title: No Effect of High-Dose Vitamin D Supplementation on Glycemic Status or Cardiovascular Risk Factors in Subjects With Prediabetes Vitamin D supplementation and endothelial function in vitamin D deficient HIV-infected patients: a randomized placebo-controlled trial. Effect of short-term vitamin D supplementation on markers of vascular health in South Asian women living in the UK--a randomised controlled trial. Effect of cholecalciferol supplementation during winter months in patients with hypertension: a randomized, placebo-controlled trial. Vitamin D and calcium intake in relation to type 2 diabetes in women. Association of low serum 25-hydroxyvitamin D levels and high arterial blood pressure in the elderly. The effect of vitamin D replacement on markers of vascular health in stroke patients - a randomised controlled trial. Cholecalciferol treatment to reduce blood pressure in older patients with isolated systolic hypertension: the VitDISH randomized controlled trial. Effects of vitamin D supplementation on markers of vascular function after myocardial infarction--a randomised controlled trial. Effects of cholecalciferol on functional, biochemical, vascular, and quality of life outcomes in hemodialysis patients. Randomized controlled trial of vitamin D supplement on endothelial function in patients with type 2 diabetes. Randomized controlled trial of cholecalciferol supplementation in chronic kidney disease patients with hypovitaminosis D. Vitamin D3 supplementation for 16 weeks improves flow-mediated dilation in overweight African-American adults. Effect of high doses of vitamin D on arterial properties, adiponectin, leptin and glucose homeostasis in type 2 diabetic patients. Vitamin D improves endothelial function in patients with Type 2 diabetes mellitus and low vitamin D levels. Effect of a single, oral, high-dose vitamin D supplementation on endothelial function in patients with peripheral arterial disease: a randomised controlled pilot study. The effects of vitamin D repletion on endothelial function and inflammation in patients with coronary artery disease
abstract: OBJECTIVE In observational studies , low serum 25-hydroxyvitamin D [ 25(OH)D ] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease . RESEARCH DESIGN AND METHODS We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose ( IFG ) and /or impaired glucose tolerance ( IGT ) r and omly assigned to 20,000 IU/week vitamin D3 or placebo .  An oral glucose tolerance test was performed at baseline and after 1 year . RESULTS Mean baseline serum 25(OH)D was 59.9 nmol/L and 61.1 nmol/L in the vitamin D and placebo groups , respectively , and increased by 45.8 nmol/L and 3.4 nmol/L , respectively . With adjustment for baseline concentrations , no differences in measures of glucose metabolism , insulin secretion or sensitivity , blood pressure , or hs-CRP were found after 1 year . There was a slight , but significant decrease in total and LDL cholesterol in the vitamin D group compared with the placebo group , but as there was also a decrease in HDL cholesterol , the change in the total/HDL cholesterol ratio did not differ significantly . Only analyzing subjects with 25(OH)D < 50 nmol/L did not change the results . CONCLUSIONS This study shows that vitamin D supplementation does not improve glycemic indices , blood pressure , or lipid status in subjects with IFG and /or IGT BACKGROUND Studies suggest that vitamin D deficiency is a risk factor for cardiovascular disease and diabetes . Vitamin D deficiency is prevalent in HIV patients but the effect of vitamin D supplementation on cardiovascular risk in this population is unknown . METHODS We conducted a r and omized , double-blind , placebo-controlled trial among 45 HIV-infected adults in Clevel and ( OH , USA ) on stable antiretroviral therapy with durable virological suppression and a baseline serum 25-hydroxyvitamin D level of ≤20 ng/ml . Participants were r and omized 2:1 to vitamin D3 4,000 IU daily or placebo  for 12 weeks . The primary outcome was a change in flow-mediated brachial artery dilation ( FMD ) . RESULTS Baseline demographics were similar except for age ( vitamin