。结果共检索到210篇相关文献,其中符合纳入标准5篇,meta分析结果显示,基线维生素D水平在SVR组（32．9 ng/mL）与非SVR组（28．3 ng/mL）的加权均数差（WMD）为6．759（95％ CI：1．786,11．733）,两组的基线维生素D水平差异有统计学意义（Z＝2．66,P＝0．008）。结论 HCV 基因1、4型慢性感染者接受标准抗HCV治疗获得SVR者的基线维生素D水平高于未获得SVR者。     

Investigating the Efficiency of Vitamin D Administration with Buccal Spray in the Treatment of Vitamin D Deficiency in Children and Adolescents

Objective:The aim of this study was to evaluate the efficiency of a buccal spray form of vitamin D compared to single oral dose (stoss therapy) and oral drops therapy in the treatment of vitamin D deficiency.Methods:Ninety healthy children and adolescents (3-18 years) with vitamin D deficiency [serum level of 25-hydroxyvitamin D (25(OH) D) <12 ng/mL] were randomized to receive vitamin D3 buccal spray (2000 U, n=30, group 1) for six weeks, oral drops (2000 U, n=30, group 2) for six weeks and a single oral dose (300 000 U) vitamin D3 (n=30, group 3). Serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone and 25(OH)D levels of the patients were measured at baseline and after the treatment on the 42^nd day.Results:All three groups had a significant increase in serum 25(OH)D concentrations (p<0.001). In group 1, baseline mean 25(OH)D was 8.0±0.41 ng/mL, which rose to 22.1 (17.8-28.2) ng/mL after treatment with a mean increase of 15.6±1.3 ng/mL. Similarly in group 2, baseline, post-treatment and mean increase in 25(OH)D concentrations were 7.9±0.45 ng/mL, 24.4 (20.6-29.6) ng/mL and 17.3±1.1 ng/mL while for group 3 these values were 7.6±0.47 ng/mL, 40.3 (29.4-58.4) ng/mL and 34.3±3.2 ng/mL, respectively.Conclusion:We conclude that vitamin D3 supplementation with buccal spray and oral drops is equally effective in terms of raising vitamin D concentrations in short-term treatment of vitamin D deficiency.     

Factors associated with 25-hydroxyvitamin D levels in patients with liver cirrhosis

Introduction. Lower 25-hydroxyvitamin D [25(OH)D] levels have been observed in cirrhotic patients and have been related to disease severity. However, most previous studies included patients with very advanced disease, lacking an adequate control for other variables that could interfere with vitamin D levels. We sought to investigate the prevalence of hypovitaminosis D and the factors related to its occurrence.Material and methods. This cross-sectional study included 133 cirrhotic patients and 30 healthy controls. Bivariate and multivariate analyses were performed to determine factors associated with 25(OH)D levels below the lower tertile. Thirty patients who had been recently hospitalized were compared in two time points.Results. Mean 25(OH)D levels were 32.34 ± 11.38 in controls and 27.03 ± 6.22 ng/mL in patients (P = 0.018). 25(OH)D levels were < 30 ng/mL in 69.9% and < 20 ng/mL in 14.3% of the sample. Levels of 25(OH)D below the lower tertile (< 24 ng/mL) were independently associated with higher triceps skinfold and non-Caucasian race. Parathyroid hormone above the reference value (65 pg/mL) was found in 24.6% of patients without association with 25(OH)D or severity of liver disease. Significantly lower levels of 25(OH)D were found at the time of acute decompensation of cirrhosis.Conclusions. In conclusion, hypovitaminosis D was prevalent in cirrhotics and it was associated with adiposity and non-Caucasian race in stable patients with relatively well preserved liver function. However, significantly lower levels were observed during admission for acute decompensation suggesting an impact of systemic inflammation or liver dysfunction on 25(OH)D levels.     

