Does an active sun exposure habit lower the risk of venous thrombotic events? A D-lightful hypothesis

Swedish obstetric thromboprophylaxis guideline: background and update

Risk estimation concerning venous thromboembolism (VTE) and thromboprophylaxis for those at risk is routine in pregnancy. For 20 years, Swedish obstetricians have followed a weighted-risk algorithm guideline for risk estimation, based on which patient selection, timing, duration and dosage of thromboprophylaxis are determined. This article presents the latest update, the basis for the algorithm and its application for assessing moderate- to high obstetric VTE risk, defined as equal or greater absolute risk per time unit than the antepartum risk of women with one prior VTE. The risk score is based on risk factors conferring approximately fivefold increased risk of VTE or a multiple thereof. This article also presents algorithm efficacy data and describes lifestyle advice provided to patients. In our experience, the Swedish guideline for obstetric VTE risk estimation is easy to follow. It helps identify women at high risk. The risk of under- or overtreatment is thus minimised.

Can active sun exposure decrease the risk of giant cell arteritis and polymyalgia rheumatica in women?

Objectives

To study if active sun exposure among women affects the risk of developing GCA or PMR in a prospective cohort study with restricted latitudinal variability.

Methods

We linked the response to questions relating to sun exposure from the Melanoma Inquiry in Southern Sweden (MISS) prospective cohort study in women to the risk of developing GCA or PMR. Healthcare data were gathered from the Skåne Healthcare Register (SHR), covering all public healthcare consultations. The direct effect of active sun exposure on the risk of developing GCA or PMR was assessed using Cox proportional hazards models adjusted for covariates based on a directed acyclic graph.

Results

A total of 14 574 women were included in the study; 601 women were diagnosed with GCA or PMR (144 and 457, respectively) during the follow-up time. Women with moderate or high sun exposure were not less likely to develop GCA or PMR compared with women that indicated they avoided sun exposure [hazard ratio (HR) 1.2 (CI 0.9, 1.6) and 1.3 (0.9, 1.9), respectively] when adjusted for diabetes, hyperlipidaemia, hypertension, smoking, obesity and stratified by age. Similar patterns were observed when studying only GCA [HR 1.2 (CI 0.7, 2.3) and 1.3 (0.7, 2.6)] and only PMR [HR 1.3 (CI 0.9, 1.8) and 1.4 (0.9, 2.0)].

Conclusion

Active sun exposure did not affect the risk of developing GCA or PMR in women in a cohort with restricted latitudinal variability.

The association of vitamin-D level with catheter-related-thrombosis in hemodialysis patients: A data mining model

PURPOSE

This study aims to investigate the association of different risk factors including vitamin-D level with catheter-related-thrombosis in hemodialysis patients by applying data mining techniques.

METHODS

This study used the retrospectively approach and was done based on the CRISP-DM framework. The data of 1048 hemodialysis patients of Hasheminejad Kidney Center whose first catheterization was between 2014 and 2019 was used for analysis. In this study, patients with a previous history of deep venous thrombosis, thrombophilic condition, and undergone anticoagulant therapy were excluded. The decision tree J48 in WEKA software was used for modeling. The K-fold cross-validation method was also used to evaluate the classification performance. Finally, the model was evaluated by using Confusion Matrix and F-Measure.

RESULTS

The approved model was accurate in 70.3% of the predictions, and it demonstrated an association between patients' vitamin-D range and catheter-related-thrombosis.

CONCLUSION

The results indicated that in hemodialysis patients without the history of cancer or high blood pressure, vitamin-D had a significant impact on catheter related thrombosis.

Thrombotic events following the BNT162b2 mRNA COVID-19 vaccine (Pfizer-BioNTech) in Aotearoa New Zealand: A self-controlled case series study

BACKGROUND

An association between thrombotic events and SARS-CoV-2 infection and the adenovirus-based COVID-19 vaccines has been established, leading to concern over the risk of thrombosis after BNT162b2 COVID-19 vaccination.

OBJECTIVES

To evaluate the risk of arterial thrombosis, cerebral venous thrombosis (CVT), splanchnic thrombosis, and venous thromboembolism (VTE) following BNT162b2 vaccination in New Zealand.

METHODS

This was a self-controlled case series using national hospitalisation and immunisation records to calculate incidence rate ratios (IRR). The study population included individuals aged ≥12 years, unvaccinated, or vaccinated with BNT162b2, who were hospitalised with one of the thrombotic events of interest from 19 February 2021 through 19 February 2022. The risk period was 0-21 days after receiving a primary or booster dose of BNT162b2.

RESULTS

6039 individuals were hospitalised with one of the thrombotic events examined, including 5127 with VTE, 605 with arterial thrombosis, 272 with splanchnic thrombosis, and 35 with CVT. The proportion of individuals vaccinated with at least one dose of BNT162b2 ranged from 82.7 % to 91.4 %. Compared with the control unexposed period, the IRR (95 % CI) of VTE, arterial thrombosis, splanchnic thrombosis, and CVT were 0.87 (0.76-1.00), 0.73 (0.56-0.95), 0.71 (0.43-1.16), and 0.87 (0.31-2.50) in the 21 days after BNT162b2 vaccination, respectively. There was no statistically significant increased risk of thrombosis following BNT162b2 in different ethnic groups in New Zealand.

CONCLUSION

The BNT162b2 vaccine was not found to be associated with thrombosis in the general population or different ethnic groups in New Zealand, providing reassurance for the safety of the BNT162b2 vaccine.

Vitamin D Deficiency is Associated With Increased Plasminogen Activator Inhibitor 1/Plasminogen Activator Inhibitor 2 Ratio in Pregnancy

BACKGROUND

Vitamin D deficiency has recently been suggested as an independent risk factor for thrombosis. Notably, vitamin D deficiency is common in pregnant populations, whom already have an increased thrombotic risk. However, pregnant women are commonly excluded from studies investigating the hemostatic system, and knowledge on the impact of vitamin D on hemostasis in pregnancy is therefore limited.

METHODS

A cross-sectional study comparing the hemostatic profile of pregnant women (gestational week 12.9 ± 0.7) with vitamin D deficiency (≤50 nmol/L) (n = 70) and high adequate vitamin D status (≥100 nmol/L) (n = 59).

RESULTS

Vitamin D deficient women displayed increased plasminogen activator inhibitor 1 levels and an increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio, even after adjusting for factors with potential influence on hemostasis (body mass index, smoking and use of fish oil supplements).

CONCLUSIONS

Vitamin D deficiency is associated with increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio in pregnant women. As an increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio with high plasminogen activator inhibitor 1 levels may increase thrombotic risk and is associated with the development of pregnancy complications, further research is needed to determine the optimal vitamin D supplementation in pregnancy.

Is Vitamin D Deficiency Prothrombotic? A Systematic Review

Observational studies indicate a relationship between vitamin D deficiency and an increased risk of venous and arterial thrombotic events, but the underlying mechanisms behind this association are uncertain. This systematic review explores if there is an association between decreased vitamin D levels and a prothrombotic profile. The systematic literature search initially identified 3,214 studies (published until December 21, 2021) investigating the relationship between vitamin D and numerous hemostatic parameters. After the screening process, 18 observational and intervention studies fulfilled the inclusion criteria and were included in this systematic review. Parameters of primary hemostasis, secondary hemostasis, and fibrinolysis were investigated in six, thirteen, and fifteen of these studies, respectively. Most of the eligible studies did not identify significant associations between decreased vitamin D levels and hemostatic parameters. Some conflicting results were found between decreased vitamin D levels and thrombin generation parameters and the tissue factor pathway inhibitor. Conflicting results were also found between decreased vitamin D levels and fibrinolytic parameters, although the evidence may point toward weak associations with some regulators of fibrinolysis, mostly decreased tissue type plasminogen activator. Overall, our systematic review did not identify any definitive link between vitamin D deficiency and a prothrombotic profile, which might otherwise help explain the observed association between vitamin D deficiency and increased risk of thrombotic events. Moreover, there is no clinical evidence to confirm or refute a possible antithrombotic effect of vitamin D. Larger high-quality randomized controlled trials are needed to better elucidate the link between vitamin D deficiency and a prothrombotic risk profile.

