Vitamin D deficiency and risk of cardiovascular disease

The estimated benefits of vitamin D for Germany

This article gives an overview of the vitamin D status in Germany, provides evidence for an independent association of vitamin D deficiency with various chronic diseases, and discusses preventive measures for improving vitamin D status in Germany. The prevalence of vitamin D insufficiency is 40-45% in the general German population. An additional 15-30% are vitamin D deficient. Vitamin D can prevent falls and osteoporotic fractures in older people. There is also accumulating evidence that vitamin D may prevent excess mortality and may probably prevent some chronic diseases that occur in early life such as type 1 diabetes and multiple sclerosis. Adherence to present sun safety policy (avoidance of the sun between 11 am and 3 pm) and dietary recommendations (5-10 microg daily for adults) would, however, definitively lead to vitamin D deficiency. The estimated cost saving effect of improving vitamin D status in Germany might be up to 37.5 billion euro annually. It should be the goal of nutrition and medical societies to erase vitamin D deficiency in Germany within the next 5-10 years. To achieve this goal, the daily production of at least 25 microg of vitamin D in the skin or an equivalent oral intake should be guaranteed.

Daily steps are low year-round and dip lower in fall/winter: findings from a longitudinal diabetes cohort

BACKGROUND

Higher walking levels lead to lower mortality in type 2 diabetes, but inclement weather may reduce walking. In this patient population, we conducted a longitudinal cohort study to objectively quantify seasonal variations both in walking and in two vascular risk factors associated with activity levels, hemoglobin A1C and blood pressure.

METHODS

Between June 2006 and July 2009, volunteer type 2 diabetes patients in Montreal, Quebec, Canada underwent two weeks of pedometer measurement up to four times over a one year follow-up period (i.e. once/season). Pedometer viewing windows were concealed (snap-on cover and tamper proof seal). A1C, blood pressure, and anthropometric parameters were also assessed. Given similarities in measures for spring/summer and fall/winter, and because not all participants completed four assessments, spring and summer values were collapsed as were fall and winter values. Mean within-individual differences (95% confidence intervals) were computed for daily steps, A1C, and systolic and diastolic blood pressure, by subtracting spring/summer values from fall/winter values.

RESULTS

Among 201 participants, 166 (82.6%) underwent at least one fall/winter and one spring/summer evaluation. Approximately half were women, the mean age was 62.4 years (SD 10.8), and the mean BMI was 30.1 kg/m2 (SD 5.7). Step counts averaged at a sedentary level in fall/winter (mean 4,901 steps/day, SD 2,464) and at a low active level in spring/summer (mean 5,659 steps/day, SD 2,611). There was a -758 (95% CI: -1,037 to -479) mean fall/winter to spring/summer within-individual difference. There were no significant differences in A1C or in anthropometric parameters. Systolic blood pressure was higher in fall/winter (mean 137 mm Hg, SD 16) than spring/summer (133 mm Hg, SD 14) with a mean difference of 4.0 mm Hg (95% CI: 2.3 to 5.7).

CONCLUSIONS

Daily step counts in type 2 diabetes patients are low, dipping lower during fall/winter. In this medication-treated cohort, A1C was stable year-round but a fall/winter systolic blood pressure increase was detected. Our findings signal a need to develop strategies to help patients increase step counts year-round and prevent both reductions in step counts and increases in blood pressure during the fall and winter.

Vitamin D deficiency and myocardial diseases

Vitamin D deficiency is common among patients with myocardial diseases because sun-induced vitamin D production in the skin and dietary intake of vitamin D is often insufficient. Knockout mice for the vitamin D receptor develop myocardial hypertrophy and dysfunction. It has also been shown that children with rickets who suffered from severe heart failure could be successfully treated with supplementation of vitamin D plus calcium. In adults, almost all patients with heart failure exhibit reduced 25-hydroxyvitamin D levels, which are used to classify the vitamin D status. In prospective studies, vitamin D deficiency was an independent risk factor for mortality, deaths due to heart failure and sudden cardiac death. Several vitamin D effects on the electrophysiology, contractility, and structure of the heart suggest that vitamin D deficiency might be a causal factor for myocardial diseases. Data from interventional trials, however, are rare and urgently needed to elucidate whether vitamin D supplementation is useful for the treatment of myocardial diseases. In our opinion, the current knowledge of the beneficial effects of vitamin D on myocardial and overall health strongly argue for vitamin D supplementation in all vitamin D-deficient patients with or at high risk for myocardial diseases.

Associations of serum 25-hydroxyvitamin D, parathyroid hormone and calcium with cardiovascular risk factors: analysis of 3 NHANES cycles (2001-2006)

Background

Increasing evidence suggests a role for mineral metabolism in cardiovascular disease risk. 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), and calcium may be directly associated with cardiovascular risk factors or mediated by each other.

Methodology/Principal Findings

We combined data for adult participants in three cycles of the National Health and Nutrition Examination Survey (2001–2, 2003–4, 2005–6), a representative sample of the civilian, non-institutionalized US population (N = 3,958). Using this data we examined joint associations of 25(OH)D, PTH and calcium with a range of cardiovascular risk factors. 25(OH)D was inversely associated with fasting insulin (mean difference in insulin per 1 standard deviation 25(OH)D: −0.053 (95%CI: −0.091, −0.015)), glucose (−0.046 95%CI: −0.081, −0.012) and systolic blood pressure (SBP) (−0.032 95%CI: −0.062, −0.001), and positively associated with high density lipoprotein cholesterol HDL-c (0.088 95%CI: 0.044, 0.148), after adjustment for ethnicity, smoking, socio-economic status and waist circumference. PTH was positively associated with diastolic blood pressure (0.110, 95%CI: 0.055, 0.164) in confounder adjusted models, but was not associated with other cardiovascular risk factors. Albumin adjusted calcium was associated with triglycerides (0.102 95%CI: 0.063, 0.141), postload glucose (0.078, 95%CI: 0.025, 0.130), fasting insulin (0.074, 95%CI: 0.044, 0.104), HbA1c (0.070, 95%CI: 0.036, 0.105), SBP (0.064, 95%CI: 0.028, 0.100), fasting glucose (0.055, 95%CI: 0.018, 0.092) and low density lipoprotein cholesterol (0.052, 95%CI: 0.014, 0.091). With mutual adjustment for each other, these associations remained essentially unchanged.

Conclusions/Significance

Lower levels of 25(OH)D and higher levels of calcium and PTH appear to be associated with different cardiovascular risk factors and may therefore affect cardiovascular disease risk through different mechanisms.

Vitamin D and cardiovascular disease risk: emerging evidence

PURPOSE OF REVIEW

Vitamin D deficiency is common throughout the world, with a particularly high prevalence in northern latitudes and colder climates. Although the best known sequelae of vitamin D deficiency involve the musculoskeletal system, a growing body of evidence suggests that vitamin D status may influence cardiovascular health as well. This review focuses on recent studies linking vitamin D and cardiovascular disease risk, emphasizing the potential relevance to primary prevention.

