The role of vitamin D in blood pressure, endothelial and renal function in postmenopausal women

Are vitamin D deficiency and VDR gene polymorphisms associated with high blood pressure as defined by the ACC/AHA 2017 criteria in postmenopausal women?

OBJECTIVES

To assess the vitamin D levels, prevalence of vitamin D deficiency and genotypes of Fok-I, Bsm-I, Apa-I and Taq-I polymorphisms in the VDR gene and to determine whether vitamin D deficiency and VDR gene variants are associated with blood pressure levels and systemic arterial hypertension as defined by the 2017 ACC/AHA criteria.

STUDY DESIGN

A cross-sectional study of biobanked blood samples from 339 postmenopausal women.

MAIN OUTCOME MEASURES

Blood pressure strata were defined according to the 2017 ACC/AHA cutoffs. Circulating 25(OH)D levels were considered deficient if <20 ng/mL.

RESULTS

Mean serum total 25(OH)D levels were 22.99 ± 8.54 ng/mL, and 40.1% of participants were deficient in vitamin D. Overall, 7.7% had elevated blood pressure, 36.6% had stage 1 and 37.8% had stage 2 hypertension. Mean total (p = 0.014) and free 25(OH)D levels (p = 0.029) were lower in women with stage 2 hypertension than in those with normal blood pressure. A higher prevalence rate of stage 2 hypertension was associated with age (PR 1.058; 95%CI 1.033-1.083; p < 0.001), BMI (PR 1.046; 95%CI 1.025-1.068; p < 0.001), vitamin D deficiency (PR 1.333; 95%CI 1.016-1.749; p = 0.038) and Taq-I polymorphism (PR 1.764; 95%CI 1.030-3.019; p = 0.039). Women with vitamin D deficiency and the AA+AG genotype of Taq-I polymorphism were 33% and 76% more likely to have stage 2 hypertension, respectively, but these associations lost significance when adjusted for age and BMI.

CONCLUSION

The results suggest that vitamin D deficiency and Taq-I polymorphism are associated with stage 2 hypertension, depending on age and BMI, in postmenopausal women.

Sex and body mass index dependent associations between serum 25-hydroxyvitamin D and pulse pressure in middle-aged and older US adults

High pulse pressure (PP) is a valid indicator of arterial stiffness. Many studies have reported that vitamin D concentration is inversely associated with vascular stiffening. This association may differ depending on sex and body mass index (BMI). This study investigated the associations between vitamin D and PP and evaluated whether these associations differ according to sex and BMI, using data for individuals aged ≥ 50 years from the National Health and Nutrition Examination Survey (NHANES) 2007-2010. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were used as biomarkers of vitamin D levels. High PP was defined as ≥ 60 mmHg. Total 25(OH)D concentrations were dose-dependently associated with lower odds ratios (ORs) for high PP (p-trend = 0.01), after controlling for sociodemographic, behavioral, and dietary factors. When stratified by sex, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in females, but not in males. When stratified by BMI, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in non-overweight subjects, but not in overweight subjects. Improving the vitamin D status could delay elevation of PP and vascular stiffening in female and non-overweight subjects.

The Role of Extracellular Vesicles (EVs) in the Epigenetic Regulation of Bone Metabolism and Osteoporosis

Extracellular vesicles (EVs) are complex phospholipidic structures actively released by cells. EVs are recognized as powerful means of intercellular communication since they contain many signaling molecules (including lipids, proteins, and nucleic acids). In parallel, changes in epigenetic processes can lead to changes in gene function and finally lead to disease onset and progression. Recent breakthroughs have revealed the complex roles of non-coding RNAs (microRNAs (miRNAs) and long non-coding RNAs (lncRNAs)) in epigenetic regulation. Moreover, a substantial body of evidence demonstrates that non-coding RNAs can be shuttled among the cells and tissues via EVs, allowing non-coding RNAs to reach distant cells and exert systemic effects. Resident bone cells, including osteoclasts, osteoblasts, osteocytes, and endothelial cells, are tightly regulated by non-coding RNAs, and many of them can be exported from the cells to neighboring ones through EVs, triggering pathological conditions. For these reasons, researchers have also started to exploit EVs as a theranostic tool to address osteoporosis. In this review, we summarize some recent findings regarding the EVs’ involvement in the fine regulation of non-coding RNAs in the context of bone metabolism and osteoporosis.

