Myocardial infarction is inversely associated with plasma 25-hydroxyvitamin D3 levels: a community-based study

Association between cardiovascular diseases and osteoporosis-reappraisal

Positive association between cardiovascular diseases and osteoporosis is important because it concerns two major public health problems. Men and women with cardiovascular diseases (including severe abdominal aortic calcification (AAC) and peripheral arterial disease) tend to have lower areal and volumetric bone mineral density (BMD) as well as faster bone loss, although findings vary according to skeletal site. On one hand, severe forms of cardiovascular diseases (heart failure, myocardial infarction, hypertension, severe AAC) are associated with higher risk of osteoporotic fracture, especially hip fracture. This link was found in the studies based on healthcare databases and the cohort studies. On the other hand, low BMD, history of fragility fracture, vitamin D deficit and increased bone resorption are associated with higher risk of major cardiovascular events (myocardial infraction, stroke, cardiovascular mortality). Moreover, osteocalcin secreted by osteoblasts may be involved in the regulation of energetic and cardiovascular metabolism. The association between both pathologies depends partially on the shared risk factors, and also on the mechanisms that are involved in the regulation of bone and cardiovascular metabolism. Interpretation of the data should take into account methodological limitations: representativeness of the cohorts, quality of the registers and the information obtained from questionnaires, severity of diseases, number of events (statistical power) and their temporal closeness, availability of the information on potential confounders. It seems that patients with severe form of osteoporosis would benefit from assessment of the cardiovascular status and vice versa. However, official guidelines for the clinical practice are still lacking.

A 21st century evaluation of the safety of oral vitamin D

The safety of daily consumption of vitamin D was examined. A detailed literature search was conducted using the search term vitamin D; primary and secondary sources of original data and meta-analyses and systematic reviews were evaluated and summarized. A large body of scientific evidence demonstrates that long-term daily intakes of 600 to 800 IU of vitamin D are insufficient to achieve and sustain vitamin D adequacy (serum 25-hydroxyergocalciferol + 25-hydroxycholecalciferol concentration >75 nmol/L). Maximization of the physiologic benefits of vitamin D to the musculoskeletal system, the central and peripheral nervous systems, the heart and central and peripheral cardiovascular systems, the respiratory system, the skin, the eyes, dentition, glucoregulation, immunoregulation, and disease resistance requires daily vitamin D intakes of at least 1500 IU. Because long-term daily intakes up to and including 10 000 IU of vitamin D do not produce signs or symptoms of vitamin D toxicity and are safe for the entire general population of otherwise healthy adults, even daily vitamin D intakes of 2000 IU allow for the often-cited and excessively conservative five-fold safety factor. In conclusion, long-term daily intakes of up to and including 10 000 IU of vitamin D maximize physiologic benefits and are safe.

Low vitamin d and cardiovascular risk factors in males and females from a sunny, rich country

BACKGROUND

Low serum vitamin (vit) D levels are common even in sunny countries. We assessed the prevalence and relationship of low vit D with cardiovascular risk factors in Qatar.

METHODS

Data were collected retrospectively from January 2008 and November 2009. In patients who had low vi t D (< 30 ng/ml ) , demographic and clinical profiles were analyzed and compared in males and females.

RESULTS

The overall mean level of vit D among 547 patients was 14.4±11 ng/mL. Among the low vitamin D group, 56% were females (mean age 48±12) and 44% males (mean age 49.6±13). Severely low vit D levels (<10 ng/mL) were found in 231 (46%) patients with mean age of 46±12 years. Compared with females, males with low vitamin D were more likely to have diabetes mellitus (38 vs 22%, p=0.001), dyslipidemia (41 vs 29%, p=0.007), myocardial infarction (5.5 vs 1.5%, p=0.001) and angiographically documented coronary artery disease (CAD) (53 vs 17%, p=0.001). Multivariate logistic regression analysis showed that in the presence of low vit D, age and hypertension were independent predictors of CAD (OR 1.07;95% CI: 1.02-1.11) and OR 8.0; 95% CI: 1.67-39.82), respectively.

CONCLUSIONS

Our study supports the widespread prevalence of low vit D in sunny regions. Low vit D is associated with 3 times increase in the rate of MI among males. Hypertension increases the risk of CAD 8 times in the presence of low vit D regardless of gender.

Low vitamin D status: definition, prevalence, consequences, and correction

Low vitamin D status is extremely common worldwide due to low dietary intake and low skin production. Suboptimal vitamin D status contributes to many conditions, including osteomalacia/rickets, osteoporosis, falls, and fractures. It is possible or even likely that low vitamin D status increases risk for a multitude of other conditions. Although consensus does not exist, it appears that circulating 25(OH)D concentrations greater than 30 to 32 ng/mL are needed for optimal health. To achieve this, daily intakes of at least 1000 IU of D3 daily are required, and it is probable that substantially higher amounts are required to achieve such values on a population basis. It seems premature to recommend widespread screening for 25(OH)D measurement. Targeted measurement in those at increased risk for vitamin D deficiency and those most likely to have a prompt positive response to supplementation is appropriate. Widespread optimization of vitamin D status likely will lead to prevention of many diseases with attendant reduction of morbidity, mortality, and expense.

Glomerular filtration rate and parathyroid hormone are associated with 1,25-dihydroxyvitamin D in men without chronic kidney disease

BACKGROUND AND AIM

Vitamin D, estimated glomerular filtration rate (eGFR) and parathyroid hormone (PTH) are related to cardiovascular disease risk. We examined the associations between the levels of 25-hydroxyvitamin D (25-D) and 1,25-dihydroxyvitamin D (1,25-D) and both eGFR and PTH.

DESIGN AND SETTING

Cross-sectional population-based study in Kuopio, Eastern Finland.

SUBJECTS

A total of 909 men without known chronic kidney disease (CKD) and not receiving antidiabetic medication, aged from 45 to 73 years, were included in the study. Main outcome measures. Fasting levels of 25-D, 1,25-D, creatinine and PTH were measured, and an oral glucose tolerance test (OGTT) was performed.