RECENT FINDINGS

There is strong experimental evidence that vitamin D status may influence cardiovascular structure and function. The number of clinical studies has steadily grown in recent years, with the largest number comprising observational studies showing associations between low vitamin D status, the presence of various cardiovascular risk factors, and adverse cardiovascular outcomes. A few small, randomized, controlled studies have been published, but these have been largely inconclusive.

SUMMARY

Despite substantial clinical evidence linking vitamin D deficiency with increased cardiovascular risk, it remains to be established whether this represents a causal association. Further study is needed with prospective, randomized controlled trials before vitamin D supplementation can be routinely recommended for the primary or secondary prevention of cardiovascular disease.

The role of the nurse in the management of osteoporosis

Osteoporosis is a chronic disease which is asymptomatic until fractures occur. It is an increasing problem within an ageing population and has many intrinsic and extrinsic risk factors. This article provides an overview of osteoporosis,including the pathogenesis, diagnosis and management.Multidisciplinary assessment and management of osteoporosis is essential with the apt use of non-pharmacologic and pharmacological options to minimize the risk of fracture and appropriately manage patients in an holistic manner.

Calcium/vitamin D supplementation and coronary artery calcification in the Women's Health Initiative

OBJECTIVE

Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D (calcium/D) supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared CAC scores after trial completion between women randomized to calcium/vitamin D supplementation and women randomized to placebo.

METHODS

In an ancillary substudy of women randomized to calcium carbonate (1,000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) or placebo, nested within the Women's Health Initiative trial of estrogen among women who underwent hysterectomy, we measured CAC with cardiac CT in 754 women aged 50 to 59 years at randomization. Imaging for CAC was performed at 28 of 40 centers after a mean of 7 years of treatment, and scans were read centrally. CAC scores were measured by a central reading center with masking to randomization assignments.

RESULTS

Posttrial CAC measurements were similar in women randomized to calcium/D supplementation and those receiving placebo. The mean CAC score was 91.6 for women receiving calcium/D and 100.5 for women receiving placebo (rank test P value = 0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, > or =10, and > or =100) for calcium/D versus placebo were 0.92 (95% CI, 0.64-1.34), 1.29 (0.88-1.87), and 0.90 (0.56-1.44), respectively. Corresponding odds ratios among women with a 50% or higher adherence to study pills and for higher levels of CAC (>300) were similar.

CONCLUSIONS

Treatment with moderate doses of calcium plus vitamin D3 did not seem to alter coronary artery calcified plaque burden among postmenopausal women. Whether higher or lower doses would affect this outcome remains uncertain.

Prevalence and predictors of vitamin D insufficiency in women of reproductive age living in northern latitude

OBJECTIVE

This study assessed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD) ≤ 50 nmol/l) and insufficiency (serum 25OHD 51-74 nmol/l) during summer and the predictors of serum 25OHD in young women of reproductive age.

DESIGN

Cross-sectional study.

METHODS

Between May and September 2006, 153 healthy, ambulatory and essentially Caucasian women, aged 18-41 years, were recruited. Serum 25OHD and parathyroid hormone (PTH) levels were measured, and questionnaires were evaluated.

RESULTS

About 3.9% of women had serum 25OHD ≤ 50 nmol/l with an additional 26.8% in the insufficient range. Most women (56.9%) had their blood sampled in September. Month of blood collection significantly influenced serum 25OHD. Body mass index (BMI) was inversely associated with serum 25OHD, while traveling to a warmer climate during winter/spring and using oral contraceptive pills (OCP) were associated with higher serum 25OHD. Sunscreen was used by 77.8% of women, but only 3.3% reported consuming vitamin D supplements. BMI, serum PTH, travel to a warmer climate, and OCP use were independently and significantly associated with serum 25OHD, after adjustment for the month of sampling, and explained 40% of the variance in serum 25OHD.

CONCLUSIONS

In Canada, the prevalence of vitamin D insufficiency is relatively high (30%) during summer in healthy women of reproductive age. Given the expected decrease in serum 25OHD during winter and the low consumption of vitamin D supplements, a high prevalence of vitamin D deficiency and insufficiency is to be anticipated during winter, except maybe for those traveling to a warmer climate.

Serum 25-hydroxyvitamin D concentration is associated with functional capacity in older adults with heart failure

BACKGROUND

Vitamin D is a fat-soluble hormone necessary for calcium homeostasis. Recently, studies have demonstrated that vitamin D may be important to the health of the cardiovascular system.

METHODS

Adults ≥ 50 years of age with heart failure were recruited for assessment of serum 25-hydroxyvitamin D (25OHD) concentrations. Cardiopulmonary exercise testing was used to assess functional capacity. Proximal muscle strength was evaluated with a Biodex isokinetic dynamometer [corrected] (Biodex, Shirley, NY), and health status was assessed with the Kansas City Cardiomyopathy Questionnaire. Univariate associations between physical performance and health status measures and 25OHD followed by a linear regression model were used to study associations, adjusting for other potential explanatory variables.

RESULTS

Forty adults 67.8 ± 10.9 years of age (55% women and 57.5% African American) with mean ejection fraction 40% were analyzed (New York Heart Association class II in 70% and class III in 30%). Comorbidities included 77.5% hypertension and 47.5% diabetes. The mean 25OHD concentration was 18.5 ± 9.1 ng/mL, and mean peak Vo₂, 14 ± 4 mL/kg/min. In univariate regression analysis, 25OHD was positively associated with peak Vo₂ (P = .045). Multivariable regression analysis sustained positive association between 25OHD and peak Vo₂ (P = .044) after adjusting for age, race, and respiratory exchange ratio (adjusted R² = 0.32). Association between proximal muscle strength with the 25OHD concentration was not significant. The Kansas City Cardiomyopathy Questionnaire physical limitation domain score was negatively associated with 25OHD (P = .04) but was not sustained in multivariable analysis.

CONCLUSIONS

25-Hydroxyvitamin D may be an important marker or modulator of functional capacity in patients with heart failure. Randomized controlled trials are needed to assess the effect of vitamin D repletion on functional performance.

High prevalence of vitamin D deficiency and its association with left ventricular dilation: an echocardiography study in elderly patients with chronic heart failure

BACKGROUND AND AIMS

Vitamin D deficiency has been associated with chronic heart failure (CHF). We evaluated vitamin D levels in relationship with New York Heart Association (NYHA) classes, N-terminal pro-brain natriuretic peptide (NT-proBNP) values and left ventricular (LV) measures in ≥60 year old patients with stable CHF. Differently from previous investigations, LV function was assessed by transthoracic echocardiography, to provide easily reproducible results.