Serum 25-hydroxyvitamin D and hypertension in premenopausal and postmenopausal women: National Health and Nutrition Examination Surveys 2007-2010

OBJECTIVE

A recent meta-analysis suggested that the association between vitamin D and risk of hypertension was markedly stronger in women aged <55 years in observational data, while the association became null in women aged ≥55 years. We therefore hypothesized that this difference in associations might potentially be caused by the change in oestrogen around menopause. Our objective was to investigate associations between vitamin D status and hypertension risk and to evaluate those associations as they may differ according to menopausal status.

DESIGN

A cross-sectional population survey conducted by the US Centers for Disease Control and Prevention, National Center for Health Statistics.

SETTING

The National Health and Nutrition Examination Surveys (NHANES) 2007-2010 formed the setting for the present study.

PARTICIPANTS

We analysed data from 2098 premenopausal women and 2298 postmenopausal women.

RESULTS

After adjustment for sociodemographic, behavioural and dietary factors, higher concentrations both of serum total 25-hydroxyvitamin D (25(OH)D) and serum 25-hydroxycholecalciferol (25(OH)D3) revealed significant dose-dependent trends with lower risk of hypertension (Ptrend = 0·005 and 0·014, respectively) in premenopausal women. In those women, 25(OH)D ≥ 50 nmol/l (sufficient; in contrast to deficient, vitamin D < 30 nmol/l) appeared to have a protective effect against hypertension (OR = 0·64, 95 % CI 0·39, 1·02 for total 25(OH)D and OR = 0·60, 95 % CI 0·36, 1·00 for 25(OH)D3). Neither association with hypertension was observed in postmenopausal women.

CONCLUSIONS

Serum 25(OH)D concentrations were associated with lower risk of hypertension in premenopausal women, but not in postmenopausal women.

Vitamin D deficiency and risk of cardiovascular diseases: a narrative review

Vitamin D, a fat-soluble prohormone, has wide-ranging roles in the regulation of many physiological processes through their interactions with the vitamin D receptors (VDR). It plays a major role in bones and calcium metabolism. Vitamin D deficiency is not uncommon and it has been associated with many health-related issues, including skeletal and non-skeletal complications. The association of low vitamin D and cardiovascular diseases and risk factors has been explored in both animal and human studies. However, studies and trials on the effect of vitamin D supplementation on cardiovascular risk factors and hypertension are conflicting with inconsistent results. Therefore, large, well-powered randomized controlled trials are warranted. If successful, supplementation with easy and low-cost vitamin D can impact our health positively. Here, we summarized the evidence for the association of vitamin D, cardiovascular diseases and risk factors, including coronary artery diseases, stroke, and hypertension, and mortality, with special consideration to resistant hypertension.

Effect modification of hypertension on the association of vitamin D deficiency with severity of coronary stenosis

AIMS

There may exist an effect modification of hypertension on the relation of vitamin D deficiency with cardiovascular disease. The aim of this study was to investigate this interaction on coronary heart disease.

METHODS

We investigated 348 consecutive patients (mean age 62.4 ± 10.5 years; 56.3% male) who underwent coronary angiography because of chest discomfort at our heart center. Serum 25-OH vitamin D was also detected by ELISA method in these patients. Multivariable logistic regression models were used to estimate odd ratios (ORs) of CHD across vitamin D levels in hypertensives and normotensives, respectively.