Vitamin D in Lupus Patients of Childbearing Age: Are We Doing Enough?

Systemic lupus erythematosus patients have long been observed to suffer from vitamin D deficiency. This can be related to either environmental factors, medication, or other comorbidities like renal disease. Moreover, lupus patients have reported conception issues including ovarian failure or recurrent miscarriages. There are vast data regarding vitamin D's ability to support the development of a healthy pregnancy and prevent complications, such as pre-eclampsia and gestational diabetes, likely through its ability to regulate both innate and adaptive immune systems. Although there is an agreement in the medical world that pregnant lupus patients should be screened and receive vitamin D supplements, there are no official guidelines on screening and often the recommended doses are suboptimal. Further research is needed to look at the potential of vitamin supplementation in pregnant lupus patients.

Influence of Vitamin D Status on the Maintenance Dose of Warfarin in Patients Receiving Chronic Warfarin Therapy

INTRODUCTION

Considering the anticoagulant actions of vitamin D, we hypothesize that vitamin D status might affect the required dose of warfarin for maintaining the therapeutic international normalized ratio (INR).

METHODS

In a retrospective single-center cohort study, serum levels of 25-hydroxyvitamin D were assessed for 89 subjects receiving a stable dose of warfarin for 3 months or longer and had a stable INR between 2 and 3.5 for at least three consecutive visits. A warfarin sensitivity index (WSI), defined as the steady-state INR divided by the mean daily warfarin dose, was used for measuring the warfarin dose response. The relation between the serum level of 25-hydroxyvitamin D and WSI value and the difference in the mean WSI value between the subjects with different vitamin D status categories (sufficient, insufficient, and deficient) were assessed.

RESULTS

Twenty-one subjects had vitamin D deficiency, 43 had vitamin D insufficiency, and only 25 had normal levels of 25-hydroxyvitamin D. Based on the multiple linear regression analysis, there was a significant but weakly positive correlation between WSI and 25-hydroxyvitamin D serum levels, as the value of WSI increases by almost 0.0027434 for every unit increase in 25-hydroxyvitamin D serum level (p value = 0.041). Using one-way ANOVA analysis, there was a trend in a significant difference between the groups with different vitamin D status categories regarding the mean WSI value (F = 2.95, p value = 0.057), as subjects with sufficient vitamin D state compared to those with vitamin D deficiency had a higher WSI value.

CONCLUSIONS

Although the study's limitations limit our ability to draw definite conclusions, the present data suggest that in addition to other traditional factors, vitamin D status might also affect warfarin sensitivity and maintenance dose requirement. However, to more clearly explain this link, further studies with high involvement subjects are required.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

Role of vitamin D in treating COVID-19-associated coagulopathy: problems and perspectives

Aggressive inflammatory response leading to hypercoagulability has been found to be associated with disease severity in COVID-19 patients and portends bad treatment outcome. A state of acute disseminated intravascular coagulation (DIC), along with pulmonary embolism and/or deep vein thrombosis, has been observed in critically ill ICU patients. Autopsy reports of COVID-19 patients demonstrated microthrombi in lungs and in other organs, as well as marked inflammatory changes, characteristic clinicopathological features that exacerbate disease severity. Vitamin D supplementation was recommended by many clinicians across the globe to improve clinical symptoms of COVID-19 patients, mainly because of its immunomodulatory roles on immune cells. Furthermore, vitamin D and its associated molecules are also known to directly or indirectly regulate various thrombotic pathways. We propose that vitamin D supplementation not only attenuates the risk of Acute Respiratory Disease Syndrome (ARDS) but it also may have a role in reducing coagulation abnormalities in critically ill COVID-19 patients. The overarching goal of this review is to discuss the effects of vitamin D on coagulation pathways and other intertwined processes leading to thrombosis. Many clinical trials are currently investigating the efficacy of vitamin D supplementation in reducing the risk of COVID-19 infection. However, randomized placebo control clinical trials are also necessary to ascertain the effect of vitamin D supplementation on reducing the risk of coagulopathy in COVID-19 patients.

Low sun exposure habits is associated with a dose-dependent increased risk of hypertension: a report from the large MISS cohort

In prospective observational cohort studies, increasing sun exposure habits have been associated with reduced risk of cardiovascular mortality. Our aim was to assess possible observational mechanisms for this phenomenon. A written questionnaire was answered by 23,593 women in the year 2000 regarding risk factors for melanoma, including factors of possible interest for hypertension, such as detailed sun exposure habits, hypertension, marital status, education, smoking, alcohol consumption, BMI, exercise, and chronic high stress. Hypertension was measured by the proxy "use of hypertension medication" 2005-2007, and high stress by "need of anti-depressive medication". Sun exposure habits was assessed by the number of `yes' to the following questions; Do you sunbath during summer?, During winter vacation?, Do you travel south to sunbath?, Or do you use sun bed? Women answering 'yes' on one or two questions had moderate and those answering 'yes' on three or four as having greatest sun exposure. The main outcome was the risk of hypertension by sun exposure habits adjusted for confounding. As compared to those women with the greatest sun exposure, women with low and moderate sun exposure were at 41% and 15% higher odds of hypertension (OR 1.41, 95% CI 1.3‒1.6, p < 0.001 and OR 1.15, 95% CI 1.1‒1.2, p < 0.001), respectively. There was a strong age-related increased risk of hypertension. Other risk factors for hypertension were lack of exercise (OR 1.36), a non-fair phenotype (OR 1.08), chronic high stress level (OR 1.8), and lack of university education (OR 1.3). We conclude that in our observational design sun exposure was associated with a dose-dependent reduced risk of hypertension, which might partly explain the fewer deaths of cardiovascular disease with increasing sun exposure.

Association between vitamin D levels and lower-extremity deep vein thrombosis: a case-control study

BACKGROUND

Vitamin D has relationships with pathogenesis and inflammation pathways in many diseases. Its deficiency may make clinicians think not only of supplementation but also of presence of other diseases.

OBJECTIVE

To investigate the relationship between vitamin D levels and deep vein thrombosis (DVT), given that reduced levels are related to increased risk of cardiovascular diseases.

DESIGN AND SETTING

Case-control study conducted in the cardiovascular surgery and family medicine departments of a hospital in Turkey.

METHODS

A total of 280 participants were included: 140 each in the DVT and control groups. Basic clinical characteristics, comorbidities and serum 25-hydroxyvitamin D (25(OH)D) levels were recorded and then compared between the groups. Serum 25(OH)D levels were also evaluated separately in three subgroups (sufficient, insufficient and deficient).

RESULTS

Serum 25(OH)D levels were significantly lower in the DVT group than in the controls (P < 0.001). Females in the DVT group had lower 25(OH)D levels than those in the control group (P = 0.002). Nonetheless, the median 25(OH)D level (16.41 ng/ml) of the control group was still below the reference value. Logistic regression analysis showed that 25(OH)D was a significant predictor of DVT. Weight, height and body mass index, which all presented interaction, were significant in the logistic regression analysis but not in individual analyses.