METHODS AND RESULTS

The study was performed at geographic latitude 44° N, from March to May and from September to November 2008. Acute HF and diseases or drugs altering vitamin D status were exclusion criteria. NYHA scores and 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D and NT-proBNP concentrations were assessed in 90 (45 F, 45 M) Caucasian patients with CHF secondary to hypertension and/or coronary artery disease. Vitamin D levels were also measured in 31 subjects without heart disease (controls). LV echocardiography was performed in 52 (26 F, 26 M) representative patients. Vitamin D concentrations were significantly lower in CHF cases than in controls. Among subject with CHF, 97.8% presented vitamin D deficiency (25(OH)D<75 nmol/L), being severe (<25 nmol/L) in 66.7%. LV end-diastolic and end-systolic diameters were significantly longer, LV end-diastolic and end-systolic volumes bigger and fractional shortening lower in CHF patients with 25(OH)D<25 nmol/L than with 25(OH)D≥25 nmol/L (p<0.05). Log-values of 25(OH)D were negatively correlated with LV end-systolic diameter and volume (r=-0.28; p<0.05). On subgroup analysis, these results persisted only in male patients.

CONCLUSIONS

In elderly CHF patients, vitamin D deficiency was highly prevalent and often severe. This first addressed echocardiography study showed a sex-specific association between vitamin D deficiency and LV dilation. Since further echocardiography data are easily obtainable, larger investigations are demanded.

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.

The dualistic role of vitamin D in vascular calcifications

Vitamin D is a multifunctional hormone that can affect many essential biological functions, ranging from the immune regulation to mineral ion metabolism. A close association between altered activity of vitamin D and vascular calcification has been reported in various human diseases, including in patients with atherosclerosis, osteoporosis, and chronic kidney disease (CKD). Vascular calcification is a progressive disorder and is a major determinant of morbidity and mortality of the affected patients. Experimental studies have shown that excessive vitamin D activities can induce vascular calcification, and such vascular pathology can be reversed by reducing vitamin D activities. The human relevance of these experimental studies is not clear, as vitamin D toxicity is relatively rare in the general population. Contrary to the relationship between vitamin D and vascular calcification, in experimental uremic models, low levels of vitamin D were shown to be associated with extensive vascular calcification, a phenomenon that is very similar to the vascular pathology seen in patients with CKD. The current treatment approach of providing vitamin D analogs to patients with CKD often poses a dilemma, as studies linked vitamin D treatment to subsequent vascular calcification. Recent genetic studies, however, have shown that vascular calcification can be prevented by reducing serum phosphate levels, even in the presence of extremely high serum 1,25-dihydroxyvitamin D and calcium levels. This article will briefly summarize the dual effects of vitamin D in vascular calcification and will provide evidence of vitamin D-dependent and -independent vascular calcification.

Oral administration of an active form of vitamin D3 (calcitriol) decreases atherosclerosis in mice by inducing regulatory T cells and immature dendritic cells with tolerogenic functions

OBJECTIVE

To determine whether the administration of an active form of vitamin D(3) (calcitriol) could prevent atherosclerosis through anti-inflammatory actions.

METHODS AND RESULTS

Recent clinical studies have shown that lack of vitamin D(3) is a risk factor for cardiovascular events. Oral calcitriol administration decreased atherosclerotic lesions, macrophage accumulation, and CD4(+) T-cell infiltration at the aortic sinus, when compared with the corresponding observations in control mice. We observed a significant increase in Foxp3(+) regulatory T cells and a decrease in CD80(+)CD86(+) dendritic cells (DCs) in the mesenteric lymph nodes, spleen, and atherosclerotic lesions in oral calcitriol-treated mice in association with increased interleukin 10 and decreased interleukin 12 mRNA expression. CD11c(+) DCs from the calcitriol group showed reduced proliferative activity of T lymphocytes, suggesting the suppression of DC maturation. Neutralization of CD25 in vivo revealed that calcitriol inhibited atherosclerosis mainly in a regulatory T cell-dependent manner but also partly because of a decrease in DC maturation.

CONCLUSIONS

Oral calcitriol treatment could prevent the development of atherosclerosis by changing the function or differentiation of DCs and regulatory T cells. These findings suggest that intestinal and systemic immune modulation by calcitriol may be a potentially valuable therapeutic approach against atherosclerosis.

The effect of sevelamer carbonate and lanthanum carbonate on the pharmacokinetics of oral calcitriol

Background. Lanthanum carbonate and sevelamer carbonate are non-calcium-based phosphate binders used to manage hyperphosphataemia in patients with chronic kidney disease (CKD). Patients with CKD may require intravenous or oral active vitamin D. We investigated the effects of lanthanum carbonate and sevelamer carbonate on the bioavailability of oral calcitriol.

Methods. This was a three-period, crossover study in healthy volunteers. Forty-one individuals were randomized to one of six possible sequences, each consisting of three treatment periods separated by washouts. The treatments were calcitriol (1 μg at lunch), calcitriol with lanthanum carbonate (3000 mg/day) and calcitriol with sevelamer carbonate (7200 mg/day). Serum calcitriol levels were assessed at baseline and throughout the study.

Results. Co-administration of lanthanum carbonate with calcitriol had no significant effect on area under the curve over 48 h (AUC_0–48) for serum exogenous calcitriol [least-squares (LS) mean, calcitriol with lanthanum carbonate vs calcitriol alone: 429 pg h/mL vs 318 pg h/mL, respectively; P = 0.171]. Similarly, there was no significant effect on maximum concentration (C_max). In contrast, co-administration with sevelamer was associated with a significant reduction in bioavailability parameters for calcitriol (calcitriol with sevelamer carbonate vs calcitriol alone, LS mean AUC_0–48: 137 pg h/mL vs 318 pg h/mL, respectively; P = 0.024; LS mean C_max: 40.1 pg/mL vs 49.7 pg/mL, respectively; P < 0.001).

Conclusions. Sevelamer carbonate significantly reduces serum concentrations of exogenous calcitriol when administered concomitantly with oral calcitriol, whereas lanthanum carbonate has no significant effect. This should be considered when treating CKD patients who require phosphate binders and oral vitamin D.

Vitamin D levels and mortality in type 2 diabetes

OBJECTIVE

To evaluate vitamin D as a predictor of all-cause and cardiovascular mortality and risk of progression to micro- or macroalbuminuria in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

In a longitudinal observational follow-up study, 289 type 2 diabetic patients with normoalbuminuria (n = 172), microalbuminuria (n = 73), and macroalbuminuria (n = 44) at baseline were followed for a median (range) of 15.0 (0.2-23) years. Mean ± SD age was 54 ± 9 years. Plasma 25-hydroxyvitamin D(3) levels were determined by high-performance liquid chromatography/tandem mass spectrometry on baseline samples. Severe vitamin D deficiency was defined as the lower 10th percentile (<13.9 nmol/l).