RESULTS

We found the multivariable-adjusted ORs of CHD in the bottom(≤8.5 ng/ml) and middle tertiles (8.5-13 ng/ml) of 25-OH vitamin D were 2.86 (95% confidence interval [CI]: 1.38, 5.92) and 1.63 (0.83, 3.20), respectively, compared with those in top tertiles (>13ng/ml) among hypertensives (P_trend=0.005). In contrast, the corresponding ORs of the above two groups were 0.88 (0.28, 2.74) and 1.23 (0.42, 4.00), respectively, in the normotensives (P_trend = 0.800; P_{effect modification} = 0.020). The multivariable-adjusted OR of CHD in patients with severe hypovitaminosis D (<10 ng/ml) versus those with higher vitamin D (≧10 ng/ml) was also greater in hypertensives (2.76; 95% CI: 1.51, 5.04) than that in normotensives (0.92; 95% CI: 0.37, 2.33; P_{effect modification}=0.013). Similar results were observed when Gensini Score was treated as a dependent variable.

CONCLUSION

Our finding suggests the presence of hypertension may modify the association of vitamin D deficiency with severity of coronary stenosis.

Nutrition and other lifestyle influences on arterial aging

As our world's population ages, cardiovascular diseases (CVD) will become an increasingly urgent public health problem. A key antecedent to clinical CVD and many other chronic disorders of aging is age-related arterial dysfunction, characterized by increased arterial stiffness and impaired arterial endothelial function. Accumulating evidence demonstrates that diet and nutrition may favorably modulate these arterial functions with aging, but many important questions remain. In this review, we will summarize the available information on dietary patterns and nutritional factors that have been studied for their potential to reduce arterial stiffness and improve endothelial function with age, with an emphasis on: 1) underlying physiological mechanisms, and 2) emerging areas of research on nutrition and arterial aging that may hold promise for preventing age-related CVD.

The association between Vitamin D and health outcomes in women: A review on the related evidence

Background:

Vitamin D has a wide range of physiological functions in skeletal and nonskeletal tissues which may play a role in many diseases. The aim of this study was to evaluate the recent evidence regarding the effects of Vitamin D on several health outcomes in women including breast cancer, ovarian and endometrial cancers, hypertension, and osteoporosis.

Materials and Methods:

We searched PubMed and Google Scholar databases through March 2016. We included the most current systematic reviews and meta-analyses assessing the associations of Vitamin D intake and/or serum 25-hydroxyvitamin D (25(OH)D) levels with the risk of incidence of breast cancer, ovarian and endometrial cancers, hypertension, and osteoporosis.

Results:

Many studies have represented that Vitamin D supplementation and high 25(OH)D levels can decrease the risk of breast cancer occurrence or mortality. However, there is no strong evidence to support the existence of a relationship between Vitamin D and ovarian or endometrial cancers. Furthermore, the results regarding the effects of Vitamin D on hypertension were inconsistent. Although observational studies have shown an association between Vitamin D and hypertension, there is no evidence regarding effectiveness of Vitamin D in lowering blood pressure in several clinical trials. On the other hand, the findings associating the impact of Vitamin D on osteoporosis were more definitive and most studies have represented that Vitamin D may have beneficial effects on osteoporosis.

Conclusion:

Although the adequate Vitamin D level can play a protective role in the incidence and development of breast cancer, hypertension, and osteoporosis, there is limited evidence regarding ovarian and endometrial cancers.

Modification of the association between smoking status and severity of coronary stenosis by vitamin D in patients suspected of coronary heart disease