CONCLUSION

The serum vitamin D levels of DVT patients were lower than those of controls. If the results obtained from our study are supported by further large-scale randomized controlled trials, vitamin D replacement may be brought into the agenda for protection against DVT.

Association between serum vitamin D levels and venous thromboembolism (VTE): A systematic review and meta-analysis of observational studies

OBJECTIVE

Although many studies have attempted to unravel the relationship between vitamin D deficiency and the incidence of VTE, the results remained inconsistent. To address this discrepancy, we performed a systematic review and meta-analysis to precisely disentangle the relationship between serum vitamin D levels and VTE risk.

METHODS

The Web of Science, Scopus, PubMed/Medline, Embase, and Google Scholar databases were searched for all available observational studies that reported the risk of venous thromboembolism (VTE) based on serum vitamin D levels categories. The search was performed up to March 2020.

RESULTS

Seven studies were included. The overall analysis showed a significantly increased risk of VTE in subjects with low levels of serum vitamin D compared with those with normal vitamin D levels (RR = 1.34; 95% CI: 1.07-1.69; P = 0.011). In a sensitivity analysis, we did not observe a significant effect of any individual study on the combined effect sizes. Nevertheless, significant heterogeneity was present among the studies (Cochrane Q test, p = 0.018, I² = 61%). In the stratified analysis, low vitamin D levels were positively associated with an increased risk of VTE in prospective population-based studies (RR = 1.31; 95% CI: 1.06-1.61; P = 0.010) and in subjects below 60 years old (RR = 1.28; 95% CI: 1.07-1.54; P = 0.060).

CONCLUSION

our systematic review and meta-analysis showed that a low serum vitamin D level was indeed associated with an increased risk of VTE.

Pathophysiological Role and Therapeutic Implications of Vitamin D in Autoimmunity: Focus on Chronic Autoimmune Diseases

Vitamin D is a pleiotropic secosteroid yielding multiple actions in human physiology. Besides the canonical regulatory activity on bone metabolism, several non-classical actions have been described and the ability of vitamin D to partake in the regulation of the immune system is particularly interesting, though far stronger and convincing evidence has been collected in in vitro as compared to in vivo studies. Whether vitamin D is able to regulate at physiological concentrations the human immune system remains unproven to date. Consequently, it is not established if vitamin D status is a factor involved in the pathogenesis of immune-mediated diseases and if cholecalciferol supplementation acts as an adjuvant for autoimmune diseases. The development of autoimmunity is a heterogeneous process, which may involve different organs and systems with a wide range of clinical implications. In the present paper, we reviewed the current evidences regarding vitamin D role in the pathogenesis and management of different autoimmune diseases.

The effect of vitamin D levels on gastrointestinal bleeding in patients with warfarin therapy

: Upper tract gastrointestinal system (GIS) bleeding is considered as an important cause of morbidity and mortality despite modern and advanced endoscopic interventions. In patients with thrombotic state and vitamin D deficiency, vitamin D analogs and vitamin D receptor activators have been determined as adjunctive anticoagulant treatment in previous studies. However, these studies did not evaluate or reveal the possible bleeding diathesis. In this article, we evaluated the vitamin D status in patients with warfarin treatment and upper tract GIS bleeding. A total of 75 patients with a definite diagnosis of upper tract GIS bleeding who had a treatment of warfarin and current vitamin D measurement; and a total of 75 control patients without any recent or prior GIS bleeding who had a treatment of warfarin and current vitamin D measurement were enrolled to the study. GIS bleeding group had a proportionally higher vitamin D treatment (29.3 vs. 17.3%). In GIS bleeding group, the prevalence of vitamin D level less than 20 ng/ml was significantly lower (66.7 vs. 82.7%; P = 0.024) and the prevalence of vitamin D level at least 30-100 ng/ml was significantly higher (25.3 vs. 10.7%; P = 0.019). According to a subgroup analysis; in patients with a vitamin D level at least 30-100 ng/ml, major bleeding rate was significantly higher compared with other patients. There was not a significant difference regarding mortality between the groups. Our study is the first which represents the possible bleeding effect of elevated vitamin D levels and vitamin D treatment in patients with warfarin treatment.

Vitamin D deficiency among patients with pulmonary hypertension

BACKGROUND

There is little information about vitamin D (Vit D) deficiency in patients with pulmonary hypertension (PH). The objective of this study was: 1) compare Vit D levels between patients with PH, left ventricular failure (LVF) and healthy subjects (HS); 2) correlate, in patients with PH, Vit D levels with prognosis-related variables, such as the 6-min walk test (6MWT).

METHODS

Vitamin D levels were measured in a cross-sectional study in 126 patients from one of three groups: patients with PH (n = 53), patients with LVF (n = 42) and healthy subjects (n = 31). In all groups, 8-h fasting blood samples were obtained in the morning. In the PH and the LVF group, functional class (WHO criteria), metres covered in the 6MWT and echocardiographic parameters were analysed. In the PH group, plasma N terminal pro B type natriuretic peptide (NT-proBNP) level was analysed and a complete haemodynamic evaluation by right heart catheterisation was made.

RESULTS

Mean Vit D levels were lower in PH than in both other groups (ng/ml, mean ± SD): PH 19.25 ± 10, LVF 25.68 ± 12, HS 28.8 ± 12 (PH vs LVF p = 0.017, PH vs HS p = 0.001 and HS vs LVF p = 0.46). Vit D deficiency prevalence was higher in PH as compared to the other groups (PH 53.8%, LVF 45.2%, HS 25%, p = 0.01). Patients with PH in functional class (FC; WHO criteria) III-IV had higher Vit D deficiency prevalence than those in FC I-II (86.7% vs 40.5%, p = 0.003). There was a significant linear correlation between the 6MWT and Vit D levels in PH (p < 0.01), but not in LVF (p = 0.69).

CONCLUSIONS

Vit D levels were lower in patients with PH as compared to patients with LVF and HS and correlated directly with 6-min walk distance.

Emerging Role of Vitamin D and its Associated Molecules in Pathways Related to Pathogenesis of Thrombosis

Vitamin D, besides having an essential role in calcium and bone metabolism, also acts as a mediator of many non-calcemic effects through modulations of several biological responses. Vitamin D exists in its two major forms, vitamin D₂, or commonly known as ergocalciferol, and vitamin D₃, or commonly known as cholecalciferol. Both of these forms bind to vitamin D-binding protein to get transported to all vital target organs, where it serves as a natural ligand to vitamin D receptors for enabling their biological actions. Clinical reports corroborating vitamin D deficiency with an increase in thrombotic episodes implicate the role of vitamin D and its associated molecule in the regulation of thrombosis-related pathways. Thrombosis is the formation and propagation of a blood clot, known as thrombus. It can occur either in the arterial or the venous system resulting in many severe complications, including myocardial infarction, stroke, ischemia, and venous thromboembolism. Vitamin D, directly or indirectly, controls the expression of several genes responsible for the regulation of cellular proliferation, differentiation, apoptosis, and angiogenesis. All of these are the processes of potential relevance to thrombotic disorders. This review, thus, discussed the effects of vitamin D on pathways involved in thrombosis, such as hemostatic process, inflammatory pathway, and endothelial cell activation, with a focus on the molecular mechanisms associated with them.