RESULTS

Median (range) vitamin D level was 35.7 (5-136.7) nmol/l. Vitamin D levels were not associated with age, sex, estimated glomerular filtration rate, urinary albumin excretion rate (UAER), or A1C at baseline, but low levels were weakly associated with elevated systolic blood pressure (R = 0.13, P = 0.03). During follow-up, 196 (68%) patients died. All-cause mortality was increased in patients with severe vitamin D deficiency (hazard ratio 1.96 [95% CI 1.29-2.98]). The association persisted after adjustment for UAER, A1C, diabetes duration, and conventional cardiovascular risk factors (2.03 [1.31-3.13]). Severe vitamin D deficiency was associated with increased cardiovascular mortality (1.95 [1.11-3.44]), and the association persisted after adjustment (1.90 [1.15-3.10]). Severe vitamin D deficiency at baseline did not predict progression to micro- or macroalbuminuria.

CONCLUSIONS

In type 2 diabetic patients, severe vitamin D deficiency predicts increased risk of all-cause and cardiovascular mortality, independent of UAER and conventional cardiovascular risk factors. Whether vitamin D substitution improves prognosis remains to be investigated.

Plasma vitamin D and mortality in older men: a community-based prospective cohort study

BACKGROUND

Vitamin D status is known to be important for bone health but may also affect the development of several chronic diseases, including cancer and cardiovascular diseases, which are 2 major causes of death.

OBJECTIVE

We aimed to examine how vitamin D status relates to overall and cause-specific mortality.

DESIGN

The Uppsala Longitudinal Study of Adult Men, a community-based cohort of elderly men (mean age at baseline: 71 y; n = 1194), was used to investigate the association between plasma 25-hydroxyvitamin D [25(OH)D] and mortality. Total plasma 25(OH)D was determined with HPLC atmospheric pressure chemical ionization mass spectrometry. Proportional hazards regression was used to compute hazard ratios (HRs).

RESULTS

During follow-up (median: 12.7 y), 584 (49%) participants died. There was a U-shaped association between vitamin D concentrations and total mortality. An approximately 50% higher total mortality rate was observed among men in the lowest 10% (<46 nmol/L) and the highest 5% (>98 nmol/L) of plasma 25(OH)D concentrations compared with intermediate concentrations. Cancer mortality was also higher at low plasma concentrations (multivariable-adjusted HR: 2.20; 95% CI: 1.44, 3.38) and at high concentrations (HR: 2.64; 95% CI: 1.46, 4.78). For cardiovascular death, only low (HR: 1.89; 95% CI: 1.21, 2.96) but not high (HR: 1.33; 95% CI: 0.69, 2.54) concentrations indicated higher risk.

CONCLUSIONS

Both high and low concentrations of plasma 25(OH)D are associated with elevated risks of overall and cancer mortality. Low concentrations are associated with cardiovascular mortality.

The effect of different doses of vitamin D(3) on markers of vascular health in patients with type 2 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

Low 25-hydroxyvitamin D levels predict future cardiovascular events and are common in patients with type 2 diabetes. We compared the effect of 100,000 and 200,000 IU doses of vitamin D(3) on endothelial function, blood pressure and markers of glycaemic control in patients with type 2 diabetes.

METHODS

This was a randomised, parallel group, placebo-controlled trial. Patients with type 2 diabetes and baseline 25-hydroxyvitamin D levels <100 nmol/l were enrolled from community and hospital-based diabetes clinics. Participants were assessed in a university department of clinical pharmacology and received a single oral dose of placebo or vitamin D(3) (100,000 IU or 200,000 IU) at baseline, randomly allocated via numbered bottles prepared offsite; participants and investigators were both blinded to treatment allocation. Endothelial function, office blood pressure, B-type natriuretic peptide, insulin resistance and glycosylated haemoglobin were measured at baseline, and at 8 and 16 weeks.

RESULTS

We randomised 61 participants to the three groups (placebo 22, 100,000 IU vitamin D(3) 19, 200,000 IU vitamin D(3) 20). There was no significant difference in the primary outcome of endothelial function at 8 weeks (placebo 5.2%, n = 22; 100,000 IU 4.3%, n = 19; 200,000 IU 4.9%, n = 17) or at 16 weeks. Insulin resistance and glycosylated haemoglobin did not improve with either dose of vitamin D(3). On covariate analysis, systolic blood pressure was significantly lower in both treatment arms than in the placebo group at 8 weeks (placebo 146.4 mmHg, 100,000 IU 141.4 mmHg [p = 0.04 vs placebo], 200,000 IU 136.8 mmHg [p = 0.03 vs placebo]). B-type natriuretic peptide levels were significantly lower in the 200,000 IU group by 16 weeks (placebo 34 pg/ml, 200,000 IU 21 pg/ml, p = 0.02). No significant excess of adverse effects was noted in the treatment arms.

CONCLUSIONS/INTERPRETATION

High-dose vitamin D(3) improved systolic blood pressure and B-type natriuretic peptide levels, but not endothelial function, insulin resistance or glycosylated haemoglobin in patients with type 2 diabetes.

25-Hydroxyvitamin D concentration correlates with insulin-sensitivity and BMI in obesity

The prevalence of hypovitaminosis D is high among obese subjects. Further, low 25-hydroxyvitamin D (25(OH)D) concentration has been postulated to be a risk factor for type 2 diabetes, although its relation with insulin-sensitivity is not well investigated. Thus, we aimed to investigate the relationship between 25(OH)D concentration and insulin-sensitivity, using the glucose clamp technique. In total, 39 subjects with no known history of diabetes mellitus were recruited. The association of 25(OH)D concentration with insulin-sensitivity was evaluated by hyperinsulinemic euglycemic clamp. Subjects with low 25(OH)D (<50 nmol/l) had higher BMI (P = 0.048), parathyroid hormone (PTH) (P = 0.040), total cholesterol (P = 0.012), low-density lipoprotein (LDL) cholesterol (P = 0.044), triglycerides (P = 0.048), and lower insulin-sensitivity as evaluated by clamp study (P = 0.047). There was significant correlation between 25(OH)D and BMI (r = -0.58; P = 0.01), PTH (r = -0.44; P < 0.01), insulin-sensitivity (r = 0.43; P < 0.01), total (r = -0.34; P = 0.030) and LDL (r = -0.40; P = 0.023) (but not high-density lipoprotein (HDL)) cholesterol, and triglycerides (r = 0.45; P = 0.01). Multivariate analysis using 25(OH)D concentration, BMI, insulin-sensitivity, HDL cholesterol, LDL cholesterol, total cholesterol, and triglycerides, as the cofactors was performed. BMI was found to be the most powerful predictor of 25(OH)D concentration (r = -0.52; P < 0.01), whereas insulin-sensitivity was not significant. Our study suggested that there is no cause-effect relationship between vitamin D and insulin-sensitivity. In obesity, both low 25(OH)D concentration and insulin-resistance appear to be dependent on the increased body size.

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.