RESULTS

High levels of 25-D were associated with low levels of eGFR and PTH (β = -0.17, P = 9 × 10(-7) and β = -0.28, P = 6 × 10(-17) , respectively, adjusted for age, body mass index and levels of calcium, phosphorus and glucose in a 2-h OGTT, and also for either eGFR or PTH). By contrast, high 1,25-D levels were associated with high levels of eGFR and PTH (β = 0.17, P = 2 × 10(-6) and β = 0.19, P = 5 × 10(-8) , respectively, adjusted as mentioned earlier and additionally for 25-D). Eighteen per cent of men in the highest 25-D quartile were in the lowest 1,25-D quartile and also had a lower eGFR than men with high levels of both 25-D and 1,25-D (P = 4 × 10(-5) ). Finally, 15% of men in the lowest 25-D quartile were in the highest 1,25-D quartile and also had higher PTH levels than men with low levels of both 25-D and 1,25-D (P = 2 × 10(-3) ).

CONCLUSION

Our findings suggest that both eGFR and PTH are significantly associated with vitamin D metabolism in men without known CKD.

Vitamin D deficiency-induced hypertension is associated with vascular oxidative stress and altered heart gene expression

Vitamin D deficiency (VDD) is associated with an increased cardiovascular risk. We investigated the effect of VDD on the cardiovascular system of growing male rats fed with a vitamin D-deficient diet. Using isolated rat aorta, we assessed both superoxide anion and endothelial-dependent relaxations. Microarray technology was used to identify changes induced by VDD in cardiac gene expression. Compared with control, VDD increased systolic blood pressure (P < 0.05) and superoxide anion production in the aortic wall (P < 0.05) and tended to increase serum levels of angiotensin II and atrial natriuretic peptide (P < 0.15). However, VDD slightly improved maximal relaxation to acetylcholine from 75 % ± 3% to 83% ± 2% (P < 0.05). Incubation of aortic rings either with nitro-l-arginine methyl ester (l-NAME) or catalase did not eliminate the enhancement of endothelial-mediated relaxation observed in vitamin D-deficient rats. Only incubation with indometacin or calcium-activated potassium channels blockers suppressed this difference. Compared with control, the expression of 51 genes showed different expression, including several genes involved in the regulation of oxidative stress and myocardial hypertrophy. In conclusion, VDD in early life increases arterial blood pressure, promotes vascular oxidative stress, and induces changes in cardiac gene expression. However, the endothelial-mediated regulation of vasomotor tone is maintained throughout the enhancement of an NO-independent compensatory pathway.

A prospective randomized controlled trial of the effects of vitamin D supplementation on cardiovascular disease risk

Vitamin D (VitD) supplementation has been advocated for cardiovascular risk reduction; however, supporting data are sparse. The objective of this study was to determine whether VitD supplementation reduces cardiovascular risk. Subjects in this prospective, randomized, double-blind, placebo-controlled trial of post-menopausal women with serum 25-hydroxyvitamin D concentrations >10 and <60 ng/mL were randomized to Vitamin D3 2500 IU or placebo, daily for 4 months. Primary endpoints were changes in brachial artery flow-mediated vasodilation (FMD), carotid-femoral pulse wave velocity (PWV), and aortic augmentation index (AIx). The 114 subjects were mean (standard deviation) 63.9 (3.0) years old with a 25-hydroxyvitamin D level of 31.3 (10.6) ng/mL. Low VitD (<30 ng/mL) was present in 47% and was associated with higher body-mass index, systolic blood pressure, glucose, CRP, and lower FMD (all p<0.05). After 4 months, 25-hydroxyvitamin D levels increased by 15.7 (9.3) ng/mL on vitamin D3 vs. −0.2 (6.1) ng/mL on placebo (p<0.001). There were no significant differences between groups in changes in FMD (0.3 [3.4] vs. 0.3 [2.6] %, p = 0.77), PWV (0.00 [1.06] vs. 0.05 [0.92] m/s, p = 0.65), AIx (2.7 [6.3] vs. 0.9 [5.6] %, p = 0.10), or CRP (0.3 [1.9] vs. 0.3 [4.2] mg/L, p = 0.97). Multivariable models showed no significant interactions between treatment group and low VitD status (<30 ng/mL) for changes in FMD (p = 0.65), PWV (p = 0.93), AIx (p = 0.97), or CRP (p = 0.26).In conclusion, VitD supplementation did not improve endothelial function, arterial stiffness, or inflammation. These observations do not support use of VitD supplementation to reduce cardiovascular disease risk.

Risk factors for community-acquired pneumonia in pre-school-aged children

AIM

To identify risk factors for children developing and being hospitalised with community-acquired pneumonia.

METHODS

Children <5 years old residing in urban Auckland, New Zealand were enrolled from 2002 to 2004. To assess the risk of developing pneumonia, children hospitalised with pneumonia (n= 289) plus children with pneumonia discharged from the Emergency Department (n= 139) were compared with a random community sample of children without pneumonia (n= 351). To assess risk of hospitalisation, children hospitalised with pneumonia were compared with the children discharged from the Emergency Department. Adjusted odds ratio (OR) with 95% confidence intervals (CIs) were used to estimate the risk of pneumonia and hospitalisation with pneumonia.

RESULTS

After adjustment for season, age and ethnicity there was an increased risk of pneumonia associated with lower weight for height (OR 1.28, 95% CI 1.10-1.51), spending less time outside (1.96, 1.11-3.47), previous chest infections (2.31, 1.55-3.43) and mould in the child's bedroom (1.93, 1.24-3.02). There was an increased risk of pneumonia hospitalisation associated with maternal history of pneumonia (4.03, 1.25-16.18), living in a more crowded household (2.87, 1.33-6.41) and one with cigarette smokers (1.99, 1.05-3.81), and mould in the child's bedroom (2.39, 1.25-4.72).

CONCLUSIONS

Lower quality living environments increase the risk of pneumonia and hospitalisation with pneumonia in New Zealand. Poorer nutritional status may also increase the risk of pneumonia. Improving housing quality, decreased cigarette smoke exposure and early childhood nutrition may reduce pneumonia disease burden in New Zealand.

Low calcidiol levels and risk of progression of aortic calcification

In this observational study, we found a positive relationship between low calcidiol levels and the risk of aortic calcification progression. A 10-ng/mL increase of calcidiol was associated with a decrease in the risk of progression by 44%. This figure was higher than that observed if we increased age by 10 years.

INTRODUCTION

The aim of this study was to investigate the relationship between serum calcidiol levels and the onset and progression of aortic calcifications in a community-based sample of ambulatory subjects.