Serum and dietary vitamin D and cardiovascular disease risk in elderly men: a prospective cohort study

Background and aimRecent research suggests that low vitamin D may be associated with cardiovascular disease (CVD).Methods and resultsWe prospectively evaluated the association of dietary plus supplemental vitamin D intake and serum 25(OH) vitamin D with CVD incidence in the Osteoporotic Fractures in Men (MrOS) Study. Vitamin D intake was measured using a food frequency questionnaire and self-reported supplemental intake in 3094 men (mean age 76.4 years). From a subset of this population, we measured 25(OH) vitamin D in 813 men. Median 25(OH) vitamin D was 25.3 ng/mL. During a median follow-up of 4.4 years, there were 472 CVD cases, including 371 from coronary heart disease (CHD) and 101 from cerebrovascular attack (CVA). In the 25(OH) vitamin D sub-cohort, there were 140 cases of CVD including 115 from CHD and 25 from CVA. We used a Cox proportional hazards regression to calculate hazard ratios (HR) for CVD by vitamin D quartile. After adjusting for age, season, and standard CVD risk factors, the lowest quartile of 25(OH) vitamin D (HR, 1.18; 95% CI, 0.69–2.03) and vitamin D intake (HR, 0.76; 95% CI, 0.56–1.04) were not significantly associated with CVD incidence, compared to the highest vitamin D quartiles. When 25(OH) vitamin D was further analyzed by sufficiency (≥30 ng/mL), insufficiency (≥15–29.9 ng/mL), and deficiency (<15 ng/mL), vitamin D deficiency was not significantly associated with CVD incidence compared to sufficiency (HR 1.34; 95% CI 0.65–2.77).ConclusionVitamin D intake and serum 25(OH) vitamin D were not associated with CVD risk.     

Vitamin D, sunlight and longevity

Humans acquire vitamin D through skin photosynthesis and digestive intake. Two hydroxylations are needed to obtain the bioactive compound, the first produces 25-hydroxyvitamin D [25(OH)D], and the second 1,25-dihydroxyvitamin D [1,25(OH)2D]. There is no consensus regarding the appropriate cut-off level to define the normal serum 25(OH)D range. Experimental, epidemiological and clinical studies have related low vitamin D status with longevity. Although some results are controversial, low serum 25(OH)D levels have been linked to all-cause, cardiovascular, cancer and infectious related mortality. Throughout life span a significant proportion of human beings display insufficient (20-30 ng/mL) or deficient (<20 ng/mL) serum 25(OH)D levels. Appropriate lifestyle changes, such as regular short exposures to sunlight (15 min a day), and an adequate diet that includes vitamin D rich components, are not always easily accomplished. Studies relating to vitamin D supplementation have methodological limitations or are based on relatively low doses. Therefore, dosages used for vitamin D supplementation should be higher than those traditionally suggested. In this sense, there is an urgent need for prospective controlled studies using high daily vitamin D doses (2,000 IU or higher) including cardiovascular, cancer, infectious and other endpoints. Relationship between vitamin D and health outcomes is not linear, and there are probably various optimal vitamin D levels influencing different endpoints.     

Quantification of hepatitis C virus in patients treated with peginterferon-alfa 2a plus ribavirin treatment by COBAS TaqMan HCV test