Role of vitamin D in cardiovascular health

Observational studies strongly associate vitamin D deficiency with a variety of cardiovascular diseases beyond defects in bone and calcium metabolism. Vitamin D has multiple mechanisms that potentially may affect cardiovascular health. Because vitamin D deficiency is common, therapies directed at the replacement of vitamin D may be beneficial. To date however, studies evaluating vitamin D supplementation are few and have not consistently shown benefit. It is possible that the lack of benefit in these studies may have arisen from suboptimal levels of vitamin D supplementation or other unknown factors. Nevertheless, the growing body of observational data and consistent findings of relatively high rates of low vitamin D serum levels warrant further well-designed studies to investigate the relation between vitamin D and cardiovascular health. In conclusion, vitamin D is now recognized as important for cardiovascular health and its deficiency as a potential risk factor for several cardiovascular disease processes.

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.

Vitamin D and Alzheimer's disease: is there a link?

OBJECTIVE

To review the research on a possible link between Alzheimer's disease (AD) and vitamin D deficiency.

DATA SOURCE

MEDLINE/PUBMED (January 1950-January 2010) and ISI Web of Science searches (January 1900-January 2010) were conducted using the key words vitamin D, Alzheimer disease, and dementia to identify pertinent studies. The Cochrane Library was searched to identify review articles along with clinicaltrials.gov to identify unpublished research.

STUDY SELECTION AND DATA EXTRACTION

Vitamin D and (Alzheimer* disease or dementia) was entered into each database. Manual review of the search results identified trials that discussed an association between AD or dementia and vitamin D. Manual bibliography searches were performed to identify other pertinent articles.

DATA SYNTHESIS

Vitamin D deficiency is a widespread problem among the elderly and has been associated with multiple disease states. Vitamin D deficiency has recently been linked to dementia, particularly AD, through several mechanisms. Current clinical trials discuss a possible link between low vitamin D levels and low cognitive test scores in AD patients.

CONCLUSION

The current observational studies seem to identify a link between vitamin D and dementia, particularly AD. Before this evidence can be used to make a recommendation for routine supplementation in elderly patients to prevent AD, more prospective trials with a longer follow-up period are needed to show a causality relationship.

Vitamin D deficiency is associated with sudden cardiac death, combined cardiovascular events, and mortality in haemodialysis patients

Aims

Dialysis patients experience an excess mortality, predominantly of sudden cardiac death (SCD). Accumulating evidence suggests a role of vitamin D for myocardial and overall health. This study investigated the impact of vitamin D status on cardiovascular outcomes and fatal infections in haemodialysis patients.

Methods and results

25-hydroxyvitamin D [25(OH)D] was measured in 1108 diabetic haemodialysis patients who participated in the German Diabetes and Dialysis Study and were followed up for a median of 4 years. By Cox regression analyses, we determined hazard ratios (HR) for pre-specified, adjudicated endpoints according to baseline 25(OH)D levels: SCD (n = 146), myocardial infarction (MI, n = 174), stroke (n = 89), cardiovascular events (CVE, n = 414), death due to heart failure (n = 37), fatal infection (n = 111), and all-cause mortality (n = 545). Patients had a mean age of 66 ± 8 years (54% male) and median 25(OH)D of 39 nmol/L (interquartile range: 28–55). Patients with severe vitamin D deficiency [25(OH)D of≤ 25 nmol/L] had a 3-fold higher risk of SCD compared with those with sufficient 25(OH)D levels >75 nmol/L [HR: 2.99, 95% confidence interval (CI): 1.39–6.40]. Furthermore, CVE and all-cause mortality were strongly increased (HR: 1.78, 95% CI: 1.18–2.69, and HR: 1.74, 95% CI: 1.22–2.47, respectively), all persisting in multivariate models. There were borderline non-significant associations with stroke and fatal infection while MI and deaths due to heart failure were not meaningfully affected.

Conclusion

Severe vitamin D deficiency was strongly associated with SCD, CVE, and mortality, and there were borderline associations with stroke and fatal infection. Whether vitamin D supplementation decreases adverse outcomes requires further evaluation.

Vitamin D deficiency and frailty in older Americans

OBJECTIVE

To explore the relation between 25-hydroxyvitamin D deficiency and frailty. Frailty is a multidimensional phenotype that describes declining physical function and a vulnerability to adverse outcomes in the setting of physical stress such as illness or hospitalization. Low serum concentrations of 25-hydroxyvitamin D are known to be associated with multiple chronic diseases such as cardiovascular disease and diabetes, in addition to all cause mortality.

DESIGN

Using data from the Third National Health and Nutrition Survey (NHANES III), we evaluated the association between low serum 25-hydroxyvitamin D concentration and frailty, defined according to a set of criteria derived from a definition previously described and validated.

SUBJECTS

Nationally representative survey of noninstitutionalized US residents collected between 1988 and 1994.

RESULTS

25-Hydroxyvitamin D deficiency, defined as a serum concentration <15 ng mL(-1), was associated with a 3.7-fold increase in the odds of frailty amongst whites and a fourfold increase in the odds of frailty amongst non-whites. This association persisted after sensitivity analyses adjusting for season of the year and latitude of residence, intended to reduce misclassification of persons as 25-hydroxyvitamin D deficient or insufficient.

CONCLUSION

Low serum 25-hydroxyvitamin D concentrations are associated with frailty amongst older adults.

Vitamin D and pregnancy: An old problem revisited

Vitamin D has historically been considered to play a role solely in bone and calcium metabolism. Human disease associations and basic physiological studies suggest that vitamin D deficiency is plausibly implicated in adverse health outcomes including mortality, malignancy, cardiovascular disease, immune functioning and glucose metabolism. There is considerable evidence that low maternal levels of 25 hydroxyvitamin D are associated with adverse outcomes for both mother and fetus in pregnancy as well as the neonate and child. Vitamin D deficiency during pregnancy has been linked with a number of maternal problems including infertility, preeclampsia, gestational diabetes and an increased rate of caesarean section. Likewise, for the child, there is an association with small size, impaired growth and skeletal problems in infancy, neonatal hypocalcaemia and seizures, and an increased risk of HIV transmission. Other childhood disease associations include type 1 diabetes and effects on immune tolerance. The optimal concentration of 25 hydroxyvitamin D is unknown and compounded by difficulties in defining the normal range. Whilst there is suggestive physiological evidence to support a causal role for many of the associations, whether vitamin D deficiency is a marker of poor health or the underlying aetiological problem is unclear. Randomised controlled trials of vitamin D supplementation with an appropriate assessment of a variety of health outcomes are required.

Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis

OBJECTIVE

To investigate whether calcium supplements increase the risk of cardiovascular events.

DESIGN

Patient level and trial level meta-analyses.

DATA SOURCES

Medline, Embase, and Cochrane Central Register of Controlled Trials (1966-March 2010), reference lists of meta-analyses of calcium supplements, and two clinical trial registries. Initial searches were carried out in November 2007, with electronic database searches repeated in March 2010.