D versus placebo , mean ±sd 47 ±8 versus 40 ±10 years ; P=0.009 ) . Both groups had reduced FMD at baseline ( median values 2.9 % [ IQR 1.6 - 4.8 ] for vitamin D versus 2.5 % [ IQR 1.7 - 6.4 ] for placebo ; P=0.819 ) . Despite an increase in the concentration of serum 25-hydroxyvitamin D from baseline to 12 weeks ( 5.0 ng/ml [ IQR -0.9 - 7.4 ] versus -1.9 ng/ml [ IQR -4.0 - 0.1 ] for vitamin D versus placebo , respectively ; P=0.003 ) , there was no difference in FMD change ( 0.55 % [ IQR -1.05 - 2.13 ] versus 0.29 % [ IQR -1.61 - 1.77 ] ; P=0.748 ) . Vitamin D supplementation was associated with a decrease in total and non-high-density lipoprotein cholesterol , and an increase in indices of insulin resistance . CONCLUSIONS Among HIV-infected individuals with vitamin D deficiency , supplementation with 4,000 IU vitamin D3 daily for 12 weeks modestly improved vitamin D status and cholesterol but worsened insulin resistance without change in endothelial function . The mechanisms of resistance to st and ard doses of vitamin D and the complex role of vitamin D in glucose metabolism in this population require further investigation OBJECTIVE Low vitamin D levels and risk factors for vascular disease are both common in South Asian women . This trial evaluated whether vitamin D supplementation could improve markers of vascular health in South Asian women with low 25-hydroxyvitamin D levels . METHODS Parallel-group , double-blind , r and omised placebo-controlled trial . Healthy South Asian women with baseline serum 25-hydroxyvitamin D levels of < 75 nmol/L were r and omised to receive a single dose of 100,000 units oral vitamin D3 or matching placebo . Outcomes were measured at baseline , 4 and 8 weeks . The primary outcome was change in endothelial function measured using brachial artery flow-mediated dilatation . Secondary outcomes included blood pressure , arterial stiffness , microvascular function measured using laser Doppler iontophoresis , insulin resistance , serum lipids , circulating markers of inflammation , thrombosis and adipokines . RESULTS 50 women were r and omised , 25 to each group . Mean age was 41 years ; mean baseline 25-hydroxyvitamin D level was 27 nmol/L.  25-Hydroxyvitamin D levels rose in the vitamin D group relative to the placebo group by 4 weeks ( 16 nmol/L , 95 % CI 11 to 21 , p < 0.001 ) . There was no improvement in flow-mediated dilatation in the vitamin D group relative to placebo at 4 weeks ( 0.1 % , 95 % CI -0.9 to 1.1 , p = 0.84 ) or 8 weeks ( 0.0 % , 95 % CI -1.4 to 1.4 , p = 0.98 ) . There was no improvement in cholesterol , insulin resistance or markers of inflammation . Both platelet activation inhibitor-1 and tissue plasminogen activator levels fell significantly in the vitamin D group relative to placebo at 8 weeks . CONCLUSION A single large dose of vitamin D3 did not improve blood pressure or endothelial function in South Asian women with low baseline 25-hydroxyvitamin D levels . TRIAL REGISTRATION IS RCT N75081811 BACKGROUND Low 25-hydroxy-vitamin D ( 25(OH)D ) levels are inversely related to blood pressure ( BP ) and have been associated with incident hypertension . In people living at northern latitudes diminished cholecalciferol synthesis in the winter increases the risk of vitamin D deficiency . We wanted to test the hypothesis that daily cholecalciferol supplementation in the winter lowers BP in patients with hypertension . METHODS We investigated the effect of 75 µg ( 3,000 IU ) cholecalciferol per day in a r and omized , placebo-controlled , double-blind study in 130 hypertensive patients residing in Denmark ( 56º N ) . Ambulatory BP ( 24-h BP ) and arterial stiffness were measured before and after 20 weeks of treatment , that took place between October and March . RESULTS A total of 112 patients ( mean age 61 ± 10 ) with a baseline p-25(OH)D of 23 ± 10 ng/ml completed the study . Compared with placebo , a nonsignificant 3/1 mm Hg ( P = 0.26/0.18 ) reduction was found in 24-h BP . In patients with vitamin D insufficiency ( < 32 ng/ml ) at baseline ( n =  92 ) , 24-h BP decreased by 4/3 mm Hg ( P = 0.05/0.01 ) . Central BP ( CBP ) estimated by applanation