METHODS

Three hundred two men and women aged 50 and over underwent two lateral X-rays and were followed up for 4 years. Abdominal aortic calcifications were classified as absent, mild-moderate, and severe. The biochemical measurements of serum calcium, phosphorus, parathyroid hormone, total alkaline phosphatase, tartrate-resistant acid phosphatase, creatinine, calcidiol, calcitriol, and osteocalcin were determined. Subjects who had received anti-osteoporotic treatments were excluded from the analysis.

RESULTS

Subjects with progression of aortic calcifications had significantly lower serum calcidiol levels than those without progression. In the multivariate analysis, using the agreed upon serum levels for calcidiol (>30 ng/mL) as the reference, those subjects with calcidiol levels between 10 and 20 ng/mL showed a higher risk of progression of aortic calcification (odds ratio (OR) = 3.95; 95% confidence interval (CI) = 1.16 to 13.40). An even higher OR was observed in subjects with calcidiol values <10 ng/mL (OR = 4.10; 95% CI = 1.12 to 14.99). In addition, an increase by 1 ng/mL in osteocalcin levels was associated with a 17% reduction of the risk of aortic calcification progression.

CONCLUSIONS

An increase by 10 ng/mL of calcidiol was associated with a decrease in the risk of aortic calcifications progression by 44%. This figure was even higher than that observed if we increased age by 10 years. Levels of calcidiol higher than 30 ng/mL seem to be desirable to reduce the progression of aortic calcification and to maintain bone turnover.

Serum 25-hydroxyvitamin D concentration and arterial stiffness among type 2 diabetes

AIM

To evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] and arterial stiffness in patients with type 2 diabetes.

METHODS

Serum 25(OH)D was measured in a cross-sectional sample of 131 men and 174 women aged 30 years and over in Korea. Arterial stiffness was assessed by pulse wave velocity (PWV) obtained with a VP-2000 pulse wave unit. Fasting plasma glucose, insulin, lipid profile, HbA1c, calcium, phosphorous, and HS-CRP were measured.

RESULTS

The prevalence of vitamin D deficiency was high (85.9%). Those with lower vitamin D levels had increased PWV. Using multivariate regression analysis, low 25(OH)D concentrations independently predicted PWV (p<0.001) in people with type 2 diabetes after adjustment for other risk factors such as age, smoking, hypertension, HS-CRP, diabetes duration, hypertension duration, HbA1c, and BMI.

CONCLUSIONS

Vitamin D deficiency is common in type 2 diabetes, and a low 25(OH)D level is significantly associated with increased arterial stiffness in these patients. Vitamin D may influence the development of cardiovascular disease. Clinical intervention studies are needed to clarify whether treatment with vitamin D decreases the risk of cardiovascular disease in patients with type 2 diabetes.

Serum vitamin D concentration status and its correlation with early biomarkers of remodeling following acute myocardial infarction

BACKGROUND

Low serum level of vitamin D was shown to be associated with cardiovascular diseases as well as the presence of diabetes, dyslipidemia, and hypertension. Vitamin D deficiency is a global problem, and is an Iranian problem as well. To the best of our knowledge, this was the first study on acute myocardial infarction that evaluates the correlation of vitamin D level with inpatients' outcomes, particularly on the early biomarkers of myocardial remodeling.

METHODS

In a prospective study, patients with acute ST segment elevation myocardial infarction were included. The patients' 25 (OH) D levels were identified and the associations with clinical characteristics, including early remodeling biomarkers and in-hospital outcomes, were investigated.

RESULTS

From the 139 included patients, 80.5% were male. The 25 (OH) deficiency was present in 72.7% of the patients. Hypertension and positive history of cardiovascular drug use were risk factors for the presence of low vitamin D levels (OR = 2.92; CI = 1.34-6.37, P < 0.05) and (OR = 2.36; CI = 1.05-5.29, P < 0.05), respectively. Moreover, a significant positive relationship between the inpatients' survival and the concentration of vitamin D was present (P < 0.001). By performing a multivariate analysis, we found that there was a significant inverse relationship between the level of 25 (OH) D and the level of MMP-9 after 72 h (P = 0.011).

CONCLUSION

The results of our study revealed a significant inverse relationship between serum MMP-9 as a biomarker of early remodeling and the level of 25(OH) D in patients after an acute myocardial infarction. Moreover, low level of vitamin D was associated with patients' mortality in this study.

25-Hydroxyvitamin D deficiency is associated with increased aortic stiffness in patients with systemic lupus erythematosus

Objective. To determine the relationship between serum vitamin D and markers of subclinical cardiovascular disease (CVD) in patients with SLE.

Methods. We recruited SLE patients (≥4 ACR 1997 criteria) from outpatient clinics between January 2007 and January 2009. Vitamin D deficiency was defined as serum 25(OH)D <20 ng/ml measured by ELISA. Disease activity was measured using the SLEDAI-2K score. Aortic pulse wave velocity (aPWV) was measured using PulseTrace 3600 (Micromedical) and carotid plaque (CP) and intima–media thickness (IMT) assessed using B-mode Doppler US.

Results. Seventy-five women with SLE were recruited with a median (interquartile range) disease duration of 16 (8–27) years. Patients with vitamin D deficiency had higher BMI (P = 0.014) and insulin resistance (P = 0.023) than those with 25(OH)D >20 ng/ml. Subjects with SLEDAI-2K ≥4 had lower 25(OH)D than those with SLEDAI-2K <4 (median 12.9 vs 20.3 ng/ml, P = 0.031). Aortic stiffness was significantly associated with serum 25(OH)D [log(aPWV) β (95% CI) −0.0217 (−0.038, −0.005), P = 0.010] independently of BMI, CVD risk factors and serum insulin. Adjustment for disease activity reduced the strength of the association. There was no association between 25(OH)D and CP or IMT.

Conclusions. Vitamin D deficiency is associated with increased aortic stiffness in SLE, independent of CVD risk factors and insulin. Increased inflammatory disease activity may be the mechanism by which vitamin D deficiency mediates vascular stiffness in this patient group.

Vitamin D: epidemiology of cardiovascular risks and events

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

Vitamin D and cardiovascular outcomes: a systematic review and meta-analysis

CONTEXT

Several studies found association between vitamin D levels and hypertension, coronary artery calcification, and heart disease.

OBJECTIVE

The aim of this study was to summarize the evidence on the effect of vitamin D on cardiovascular outcomes.

DESIGN AND METHODS

We searched electronic databases from inception through August 2010 for randomized trials. Reviewers working in duplicate and independently extracted study characteristics, quality, and the outcomes of interest. Random-effects meta-analysis was used to pool the relative risks (RR) and the weighted mean differences across trials.