STUDY SELECTION

Eligible studies were randomised, placebo controlled trials of calcium supplements (>or=500 mg/day), with 100 or more participants of mean age more than 40 years and study duration more than one year. The lead authors of eligible trials supplied data. Cardiovascular outcomes were obtained from self reports, hospital admissions, and death certificates.

RESULTS

15 trials were eligible for inclusion, five with patient level data (8151 participants, median follow-up 3.6 years, interquartile range 2.7-4.3 years) and 11 with trial level data (11 921 participants, mean duration 4.0 years). In the five studies contributing patient level data, 143 people allocated to calcium had a myocardial infarction compared with 111 allocated to placebo (hazard ratio 1.31, 95% confidence interval 1.02 to 1.67, P=0.035). Non-significant increases occurred in the incidence of stroke (1.20, 0.96 to 1.50, P=0.11), the composite end point of myocardial infarction, stroke, or sudden death (1.18, 1.00 to 1.39, P=0.057), and death (1.09, 0.96 to 1.23, P=0.18). The meta-analysis of trial level data showed similar results: 296 people had a myocardial infarction (166 allocated to calcium, 130 to placebo), with an increased incidence of myocardial infarction in those allocated to calcium (pooled relative risk 1.27, 95% confidence interval 1.01 to 1.59, P=0.038).

CONCLUSIONS

Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.

Vitamin D nutritional policy needs a vision for the future

Historically vitamin D is known to be essential for normal bone growth and quality, and thus appropriate dietary vitamin D supplementation can eliminate vitamin D deficiency childhood rickets and adult osteomalacia. In spite of many government and medical associations' worldwide guidelines for the reference daily intake (RDI) of vitamin D, scientists and nutritionists from many countries agree that at present about half of elderly North Americans and Western Europeans and probably also of the rest of the world are not receiving enough vitamin D to maintain healthy bone. In addition, over the past decade there has been a dramatic increase in our understanding of the many biological actions that result from vitamin D acting through its daughter steroid hormone, 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] in collaboration with its cognate vitamin D receptor (VDR). Consequently, evidence has accumulated that beside intestine and bone, there are five additional physiological systems where the VDR with 1alpha,25(OH)(2)D generates biological responses. These include the immune system (both the innate and adaptive), pancreas and metabolic homeostasis, heart-cardiovascular, muscle and brain systems as well as the control of the cell cycle, and thus of the disease process of cancer. Acting through the VDR, 1alpha,25(OH)(2)D(3) can produce a wide array of favorable biological effects that collectively are projected to contribute to the improvement of human health. Responsible medicine demands that worldwide vitamin D nutritional guidelines reflect current scientific knowledge about vitamin D's spectrum of activities. Thus, worldwide vitamin D nutritional policy is now at a crossroads. This paper presents several proposed policy changes with regard to the amount of vitamin D daily intake that if implemented will maximize vitamin D's contribution to reducing the frequency of many diseases, which would then increase the quality and longevity of life and significantly reduce the cost of medical care worldwide.

Regulatory mechanisms in vascular calcification

In the past decade, the prevalence, significance, and regulatory mechanisms of vascular calcification have gained increasing recognition. Over a century ago, pathologists recognized atherosclerotic calcification as a form of extraskeletal ossification. Studies are now identifying the mechanism of this remarkable process as a recapitulation of embryonic endochondral and membranous ossification through phenotypic plasticity of vascular cells that function as adult mesenchymal stem cells. These embryonic developmental programs, involving bone morphogenetic proteins and potent osteochondrogenic transcription factors, are triggered and modulated by a variety of inflammatory, metabolic, and genetic disorders, particularly hyperlipidemia, chronic kidney disease, diabetes, hyperparathyroidism, and osteoporosis. They are also triggered by loss of powerful inhibitors, such as fetuin A, matrix Gla protein, and pyrophosphate, which ordinarily restrict biomineralization to skeletal bone. Teleologically, soft-tissue calcification might serve to create a wall of bone to sequester noxious foci such as chronic infections, parasites, and foreign bodies. This Review focuses on atherosclerotic and medial calcification. The capacity of the vasculature to produce mineral in culture and to produce de novo, vascularized, trabecular bone and cartilage tissue, even in patients with osteoporosis, should intrigue investigators in tissue engineering and regenerative biology.

Vitamin D, blood pressure, and African Americans: toward a unifying hypothesis

Vitamin D deficiency has increasingly been recognized in the general population and especially in African Americans whose deep skin pigmentation makes vitamin D photosynthesis inefficient. Over the last decade there has been increasing interest in the role that vitamin D deficiency may play in BP modulation because many epidemiologic studies have shown an inverse association between serum vitamin D concentration and BP. There is a high prevalence of vitamin D deficiency in African Americans who also have an increased susceptibility to develop hypertension and its consequences. This paper will review the circumstances leading to vitamin D deficiency in the African American population and will also discuss how vitamin D deficiency can affect the renin-angiotensin system, free radical production, inflammatory processes, and carbohydrate tolerance that in turn influence vascular endothelial function and vascular structure producing increased vascular resistance. It will speculate that the presence of vitamin D deficiency throughout life from its earliest phases may adversely affect the microvasculature in African Americans, thereby playing a major role in the genesis and maintenance of hypertension.

Is hypovitaminosis D one of the environmental risk factors for multiple sclerosis?

The role of hypovitaminosis D as a possible risk factor for multiple sclerosis is reviewed. First, it is emphasized that hypovitaminosis D could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. Secondly, the classical physiological notions about vitamin D have recently been challenged and the main new findings are summarized. This vitamin could have an important immunological role involving a number of organs and pathologies, including autoimmune diseases and multiple sclerosis. Furthermore, human requirements for this vitamin are much higher than previously thought, and in medium- or high-latitude countries, they might not be met in the majority of the general population due to a lack of sunshine and an increasingly urbanized lifestyle. Thereafter, the different types of studies that have helped to implicate hypovitaminosis D as a risk factor for multiple sclerosis are reviewed. In experimental autoimmune encephalomyelitis, vitamin D has been shown to play a significant immunological role. Diverse epidemiological studies suggest that a direct chain of causality exists in the general population between latitude, exposure to the sun, vitamin D status and the risk of multiple sclerosis. New epidemiological analyses from France support the existence of this chain of links. Recently reported immunological findings in patients with multiple sclerosis have consistently shown that vitamin D significantly influences regulatory T lymphocyte cells, whose role is well known in the pathogenesis of the disease. Lastly, in a number of studies on serum levels of vitamin D in multiple sclerosis, an insufficiency was observed in the great majority of patients, including at the earliest stages of the disease. The questionable specificity and significance of such results is detailed here. Based on a final global analysis of the cumulative significance of these different types of findings, it would appear likely that hypovitaminosis D is one of the risk factors for multiple sclerosis.