tonometry and calibrated with a st and ardized office BP was reduced by 7/2 mm Hg ( P = 0.007/0.15 ) vs. placebo . No differences in carotid-femoral pulse wave velocity ( PWV ) or central augmentation index ( AIx ) were found between treatment arms . CONCLUSIONS Cholecalciferol supplementation , by a dose that effectively increased vitamin D levels , did not reduce 24-h BP , although central systolic BP decreased significantly . In a post-hoc subgroup analysis of 92 subjects with baseline p-25(OH)D levels < 32 ng/ml , significant decreases in 24-h systolic and diastolic BP occurred during cholecalciferol supplementation OBJECTIVE The purpose of this study was to prospect ively examine the association between vitamin D and calcium intake and risk of type 2 diabetes .  RESEARCH DESIGN AND METHODS In the Nurses ' Health Study , we followed 83,779 women who had no history of diabetes , cardiovascular disease , or cancer at baseline for the development of type 2 diabetes .  Vitamin D and calcium intake from diet and supplements was assessed every 2 - 4 years . During 20 years of follow-up , we documented 4,843 incident cases of type 2 diabetes . RESULTS After adjusting for multiple potential confounders , there was no association between total vitamin D intake and type 2 diabetes . However , the relative risk ( RR ) of type 2 diabetes was 0.87 ( 95 % CI 0.75 - 1.00 ; P for trend = 0.04 ) comparing the highest with the lowest category of vitamin D intake from supplements . The multivariate RRs of type 2 diabetes were 0.79 ( 0.70 - 0.90 ; P for trend < 0.001 ) comparing the highest with the lowest category of calcium intake from all sources and 0.82 ( 0.72 - 0.92 ; P for trend < 0.001 ) comparing the highest with the lowest category of calcium intake from supplements . A combined daily intake of > 1,200 mg calcium and > 800 IU vitamin D was associated with a 33 % lower risk of type 2 diabetes with RR of 0.67 ( 0.49 - 0.90 ) compared with an intake of < 600 mg and 400 IU calcium and vitamin D , respectively . CONCLUSIONS The results of this large prospect i ve study suggest a potential beneficial role for both vitamin D and calcium intake in reducing the risk of type 2 diabetes BACKGROUND Vitamin D and calcium metabolism are involved in vascular smooth muscle cell proliferation , endothelial function and blood pressure ( BP ) regulation . Their physiopathology has been a matter of intensive clinical investigation with variable and sometimes contradictory results . Vitamin D insufficiency is highly prevalent in the general population , particularly among the elderly . We evaluated the association between serum 25(OH)-D levels and arterial BP in this population . METHODS An epidemiological cross-sectional study was design ed to analyse the prevalence of hypovitaminosis D ( ' D'AVIS ' study ) in our reference area . The study was performed on a representative r and om sample of the population over 64 years of age obtained from five primary health care areas . A medical record , arterial BP and biological analysis : serum 25(OH)-D , iPTH , creatinine , urea , calcium , albumin were obtained . RESULTS A total of 237 subjects ( 53 % women ) , aged between 64 and 93 ( mean 71.7 + /- 5.3 ) , were evaluated . The mean serum 25(OH)-D levels were 17.21 + /- 7.57 ng/ml ( interval 5 - 54 ; 86 % had < 25 ng/ml ) . The mean BP was 138.8 + /- 14/80 + /- 7.4 mmHg , and 46 % were on antihypertensive treatment . A significant negative association was observed between serum 25(OH)-D levels and systolic ( r = -0.153 , P = 0.018 ) and diastolic BP ( r = -0.152 , P = 0.019 ) . This association persisted after controlling for possible confounders in the multivariate analyses . CONCLUSIONS Low serum 25(OH)-D levels were inversely and independently associated with BP . Supplemental measures to prevent hypovitaminosis D in this population would be important , not only to protect the skeletal system but also for the possible beneficial effects on the cardiovascular system and the BP regulation BACKGROUND AND AIMS Low vitamin D levels are associated with increased incidence of future cardiovascular events and are common in