Association of sun and UV exposure with blood pressure and cardiovascular disease: A systematic review

BACKGROUND

Ecological studies show that sun or ultraviolet (UV) exposure have inverse associations with blood pressure (BP) and cardiovascular disease (CVD). Although sunlight is the primary source of vitamin D, recent meta-analyses of clinical trials have not reported a beneficial effect from vitamin D supplementation on BP or CVD. Sunlight may have beneficial effects independent of vitamin D. We carried out a systematic review to appraise the extent and quality of the evidence from human studies.

METHODS

Observational and interventional studies that measured sun or UV exposure, along with BP or CVD, were selected after searching databases.

RESULTS

Identified studies could not be combined quantitatively in meta-analysis because of different exposure measures. Solar exposure was inversely associated with BP in 3 out of 4 cross-sectional publications, and with CVD and/or total mortality in 5 out of 6 publications of cohort studies. Two of the cohort studies reported inverse associations between sun exposure and CVD, after adjusting for serum 25-hydroxyvitamin D. Five clinical trials with an appropriate control group were identified, the outcome being BP. Two trials compared UVB with UVA (as control), with only one finding a significant reduction in BP (after 6 weeks). Three trials compared short-term UVA exposure (<30 min) with placebo (or crossover control), of which two reported short-term lowering of BP.

CONCLUSION

This review has identified a small body of evidence that suggests sun exposure protects against high BP and CVD, but further research is required to determine if this is independent of vitamin D.

Venous Thromboembolism is Associated With Lack of Vitamin D Supplementation in Patients With Spinal Cord Injury and Low Vitamin D Levels

BACKGROUND

The role of vitamin D in the pathogenesis of venous thromboembolism (VTE) and prevalence of low vitamin D (LVitD) in spinal cord injury (SCI) has motivated vitamin D testing and supplementation. This is an exploratory study of data collected at a time before the routine clinical practice of vitamin D supplementation, allowing for evaluation of the natural history of vitamin D levels in patients with SCI.

OBJECTIVE

To determine if vitamin D supplementation in persons with SCI and LVitD levels is associated with decreased prevalence of VTE.

DESIGN

Retrospective cohort study.

SETTING

Rehabilitation Center at a Level I Trauma Center.

PARTICIPANTS

Patients with SCI admitted to acute inpatient rehabilitation (N = 282).

MAIN OUTCOME MEASURES

VTE prevalence in patients with LVitD levels, grouped by presence or absence of vitamin D supplementation.

RESULTS

Of the acute inpatient SCI population, 80% (227/282) of patients demonstrated vitamin D levels <30 ng/mL (LVitD). Although the incidence of VTE was almost double in the LVitD group, 19% (43/227) of the patients in the LVitD group had VTE versus 9% (5/55) of patients with vitamin D levels ≥30 ng/mL (normal VitD [NVitD]); this difference was not statistically significant (P = .108, Cramer's V = .104). When the role of vitamin D supplementation was analyzed, individuals in the LVitD group who received no vitamin D supplementation (LVitDSuppNegative) had a higher incidence of VTE (statistically significant) compared to the LVitD group with vitamin D supplementation (LVitDSuppPositive) (24% [42/178] vs. 2% [1/49]) (P < .001, Cramer's V = .226). In post hoc exploratory analyses, the VTE rate of patients in the LVitDSuppNegative group was noted to be significantly higher than that in all other patient groups combined (P < .001, Cramer's V = .229). A binary logistic regression model incorporating clinical covariates also showed this grouping to be significant.

CONCLUSION

A significant association appears to exist between lack of vitamin D supplementation and VTE occurrence in persons with acute SCI and LVitD levels.

LEVEL OF EVIDENCE

III.

The anti-thrombotic effects of vitamin D and their possible relationship with antiphospholipid syndrome

The importance of the immunomodulatory effects of vitamin D has recently been associated with autoimmune and chronic inflammatory diseases. Vitamin D deficiency has been linked to the development of autoimmune conditions. Antiphospholipid syndrome is an autoimmune disease characterized by thrombotic events and obstetric complications in patients with antiphospholipid antibodies. Current data show that patients with antiphospholipid syndrome have a high prevalence of vitamin D deficiency even without classic risk factors. Several studies have suggested vitamin D may have anti-thrombotic functions. In antiphospholipid syndrome, low vitamin D serum levels have been associated with thrombotic manifestations, suggesting a possible protective role of vitamin D in antiphospholipid syndrome. This literature review presents current evidence on the haemostatic functions of vitamin D and their possible relationship with the clinical manifestations of antiphospholipid syndrome.

Low Vitamin D Levels Are Associated With the Development of Deep Venous Thromboembolic Events in Patients With Ischemic Stroke

The objective is to determine whether a low serum 25-hydroxyvitamin D (25(OH)D) level is associated with an increased incidence of deep venous thromboembolic events in patients with ischemic stroke. One hundred eighty persons admitted consecutively for inpatient rehabilitation at the Department of Rehabilitation of the First Affiliated Hospital of Wenzhou Medical University with a diagnosis of ischemic stroke from January 2015 to December 2015 were enrolled. The following demographic data were collected: age, sex, body mass index, and history of risk factors. The levels of 25(OH)D and the presence of deep vein thrombosis (DVT) by routine duplex imaging were also recorded. The value of 25(OH)D needed to predict DVT was analyzed using logistic regression analysis, after adjusting for the possible confounders. We found that 80% of patients admitted to the acute inpatient rehabilitation unit had low levels of vitamin D. Forty-seven patients had DVT, and the incidence of DVT was 26.1% within 3 weeks after the stroke event. With all patients taken together, DVT occurrence as a dependent variable with the sufficient group as the reference used for vitamin D levels in the logistic analysis, deficiency of vitamin D was independently associated with the development of DVT (odds ratio = 4.683, 95% confidence interval: 1.396-15.703, P = .012). In conclusion, low serum 25(OH)D levels were independent predictors of DVT in patients with ischemic stroke during inpatient rehabilitation stay in China. This finding reveals the critical role played by 25(OH)D in the pathogenesis of DVT.

Ultraviolet radiation, vitamin D and the development of obesity, metabolic syndrome and type-2 diabetes

Obesity is increasing in prevalence in many countries around the world. Its causes have been traditionally ascribed to a model where energy intake exceeds energy consumption. Reduced energy output in the form of exercise is associated with less sun exposure as many of these activities occur outdoors. This review explores the potential for ultraviolet radiation (UVR), derived from sun exposure, to affect the development of obesity and two of its metabolic co-morbidities, type-2 diabetes and metabolic syndrome. We here discuss the potential benefits (or otherwise) of exposure to UVR based on evidence from pre-clinical, human epidemiological and clinical studies and explore and compare the potential role of UVR-induced mediators, including vitamin D and nitric oxide. Overall, emerging findings suggest a protective role for UVR and sun exposure in reducing the development of obesity and cardiometabolic dysfunction, but more epidemiological and clinical research is required that focuses on measuring the direct associations and effects of exposure to UVR in humans.

Association of vitamin D receptor gene TaqI, FokI and ApaI variants with arteriovenous fistula failure in hemodialysis patients

PURPOSE

We investigated the influence of the vitamin D receptor gene TaqI (rs731236), ApaI (rs7975232), and FokI (rs2228570) polymorphisms in arteriovenous fistula failure in hemodialysis patients.

METHODS

This study was carried out with 54 patients who experienced two or more fistula failures in the late period after arteriovenous fistula operation and 58 control patients with no history of arteriovenous fistula failure in 3 years or longer. The polymerase chain reaction-restriction fragment length polymorphism method was used to determine the vitamin D receptor TaqI, FokI, and ApaI polymorphisms.