Given both smoking and vitamin D are associated with coronary heart disease (CHD) via inflammation and smoking may interfere with the local antiinflammatory effects of vitamin D. We hypothesized that the relationship between smoking and severity of CHD may be modified by vitamin D.A cross-sectional study was conducted. 25-OH vitamin D values were determined in 348 consecutive patients (mean age 62.4 ± 10.5 years; 56.3% male) undergoing coronary angiography at the Heart Center of Chaoyang Hospital affiliated to Capital Medical University between the period of September 2014 and May 2015. We categorized the patients into 2 groups based on 25-OH vitamin D levels, that is, severe hypovitaminosis D (25-OH vitamin D < 10 ng/mL) and higher vitamin D (25-OH vitamin D > =  10 ng/mL). Multivariable logistic regression models were used to estimate odds ratios (ORs) of severe coronary stenosis or higher Gensini score across three smoking status, that is, never smokers, former smokers, and current smokers in severe hypovitaminosis D and higher vitamin D groups, respectively.Of these patients, we identified 212 (60.9%) cases of severe CHD and 161 (46.3%) cases of severe hypovitaminosis D. Multivariable logistic regression model showed the ORs of severe CHD were 1.94 (95% confidence interval [CI]: 0.47, 7.98) for former smokers and 2.62 (95% CI: 0.83, 8.24) for current smokers, compared with never smokers in group with severe hypovitaminosis D (P-trend = 0.005). In contrast, smoking was not found to be significantly associated with severe CHD in group with higher 25-OH vitamin D (P-trend = 0.115). We found a significant interaction between smoking status and vitamin D on presence of severe CHD (P-interaction = 0.015). In terms of Gensini score as a dependent variable, similar results were identified.Our finding indicated the association between smoking and severity of CHD appeared to be substantially stronger among patients with severe hypovitaminosis D as compared with those with higher vitamin D levels. This suggests vitamin D sufficiency may have a protective effect against the damaging effects of smoking on coronary artery. Future cohort studies are warranted to confirm this finding.

Eldecalcitol prevents endothelial dysfunction in postmenopausal osteoporosis model rats

Postmenopausal women have high incidence of cardiovascular events as estrogen deficiency can cause endothelial dysfunction. Vitamin D is reported to be beneficial on endothelial function, but it remains controversial whether vitamin D is effective for endothelial dysfunction under the treatment for osteoporosis in postmenopausal women. The aim of this study was to evaluate the endothelial protective effect of eldecalcitol (ELD) in ovariectomized (OVX) rats. ELD (20  ng/kg) was orally administrated five times a week for 4 weeks from 1 day after surgery. After that, flow-mediated dilation (FMD) as an indicator of endothelial function was measured by high-resolution ultrasound in the femoral artery of living rats. ELD ameliorated the reduction of FMD in OVX rats. ELD inhibited the increase in NOX4, nitrotyrosine, and p65 and the decrease in dimer/monomer ratio of nitric oxide synthase in OVX rat femoral arteries. ELD also prevented the decrease in peroxisome proliferator-activated receptor gamma (PPARγ) in femoral arteries and cultured endothelial cells. Although PPARγ is known to inhibit osteoblastogenesis, ELD understandably increased bone mineral density of OVX rats without increase in PPARγ in bone marrow. These results suggest that ELD prevented the deterioration of endothelial function under condition of preventing bone loss in OVX rats. This endothelial protective effect of ELD might be exerted through improvement of endothelial nitric oxide synthase uncoupling, which is mediated by an antioxidative effect through normalization of vascular PPARγ/NF-κB signaling.

Spectacular improvement in vitamin D status in elderly osteoporotic women: 8-year analysis of an osteoporotic population treated in a dedicated fracture liaison service

In a population of postmenopausal women with a fragility fracture, we found a drastic reduction in the proportion of women with severe (<25 nmol/L) and moderate (25 to 75 nmol/L) hypovitaminosis D, especially from 2009 onwards. These results show that supplementation has been very widely integrated into current practice.

INTRODUCTION

Vitamin D (25(OH)D) is essential for bone health. In institutionalised osteoporotic women, it reduces the risk of fragility fractures. Numerous articles suggesting the possibility of extraosseous effects have generated a growing number of publications and recommendations on more widespread administration, to limit the risks of moderate or severe hypovitaminosis D. We assessed the impact on clinical practice of these recommendations concerning 25(OH)D supplementation in elderly at-risk populations.

METHODS

A total of 1486 postmenopausal osteoporotic women were seen in the context of a fracture liaison service (i.e. a rheumatology consultation following a peripheral fragility fracture), between May 2005 and December 2012. Of these, 1107 had a 25(OH)D assay (femur, n = 520; humerus, n = 207; wrist, n = 380).