stroke patients . We tested whether vitamin D supplementation could reduce blood pressure and improve markers of vascular health in patients who had previously suffered a stroke . METHODS AND RESULTS R and omised , placebo-controlled , double-blind trial . Community-dwelling patients with a history of stroke and baseline 25-hydroxyvitamin D levels < 75 nmol/L received 100,000 units of oral vitamin D2 or placebo at baseline . Office and 24 h blood pressure , endothelial function measured by flow-mediated dilatation of the brachial artery , cholesterol , oxidised low density lipoprotein , B-type natriuretic peptide and heart rate turbulence were measured at baseline , 8 weeks and 16 weeks . 58 patients were r and omised . Mean age was 67 years , mean baseline blood pressure 128/72 mmHg , mean baseline 25-hydroxyvitamin D level was 38 nmol/L.  Serum 25-hydroxyvitamin D levels were higher in the intervention group at 8 weeks compared to placebo ( 54 vs 42 nmol/L , P = 0.002 ) and remained higher at 16 weeks . Office systolic and diastolic blood pressure showed no significant change between groups at 8 weeks ( systolic 126.1 vs 131.3 mmHg ; adjusted P = 0.97 ) ; ( diastolic 73.1 vs 74.9 mmHg , adjusted P = 0.15 ) . Flow mediated dilatation was significantly higher in the intervention group at 8 weeks ( 6.9 % vs 3.7 % , adjusted P = 0.007 ) but was not significantly different at 16 weeks . CONCLUSIONS High dose oral vitamin D supplementation did not improve blood pressure but produced short-term improvement in endothelial function in stroke patients with well-controlled baseline blood pressure . CLINICAL TRIALS REGISTRATION IS RCT N28737567 IMPORTANCE Observational data link low 25-hydroxyvitamin D levels to both prevalent blood pressure and incident hypertension . No clinical trial has yet examined the effect of vitamin D supplementation in isolated systolic hypertension , the most common pattern of hypertension in older people . OBJECTIVE To test whether high-dose , intermittent cholecalciferol supplementation lowers blood pressure in older patients with isolated systolic hypertension . DESIGN Parallel group , double-blind , placebo-controlled  r and omized trial . SETTING Primary care clinics and hospital clinics . PARTICIPANTS Patients 70 years and older with isolated systolic hypertension ( supine systolic blood pressure > 140 mm Hg and supine diastolic blood pressure < 90 mm Hg ) and baseline 25-hydroxyvitamin D levels less than 30 ng/mL were r and omized into the trial from June 1 , 2009 , through May 31 , 2011 . INTERVENTIONS A total of 100,000 U of oral cholecalciferol or matching placebo every 3 months for 1 year . MAIN OUTCOMES AND MEASURES Difference in office blood pressure , 24-hour blood pressure , arterial stiffness , endothelial function , cholesterol level , insulin resistance , and b-type natriuretic peptide level during 12 months . RESULTS A total of 159 participants were r and omized ( mean age , 77 years ) .  Mean baseline office systolic blood pressure was 163/78 mm Hg . Mean baseline 25-hydroxyvitamin D level was 18 ng/mL. 25-Hydroxyvitamin D levels increased in the treatment group compared with the placebo group ( + 8 ng/mL at 1 year , P < .001 ) . No significant treatment effect was seen for mean ( 95 % CI ) office blood pressure ( −1 [ −6 to 4]/−2 [ −4 to 1 ] mm Hg at 3 months and 1 [ −2 to 4]/0 [ −2 to 2 ] mm Hg overall treatment effect ) . No significant treatment effect was evident for any of the secondary outcomes ( 24-hour blood pressure , arterial stiffness , endothelial function , cholesterol level , glucose level , and walking distance ) . There was no excess of adverse events in the treatment group , and the total number of falls was nonsignificantly lower in the group receiving vitamin D ( 36 vs 46 , P = .24 ) . CONCLUSIONS AND RELEVANCE Vitamin D supplementation did not improve blood pressure or markers of vascular health in older patients with isolated systolic hypertension . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N92186858 BACKGROUND Low vitamin D levels are common , and are associated with a higher incidence of future vascular events . We tested whether vitamin D supplementation could improve endothelial function and other markers of vascular function in patients with a history of myocardial infa rct ion . METHODS Parallel group , placebo-controlled , double-blind r and omised trial . Patients with a history of myocardial infa rct ion were r and omised to receive 100,000 units of oral vitamin D3 or placebo at baseline , 2 months and 4 months . Outcomes were measured at baseline , 2 and 6 months . Reactive hyperaemia index on fingertip plethysmography was the primary outcome . Secondary outcome measures included blood pressure , cholesterol , C-reactive protein , von Willebr and factor , tumour necrosis factor alpha , E-selectin , B-type natriuretic peptide , thrombomodulin and 25-hydroxyvitamin D levels . RESULTS 75 patients were r and omised , mean age 66 years . 74/75 ( 99 % ) completed 6 month follow-up . 25 hydroxyvitamin D levels increased in the intervention group relative to placebo ( + 13 vs + 1 nmol/L , p=0.04 ) . There was no between-group difference in change in reactive hyperaemia index between baseline and 6 months ( -0.18 vs -0.07 , p=0.40 ) . Of the secondary outcomes , only C-reactive protein showed a significant decline in the intervention arm relative to placebo at 6 months ( -1.3 vs 2.0mg/L , p=0.03 ) . Systolic blood pressure ( + 1.4 vs + 2.3 mmHg , p=0.79 ) , diastolic blood pressure ( + 2.0 vs + 0.8 mmHg , p=0.54 ) and total cholesterol ( + 0.26 vs + 0.24 mmol/L , p=0.88 ) showed no between-group difference at 6 months . CONCLUSIONS Supplementation with vitamin D did not improve markers of vascular function in patients with a history of myocardial infa rct ion BACKGROUND AND OBJECTIVES Observational studies suggest that calciferol supplementation may improve laboratory and patient-level outcomes of hemodialysis patients with reduced 25-hydroxyvitamin D [ 25(OH)D ] levels . This r and omized controlled trial examined effects of cholecalciferol supplementation in patients on hemodialysis . DESIGN , SETTING , PARTICIPANTS , & MEASUREMENTS Sixty patients with 25(OH)D levels ≤24 ng/ml ( ≤60 nmol/L ) were r and omized to receive 50,000 IU oral cholecalciferol or placebo , once weekly for 8 weeks and then monthly for 4 months . At baseline ( autumn 2011 ) and 6 months , testing evaluated muscle strength , functional capacity , laboratory parameters , pulse wave velocity ( PWV ) , and health-related quality of life ( HRQOL ) using the Kidney Disease Quality of Life-36 survey . RESULTS Patients were well matched by treatment allocation . Median age was 62 years ( range , 20 - 86 ) , 52 % were women , 55 % had a history of diabetes , and mean serum 25(OH)D was 17±5 ng/ml ( 43±13 nmol/L ) . Patients were assessed over 6 months by repeated- measures ANOVA . Patients allocated to cholecalciferol had significantly higher values of 25(OH)D ( P<0.001 ) , 1,25-dihydroxyvitamin D ( P=0.04 ) , and tartrate-resistant acid phosphatase-5b ) ( P=0.04 ) and a greater reduction in phosphorus values ( P=0.03 ) than placebo-treated  patients Values of serum calcium , intact parathyroid hormone , and episodes of hypercalcemia and hyperphosphatemia did not differ significantly between the groups . No significant differences were detected in muscle strength , functional capacity , PWV , or HRQOL . CONCLUSIONS In this r and omized controlled trial , patients supplemented with cholecalciferol  had higher 25(OH)D , 1,25-dihydroxyvitamin D , and tartrate-resistant acid phosphatase-5b levels , without increased calcium or phosphorus values . However , no effects were detected in muscle strength , functional capacity , PWV , or HRQOL BACKGROUND Suboptimal vitamin D status is associated with endothelial dysfunction and an increased risk of cardiovascular diseases but it is unclear whether vitamin D supplementation is beneficial . The aim was to investigate the effect of vitamin D supplementation on endothelial function in patients with type 2 diabetes mellitus ( DM ) . METHODS In a double-blind , placebo-controlled trial , we r and omized 100 type 2 DM patients to vitamin D supplement  ( 5000 IU/day , n = 50 ) or placebo ( controls , n = 50 ) for 12 weeks . Assessment of vascular function with brachial artery flow-mediated dilatation ( FMD ) , circulating levels of endothelial progenitor cells ( EPCs ) and brachial-ankle pulse wave velocity , and metabolic parameter , high-sensitivity C-reactive protein ( hsCRP ) and oxidative stress markers were performed before and after the supplementation . RESULTS After 12 weeks , vitamin D treated patients had significant increases in serum 25-hydroxyvitamin D [ 25(OH)D ] concentration ( treatment effect 34.7 ng/mL , 95 % CI 26.4 - 42.9 , P < 0.001 ) and serum ionized calcium ( treatment effect 0.037 mmol/L , 95 % CI 0.007 - 0.067 , P = 0.018 ) ; decreased serum parathyroid hormone concentration ( treatment effect -0.55 pmol/L , 95 % CI -1.08 to -0.02 , P = 0.042 ) compared to patients who received placebo . Nevertheless , vitamin D supplementation did not improve vascular function as determined by FMD , circulating EPC count or baPWV ( all P > 0.05 ) . Furthermore , hsCRP , oxidative stress markers , low- and high-density lipoprotein and glycated hemoglobin were also similar between two groups ( all P > 0.05 ) . CONCLUSION In patients with type 2 DM , 12 weeks oral supplementation of vitamin D did not significantly affect vascular function or serum biomarkers of inflammation and oxidative stress . CLINICAL TRIAL NUMBER HKCTR-867 , www.hk clinical trials.com BACKGROUND Hypovitaminosis D is common in chronic kidney disease ( CKD ) . Effects of 25-hydroxyvitamin D replenishment in CKD are not well described . METHODS An 8-week r and omized , placebo-controlled , double-blind parallel intervention study was conducted in haemodialysis ( HD ) and non-HD CKD patients . Treatment consisted of 40,000 IU of cholecalciferol orally per week . Plasma 25-hydroxyvitamin D ( 25-OHD ) , plasma 1,25-dihydroxyvitamin D ( 1,25-diOHD ) , plasma parathyroid hormone ( PTH ) , serum phosphate , ionized serum calcium and serum fibroblast growth factor 23 ( FGF-23 ) were analysed . We also investigated biomarkers related to cardiovascular disease ( plasma D-dimer , plasma fibrinogen , plasma von Willebr and factor antigen and activity , plasma interleukin 6 , plasma C-reactive protein , blood pressure , aortic augmentation index , aortic pulse wave velocity and 24-h urinary protein loss ) . Objective and subjective health variables were assessed ( muscle function tests , visual analogue scores and Health Assessment Question naire ) . RESULTS Fifty-two CKD patients with 25-OHD < 50 nmol/L at screening were included .  Cholecalciferol supplementation led to a significant increase to a median of 155 nmol/L 25-OHD ( interquartile range 137 - 173 nmol/L ) in treated patients ( n = 25 , P < 0.001 ) . In non-HD patients , we saw a significant increase in 1,25-diOHD ( n = 13 , P < 0.01 ) and a lowering of PTH ( n = 13 , P < 0.001 ) . This was not observed in HD patients .  Cholecalciferol supplementation caused a significant increase in serum calcium and FGF-23 . CONCLUSIONS 25-OHD replenishment was effectively obtained with the employed cholecalciferol dosing . In non-HD patients , it had favourable effects on 1,25-diOHD and PTH .  Vitamin D-supplemented patients must be monitored for hypercalcaemia . The present study could not identify significant pleiotropic effects of 25-OHD replenishment BACKGROUND A growing body of evidence has linked vitamin D deficiency to increased risk of cardiovascular disease . Vitamin D deficiency is also more common in African Americans for whom an increased cardiovascular disease risk exists . This study sought to test the hypothesis that 16 weeks of 60,000 IU monthly supplementation of oral vitamin D(3 ) would improve flow-mediated dilation ( FMD ) in African Americans , whereas no change would be observed in the placebo group . METHODS A r and omized , double-blind , placebo-controlled clinical trial was conducted . Fifty-seven African-American adults were r and omly assigned to either the placebo group or vitamin D group . RESULTS Following 16 weeks of placebo ( n = 23 ; mean age 31 ± 2 years ) or 60,000 IU monthly oral vitamin D(3 ) ( n = 22 ; mean age 29 ± 2 years ) , serum concentrations of 