RESULTS

We found 51 eligible trials with moderate quality. Vitamin D was associated with nonsignificant effects on the patient-important outcomes of death [RR, 0.96; 95% confidence interval (CI), 0.93, 1.00; P = 0.08], myocardial infarction (RR, 1.02; 95% CI, 0.93, 1.13; P = 0.64), and stroke (RR, 1.05; 95% CI, 0.88, 1.25; P = 0.59). These analyses were associated with minimal heterogeneity. There were no significant changes in the surrogate outcomes of lipid fractions, glucose, or diastolic or systolic blood pressure. The latter analyses were associated with significant heterogeneity, and the pooled estimates were trivial in absolute terms.

CONCLUSIONS

Trial data available to date are unable to demonstrate a statistically significant reduction in mortality and cardiovascular risk associated with vitamin D. The quality of the available evidence is low to moderate at best.

Vitamin D and public health: an overview of recent research on common diseases and mortality in adulthood

OBJECTIVE

There is increasing interest in vitamin D and its possible health effects. The aims of the present overview are to summarise the research on common diseases for which there is substantial evidence on vitamin D, identify diseases where vitamin D may be beneficial and discuss the public health implications of these findings.

DESIGN

Literature search of PubMed for the years 2000 to 2010 to identify cohort studies with baseline measures of 25-hydroxyvitamin D (25(OH)D) and randomised controlled trials (RCT) of vitamin D supplementation in relation to fractures, colorectal cancer, CVD and all-cause mortality. Risk ratios of disease from comparisons between 25(OH)D quantiles in these studies were summarised using RevMan software version 5·1 (The Nordic Cochrane Centre, Copenhagen).

SETTING

Community-based samples recruited into cohort studies from many countries.

SUBJECTS

Older men and women, mostly above 50 years of age.

RESULTS

When comparing the lowest 25(OH)D category with the highest (or reference), the pooled risk ratio (95 % CI) was: 1·34 (1·13, 1·59) for fractures from nine studies; 1·59 (1·30, 1·95) for colorectal cancer from nine studies; 1·35 (1·17, 1·56) for CVD from twelve studies; and 1·42 (1·23, 1·63) for all-cause mortality from twelve studies.

CONCLUSIONS

Cohort studies show that baseline 25(OH)D levels predict increased risk of fractures, colorectal cancer, CVD and all-cause mortality. These associations are weak and could be explained by confounding variables such as obesity and physical activity. Because of their potential public health significance, RCT using vitamin D doses ≥50 μg/d are required to determine whether vitamin D protects against these diseases.

High-Dose Cholecalciferol Supplementation for Vitamin D Deficiency in Haemodialysis Patients

Vitamin D deficiency, which is a recognized problem in haemodialysis (HD) patients, has been associated with higher all-cause mortality. There are no guidelines concerning vitamin D supplementation in HD patients. This study aimed to assess the effects of once-monthly supplementation with high-dose cholecalciferol (vitamin D3) in HD patients. Patients with 25-hydroxyvitamin D (25[OH]D) levels of < 75 nmol/l received 40 000 IU of cholecalciferol once-monthly for 3 months in succession. Every 4 months, 25(OH)D levels were measured and, based on the findings, cholecalciferol therapy was continued for another cycle if necessary. Six cycles were completed in the 24-month study period. The majority of HD patients had mild or severe vitamin D deficiency at baseline. Monthly supplementation with cholecalciferol at 40000 IU was well tolerated, safe and inexpensive. The treatment regime was effective for vitamin D insufficiency but did not prove to be enough to restore 25(OH)D levels in HD patients with mild or severe vitamin D deficiency.

The effect of vitamin D3 and ketoconazole combination on VDR-mediated P-gp expression and function in human colon adenocarcinoma cells: implications in drug disposition and resistance

The vitamin D3 metabolite 1,25-dihydroxycholecalciferol (DHC) and analogues derived from it are being investigated as potential agents for the treatment of cancer. Combining ketoconazole (KTZ) with DHC has been recommended to enhance the anticancer activity of DHC. DHC exerts its biological activities through the vitamin D receptor (VDR). VDR is recognized to be a regulator of P-glycoprotein (P-gp), a member of the ABC transporter family well known for its role in multidrug resistance in cancer chemotherapy. We have investigated the effect of DHC and adding KTZ together with DHC on P-gp and VDR expression and the functional consequences of P-gp induction in intestinal human colonic adenocarcinoma cells LS174T cells. DHC increased P-gp expression by two times, and the addition of KTZ further increased the expression to four times. The combination of DHC + KTZ also significantly increased VDR expression, consistent with the enhanced increase in P-gp expression by this combination. The increase in P-gp expression was accompanied by increased P-gp function, as measured by decreased Rh123 accumulation in the LS174T cells. In addition, DHC significantly decreased colchicine cytotoxicity in a dose-sensitive manner, and the addition of KTZ further decreased the colchicine cytotoxicity, indicating the chemo-protective effect of DHC is enhanced by KTZ, consistent with the enhanced expression of P-gp. The results of this study raise the possibility that DHC and the addition of KTZ to DHC treatment may decrease the effectiveness of cancer chemotherapy by promoting P-gp-mediated drug resistance.

Vitamin D deficiency prevalence and cardiovascular risk in Israel

BACKGROUND

Accumulated data in the past years suggest that vitamin D deficiency has an adverse effect on cardiovascular (CVD) health and that its prevalence is significantly higher among patients with CVD risk factors, contributing to the pathogenesis of CVD.

MATERIALS AND METHODS

This is a cross-sectional analysis of a relatively large database derived from a health care maintenance organization. The population consisted of individuals 18 years and older who had undergone blood tests for vitamin D levels for any reason during 2001-2008.

RESULTS

The study population consisted of 34,874 individuals: 26,699 (76·6%) were women at a mean ± SD age of 55 ± 15 and 8175 men (23·4%) aged 55 ± 17. The mean ± SD vitamin D level was 23·2 ± 10·1 and 22·7 ± 9·9 for men and women, respectively. The prevalence of vitamin D deficiency or insufficiency (vitamin D levels < 30 ng mL(-1)) for the entire study population was surprisingly high for men and women (79·2% and 77·5%, respectively). This remained consistent with only little variation when stratified by age. The group with vitamin D < 15 ng mL(-1) vs. the group with vitamin D levels ≥ 30 ng mL(-1) demonstrated a significant (P < 0·031) age-adjusted odds ratios for the presence of hypertension, diabetes mellitus, dyslipidemia, obesity and peripheral vascular disease for women (OR = 1·19; 1·65; 1·13; 2·28; 1·85, respectively), and the presence of all the above except hypertension in men (OR = 1·51; 1·28; 2·06; 1·73, respectively).