RESULTS

For vitamin D receptor gene TaqI and Fok1 polymorphisms, no significant association was found between the two groups ( p > 0.05). However, a statistically significant association was determined for ApaI polymorphism between the two groups ( p = 0.02). In patients, ApaI AA, AC, and CC genotype frequencies were found as 21 (38.9%), 32 (59.3%), and 1 (1.8%), respectively. However, genotype frequencies of AA, AC, and CC in the control group were 29 (50%), 22 (37.9%), and 7 (12.1%), respectively. In all three polymorphisms, no significant difference was found between the two groups in terms of allele frequencies ( p > 0.05).

CONCLUSION

Vitamin D receptor ApaI AC genotype may be a possible cardiovascular risk factor for the development of arteriovenous fistula failure.

Indoor Tanning a Gianus Bifrons: Vitamin D and Human Cancer

Despite it is now undeniable that indoor tanning exposure is associated with a number of skin cancers, its favorable effects on vitamin D status may bear some underestimated and currently unexplored health benefits. Vitamin D is a fat-soluble vitamin naturally present in a limited number of foods, the concentration of which largely depends on ultraviolet (UV) B sources exposure in humans. A strong, graded, and inverse association has been documented between serum vitamin D and the risk of developing certain types of malignancy, especially colorectal, breast, lung, bladder, and kidney cancers. The overall mortality from any type of cancer is also apparently lower in subjects with increased values of serum vitamin D. Both genomic and nongenomic mechanisms have been identified to support the anticancer effects of vitamin D. Notably, UVB radiation emitted from indoor tanning devices is effective to linearly increase the serum vitamin D concentration, up to twofold. Therefore, some favorable effects against the risk of developing many human diseases, including nonskin cancers, cannot be excluded at first glance, although they may not be only linked to vitamin D status. Further large, prospective or randomized studies should be hence planned to definitely establish whether the unfavorable effects of indoor tanning exposure on skin cancers may be outweighed by the still unexplored benefits attributable to amelioration of vitamin D status.

Serum levels of vitamin D are not associated with future risk of venous thromboembolism

Previous studies have provided indirect evidence for a possible association between vitamin D status and risk of venous thromboembolism (VTE). However, no study has so far investigated the association between serum levels of 25-hydroxyvitamin D (25(OH)D), the biomarker of vitamin D status, and risk of VTE. The aim of our study was to investigate whether high levels of 25(OH)D were associated with decreased risk of VTE in a prospective population-based study. Serum levels of 25(OH)D were measured in 6,021 men and women, aged 25–84 years, who participated in the Tromsø Study in 1994–1995. Incident VTE-events were registered from date of inclusion through the end of follow-up, September 1, 2007. Cox-regression models were used to calculate hazard ratios (HR) with 95% confidence interval (CI) for VTE. There were 201 incident VTE-events during a median of 10.7 years of follow-up. The risk of VTE did not decrease per one standard deviation (SD) (19.8 nmol/l) increase in serum 25(OH)D (multivariable HR 1.02; 95% CI 0.91–1.22). Moreover, subjects with serum 25(OH)D ≥ 70 nmol/l (upper quartile) did not have decreased risk of VTE compared to those ≤ 44 nmol/l (lower quartile) in age- and sex-adjusted analysis (HR 0.91, 95% CI: 0.60–1.37, p for trend across quartiles 0.9) or multivariable analysis adjusted for age, sex, body mass index, smoking, and physical activity (HR 0.76, 95% CI: 0.45–1.28, p for trend across quartiles 0.9). Subgroup analyses showed no associations between serum levels of 25(OH)D and unprovoked or provoked VTE. In conclusion, in our study, normal serum levels of 25(OH)D were not associated with future risk of VTE, suggesting that vitamin D status does not play an important role in the pathogenesis of VTE. However, our findings did not apply to subjects with vitamin D deficiency (< 30 nmol/l) due to lack of statistical power among these subjects.

Seasonal variations of U.S. mortality rates: Roles of solar ultraviolet-B doses, vitamin D, gene exp ression, and infections

Death rates in the U.S. show a pronounced seasonality. The broad seasonal variation shows about 25% higher death rates in winter than in summer with an additional few percent increase associated with the Christmas and New Year's holidays. A pronounced increase in death rates also starts in mid-September, shortly after the school year begins. The causes of death with large contributions to the observed seasonality include diseases of the circulatory system; the respiratory system; the digestive system; and endocrine, nutritional, and metabolic diseases. Researchers have identified several factors showing seasonal variation that could possibly explain the seasonal variations in mortality rate. These factors include seasonal variations in solar ultraviolet-B(UVB) doses and serum 25-hydroxyvitamin D [25(OH)D] concentrations, gene expression, ambient temperature and humidity, UVB effects on environmental pathogen load, environmental pollutants and allergens, and photoperiod (or length of day). The factors with the strongest support in this analysis are seasonal variations in solar UVB doses and 25(OH)D concentrations. In the U.S., population mean 25(OH)D concentrations range from 21ng/mL in March to 28ng/mL in August. Measures to ensure that all people had 25(OH)D concentrations >36ng/mL year round would probably reduce death rates significantly.

Venous thromboembolism following L-asparaginase treatment for lymphoid malignancies in Korea

Essentials Data on venous thromboembolism (VTE) after L-asparaginase (L-asp) in Asian lymphoma are scarce. This is a population-based study in Asian patients with lymphoid disease and L-asp-related VTE. The overall incidence of L-asp-associated VTE was similar to reports on Caucasians. This first and largest study in Asians shows that mainly adult patients are at risk of thrombosis.

SUMMARY

Background L-asparaginase (L-asp)-associated venous thromboembolism (VTE) is a serious adverse complication associated with acute lymphoblastic leukemia (ALL) and lymphoma treatment. The incidence rate of L-asp-related VTE in Asian cancer patients is not well known. Methods We performed a population-based study between 2009 and 2013 using claim databases, including both diagnostic and medication codes, such as anti-cancer treatment with L-asp and VTE diagnoses from the starting date until 3 months after cessation of L-asp. Results A total of 3286 patients were prescribed L-asp treatment for any type of lymphoid malignancy including ALL and lymphoma; 116 patients (3.5%) experienced VTE. The most common site of thrombosis was the upper extremities (34.5%). Cerebral vein thrombosis (1.7%) occurred in two pediatric patients; 2.4% (43/1795) of pediatric patients and 4.9% (72/1486) of adult patients suffered from VTE, respectively; 2.7% (56/2064) of ALL and 4.9% (59/1217) of lymphoma patients were diagnosed with VTE after L-asp exposure. After univariate analysis, both the diagnosis of lymphoma (vs. ALL) and being an adult patient (vs. pediatric patient) were risk factors for VTE occurrence. However, after multivariate analysis, only age > 18 remained a risk factor for VTE (odds ratio, 1.79; 95% confidence interval, 1.14-2.81). Conclusions This is the first and largest population-based study in Asian patients with lymphoid malignancies treated with L-asp demonstrating that adult patients are at elevated risk of thrombosis after L-asp exposure. The overall incidence of L-asp-related VTE amongst these patients was similar to that in Caucasian populations.