Common genetic determinants of vitamin D insufficiency: a genome-wide association study

BACKGROUND

Vitamin D is crucial for maintenance of musculoskeletal health, and might also have a role in extraskeletal tissues. Determinants of circulating 25-hydroxyvitamin D concentrations include sun exposure and diet, but high heritability suggests that genetic factors could also play a part. We aimed to identify common genetic variants affecting vitamin D concentrations and risk of insufficiency.

METHODS

We undertook a genome-wide association study of 25-hydroxyvitamin D concentrations in 33 996 individuals of European descent from 15 cohorts. Five epidemiological cohorts were designated as discovery cohorts (n=16 125), five as in-silico replication cohorts (n=9367), and five as de-novo replication cohorts (n=8504). 25-hydroxyvitamin D concentrations were measured by radioimmunoassay, chemiluminescent assay, ELISA, or mass spectrometry. Vitamin D insufficiency was defined as concentrations lower than 75 nmol/L or 50 nmol/L. We combined results of genome-wide analyses across cohorts using Z-score-weighted meta-analysis. Genotype scores were constructed for confirmed variants.

FINDINGS

Variants at three loci reached genome-wide significance in discovery cohorts for association with 25-hydroxyvitamin D concentrations, and were confirmed in replication cohorts: 4p12 (overall p=1.9x10(-109) for rs2282679, in GC); 11q12 (p=2.1x10(-27) for rs12785878, near DHCR7); and 11p15 (p=3.3x10(-20) for rs10741657, near CYP2R1). Variants at an additional locus (20q13, CYP24A1) were genome-wide significant in the pooled sample (p=6.0x10(-10) for rs6013897). Participants with a genotype score (combining the three confirmed variants) in the highest quartile were at increased risk of having 25-hydroxyvitamin D concentrations lower than 75 nmol/L (OR 2.47, 95% CI 2.20-2.78, p=2.3x10(-48)) or lower than 50 nmol/L (1.92, 1.70-2.16, p=1.0x10(-26)) compared with those in the lowest quartile.

INTERPRETATION

Variants near genes involved in cholesterol synthesis, hydroxylation, and vitamin D transport affect vitamin D status. Genetic variation at these loci identifies individuals who have substantially raised risk of vitamin D insufficiency.

FUNDING

Full funding sources listed at end of paper (see Acknowledgments).

Therapeutic effects of vitamin D analogs on cardiac hypertrophy in spontaneously hypertensive rats

Vitamin D inhibits renin expression and blocks the compensatory induction of renin associated with the use of renin-angiotensin system inhibitors. Here we test the therapeutic effects of two commonly used vitamin D analogs and their combination with losartan on the development of left ventricular hypertrophy. One-month-old male spontaneously hypertensive rats were treated with vehicle, losartan, paricalcitol, doxercalciferol, a combination of losartan and paricalcitol, or a combination of losartan and doxercalciferol for 2 months. Blood pressure was markedly reduced by losartan, but not by paricalcitol or doxercalciferol alone. Echocardiograpy demonstrated a 65 to 80% reduction in left ventricular wall thickness with losartan, paricalcitol, or doxercalciferol monotherapy and almost complete prevention of left ventricular hypertrophy with the combination therapies. Attenuation of cardiac and cardiomyocyte hypertrophy, and suppression of atrial and brain natriuretic peptides, were most marked in the combination therapy groups. These changes were well correlated with left ventricular gene and microRNA expression profiles in the different treatment groups. Renal and cardiac renin expression was markedly increased in losartan-treated animals, but nearly normalized with combination therapy. The same vitamin D analogs suppressed plasma renin activity in patients receiving chronic hemodialysis. These data demonstrate that vitamin D analogs have potent antihypertrophic activity in part via suppression of renin in the kidney and heart, and combination of these analogs with losartan achieves much better therapeutic effects because of the blockade of the compensatory renin increase.

Vitamin D deficiency: appropriate replenishment therapies and the effects of vitamin D toxicity

An 84-year-old patient diagnosed with a vitamin D deficiency was given a prescription for ergocalciferol (vitamin D2) 50,000 units weekly. The prescription was incorrectly filled for ergocalciferol 50,000 units daily. Incorrect therapy continued for two months. The patient's vitamin D level increased from < 7.0 ng/mL to 100 ng/mL over a six-month span. The patient complained of decreased appetite and significant weight loss and presented with an elevated International Normalized Ratio at a pharmacist-run anticoagulation clinic. In conjunction with the physician, the pharmacist discontinued vitamin D therapy and monitored levels.Vitamin D plays an integral role in the body's ability to absorb calcium and regulate calcium homeostasis. Further benefits have been reported regarding the role of vitamin D in muscle strength, cardiovascular health, and in preventing osteoporosis and falls. Vitamin D deficiency is widespread in the older adult population as a result of low dietary intake, decreased sun exposure, decreased intrinsic vitamin D production, and decreased vitamin D receptor activity. Replenishment using high-dose ergocalciferol is one common replenishment therapy. Patients also are able to supplement with nonprescription vitamin D products of varying strengths. While many older patients can be expected to have vitamin D deficiencies, pharmacists should be aware of appropriate replenishment therapies and correct dosing of different vitamin D products. Pharmacists also should be familiar with possible toxic effects of vitamin D, particularly as public awareness of benefits continues to increase.

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.

Nutritional composition of the diets of South Asian, black African-Caribbean and white European children in the United Kingdom: the Child Heart and Health Study in England (CHASE)

In the UK, South Asian adults have increased risks of CHD, type 2 diabetes and central obesity. Black African-Caribbeans, in contrast, have increased risks of type 2 diabetes and general obesity but lower CHD risk. There is growing evidence that these risk differences emerge in early life and that nutritional factors may be important. We have therefore examined the variations in nutritional composition of the diets of South Asian, black African-Caribbean and white European children, using 24 h recalls of dietary intake collected during a cross-sectional survey of cardiovascular health in eighty-five primary schools in London, Birmingham and Leicester. In all, 2209 children aged 9-10 years took part, including 558 of South Asian, 560 of black African-Caribbean and 543 of white European ethnicity. Compared with white Europeans, South Asian children reported higher mean total energy intake; their intakes of total fat, polyunsaturated fat and protein (both absolute and as proportions of total energy intake) were higher and their intakes of carbohydrate as a proportion of energy (particularly sugars), vitamin C and D, Ca and haem Fe were lower. These differences were especially marked for Bangladeshi children. Black African-Caribbean children had lower intakes of total and saturated fat (both absolute and as proportions of energy intake), NSP, vitamin D and Ca. The lower total and saturated fat intakes were particularly marked among black African children. Appreciable ethnic differences exist in the nutritional composition of children's diets, which may contribute to future differences in chronic disease risk.

Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice

BACKGROUND

There is increasing evidence that, in addition to the well-known effects on musculoskeletal health, vitamin D status may be related to a number of non-skeletal diseases. An international expert panel formulated recommendations on vitamin D for clinical practice, taking into consideration the best evidence available based on published literature today. In addition, where data were limited to smaller clinical trials or epidemiologic studies, the panel made expert-opinion based recommendations.