CONCLUSIONS

Vitamin D deficiency is associated with CVD and other risk factors in this Israeli study population. The prevalence of the deficiency in Israel is similar to the prevalence found in less sunny regions.

Vitamin D deficiency and coronary artery calcification in subjects with type 1 diabetes

OBJECTIVE

The objective of this study is to examine the relationship among serum levels of 25-hydroxyvitamin D (25[OH]D), polymorphisms in vitamin D-associated genes, and the presence and progression of coronary artery calcification (CAC) in adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This prospective study included 374 non-Hispanic white individuals with type 1 diabetes (mean age 40 ± 9 years; 46% were male). CAC was measured at the baseline and 3- and 6-year follow-up visits were determined by electron beam computed tomography. Serum 25[OH]D levels were measured by liquid chromatography tandem mass spectrometry at the 3-year visit.

RESULTS

Normal (>30 ng/mL), insufficient (20-30 ng/mL), and deficient (<20 ng/mL) 25-[OH]D levels were present in 65%, 25%, and 10% of the individuals with type 1 diabetes, respectively. 25[OH]D deficiency was associated with the presence of CAC at the 3-year visit, odds ratio (OR) = 3.3 (95% CI 1.6-7.0), adjusting for age, sex, and hours of daylight. In subjects free of CAC at the 3-year visit, 25[OH]D deficiency predicted the development of CAC over the next 3 years in those with the vitamin D receptor M1T CC genotype (OR = 6.5 [1.1-40.2], P = 0.04) than in those with the CT or TT genotype (OR = 1.6 [0.3-8.6], P = 0.57).

CONCLUSIONS

Vitamin D deficiency independently predicts prevalence and development of CAC, a marker of coronary artery plaque burden, in individuals with type 1 diabetes.

Trace elements, heavy metals and vitamin levels in patients with coronary artery disease

AIM

In the present study, we aimed to assess serum concentrations of zinc (Zn), copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), manganese (Mn), vitamins A (retinol), D (cholecalciferol) and E (α-tocopherol) in patients with coronary artery disease (CAD) and to compare with healthy controls.

METHODS

A total of 30 CAD patients and 20 healthy subjects were included in this study. Atomic absorption spectrophotometry (UNICAM-929) was used to measure heavy metal and trace element concentrations. Serum α-tocopherol, retinol and cholecalciferol were measured simultaneously by high performance liquid chromatography (HPLC).

RESULTS

Demographic and baseline clinical characteristics were not statistically different between the groups. Serum concentrations of retinol (0.3521 ± 0.1319 vs. 0.4313 ± 0.0465 mmol/I, p=0.013), tocopherol (3.8630 ± 1.3117 vs. 6.9124 ± 1.0577 mmol/I, p<0.001), cholecalciferol (0.0209 ± 0.0089 vs. 0.0304±0.0059 mmol/I, p<0.001) and Fe (0.5664 ± 0.2360 vs. 1.0689 ± 0,4452 µg/dI, p<0.001) were significantly lower in CAD patients. In addition, while not statistically significant serum Cu (1.0164 ± 0.2672 vs. 1.1934 ± 0.4164 µg/dI, p=0.073) concentrations were tended to be lower in patients with CAD, whereas serum lead (0.1449 ± 0.0886 vs. 0.1019 ± 0.0644 µg/dI, p=0.069) concentrations tended to be higher.

CONCLUSIONS

Serum level of trace elements and vitamins may be changed in patients with CAD. In this relatively small study we found that serum levels of retinol, tocopherol, cholecalciferol, iron and copper may be lower whereas serum lead concentrations may be increased in patients with CAD.

Are commonly recommended dosages for vitamin D supplementation too low? Vitamin D status and effects of supplementation on serum 25-hydroxyvitamin D levels--an observational study during clinical practice conditions

Vitamin D deficiency is associated with increased fracture risk. The observational study aimed to investigate vitamin D status and supplementation in ambulatory patients. Only 20% of patients had optimal serum 25-hydroxyvitamin D [25(OH)D] levels. Commonly recommended dosages were insufficient to achieve clinically relevant increase of 25(OH)D levels. Higher dosages were safe and effective under clinical practice conditions.

INTRODUCTION

Vitamin D deficiency is associated with adverse health outcome. The study aimed to investigate vitamin D status and supplementation in ambulatory patients.

METHODS

Nine hundred seventy-five women and 188 men were evaluated for bone status from January 2008 to August 2008 within an observational study; 104 patients (n = 70 osteoporosis) received follow-up after 3 months. Dosage of vitamin D supplementation was documented and serum 25(OH)D and parathyroid hormone (PTH) determined.

RESULTS

In all patients (age, 60.4 ± 14.1 years), distribution of 25(OH)D was 56.3 ± 22.3 nmol/L (normal range, 52-182 nmol/L) and PTH 53.8 ± 67.5 ng/L (normal range, 11-43 ng/L). The proportion of patients with 25(OH)D < 25, 25 to <50, 50 to <75, ≥75 nmol/L was 7.5%, 33.3%, 38.9% and 20.2% in the total group and 20.1%, 38.5%, 30.8%, 10.6% at baseline in the follow-up group, respectively. After 3 months, 3.9% had still 25(OH)D < 25 nmol/L; only 12.5% achieved 25(OH)D ≥ 75 nmol/L. In osteoporosis patients, 25(OH)D increased more in those taking ≥1,500 (median, 3,000) IU vitamin D per day (33.1 ± 14.7 nmol/L) compared with ≤1,000 (median, 800) IU/day (10.6 ± 20.0 nmol/L) (p < 0.0008). PTH decreased more in patients taking ≥1,500 IU/day (-13.2 ± 15.2 ng/L) compared with ≤1,000 IU/day (-7.6 ± 19.2 ng/L; p = 0.29). 25(OH)D was negatively correlated to PTH (r = -0.49, p < 0.0001). An increase of 25(OH)D ≥ 75 nmol/L resulted in normalised PTH.

CONCLUSION

Supplementation with higher vitamin D dosages (2,000-3,000 IU/day) is required to achieve a relevant increase of 25(OH)D and normalisation of PTH.