Sub-erythemal ultraviolet radiation reduces metabolic dysfunction in already overweight mice

Exposure to sunlight may limit cardiometabolic risk. In our previous studies, regular exposure to sub-erythemal (non-burning) ultraviolet radiation (UVR) reduced signs of adiposity and cardiometabolic dysfunction in mice fed a high-fat diet. Some of the observed effects were dependent on skin release of nitric oxide after UVR exposure. Here, we examine the effects of sub-erythemal UVR on signs of adiposity and metabolic dysfunction in already overweight mice, comparing the effects of two sunlamps with distinct emitted light spectra. Mice were fed a high-fat diet from 8 weeks of age, with UVR administered twice a week from 14 weeks of age until they were killed at 20 weeks of age. Mice were irradiated with the same dose of UVB radiation (1 kJ/m²) from either FS40 (65% UVB, 35% UVA) or CLEO (4% UVB, 96% UVA) sunlamps, but substantially more UVA from the latter. FS40 UVR (but not CLEO UVR) significantly reduced mouse weights and weight gain, compared to mice fed a high-fat diet (only). These effects were dependent on nitric oxide. Conversely, CLEO UVR (but not FS40 UVR) significantly reduced circulating LDL cholesterol. Both light sources reduced fasting insulin levels, and the extent of hepatic steatosis; the latter was reversed by topical application of cPTIO, suggesting an important role for skin release of nitric oxide in preventing hepatic lipid accumulation. These results suggest that there may be a number of benefits achieved by regular exposure to safe (non-burning) levels of sunlight or UV-containing phototherapy, with effects potentially dependent on the predominance of the wavelengths of UVR administered.

Deep vein thrombosis related to environment (Review)

The first-time venous thromboembolism (VTE) is less frequent than other thrombotic events, however, both the pulmonary embolism (PE) and the deep vein thrombosis (DVT) show a frequent morbidity. Many factors play as risk situations in determining VTE, and the air exposure to the fine and ultrafine particulate matter (PM) as PM10, PM2.5, PM0.1 is considered. Epidemiological studies have supported this association although both the effective burden of the association and the mechanisms are to date unclear. The PM concentrations and the exposure time are notable as emerging factors. Interestingly, the seasonal climate variations resulted as effective risk factor for appearance of VTE or DVT. There is a need to ameliorate the environment by reducing the air pollution at global scale.

The relationship between sun exposure and all-cause mortality

Women with low sun exposure are at a dose-dependently increased risk of all-cause mortality, mainly due to an increased risk of death from cardiovascular or noncancer/noncardiovascular disease compared higher exposure.

Sun Exposure and Its Effects on Human Health: Mechanisms through Which Sun Exposure Could Reduce the Risk of Developing Obesity and Cardiometabolic Dysfunction

Obesity is a significant burden on global healthcare due to its high prevalence and associations with chronic health conditions. In our animal studies, ongoing exposure to low dose ultraviolet radiation (UVR, found in sunlight) reduced weight gain and the development of signs of cardiometabolic dysfunction in mice fed a high fat diet. These observations suggest that regular exposure to safe levels of sunlight could be an effective means of reducing the burden of obesity. However, there is limited knowledge around the nature of associations between sun exposure and the development of obesity and cardiometabolic dysfunction, and we do not know if sun exposure (independent of outdoor activity) affects the metabolic processes that determine obesity in humans. In addition, excessive sun exposure has strong associations with a number of negative health consequences such as skin cancer. This means it is very important to "get the balance right" to ensure that we receive benefits without increasing harm. In this review, we detail the evidence around the cardiometabolic protective effects of UVR and suggest mechanistic pathways through which UVR could be beneficial.

The Effect of Treatment of Vitamin D Deficiency on the Level of P-Selectin and hs-CRP in Patients With Thromboembolism: A Pilot Randomized Clinical Trial

Despite the known role of vitamin D deficiency in development of thrombosis, no studies have evaluated the impact of treating of vitamin D deficiency on the markers of thrombosis. A pilot randomized clinical trial was done on 40 vitamin D-deficient patients with deep vein thrombosis (DVT) or pulmonary embolism (PE). The intervention group received an oral dose of 50,000 IU vitamin D₃ every week for 8 weeks, followed by 1 pearl every 2 weeks for 4 weeks (a total of 3 months), while the control group did not receive vitamin D. Then, P-selectin and hs-CRP were measured at baseline and 1 and 3 months after the intervention. There was no significant decrease in hs-CRP in either group after 1 month (P = .955) or after 3 months (P = .525). Likewise, there was no significant decrease in P-selectin between the 2 groups after 1 month (P = .921) or 3 months (P = .795). The results indicated that treatment of vitamin D deficiency had no significant effect on hs-CRP or P-selectin after 3 months among DVT/PE patients. However, treatment of vitamin D deficiency in these patients resulted in the control of the international normalized ratio (INR) with the lower doses of warfarin. This observation is the first clinical report of enhancement of the anticoagulant effect of warfarin by the supplementing of vitamin D. Larger trials are needed to clearly show the effect of treating of vitamin D deficiency on thrombosis.

Serum levels of 25(OH)D are not associated with venous thromboembolism in the elderly population. A case-control study

The prevalence of both vitamin D deficiency and venous thromboembolism (VTE) is important in the elderly. Previous studies have provided evidence for a possible association between vitamin D status and the risk of VTE. Thus, we aimed to investigate the association between vitamin D levels and VTE in the population aged 75 and over included in the EDITH case-control study. The association between vitamin D status and VTE was analysed. We also analysed the monthly and seasonal variations of VTE and vitamin D. Between May 2000 and December 2009, 340 elderly patients (mean age 81.5 years, 32% men) with unprovoked VTE and their controls were included. The univariate and multivariate analysis found no significant association between serum levels of vitamin D and the risk of unprovoked VTE. In the unadjusted analysis, a higher BMI was statistically associated with an increased risk of VTE (OR 1.09; 95% CI 1.05-1.13) whereas a better walking capacity and living at home were associated with a decreased rate of VTE: OR 0.57; 95% CI 0.36-0.90 and 0.40; 95% CI 0.25-0.66, respectively. Although not significant, more VTE events occurred during winter (p=0.09). No seasonal variations of vitamin D levels were found (p=0.11). In conclusion, in contrast with previous reports our findings suggest that vitamin D is not associated with VTE in the elderly population.

Vitamin D metabolites and fibroblast growth factor-23 in patients with left ventricular assist device implants: association with stroke and mortality risk

PURPOSE

Stroke and mortality risk in patients with left ventricular assist device (LVAD) implants continue to be high. Whether nonclassical cardiovascular risk markers such as vitamin D metabolites and fibroblast growth factor (FGF)-23 contribute to this risk remains to be studied, and this was the objective of our work.

METHODS

In 154 LVAD patients (91 HeartWare and 63 HeartMate II implants), we measured circulating 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D3 (1,25[OH]2D3), parathyroid hormone (PTH) and FGF-23 shortly before LVAD implantation and investigated their association with stroke and mortality risk during 1-year follow-up.

RESULTS

Of the study cohort, 34.4 and 92.2%, respectively, had deficient 25OHD (<25 nmol/l) and 1,25(OH)2D3 (<41 pmol/l) values, whereas 42.6 and 98.7%, respectively, had elevated PTH levels (>6.7 pmol/l) and FGF-23 values above the reference range (100 RU/ml). One-year freedom from stroke was 80.9 %, and 1-year survival was 64.3%. The multivariable-adjusted hazard ratio of stroke was 2.44 (95% CI: 1.09-5.45; P = 0.03) for the subgroup of 25OHD levels <25 nmol/l (reference group: 25OHD levels ≥25 nmol/l). The multivariable-adjusted hazard ratio of 1-year mortality was 2.78 (95% CI: 1.52-5.09; P = 0.001) for patients with 25OHD levels <25 nmol/l compared with patients with 25OHD levels ≥25 nmol/l. PTH, FGF-23 and 1,25(OH)2D3 were not associated with stroke or mortality risk.