RESULTS

The average age of the total population was 76.7 ± 9.9 years, while for women with an available 25(OH)D assay, the average age was 75.1 ± 11.8 years. The average 25(OH)D (nmol/L) level was similar for the three fracture sites: femur, 30 ± 36.2; humerus, 27.5 ± 24; and wrist, 31 ± 26. A drastic reduction in the proportion of women with severe (<25 nmol/L) and moderate (25 to 75 nmol/L) hypovitaminosis D was observed, especially from 2009 onwards, with a mean prevalence of 69 and 30 % respectively before that year and 35 and 52 % thereafter. Conversely, the proportion of women with 25(OH)D at the threshold value of 75 nmol/L increased from 1.2 to 24 %. Overall, mean serum 25(OH)D levels were significantly higher when comparing the two periods 2005-2008 and 2009-1012 (17.6 ± 14.6 and 48.4 ± 39.2 nmol/L, respectively; p < 0.0001).

CONCLUSION

These results show that supplementation has been very widely integrated into current practice. We can expect it to yield beneficial effects in osseous and extraosseous terms in osteoporotic women, particularly the very elderly.

Relationship between serum vitamin D levels and angiographic severity and extent of coronary artery disease

BACKGROUND

Vitamin D is known for its effect in calcium and bone homeostasis. There is an increasing evidence for health benefits accomplished by activated vitamin D that go beyond these classical functions. Previous studies have suggested that lower vitamin D levels are associated with increased cardiovascular disease risk. Therefore, we aimed to evaluate relationship between vitamin D levels and extent and severity of coronary artery disease.

MATERIALS AND METHODS

A total of 746 patients in whom coronary angiography was performed between August 2012 and July 2013 were enrolled in this study. Serum vitamin D levels were measured, and patients were grouped according to their serum vitamin D levels (vitamin D <20 ng/mL (n = 602) Group 1 versus >20 ng/dL (n = 144) Group 2). Gensini score system was used to evaluate the association between serum vitamin D levels and severity and extent of coronary artery disease.

RESULTS

There was no significant difference between the groups in terms of baseline characteristics and demographic characteristics. Mean serum vitamin D levels of all patient cohort was 15.54 ± 7.46 ng/mL. Group 1 and Group 2 had an average serum vitamin D levels of 12.6 ± 3.3 ng/mL and 27.5 ± 7.8 ng/mL, respectively. Gensini score for all cohort was 26.25 ± 34.32. Group 1 had an average Gensini score of 26.4 ± 35.7; on the other hand, Gensini score was 25.5 ± 27.5 in Group 2 (P = 0.097).

CONCLUSIONS

This study failed to demonstrate significant relationship between serum vitamin D levels and the severity and extent of coronary artery disease. Further studies with more participation and homogenous groups with comparable individual and environmental features are needed to evaluate the association of serum vitamin D levels and cardiovascular diseases.

A systematic review protocol examining the effect of vitamin D supplementation on endothelial function

INTRODUCTION

Vitamin D has potential benefits for extraskeletal health. These could include an anti-inflammatory effect as well as a reduction in endothelial dysfunction. We aim to provide quality evidence for the hypothesis that supplementation with vitamin D will improve endothelial function (EF), possibly through the abrogation of systemic inflammation.

METHODS AND ANALYSIS

We will conduct a systematic review of all randomised controlled trials on vitamin D supplementation and EF lasting 12 weeks or more. The search will cover the period 2000-2015 and include studies that describe direct measures of EF, markers of endothelial cell (EC) activation and if concurrently reported, indicators of systemic inflammation. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and study quality will be assessed by the Jadad score in addition to an evaluation of allocation concealment and data analysis. If sufficient data are available, a meta-analysis will be conducted. The effect sizes will be generated using Hedges' g score, for both fixed and random effect models. I(2) statistics and Galbraith plots will be used to assess heterogeneity and identify their potential sources. Potential publication and small sample size bias will be assessed by visual inspections of funnel plots and also Egger's test. Meta-regression analysis (if feasible) will be conducted with restricted maximum likelihood (REML) estimation method, controlling for potential confounders (demographics, study methods, location, etc). A backward elimination process will be applied in the regression modelling procedure. Subgroup analysis, conditional on number of studies retrieved and their sample size, will be stratified on participant disease category, total dose administered, degree of 25(OH)D change and type of supplement used.