Summary. Extremely low levels of serum hepatitis C virus (HCV) RNA can be detected by COBAS TaqMan HCV test. To investigate whether the COBAS TaqMan HCV test is useful for measuring rapid virological response (RVR) and early virological response (EVR) to predict sustained virological response (SVR), we compared the virological response to PEG‐IFN‐alfa 2a plus RBV in 76 patients infected with HCV genotype 1 when undetectable HCV RNA by the COBAS TaqMan HCV test was used, with those when below 1.7 log IU/mL HCV RNA by COBAS TaqMan HCV test was used, which corresponded to the use of traditional methods. Among the 76 patients, 28 (36.8%) had SVR, 13 (17.1%) relapsed, 19 (25.0%) did not respond, and 16 (21.0%) discontinued the treatment due to side effects. The positive predictive values for SVR based on undetectable HCV RNA by COBAS TaqMan HCV test at 24 weeks after the end of treatment [10/10 (100%) at week 4, 21/23 (91.3%) at week 8 and 26/33 (78.7%) at week 12] were superior to those based on <1.7 log IU/mL HCV RNA [17/19 (89.4%) at week 4, 27/38 (71.0%) at week 8, and 27/43 (62.7%) at week 12]. The negative predictive values for SVR based on <1.7 log IU/mL HCV RNA by COBAS TaqMan HCV test [46/57 (80.7%) at week 4, 37/38 (97.3%) at week 8, and 32/33 (96.9%) at week 12] were superior to those based on undetectable HCV RNA [48/66 (72.7%) at week 4, 46/53 (86.7%) at week 8, and 41/43 (95.3%) at week 12]. The utilization of both undetectable RNA and <1.7 log IU/mL HCV RNA by COBAS TaqMan HCV test is useful and could predict SVR and non‐SVR patients with greater accuracy.     

The prevalence of vitamin D inadequacy amongst women with osteoporosis: an international epidemiological investigation

INTRODUCTION: Vitamin D is essential for calcium metabolism as well as for fracture prevention, and a recent review suggested that the optimal serum 25(OH)D lies in the region of 50-80 nmol L-1 (20-32 ng mL-1). A high prevalence of inadequacy has been reported in many studies but the prevalence of inadequacy amongst women with osteoporosis in different regions of the world has not been well characterized. SETTING AND SUBJECTS: A multinational study of 18 countries at various latitudes (range 64N-38S) was conducted in 2004 and 2005 to determine the average levels of serum 25(OH)D and the prevalence of vitamin D inadequacy. A total of 2606 postmenopausal women with osteoporosis (low bone mineral density, history of fragility fracture) seeking routine medical care were enrolled and serum 25(OH)D levels were measured at a single laboratory visit. RESULTS: Mean serum 25(OH)D level was 26.8 ng mL-1 (SE 0.3) and ranged from 7 to 243 ng mL-1. Regional mean values were highest in Latin America (29.6 ng mL-1, SE 0.6) and lowest in the Middle East (20.4 ng mL-1, SE 0.5). Overall, 64% of women had serum levels<30 ng mL-1. Serum parathyroid hormone reached a nadir at serum 25(OH)D levels>35 ng mL-1. In nonequatorial countries, women recruited during the winter months had somewhat lower serum 25(OH)D levels than those recruited during the summer months in some, but not all, countries. CONCLUSIONS: Low levels of serum 25(OH)D are common amongst women with osteoporosis. The results underscore the value of assuring vitamin D adequacy in these women.     

Genetic variation in interleukin-28B predicts SVR in hepatitis C genotype 1 Argentine patients treated with PEG IFN and ribavirin

Background and aims. Genetic variations in the interleukin 28B (IL28B) gene have been associated with viral response to PEG-interferon-a/ribavirin (PR) therapy in hepatitis C virus (HCV) genotype 1 infected patients from North America, Europe and Asia. The importance of these IL28B variants for Argentine patients remains unknown.Material and methods. IL28B host genotypes (rs8099917 and rs12979860) were determined in a population of Argentine patients with European ancestry. Results were analyzed looking for their association with sustained virologic response (SVR) to PR therapy and compared with other baseline hosts’ biochemical, histological and virological predictors of response.Results. We studied 102 patients, 60% were men, and 40% of them were rs8099917 TT and 18% rs12979860 CC. Mean baseline serum HCV RNA was 1.673.092 lU/mL and mean F score was: 2.10 ± 1.18 (21% cirrhotic). SVR rate was higher in rs8099917 TT genotypes (55%) when compared to GT/GG (25%) (p = 0.002) and in rs1512979860 CC (64%) than in CT/TT (30%) (p = 0.004). The univariate analysis showed that rs8099917 TT (OR 3.7; 95 %CI 1.5-8.7; p = 0.002), rs12979860 CC (OR 4.6; 95%CI 1.5-13.7; p = 0.006), low viral load (OR 4.6; 95°% CI 1.7-12.6; p = 0.002) and F0-2 (OR 8.5; 95°% CI 2.3-30.6; p = 0.001) were significantly associated with SVR. In the multivariate analysis, rs12979860 CC, rs8099917 TT, viral load < 400.000 IU/mL and F0-2 were associated with SVR rates (p = 0.029, p = 0.012, p = 0.013 and p = 0.004, respectively).Conclusion. IL28B host genotypes should be added to baseline predictors of response to PR therapy in Latin American patients with European ancestry.     