CONCLUSIONS

In LVAD patients, deficient 25OHD levels are independently associated with high stroke and mortality risk. If confirmed in randomized controlled trials, preoperative correction of deficient vitamin D status could be a promising measure to reduce stroke and mortality risk in LVAD patients.

The Effect of High-Dose Vitamin D3 on Soluble P-Selectin and hs-CRP Level in Patients With Venous Thromboembolism

High plasma level of P-selectin is associated with the development of venous thromboembolism (VTE). Furthermore, supplementation of vitamin D could decrease thrombotic events. Hence, this study was designed to examine whether the administration of vitamin D can influence the plasma level of P-selectin in patients with VTE. In the randomized controlled trial, 60 patients with confirmed acute deep vein thrombosis and/or pulmonary embolism (PE) were randomized into the intervention (n = 20) and control (n = 40) groups. The intervention arm was given an intramuscular single dose of 300 000 IU vitamin D3. Plasma level of 25-hydroxy vitamin D, P-selectin, and high-sensitive C-reactive protein (hs-CRP) was measured at baseline and 4 weeks after. The plasma level of P-selectin (95% confidence interval = −5.99 to −1.63, P = .022) and hs-CRP ( P = .024) significantly declined in vitamin D-treated group, while only hs-CRP was significantly decreased in the control group ( P = .011). However, the magnitude of these reductions was not statistically significant. This study could not support the potential benefit of the high-dose vitamin D on plasma level of P-selectin and hs-CRP in patients with VTE.

Serum 25-hydroxyvitamin D and risk of venous thromboembolism: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Some evidence suggests that an inadequate vitamin D level may increase the risk for atherosclerotic cardiovascular disease. Whether a low vitamin D level plays a role in venous thromboembolism (VTE), that is, venous thrombosis and pulmonary embolism, is largely unexplored.

OBJECTIVES

We tested prospectively, in the Atherosclerosis Risk in Communities (ARIC) cohort, whether the serum level of 25-hydroxyvitamin D (25[OH]D) is inversely associated with VTE incidence, and whether it partly explains the African American excess of VTE in the ARIC Study.

PATIENTS AND METHODS

We measured 25(OH)D by using mass spectroscopy in stored samples of 12 752 ARIC Study participants, and followed them over a median of 19.7 years (1990-1992 to 2011) for the incidence of VTE (n = 537).

RESULTS

The seasonally adjusted 25(OH)D level was not associated with VTE incidence. In a model adjusted for age, race, sex, hormone replacement therapy, and body mass index, the hazard ratios of VTE across 25(OH)D quintiles 5 (high) to 1 (low) were: 1 (ref.), 0.84 (95% confidence interval [CI] 0.65-1.08), 0.88 (95% CI 0.68-1.13), 1.04 (95% CI 0.78-1.38), and 0.90 (95% CI 0.64-1.27). The lowest 25(OH)D quintile contained 59% African Americans, whereas the highest quintile contained 7% African Americans. However, lower 25(OH)D levels explained little of the 63% greater VTE risk of African Americans over whites in this cohort.

CONCLUSIONS

A low 25(OH)D level was not a risk factor for VTE in this prospective study. However, the totality of the literature (three studies) suggests that a low 25(OH)D level might modestly increase VTE risk in whites, but this needs further confirmation.

Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort

BACKGROUND

Sunlight exposure and fair skin are major determinants of human vitamin D production, but they are also risk factors for cutaneous malignant melanoma (MM). There is epidemiological evidence that all-cause mortality is related to low vitamin D levels.

METHODS

We assessed the avoidance of sun exposure as a risk factor for all-cause mortality for 29 518 Swedish women in a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort. Women were recruited from 1990 to 1992 and were aged 25 to 64 years at the start of the study. We obtained detailed information at baseline on their sun exposure habits and potential confounders. Multivariable flexible parametric survival analysis was applied to the data.

RESULTS

There were 2545 deaths amongst the 29 518 women who responded to the initial questionnaire. We found that all-cause mortality was inversely related to sun exposure habits. The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group, resulting in excess mortality with a population attributable risk of 3%.

CONCLUSION

The results of this study provide observational evidence that avoiding sun exposure is a risk factor for all-cause mortality. Following sun exposure advice that is very restrictive in countries with low solar intensity might in fact be harmful to women's health.

The relationship between vitamin D status and idiopathic lower-extremity deep vein thrombosis

Background

Vitamin D has been shown to have an anticoagulant effect. A decrease in 25-hydroxyvitamin D [25(OH)D] concentration has also been associated with an increased risk of venous thromboembolism. Hence, we sought to determine the relationship between 25(OH) D levels and idiopathic lower-extremity deep vein thrombosis (DVT).

Methods

In a case control study, a total of 82 participants with idiopathic lower-extremity DVT were enrolled along with 85 sex- and age-matched healthy participants as controls. The plasma 25(OH)D levels were measured in all the studied samples.

Results

The participants’ mean age was 47.1±12.3 years. Baseline characteristics were not significantly different between the groups. The concentration of 25(OH)D was significantly lower in the DVT group compared to that of the control group (17.9±10.3 versus 23.1±12.5 ng/mL, P=0.004). The prevalence of participants with deficient 25(OH)D levels was significantly higher in the both DVT and control groups than those with sufficient 25(OH)D levels (68.3% versus 13.4%, and 49.4% versus 28.2%, respectively, P=0.027). In a multivariate analysis, 25(OH)D levels and sex were found to be the only independent predictors of DVT (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.02–1.08, P=0.001 and OR 0.51, 95% CI 0.26–1.00, P=0.049, respectively).

Conclusion

Low levels of 25(OH)D are associated with idiopathic lower-extremity DVT. Further investigation is needed to establish determinants and probable causative role of 25(OH)D.

Vitamin D in systemic and organ-specific autoimmune diseases

Lately, vitamin D has been linked with metabolic and immunological processes, which established its role as an essential component of human health preservation. Vitamin D has been defined as natural immune modulators, and upon activation of its receptors (VDRs), it regulates calcium metabolism, cellular growth, proliferation and apoptosis, and other immunological functions. Epidemiological data underline a strong correlation between poor vitamin D status and higher risk for chronic inflammatory illnesses of various etiologies, including autoimmune diseases. Epidemiological, genetic, and basic studies indicated a potential role of vitamin D in the pathogenesis of certain systemic and organ-specific autoimmune diseases. These studies demonstrate correlation between low vitamin D and prevalence of diseases. In addition, VDRs' polymorphisms observed in some of these autoimmune diseases may further support a plausible pathogenic link. Notably, for some autoimmune disease, no correlation with vitamin D levels could be confirmed. Thus, in the current review we present the body of evidence regarding the plausible roles of vitamin D and VDR's polymorphism in the pathogenesis of autoimmunity. We summarize the data regarding systemic (i.e., systemic lupus erythematosus, rheumatoid arthritis, etc.) and organ-specific (i.e., multiple sclerosis, diabetes mellitus, primary biliary cirrhosis, etc.) autoimmune diseases, in which low level of vitamin D was found comparing to healthy subjects. In addition, we discuss the correlations between vitamin D levels and clinical manifestations and/or activity of diseases. In this context, we address the rational for vitamin D supplementation in patients suffering from autoimmune diseases. Further studies addressing the mechanisms by which vitamin D affects autoimmunity and the proper supplementation required are needed.