Vitamin D deficiency and toxicity in chronic kidney disease: in search of the therapeutic window

Both vitamin D deficiency and vitamin D toxicity are associated with cardiovascular complications in chronic kidney disease (CKD). Clinical and experiment data indicate that the association of vitamin D levels with cardiovascular disease is best illustrated as a biphasic, or U-shaped, curve. Children and adolescents with CKD need vitamin D due to the demands of a growing skeleton, to prevent renal rickets. However, this therapy carries the risk of severe side effects and chronic toxicity. Observational studies show that vitamin D deficiency and toxicity are frequently present in patients with CKD. In view of the importance of cardiovascular complications for the long-term survival of young patients, these findings demand a judicious use of vitamin D preparations. In clinical practice, the therapeutic window is rather small, presenting a therapeutic challenge to avoid both vitamin D deficiency and toxicity.

Diverse associations of 25-hydroxyvitamin D and 1,25-dihydroxy-vitamin D with dyslipidaemias

BACKGROUND AND AIM

Previous studies have suggested a link between circulating levels of 25-hydroxyvitamin D (25-D) and dyslipidaemias. However, it is not known whether 25-D and the active hormone 1,25-dihydroxyvitamin D (1,25-D) have similar associations with dyslipidaemias. Therefore, we studied the associations between both 25-D and 1,25-D and total cholesterol (total-C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides in a population-based study.

DESIGN

Cross-sectional population-based study.

SETTING

Kuopio, Eastern Finland.

SUBJECTS

A total of 909 men, aged from 45 to 70 years, who were not receiving antidiabetic medication were enrolled.

MAIN OUTCOME MEASURES

Fasting serum samples were obtained for measurement of 25-D, 1,25-D and lipid levels. An oral glucose tolerance test was performed, and insulin sensitivity was evaluated using the Matsuda insulin sensitivity index (Matsuda ISI).

RESULTS

We found a significant inverse association between 25-D and total-C, LDL-C and triglycerides (β = -0.15, -0.13 and -0.17, respectively, P < 0.001), but no association between 25-D and HDL-C was observed. By contrast, 1,25-D was associated with HDL-C (β = 0.18, P < 0.001), whereas no relationship was found between 1,25-D and LDL-C or triglycerides. The associations remained significant after the exclusion of subjects receiving statin treatment and after adjustment for age, waist circumference, body mass index, alcohol consumption, smoking, renal function, glucose tolerance and Matsuda ISI.

CONCLUSION

Low levels of active vitamin D (1,25-D) are associated with low HDL-C levels, whereas low levels of the storage form 25-D are associated with high levels of total-C, LDL-C and triglycerides. Our findings may provide new insights into the understanding of the link between vitamin D deficiency and cardiovascular disease.

Decrease of vitamin D concentration in patients with HIV infection on a non nucleoside reverse transcriptase inhibitor-containing regimen

Background

Vitamin D is an important determinant of bone health and also plays a major role in the regulation of the immune system. Interestingly, vitamin D status before the start of highly active antiretroviral therapy (HAART) has been recently associated with HIV disease progression and overall mortality in HIV-positive pregnant women. We prospectively studied vitamin D status in HIV individuals on HAART in Belgium.

We selected samples from HIV-positive adults starting HAART with a pre-HAART CD4 T-cell count >100 cells/mm³ followed up for at least 12 months without a treatment change. We compared 25-hydroxyvitamin D plasma [25-(OH)D] concentration in paired samples before and after 12 months of HAART. 25-(OH)D levels are presented using two different cut-offs: <20 ng/ml and <30 ng/ml.

Results

Vitamin D deficiency was common before HAART, the frequency of plasma 25-(OH)D concentrations below 20 ng/ml and 30 below ng/ml was 43.7% and 70.1% respectively. After 12 months on HAART, the frequency increased to 47.1% and 81.6%.

HAART for 12 months was associated with a significant decrease of plasma 25-(OH)D concentration (p = 0.001). Decreasing plasma 25-(OH)D concentration on HAART was associated in the multivariate model with NNRTI-based regimen (p = 0.001) and lower body weight (p = 0.008). Plasma 25-(OH)D concentrations decreased significantly in both nevirapine and efavirenz-containing regimens but not in PI-treated patients.

Conclusions

Vitamin D deficiency is frequent in HIV-positive individuals and NNRTI therapy further decreases 25-(OH)D concentrations. Consequently, vitamin D status need to be checked regularly in all HIV-infected patients and vitamin D supplementation should be given when needed.

Vitamin D deficiency and its correlations with increased cardiovascular incidences

Cardiovascular disease is a worldwide epidemic in terms of mortality. It is especially serious in Western countries with heart disease, surpassing even cancer in mortality. Although our understanding of how to prevent and treat the traditional cardiovascular risk factors is largely known, cardiovascular disease still remains the leading cause of death in the United States. There is a need for further investigations into the nontraditional triggers for cardiovascular incidences. Vitamin D has been tagged as very important for such mechanisms as bone mineralization for a very long time, but more recently emerged the idea that it may in fact be related to cardiovascular incidences. The associated studies gathered are reviews and randomized, controlled trials. They were obtained by using electronic searches, such as Medline and the Cochrane Library. Searches were limited in that certain keywords took precedence, and articles mainly focusing on niacin therapy as opposed to fibrates and statins were chosen. The studies selected were assessed for quality of data and relevance to this review through the study's methodology, results, and data. With the scientific evidence provided by the studies, they were further rated and evaluated. It was proven through a range of studies that there is a striking correlation between low serum 25-hydroxyvitamin D levels and different cardiovascular incidences. It was noted in many studies that only a fraction of the patients had serum levels of vitamin D in the desired range, calling for more research to help in the fight against cardiovascular disease. There is a need for further research studies to come to a clear conclusion addressing serum vitamin D levels with overall and cardiovascular mortality. Although it is easy to screen for vitamin D deficiency and to add supplements to one's diet, there is a need for more research before the general public may begin to take note of these associations.

Extraskeletal effects of vitamin D in older adults: cardiovascular disease, mortality, mood, and cognition

BACKGROUND

Vitamin D insufficiency is prevalent among older adults and may be associated with higher risk for cardiovascular (CV) disease, mortality, depression, and cognitive deficits.

OBJECTIVE

The aim of this article was to review published observational and experimental studies that explored the association between vitamin D insufficiency and CV disease, mortality, mood, and cognition with an emphasis on older adults.