25‐hydroxyvitamin D and cardiovascular risk factors in women with systemic lupus erythematosus

Objective

Low serum levels of 25‐hydroxyvitamin D (25[OH]D; vitamin D) are associated with a higher frequency of cardiovascular disease and risk factors in the general population. Vitamin D deficiency has also been noted in systemic lupus erythematosus (SLE). The objective of this study was to evaluate the associations of serum 25(OH)D levels with cardiovascular risk factors in women with SLE.

Methods

Data collected in 181 women with SLE included demographics, SLE activity and damage assessments, cardiovascular risk factors, medications, and laboratory assessments of inflammatory markers and 25(OH)D levels. Multiple linear and logistic regressions were used to estimate the association of 25(OH)D levels with cardiovascular risk factors.

Results

The mean age and disease duration were 43.2 and 11.9 years, respectively. The mean 25(OH)D level was 27.1 ng/ml and 62.2% had 25(OH)D levels <30 ng/ml. In unadjusted analyses, lower 25(OH)D levels were significantly associated with higher diastolic blood pressure, low‐density lipoprotein cholesterol, lipoprotein(a), body mass index (BMI), and fibrinogen levels, as well as self‐reported hypertension and diabetes mellitus. Lower 25(OH)D levels were also significantly associated with higher SLE disease activity and damage scores. After adjustment for age, seasonal variation, and race/ethnicity, lower 25(OH)D levels were also significantly related to higher fasting serum glucose. With further adjustment for BMI, associations between 25(OH)D and cardiovascular risk factors were no longer significant.

Conclusion

This study demonstrates that vitamin D levels are low in women with SLE and significant associations exist with selected cardiovascular risk factors, although most of these associations can be explained by BMI.     

High-Dose Vitamin D: Helpful or Harmful?

If the optimal serum 25(OH)D level for skeletal health is 30 ng/mL or greater, then vitamin D insufficiency is widespread, affecting about 75% of adults based on a recent survey of more than 20,000 Americans. However, after a comprehensive analysis of existing research studies, the Institute of Medicine recently concluded that nearly all individuals are vitamin D replete when their 25(OH)D levels are 20 ng/mL or greater. Furthermore, two recent publications challenge the belief that 25(OH)D levels greater than 30 ng/mL are optimal for bone health. In a randomized, placebo-controlled trial, high-dose, once-yearly vitamin D therapy increased the incidence of fractures and falls. The second study reported that high-dose vitamin D did not reduce levels of parathyroid hormone or bone resorption among adults with 25(OH)D levels less than 32 ng/mL at baseline. It is time to question whether serum 25(OH)D levels of 30 ng/mL or greater are necessary for all individuals.     