METHODS

Twenty-five experts from various disciplines (classical clinical applications, cardiology, autoimmunity, and cancer) established draft recommendations during a 2-day meeting. Thereafter, representatives of all disciplines refined the recommendations and related texts, subsequently reviewed by all panelists. For all recommendations, panelists expressed the extent of agreement using a 5-point scale.

RESULTS AND CONCLUSION

Recommendations were restricted to clinical practice and concern adult patients with or at risk for fractures, falls, cardiovascular or autoimmune diseases, and cancer. The panel reached substantial agreement about the need for vitamin D supplementation in specific groups of patients in these clinical areas and the need for assessing their 25-hydroxyvitamin D (25(OH)D) serum levels for optimal clinical care. A target range of at least 30 to 40 ng/mL was recommended. As response to treatment varies by environmental factors and starting levels of 25(OH)D, testing may be warranted after at least 3 months of supplementation. An assay measuring both 25(OH)D(2) and 25(OH)D(3) is recommended. Dark-skinned or veiled individuals not exposed much to the sun, elderly and institutionalized individuals may be supplemented (800 IU/day) without baseline testing.

Vitamin D regulates macrophage cholesterol metabolism in diabetes

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). In type 2 diabetics, the prevalence of vitamin D deficiency is 20% higher than in non-diabetics, and low vitamin D levels nearly double the relative risk of developing CVD compared to diabetic patients with normal vitamin D levels. However, the mechanism(s) by which vitamin D deficiency leads to an increased susceptibility to atherosclerosis in these patients is unknown. We studied the effects of vitamin D replacement on macrophage cholesterol metabolism and foam cell formation in obese, hypertensive diabetics and non-diabetic controls. We found that 1,25-dihydroxy vitamin D3 [1,25(OH)2D3] suppressed foam cell formation by reducing acetylated low density lipoprotein (AcLDL) and oxidized low density lipoprotein (oxLDL) cholesterol uptake in diabetics only. 1,25(OH)2D3 downregulation of c-Jun N-terminal kinase activation reduced PPARgamma and CD36 expression, and prevented oxLDL-derived cholesterol uptake. In addition, 1,25(OH)2D3 suppression of macrophage endoplasmic reticulum stress improved insulin signaling, downregulated SR-A1 expression, and prevented oxLDL- and AcLDL-derived cholesterol uptake. The results of this research reveal novel insights into the mechanisms linking vitamin D signaling to foam cell formation in diabetics and suggest a potential new therapeutic target to reduce cardiovascular risk in this population.

[Effect of vitamin D deficiency on cardiovascular risk]

Vitamin D deficiency affects almost 50 % of the population worldwide. Besides its classical effects on bone and calcium metabolism, vitamin D displays a wide spectrum of non classical effects. Among these effects, those targeting the cardiovascular system are mostly documented by observational, experimental and small intervention trials that most often evaluated intermediate parameters. The time has now come for large placebo-controlled trials targeting clinical endpoints such as the incidence of major cardiovascular events and mortality.

1,25-dihydroxyvitamin D3 reduces systolic blood pressure in hypertensive adults: a pilot feasibility study

Vitamin D has been reported to lower blood pressure in vivo by regulating the renin-angiotensin system; however, there are limited clinical studies to support this finding in humans. We investigated the effect of vitamin D treatment on hypertension in a three-arm randomized placebo controlled pilot and feasibility study. We tested placebo with two forms of vitamin D: cholecalciferol (vitamin D(3)) and the active form of vitamin D, calcitriol. Subjects were recruited from the Atlanta Veterans Affairs Medical Center in Decatur, GA between April and August 2008. Subjects received 200,000IU of vitamin D(3) (n=3) weekly for 3 weeks or matching placebo (n=3) weekly for 3 weeks (n=3) or 0.5mug calcitriol (n=2) taken twice daily for one week. Our primary endpoint was blood pressure measured by 24h ambulatory blood pressure monitor. Subjects receiving calcitriol experienced a 9% decrease in mean systolic blood pressure (SBP) compared placebo (p<0.001). One week after conclusion of calcitriol therapy SBP returned to pre-treatment levels. There was no reduction in blood pressure in the placebo or vitamin D(3) groups. Results from this pilot study suggests that active vitamin D therapy may be an effective short-term intervention for reducing blood pressure and needs to be explored further in larger controlled studies.

Primary antiphospholipid syndrome in premenopausal women: low vitamin D, high fat mass and maintained bone mineral mass

The aim of this study was to analyze vitamin D levels and their association with bone mineral density and body composition in primary antiphospholipid syndrome. For this cross-sectional study 23 premenopausal women with primary antiphospholipid syndrome (Sapporo criteria) and 23 age- and race-matched healthy controls were enrolled. Demographic, anthropometric, clinical and laboratorial data were collected using clinical interview and chart review. Serum 25-hydroxyvitamin D levels, parathormone, calcium and 24-hour urinary calcium were evaluated in all subjects. Bone mineral density and body composition were studied by dual X-ray absorptiometry. The mean age of patients and controls was 33 years. Weight (75.61 [20.73] vs. 63.14 [7.34] kg, p = 0.009), body mass index (29.57 [7.17] vs. 25.35 [3.37] kg, p = 0.014) and caloric ingestion (2493 [1005.6] vs. 1990 [384.1] kcal/day, p = 0.03) were higher in PAPS than controls. All PAPS were under oral anticoagulant with INR within therapeutic range. Interestingly, biochemical bone parameters revealed lower levels of 25-hydroxyvitamin D [21.64 (11.26) vs. 28.59 (10.67) mg/dl, p = 0.039], serum calcium [9.04 (0.46) vs. 9.3 (0.46) mg/dl, p = 0.013] and 24-hour urinary calcium [106.55 (83.71) vs. 172.92 (119.05) mg/d, p = 0.027] in patients than in controls. Supporting these findings, parathormone levels were higher in primary antiphospholipid syndrome than in controls [64.82 (37.83) vs. 44.53 (19.62) pg/ml, p = 0.028]. The analysis of osteoporosis risk factors revealed that the two groups were comparable (p > 0.05). Lumbar spine, femoral neck, total femur and whole body bone mineral density were similar in both groups (p > 0.05). Higher fat mass [28.51 (12.93) vs. 20.01 (4.68) kg, p = 0.005] and higher percentage of fat [36.08 (7.37) vs. 31.23 (4.64)%, p = 0.010] were observed in PAPS in comparison with controls; although no difference was seen regarding lean mass. In summary, low vitamin D in primary antiphospholipid syndrome could be secondary to higher weight and fat mass herein observed most likely due to adipocyte sequestration. This weight gain may also justify the maintenance of bone mineral density even with altered biochemical bone parameters.