ETHICS AND DISSEMINATION

Formal ethical approval is not required as primary data will not be collected. The results will be disseminated through a peer-reviewed publication, conference presentation and the popular press.

TRIAL REGISTRATION NUMBER

International Prospective Register for Systematic Reviews (PROSPERO) number CRD42014013523.

You're only as old as your arteries: translational strategies for preserving vascular endothelial function with aging

Endothelial dysfunction develops with age and increases the risk of age-associated vascular disorders. Nitric oxide insufficiency, oxidative stress, and chronic low-grade inflammation, induced by upregulation of adverse cellular signaling processes and imbalances in stress resistance pathways, mediate endothelial dysfunction with aging. Healthy lifestyle behaviors preserve endothelial function with aging by inhibiting these mechanisms, and novel nutraceutical compounds that favorably modulate these pathways hold promise as a complementary approach for preserving endothelial health.

Effects of supplementation with the fat-soluble vitamins E and D on fasting flow-mediated vasodilation in adults: a meta-analysis of randomized controlled trials

The effects of fat-soluble vitamin supplementation on cardiovascular disease (CVD) risk are not clear. Therefore, we performed a meta-analysis to quantify effects of fat-soluble vitamin supplements on fasting flow-mediated vasodilation (FMD) of the brachial artery, a validated marker to assess CVD risk. Randomized placebo-controlled trials (RCTs) were identified by a systematic search till July 2014. Seven RCTs studying the effects of vitamin E supplements (range: 300 to 1800 IU per day) and nine RCTs examining the effects of vitamin D supplements, that involved, respectively, 303 and 658 adults, were included. No studies with carotenoid or vitamin K supplements were found. Vitamin E supplementation increased FMD vs. control by 2.42% (95% CI: 0.46% to 4.37%; p = 0.015). No effects of vitamin D supplementation were found (0.15%; 95% CI: −0.21% to 0.51%; p = 0.41). These effects did not depend on subject characteristics, treatment characteristics or technical aspects of the FMD measurement. However, no dose-response relationship was evident for vitamin E, statistical significance depended on one study, while the levels of supplement were far above recommended intakes. The current meta-analysis, therefore, does not provide unambiguous evidence to support the use of fat-soluble vitamin supplements to improve fasting FMD in adults.

Vitamin D and endothelial vasodilation in older individuals: data from the PIVUS study

CONTEXT

Vitamin D plays a role in a wide range of extraskeletal processes, including vascular function. Endothelial dysfunction is a predictor of cardiovascular disease, especially in older subjects. However, the relationship between vitamin D levels and indexes of endothelial vasodilation has never been fully addressed in older individuals.

OBJECTIVE

The objective of this study was to examine the association between vitamin D and endothelial function in a large community-based sample of older subjects.

METHODS

This cross-sectional study involved 852 community-dwelling men and women aged 70 years from the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS), with complete data on vascular function and 25-hydroxyvitamin D. We evaluated endothelium-dependent vasodilation by an invasive forearm technique with acetylcholine, endothelium-independent vasodilation by sodium nitroprussiate, flow-mediated vasodilation, and the pulse wave analysis (reflectance index). Vitamin D levels were measured by chemiluminescence. We used multivariate regression models adjusted for body mass index (model 1) and for multiple confounders (high-sensitivity C-reactive protein, insulin, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, smoking, sex hormones, season of blood collection, hypertension, diabetes, cardiovascular medications and diseases, statin usage, plasma calcium and calcium intake, PTH, physical exercise, liver and kidney function tests, albumin; model 2).

RESULTS

In women, but not in men, vitamin D levels were positively associated with endothelium-independent vasodilation in both model 1 (β ± SE = 1.41 ± 0.54; P = .001), and model 2 (β ± SE = 2.01 ± 0.68; P = .003).We found no significant relationship between vitamin D levels and endothelium-dependent vasodilation, flow-mediated vasodilation, and reflectance index in both sexes.

CONCLUSIONS

In older women, but not in men, vitamin D is positively and independently associated with EIDV.

Does vitamin D deficiency increase orthostatic hypotension risk in the elderly patients?