25-hydroxyvitamin D ( 25(OH)D ) increased from 38.2 ± 3.0 to 48.7 ± 3.2 nmol/l and 34.3 ± 2.2 to 100.9 ± 6.6 nmol/l , respectively . No changes in serum parathyroid hormone ( PTH ) , serum calcium , or urine calcium/creatinine were observed following either treatment . Following 16 weeks of treatment , significant improvements in FMD were only observed in the vitamin D group ( 1.8 ± 1.3 % ) , whereas the placebo group had no change ( -1.3 ± 0.6 % ) . Similarly , the vitamin D group exhibited an increase in absolute change in diameter ( 0.005 ± 0.004 cm ) and FMD/shear ( 0.08 ± 0.04 % /s(-1 ) , area under the curve ( AUC ) × 10(3 ) ) following treatment , whereas no change ( -0.005 ± 0.002 cm and -0.02 ± 0.02 % /s(-1 ) , AUC , respectively ) was observed following placebo . CONCLUSION Supplementation of 60,000 IU monthly oral vitamin D(3 ) ( ~2,000 IU/day ) for 16 weeks is effective at improving vascular endothelial function in African-American adults BACKGROUND & AIMS Vitamin D supplementation has the potential to alleviate the cardiovascular damage in diabetic patients . The present study was design ed to evaluate long term impact of high doses of vitamin D on arterial properties , glucose homeostasis , adiponectin and leptin in patients with type 2 diabetes mellitus . METHODS AND RESULTS In r and omized , placebo-controlled study 47 diabetic patients were assigned into two groups : Group 1 received oral daily supplementation with vitamin D at a dose of 1000 U/day for 12 months . Group 2 received matching placebo capsules . Blood sampling for metabolic parameters , including fasting glucose , lipid profile , HbA1C , insulin , hs-CRP , 25 OH Vit D , adiponectin and leptin was performed at baseline and at the end of the study . Insulin resistance was assessed by homeostasis model assessment ( HOMA-IR ) . Central aortic augmentation index ( AI ) was evaluated using SphygmoCor . RESULTS The two groups were similar at baseline in terms of hemodynamic parameters . After 12 months , AI decreased significantly during the treatment period in patients received vitamin D ( p < 0.0001 ) and did not change in placebo group . Glucose homeostasis parameters , leptin as well as leptin adiponectin ratio did not change in both groups . 25 OH Vit D level significantly increased ( p = 0.022 ) and circulating adiponectin marginally increased ( p = 0.065 ) during 12 month treatment period in active treatment and did not change in placebo group . CONCLUSIONS High doses of  vitamin D supplementation in diabetic patients was associated with significant decrease in AI during one year treatment . This beneficial vascular effect was not associated with improvement in glucose homeostasis parameters AIMS To test whether a single large dose of vitamin D2 can improve endothelial function in patients with Type 2 diabetes mellitus and low serum 25-hydroxyvitamin D levels . METHODS Double-blind , parallel group , placebo-controlled r and omized trial . A single dose of 100,000 IU vitamin D2 or placebo was administered to patients with Type 2 diabetes over the winter , when levels of circulating 25-hydroxyvitamin D were likely to be lowest . Patients were enrolled if their baseline 25-hydroxyvitamin D level was < 50 nmol/l .  Endothelial function and blood pressure were measured and fasting blood sample s were taken at baseline and 8 weeks after administration of vitamin D. RESULTS Forty-nine per cent of subjects screened had 25-hydroxyvitamin D levels < 50 nmol/l . Thirty-four subjects completed the study , with a mean age of 64 years and a baseline 25-hydroxyvitamin D level of 38.3 nmol/l .  Vitamin D supplementation  increased 25-hydroxyvitamin D levels by 15.3 nmol/l relative to placebo and significantly improved flow mediated vasodilatation ( FMD ) of the brachial artery by 2.3 % . The improvement in FMD remained significant after adjusting for changes in blood pressure .  