METHODS

PubMed and Web of Science databases were searched for English-language articles from January 1966 through June 2009 relating to vitamin D, using the following MeSH terms: aged, vitamin D deficiency, physiopathology, drug therapy, cardiovascular diseases, blood pressure, mortality, delirium, dementia, cognitive disorders, depression, depressive disorder, seasonal affective disorder, mental disorders, and vitamin D/therapeutic use. Publications had to include patients > or =65 years of age who had > or =1 recorded measurement of 25-hydroxyvitamin D (25[OH]D) or were receiving vitamin D supplementation. All case-control, cohort, and randomized studies were reviewed.

RESULTS

Forty-two case-control, cohort, and randomized trials were identified and included in the review. Based on these publications, the prevalence of vitamin D insufficiency (25[OH]D concentration <30 ng/mL) in communitydwelling older adults (> or =65 years of age) ranged from 40% to 100%. Epidemiologic data and several small randomized trials found a potential association between vitamin D deficiency (25[OH]D concentration <10 ng/mL) and CV disease, including hypertension and ischemic heart disease. Although subgroup analyses of data from the Women's Health Initiative Randomized Trial (the largest randomized, placebo-controlled trial of vitamin D plus calcium therapy) did not find reductions in blood pressure, myocardial infarction, or CV disease-related deaths, intervention contamination limited the findings. Observational studies and a meta-analysis of randomized controlled trials found a mortality benefit associated with higher serum 25(OH)D concentrations or vitamin D(2) or D(3) supplementation (mean dose, 528 IU/d). Observational and small randomized trials found a potential benefit of sunlight or vitamin D on symptoms of depression and cognition, but the findings were limited by methodologic problems.

CONCLUSIONS

Vitamin D insufficiency appears to be highly prevalent among older adults. Evidence from epidemiologic studies and small clinical trials suggests an association between 25(OH)D concentrations and systolic blood pressure, risk for CV disease-related deaths, symptoms of depression, cognitive deficits, and mortality. The Women's Health Initiative Randomized Trial did not find a benefit of vitamin D supplementation on blood pressure, myocardial infarction, or mortality in postmenopausal women.

Relation of serum phosphorus levels to carotid intima-media thickness in asymptomatic young adults (from the Bogalusa Heart Study)

Increased serum phosphorus has been associated with increased mortality from cardiovascular (CV) disease. However, information is scant regarding the influence of serum phosphorus within the normal range on vascular risk in subclinical atherosclerosis in asymptomatic young adults. Serum phosphorus and other CV risk factor variables were measured in 856 white and 354 black subjects without known CV disease or renal disease. Carotid intima-media thickness (IMT) was measured by B-mode ultrasonography. Significant race and gender differences were noted for serum phosphorus (blacks > whites) and carotid IMT (black women > white women; men > women). In bivariate analyses, serum phosphorus was correlated with carotid IMT (p <0.001), and smokers showed higher phosphorus levels than nonsmokers (p = 0.008). In multivariate regression analyses, carotid IMT was significantly associated with serum phosphorus (regression coefficient beta = 0.028, p <0.001) and smoking (beta = 0.032, p <0.001), adjusting for other CV risk factors and estimated glomerular filtration rate. In addition, a significant interaction effect of cigarette smoking and serum phosphorus on carotid IMT was noted, with a greater increasing trend of carotid IMT with phosphorus in smokers than in nonsmokers (p = 0.019 for interaction). In conclusion, serum phosphorus within the normal range is an important correlate of carotid IMT in asymptomatic young adults, with smoking potentiating this adverse association.

Vitamin D and cardiovascular disease: systematic review and meta-analysis of prospective studies

BACKGROUND

Low serum 25-hydroxyvitamin D (25-OH-D) has recently been linked to cardiovascular diseases. This review summarizes evidence from prospective studies evaluating the prognostic value of 25-OH-D for cardiovascular disease incidence and mortality.

METHOD

A systematic literature search in EMBASE and Pubmed-Medline databases was performed until November 2009. Prospective studies published in English were selected reporting estimates for the association of 25-OH-D with primary or secondary cardiovascular event incidence or mortality in the general population or subjects with prevalent cardiovascular disease. Pooled risk estimators were derived by meta-analysis using a random effects model approach.

RESULTS

Four incidence and five independent mortality studies were included. Two incidence and three mortality studies reported a two- to five-fold risk increase for both outcomes in subjects with lower 25-OH-D, while the others did not detect a significant association. Meta-analysis supported the existence of an inverse association.

CONCLUSION

Data from prospective investigations suggest an inverse association between 25-OH-D and cardiovascular risk. However, given the heterogeneity and small number of longitudinal studies, more research is needed to corroborate a potential prognostic value of 25-OH-D for cardiovascular disease incidence and mortality.

Seasonal variation in pregnancy hypertension is correlated with sunlight intensity

OBJECTIVE

To examine seasonality of pregnancy hypertension rates, and whether they related to sunlight levels around conception.

STUDY DESIGN

Data were obtained for 424,732 singleton pregnancies conceived from 2001 through 2005 in Australia. We analyzed monthly rates of pregnancy hypertension and preeclampsia in relation to monthly solar radiation.

RESULTS

Pregnancy hypertension rates, by month of conception, were lowest in autumn (7.3%) and highest in spring (8.9%). Higher sunlight intensity before delivery, but not around conception, was associated with decreased pregnancy hypertension (r = -0.67). Increased sunlight around conception may correlate with decreased rates of early-onset preeclampsia (r = -0.51; P = .09).

CONCLUSION

The correlation between sunlight after conception and pregnancy hypertension was opposite to that hypothesized; however, sunlight levels before delivery did correlate with lower hypertension rates. For sunlight or ambient temperature to explain seasonal variation, the plausible exposure window is the period before delivery, but this may not apply to early-onset preeclampsia.