Orthostatic hypotension (OH) is closely associated with falls, cardiovascular events and mortality in the elderly patients. The aim of the study is to evaluate the OH prevalence among patients over the age of 65 years, to find out the impact of this condition on daily living activities, and to determine the possible effects of vitamin D levels on OH in elderly patients. Eight hundred and forty nine geriatric patients who had undergone comprehensive geriatric assessment were retrospectively evaluated and 546 patients were included in the study. The patient's demographic characteristics, blood pressures, comorbid diseases, polypharmacy status, cognitive and nutritional states, basic and instrumental daily living activity indexes and laboratory values were obtained from hospital files. Serum 25-hydroxyvitamin D [25(OH)D] was measured by radioimmunoassay. The prevalence of OH was found to be 27.5%. Both daily living activity indexes were significantly lower in older patients with OH (p<0.02), and serum 25(OH)D levels were significantly lower in older patients with OH (p<0.01). Our findings suggest that vitamin D deficiency may be a factor in OH development. Because this condition is also preventable and correctable, serum vitamin D levels should be checked during the evaluation of OH patients and any detected deficiency should be treated accordingly.

Mean platelet volume and vitamin D level

BACKGROUND

Vitamin D deficiency and a high mean platelet volume (MPV) are related to cardiovascular disease. We investigated whether vitamin D deficiency is associated with high MPV.

METHODS

This study included 434 patients without chronic disease who were not taking vitamin D or calcium supplements. Vitamin D was measured by chemiluminescent microparticle immunoassay on the Architect-I2000 system (Abbott Diagnostics, USA), and MPV was measured on the Cell-Dyn Ruby analyzer (Abbott Diagnostics). Patients were divided into Groups 1 (138 [men/women, 46/92]), 2 (148 [men/women, 54/94]), and 3 (148 [men/women, 50/98]) according to vitamin D levels of <10 ng/mL, 10-20 ng/mL, and >20 ng/mL, respectively.

RESULTS

The vitamin D level in Group 1 (7.7±1.9 ng/mL) was lower than that in Group 2 (15.1±1.6 ng/mL, P<0.001) and Group 3 (25.6±6.3 ng/mL, P<0.001). The MPV in Group 3 (7.5±1.0 fL) was lower than that in Group 1 (8.1±1.1 fL, P<0.001) and Group 2 (7.9±1.0 fL, P=0.009). Linear regression analysis showed that low levels of vitamin D (β=-0.109, P=0.019) was independently associated with increased MPV.

CONCLUSIONS

There was a strong association between a low vitamin D level and a high MPV; therefore, vitamin D deficiency may be associated with increased MPV.

Mean platelet volume and vitamin D level

BACKGROUND

Vitamin D deficiency and a high mean platelet volume (MPV) are related to cardiovascular disease. We investigated whether vitamin D deficiency is associated with high MPV.

METHODS

This study included 434 patients without chronic disease who were not taking vitamin D or calcium supplements. Vitamin D was measured by chemiluminescent microparticle immunoassay on the Architect-I2000 system (Abbott Diagnostics, USA), and MPV was measured on the Cell-Dyn Ruby analyzer (Abbott Diagnostics). Patients were divided into Groups 1 (138 [men/women, 46/92]), 2 (148 [men/women, 54/94]), and 3 (148 [men/women, 50/98]) according to vitamin D levels of <10 ng/mL, 10-20 ng/mL, and >20 ng/mL, respectively.

RESULTS

The vitamin D level in Group 1 (7.7±1.9 ng/mL) was lower than that in Group 2 (15.1±1.6 ng/mL, P<0.001) and Group 3 (25.6±6.3 ng/mL, P<0.001). The MPV in Group 3 (7.5±1.0 fL) was lower than that in Group 1 (8.1±1.1 fL, P<0.001) and Group 2 (7.9±1.0 fL, P=0.009). Linear regression analysis showed that low levels of vitamin D (β=-0.109, P=0.019) was independently associated with increased MPV.

CONCLUSIONS

There was a strong association between a low vitamin D level and a high MPV; therefore, vitamin D deficiency may be associated with increased MPV.