Vitamin D supplementation significantly decreased systolic blood pressure by 14 mmHg compared with placebo ; this did not correlate with change in FMD . CONCLUSIONS Vitamin D insufficiency is common in patients with Type 2 diabetes during winter in Scotl and . A single large dose of oral vitamin D2 improves endothelial function in patients with Type 2 diabetes and vitamin D insufficiency OBJECTIVE Apart from its role in bone metabolism , vitamin D may also influence cardiovascular disease . The objective of this study was : ( 1 ) to determine the effect of a single , oral , high-dose vitamin D supplementation on endothelial function and arterial stiffness in patients with peripheral arterial disease ( PAD ) and ( 2 ) to investigate the impact of this supplementation on coagulation and inflammation parameters . METHODS In this double-blind , placebo-controlled , interventional pilot study , we screened 76 Caucasian patients with PAD for vitamin D deficiency . Sixty-two were r and omised to receive a single , oral supplementation of 100,000 IU vitamin D3 or placebo . At baseline and after 1 month , we measured serum vitamin D and parathormone levels , and surrogate parameters for cardiovascular disease . RESULTS Sixty-five of 76 patients ( 86 % ) had low 25-hydroxyvitamin D levels ( < 30 ng ml(-1 ) ) ; of those , 62 agreed to participate in the study . At baseline , only parathormone was related to vitamin D. In supplemented patients , vitamin D levels increased from 16.3 ± 6.7 to 24.3 ± 6.2 ng ml(-1 ) ( P < 0.001 ) , with wide variations between single patients ; in the placebo group vitamin levels did not change . Seasonal factors accounted for a decrease of vitamin D levels by 8 ng ml(-1 ) between summer and winter . After 1 month , none of the measured parameters was influenced by vitamin substitution . CONCLUSION In this pilot study , most patients with PAD were vitamin D deficient . Vitamin D supplementation  increased serum 25-hydroxyvitamin D without influencing endothelial function , arterial stiffness , coagulation and inflammation parameters , although the study was underpowered for definite conclusions Adequate vitamin D levels may promote cardiovascular health by improving endothelial function and down-regulating inflammation . The objective of this pilot trial was to investigate the effects of vitamin D repletion on endothelial function and inflammation in patients with coronary artery disease ( CAD ) . Using a double-blind placebo wait-list control design , 90 subjects with CAD and vitamin D deficiency ( < 20 ng/ml ) were r and omized 1:1 to 50,000 IU of oral ergocalciferol or placebo weekly for 12 weeks . Endothelial function ( reactive hyperemia peripheral arterial tonometry , RH-PAT ) , circulating adhesion molecules , and pro-inflammatory cytokines were measured at baseline and 12 weeks . The median increase in serum 25-vitamin D from baseline was 26 ± 17 ng/ml in the active group and 4 ± 8 ng/ml in the placebo group ( between-group difference = 22 ng/ml , p < 0.001 ) . The median within-subject change in RH-PAT score was 0.13 ± 0.73 with active treatment and −0.04 ± 0.63 with placebo ( between-group difference = 0.17 , p = 0.44 ) . Within-group and between-group differences in intercellular adhesion molecule levels were greater with placebo ( between-group difference = 6 ng/ml , p = 0.048 ) . Vascular cell adhesion molecule levels decreased in both groups by a similar magnitude ( median difference between groups = 8.5 ng/ml , p = 0.79 ) . There was no difference between groups in magnitude of reduction in interleukin (IL)-12 ( −8.6 ng/ml , p = 0.72 ) and interferon-gamma ( 0.52 ng/ml , p = 0.88 ) . No significant differences in blood pressure , e-selectin , high-sensitivity c-reactive protein , IL-6 or the chemokine CXCL-10 were found with treatment . In conclusion , repleting vitamin D levels in subjects with CAD failed to demonstrate any benefits on surrogate markers of cardiovascular health . These results question the role of vitamin D supplementation in modifying cardiovascular disease
target: Conclusions Vitamin D supplementation did not improve EF .
  The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function .
background: Abstract Background In addition to regulating calcium homoeostasis and bone health , vitamin D influences vascular and metabolic processes including endothelial function ( EF ) and insulin signalling .