The relationship between 25-hydroxyvitamin D levels and treatment course of pulmonary tuberculosis

BackgroundLow serum vitamin D level is associated with a high risk of developing active tuberculosis (TB). We investigated the relationships between serum vitamin D levels and clinical course of TB after standard chemotherapy in hospitalized non-HIV patients with TB.MethodsHospitalized patients with TB were recruited between February 2008 and July 2010. Confirmatory tests were performed using sputum smear and culture positivity tests for Mycobacterium tuberculosis. Drug sensitivity testing was performed for all the subjects and those not showing drug resistances for the first-line anti-TB drugs were included in the study. These patients were treated with the standard first-line anti-TB drugs. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured on admission, and the relationships between 25(OH)D and clinical characteristics (laboratory data on admission and treatment outcomes) were examined. We defined vitamin D deficiency as a condition where serum level of 25(OH)D was lower than 20 ng/ml.ResultsA total of 38 patients were included in the study. Mean (±SD) 25(OH)D levels were 13.7±5.9 ng/ml. The prevalence of vitamin D deficiency was 87%. In 23 patients treated with the standard first-line 4-drug regimen (Age <80 years) serum 25(OH)D levels showed significant negative correlation with time taken to obtain 3 consecutive negative sputum smears or TB bacteria cultures. This relationship suggests that low serum vitamin D level may not only increase the risk of developing active TB but may also be related to the poor treatment outcomes in these patients.ConclusionsLow serum vitamin D level is a good predictor of prolonged clinical course in patients with active pulmonary TB.     

Hyperparathyroidism secondary to hypovitaminosis D in hypoalbuminemic is less intense than in normoalbuminemic patients: a prevalence study in medical inpatients in southern Brazil

Hypovitaminosis D has been reported in tropical countries, but this hormone has seldom been studied in Brazil. Our purpose was to study the prevalence of hypovitaminosis D in patients hospitalized in internal medicine wards in Southern Brazil. Possible associated factors were studied. We studied 81 adult patients in early spring. Mean serum 25(OH)D was 12±8.57 ng/mL; hypovitaminosis D was severe (<10 ng/mL) in 27 (33.3%) patients, and moderate (≥10 ng/mL and <20 ng/mL) in 36 (44.5%) patients. Clinical evaluation did not yield any data associated with hypovitaminosis D. Serum 25(OH)D levels of up to 20 ng/mL were associated with decreased mean serum total calcium (p=0.001), ionized calcium (p=0.01), and phosphorus (p=0.044) levels, and increased mean serum PTH level (p=0.001). In a multiple regression model, serum PTH level was independently affected by serum total calcium (p=0.01), phosphorus (p=0.009), and albumin (p=0.009) levels. Hypovitaminosis D patients had lower mean serum albumin levels (p=0.004), and serum 25(OH)D levels were directly correlated to serum albumin levels (p<0.0001). Albumin influenced independently PTH response to hypovitaminosis D; normoalbuminemic hypovitaminosis D patients had higher mean serum PTH than hypoalbuminemic patients. Conclusion: Hypovitaminosis D prevalence was very high in medical inpatients in Southern Brazil, in early spring. Nevertheless, secondary hyperparathyroidism was less intense in hypoalbuminemic hypovitaminosis D patients suggesting that in these patients free serum 25(OH)D was closer to normal.     

Vitamin D: epidemiology of cardiovascular risks and events

Vitamin D may influence blood pressure through the renin-angiotensin system, parathyroid hormone levels, myocardial function, inflammation, and vascular calcification. In the past several years, a number of high-quality prospective studies have examined 25(OH)vitamin D (25(OH)D) levels in relation to risk of cardiovascular disease (CVD). Studies consistently show that levels of 25(OH)D below 20-25 ng/mL are associated with an increased risk of CVD incidence or mortality. Risk appears especially elevated at 25(OH)D levels below 10 or 15 ng/mL. It is unclear if levels higher that 25 ng/mL provide further benefits for CVD disease. Currently, results from randomized clinical trials are sparse and do not allow a definitive conclusion. Given other potential benefits of vitamin D, and low potential for toxicity, deficient levels below 25-30 ng/mL should be avoided and treated when identified. Further observational and randomized clinical trial data are important to better characterize the optimal range for 25(OH)D.