Investigating the association of vitamin D seasonality on inflammatory and hemostatic markers

Seasonal variations in health outcomes are commonly used to hypothesize a link with nutritional vitamin D (25-hydroxyvitamin D, 25(OH)D) status. The majority of vitamin D intake is from skin exposure to sunlight and varies seasonally in countries at a distance away from the Equator. However, despite the strong seasonality of vitamin D intake, no statistical method using cyclical patterns has been proposed to deduce an association between 25(OH)D and health indicators. Our motivation was to overcome the influence of related confounders, such as obesity, between 25(OH)D and health indicators: obesity would be expected to have little or no effect on the seasonal variations in 25(OH)D and in five inflammatory/hemostatic health outcomes (fibrinogen, tissue plasminogen activator [tPA], von Willebrand factor [vWF], C-reactive protein [CRP], and D-dimer). The data analyzed was from the 1958 British birth cohort biomedical survey (n = 6195) and the biomarkers were ascertained from blood drawn over an 18-mo period. We used mediation analysis to determine whether the seasonal variations of the outcomes were mediated by 25(OH)D to infer an association. The assumptions of mediation analysis fit naturally into the study's cross-sectional setting, where day of year of blood collection is the independent variable transformed by the harmonic function, and 25(OH)D is the mediator of the seasonal variation of the outcomes. The harmonic terms were tested to establish the presence of seasonal variation in the outcomes and 25(OH)D in order to determine whether the statistical mediation test could be applied. The data were collected over an 18-mo period and assayed in multiple batches to measure the serum biomarkers. When the assay batches were modeled as fixed effects, significant correlation was found with date of when blood was drawn. Thus, variation in assay batches was accounted for as random effects terms on the intercept in linear mixed-effects models. Inferences were based on tests from mediation analysis defined by the product of regression coefficients; we extended this test to allow for harmonic functions with multiple frequencies in order to statistically test the mediated effect through 25(OH)D. This was done using parametric bootstrap when the models were run in the Frequentist setting. We also replicated the analyses in the Bayesian setting to ascertain the change in amplitude of the seasonal variation that was due to 25(OH)D. Out of the five health outcomes, three (tPA, D-dimer, and fibrinogen) had significant seasonal associations that were partially mediated through 25(OH)D, one (vWF) had a seasonal pattern not mediated through 25(OH)D, and finally another (CRP) had no significant seasonal pattern. The association of 25(OH)D was strongest for tPA, and less so for D-dimer and fibrinogen. Our results and adaption of the mediation test show that there is broad potential in using seasonal variations of health indicators to deduce an association that may have not been affected by nonseasonal confounding.

Relationship between mean platelet volume and low-grade systemic coagulation with vitamin D deficiency in primary ovarian insufficiency

OBJECTIVE

Premature menopause in young women is associated with an increased incidence of cardiovascular disease. The present study was designed to determine vitamin D (vit D) and the coagulation parameters such as activated partial thromboplastin time (APTT), PT, D-dimer, white blood cell (WBC), and mean platelet volume (MPV) levels, in primary ovarian insufficiency (POI) patients and control women with a normal menstrual cycle.

MATERIALS AND METHODS

A total of 43 patients with non-diabetic POI were studied in order to evaluate and compare with the control group comprising 33 women with a normal menstrual cycle.

RESULTS

There was no significant difference between the groups for age and body mass index (BMI). D-dimer, WBC, MPV, PT, total cholesterol, and LDL cholesterol were higher in women with POI. APTT levels were also increased but missed the significance in POI group. Women with POI had significantly lower serum vit D levels compared with healthy control group. FSH level was positively correlated with D-dimer, WBC, MPV, and negatively correlated to vit D and serum D vit level was inversely correlated with MPV, APTT, D-dimer, FSH levels in individual women.

CONCLUSIONS

The obtained results seem to indicate that POI patients had low-grade systemic coagulation and fibrinolytic activation as evidenced by elevated D-dimer, WBC, MPV, PT values potentially be used as indicators of risk factor for thrombosis and atherosclerosis in POI women. All of our patients with POI were deficient in vit D. These results also suggest that vit D deficiency plays important roles of POI women and associated with coagulation, independently from age and BMI.

Effect of a single, oral, high-dose vitamin D supplementation on endothelial function in patients with peripheral arterial disease: a randomised controlled pilot study

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 randomised 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.

Vitamin D and antiphospholipid syndrome

Vitamin D (vitD) has been shown to have multiple immunomodulatory properties. Hypovitaminosis D has been described in many systemic autoimmune diseases. Antiphospholipid syndrome (APS), an autoimmune disease characterized by immune-mediated thrombosis and pregnancy loss, is a peculiar model for studying vitD, since these patients do not usually have a full-blown autoimmune disease, nor do they have particular restrictions regarding sun exposure. We assessed 25-OH vitD levels in 115 APS and 128 normal healthy donors (NHD) with the LIAISON® chemiluminescent immunoassay by DiaSorin (Italy). Median values were lower in APS patients than in NHD, with the greatest difference occurring during summertime ( p < 0.01), suggesting that APS patients may be somehow prevented from vitD generation upon sun exposure. In our cohort, APS patients may have been instructed to use sunscreens in the presence of positive antinuclear antibodies (ANA). Comparing patients with positive and negative ANA, we found comparable vitD levels during the summer. By subdividing APS patients according to clinical features, thrombotic APS patients showed significantly lower levels than did pure obstetric APS patients ( p < 0.01). In conclusion, our study confirms previous reports of hypovitaminosis D in APS patients, making them more similar to patients with other systemic autoimmune diseases than NHD. Hypovitaminosis D may be part of the mosaic of factors that determine autoimmunity, rather than a consequence of chronic disease and its treatment. The observation that patients with thrombotic APS, an aggressive phenotype, may be more deficient than those with exclusive obstetric manifestations fits well with the beneficial effects of vitD on thrombosis described both in vitro and in vivo. Therefore, there may be a rationale to assess the efficacy of vitD supplementation in APS patients.

Cardiovascular disease, statins and vitamin D

Cardiovascular disease is the number one killer in the UK, causing more than 50 000 premature deaths per year, at a cost of over £30 billion to the economy (British Heart Foundation, 2010). Reducing this burden is a priority of the Government and health professionals (Department of Health, 2000). The aim of this paper is to inform and update nurses on four aspects. Firstly, to examine a more accurate test than cholesterol to predict cardiovascular risk that used C-reactive protein (CRP), an inflammatory marker, called the Reynold's Risk Score. Use of this score reclassified almost half of women, and one-fifth of men, into lower or higher risk categories, more accurately compared to conventional tools (Ridker et al, 2007; Ridker et al, 2008b). Secondly, to highlight a potential change to the indications for statin-therapy; an indication for those who ordinarily would not receive a statin: healthy middle-aged adults with normal or low cholesterol, but elevated CRP. This includes discussion of the JUPITER trial and its sub-analyses. This large, multicentre, double-blind randomized, placebo-controlled trial in apparently healthy men over the age of 50 years and women over 60 years, with normal or low cholesterol but elevated CRP, demonstrated significant benefit. Rosuvastatin 20 mg per day compared to a placebo reduced myocardial infarction and stroke by half, and reduced venous thromboembolism by almost half (Ridker et al, 2008a; Glynn et al. 2009; Everett, et al, 2010). Thirdly, to discuss the pleiotropic effects of statins, which include reduction of CRP (Ridker et al, 2008a), increases in endothelial repair cells (Spiel, et al, 2008), alteration of clotting factors (Glynn, et al, 2009), and enhancement of vitamin D metabolism (Yavuz et al, 2009). Fourthly, to discuss evidence that the pleiotropic effects of statins may be attributable to the vitamin D effect. This paper therefore evaluates the evidence suggesting that vitamin D supplementation may attain the same benefit as statins (Grimes, 2006), in addition to reducing statinassociated side-effects when co-administered (Ahmed et al, 2009).