Chronic treatment with vitamin D lowers arterial blood pressure and reduces endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat

Vitamin D has cardiovascular protective effects besides regulating calcium homeostasis. To examine the chronic in vivo effect of a physiological dose of 1,25-dihydroxyvitamin D(3) on the occurrence of endothelium-dependent contractions, spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were treated with the vitamin D derivative for 6 wk. The serum 1,25-dihydroxyvitamin D(3) level of both treated WKY and SHR was significantly higher than in untreated rats while the mean arterial blood pressure of the treated SHR was significantly lower than that of control SHR. Aortic rings with or without endothelium were studied in conventional organ chambers for isometric force measurement. Confocal microscopy was used to measure the cytosolic free calcium concentration (with the fluorescent dye fluo 4) and reactive oxygen species (ROS; with dichlorodihydrofluorescein diacetate). Reverse transcription PCR and Western blotting were used to determine the mRNA and protein expression level of cyclooxygenase-1 (COX-1), prostacyclin synthase, and thromboxane synthase. The endothelium-dependent concentration-contraction curves to both acetylcholine- and A-23187-induced contractions were shifted to the right in aortas from treated SHR but not from treated WKY. The chronic treatment normalized the relaxations of contracted preparations to acetylcholine. There were no significant differences in the increases in cytosolic free calcium concentration evoked by acetylcholine and A-23187 between control and treated groups. The endothelial ROS level was higher in SHR than WKY aortas and reduced by the chronic treatment. The gene and protein expression studies indicated that the overexpression of COX-1 observed in SHR aorta was reduced by the chronic treatment. These results demonstrate that chronic treatment with 1,25-dihydroxyvitamin D(3) modulates vascular tone and this modulation is accompanied by a lowered blood pressure, reduced expression of COX-1 mRNA and protein, and reduced ROS level in SHR. The reduction in endothelium-dependent contractions does not involve the surge in endothelial cytosolic calcium concentration that initiates the contractions.

The vitamin D system: a crosstalk between the heart and kidney

Chronic kidney disease (CKD) independently increases the rates of cardiovascular disease, whereas the severity of kidney disease correlates with increased cardiovascular morbidity and death. Vitamin D is modified in the liver and the kidney to its active form (1,25-dihydroxyvitamin D) by the 25-hydroxy vitamin D 1-hydroxylase enzyme (CYP27B1). The activated vitamin D brings about its actions through the vitamin D receptor (VDR). The VDRs and CYP27B1 have recently been shown to be expressed in several tissues, not directly involved in mineral homeostasis, including the cardiovascular, immune, and epithelial systems. The action of vitamin D in these tissues is implicated in the regulation of endothelial, vascular smooth muscle, and cardiac cell function, the renin-angiotensin system, inflammatory and fibrotic pathways, and immune response. Impaired VDR activation and signalling results in cellular dysfunction in several organs and biological systems, which leads to reduced bone health, an increased risk for epithelial cancers, metabolic disease, and uncontrolled inflammatory responses. Failure of cardiovascular VDR activation results in hypertension, accelerated atherosclerosis and vascular calcification, cardiac hypertrophy with vascular rarification and fibrosis, and progressive renal dysfunction. An emerging body of evidence has prompted attention to the relationship between CKD, mineral bone disorder (CKD-MBD), and cardiovascular disease in the new guidelines from Kidney Disease: Improving Global Outcomes. Vitamin D receptor activators, commonly used to treat CKD-MBD, and an appropriate treatment of vitamin D hormonal system failure in patients with CKD, may help to reduce cardiovascular morbidity and mortality in these patients.

Low vitamin D status: definition, prevalence, consequences, and correction

Vitamin D is obtained from cutaneous production when 7-dehydrocholesterol is converted to vitamin D(3) (cholecalciferol) by ultraviolet B radiation or by oral intake of vitamin D(2) (ergocalciferol) and D(3). An individual's vitamin D status is best evaluated by measuring the circulating 25-hydroxyvitamin D (25(OH)D) concentration. Although controversy surrounds the definition of low vitamin D status, there is increasing agreement that the optimal circulating 25(OH)D level should be approximately 30 to 32 ng/mL or above. Using this definition, it has been estimated that approximately three-quarters of all adults in the United States have low levels. Low vitamin D status classically has skeletal consequences such as osteomalacia/rickets. More recently, associations between low vitamin D status and increased risk for various nonskeletal morbidities have been recognized; whether all of these associations are causally related to low vitamin D status remains to be determined. To achieve optimal vitamin D status, daily intakes of at least 1000 IU or more of vitamin D are required. The risk of toxicity with "high" amounts of vitamin D intake is low. Substantial between-individual variability exists in response to the same administered vitamin D dose. When to monitor 25(OH)D levels has received little attention. Supplementation with vitamin D(3) may be preferable to vitamin D(2).

25-Hydroxyvitamin D and pre-clinical alterations in inflammatory and hemostatic markers: a cross sectional analysis in the 1958 British Birth Cohort

BACKGROUND

Vitamin D deficiency has been suggested as a cardiovascular risk factor, but little is known about underlying mechanisms or associations with inflammatory or hemostatic markers. Our aim was to investigate the association between 25-hydroxyvitamin D [25(OH)D, a measure for vitamin D status] concentrations with pre-clinical variations in markers of inflammation and hemostasis.

METHODOLOGY/PRINCIPAL FINDINGS

Serum concentrations of 25(OH)D, C-reactive protein (CRP), fibrinogen, D-dimer, tissue plasminogen activator (tPA) antigen, and von Willebrand factor (vWF) were measured in a large population based study of British whites (aged 45 y). Participants for the current investigation were restricted to individuals free of drug treated cardiovascular disease (n = 6538). Adjusted for sex and month, 25(OH)D was inversely associated with all outcomes (p < or =0.015 for all), but associations with CRP, fibrinogen, and vWF were explained by adiposity. Association with tPA persisted after full adjustment (body mass index, waist circumference, physical activity, TV watching, smoking, alcohol consumption, social class, sex, and month), and average concentrations were 18.44% (95% CI 8.13, 28.75) lower for 25(OH)D > or =75 nmol/l compared to < 25 nmol/l. D-dimer concentrations were lower for participants with 25(OH)D 50-90 nmol/l compared to others (quadratic term p = 0.01). We also examined seasonal variation in hemostatic and inflammatory markers, and evaluated 25(OH)D contribution to the observed patterns using mediation models. TPA concentrations varied by season (p = 0.02), and much of this pattern was related to fluctuations in 25(OH)D concentrations (p < or =0.001). Some evidence of a seasonal variation was observed also for fibrinogen, D-dimer and vWF (p < 0.05 for all), with 25(OH)D mediating some of the pattern for fibrinogen and D-dimer, but not vWF.

CONCLUSIONS

Current vitamin D status was associated with tPA concentrations, and to a lesser degree with fibrinogen and D-dimer, suggesting that vitamin D status/intake may be important for maintaining antithrombotic homeostasis.