25-hydroxyvitamin D insufficiency is associated with impaired renal endothelial function and both are improved with rosuvastatin treatment

Evidence of Drug-Nutrient Interactions with Chronic Use of Commonly Prescribed Medications: An Update

The long-term use of prescription and over-the-counter drugs can induce subclinical and clinically relevant micronutrient deficiencies, which may develop gradually over months or even years. Given the large number of medications currently available, the number of research studies examining potential drug-nutrient interactions is quite limited. A comprehensive, updated review of the potential drug-nutrient interactions with chronic use of the most often prescribed medications for commonly diagnosed conditions among the general U.S. adult population is presented. For the majority of the interactions described in this paper, more high-quality intervention trials are needed to better understand their clinical importance and potential consequences. A number of these studies have identified potential risk factors that may make certain populations more susceptible, but guidelines on how to best manage and/or prevent drug-induced nutrient inadequacies are lacking. Although widespread supplementation is not currently recommended, it is important to ensure at-risk patients reach their recommended intakes for vitamins and minerals. In conjunction with an overall healthy diet, appropriate dietary supplementation may be a practical and efficacious way to maintain or improve micronutrient status in patients at risk of deficiencies, such as those taking medications known to compromise nutritional status. The summary evidence presented in this review will help inform future research efforts and, ultimately, guide recommendations for patient care.

Lack of association of statin use with vitamin D levels in a hospital based population of type 2 diabetes mellitus patients

Objective

To investigate the relationship of statins (drug given to reduce serum levels of LDL-cholesterol) on vitamin D levels of Pakistani type 2 diabetes mellitus (DM) patients in a hospital in Karachi.

Methods

In a cross-sectional survey, 312 consecutive patients with type 2 DM (219 males and 93 females, age 22-70 years) were recruited with informed consent. A questionnaire was administered to find out whether they were statin users or non-users. Serum was analyzed for concentrations of 25(OH) vitamin D [25(OH)D] and other related biomarkers such as serum cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, phosphate and calcium using kit methods. Multiple Linear Regression was used to evaluate association of statin use with serum levels of vitamin D while adjusting for related covariates including duration of statin use, duration of type 2 DM and smoking.

Results

Mean concentrations of serum cholesterol, and LDL-cholesterol were lower among statin users compared to statin non-users (P < 0.01), while HDL-cholesterol levels were higher (P<0.01). No relationship was observed between statin use and serum levels of vitamin D (P=0.768), when adjusted for age, gender, BMI, duration of type 2 DM, smoking, serum cholesterol and LDL-cholesterol. The adjusted regression coefficient (β) and standard error [SE(β)] for statin use duration were 0.012 (0.042), when serum levels of vitamin D was taken as an outcome.

Conclusion

Lack of association was found between statin use and vitamin D levels in a hospital-based population of Pakistani patients with type 2 DM.

Vitamin D signaling and melanoma: role of vitamin D and its receptors in melanoma progression and management

Ultraviolet B (UVB), in addition to having carcinogenic activity, is required for the production of vitamin D3 (D3) in the skin which supplies >90% of the body's requirement. Vitamin D is activated through hydroxylation by 25-hydroxylases (CYP2R1 or CYP27A1) and 1α-hydroxylase (CYP27B1) to produce 1,25(OH)₂D3, or through the action of CYP11A1 to produce mono-di- and trihydroxy-D3 products that can be further modified by CYP27B1, CYP27A1, and CYP24A1. The active forms of D3, in addition to regulating calcium metabolism, exert pleiotropic activities, which include anticarcinogenic and anti-melanoma effects in experimental models, with photoprotection against UVB-induced damage. These diverse effects are mediated through an interaction with the vitamin D receptor (VDR) and/or as most recently demonstrated through action on retinoic acid orphan receptors (ROR)α and RORγ. With respect to melanoma, low levels of 25(OH)D are associated with thicker tumors and reduced patient survival. Furthermore, single-nucleotide polymorphisms of VDR and the vitamin D-binding protein (VDP) genes affect melanomagenesis or disease outcome. Clinicopathological analyses have shown positive correlation between low or undetectable expression of VDR and/or CYP27B1 in melanoma with tumor progression and shorter overall (OS) and disease-free survival (DFS) times. Paradoxically, this correlation was reversed for CYP24A1 (inactivating 24-hydroxylase), indicating that this enzyme, while inactivating 1,25(OH)₂D3, can activate other forms of D3 that are products of the non-canonical pathway initiated by CYP11A1. An inverse correlation has been found between the levels of RORα and RORγ expression and melanoma progression and disease outcome. Therefore, we propose that defects in vitamin D signaling including D3 activation/inactivation, and the expression and activity of the corresponding receptors, affect melanoma progression and the outcome of the disease. The existence of multiple bioactive forms of D3 and alternative receptors affecting the behavior of melanoma should be taken into consideration when applying vitamin D management for melanoma therapy.

Statin Use and 25-Hydroxyvitamin D Blood Level Response to Vitamin D Treatment of Older Adults

OBJECTIVES

To determine whether statin use alters response of 25-hydroxyvitamin D (25(OH)D) level to vitamin D treatment.

DESIGN

Pooled analysis.

SETTING

Three double-blind randomized controlled trials that tested different doses of vitamin D.

PARTICIPANTS

Participants of three trials (N = 646; mean age 76.3 ± 8.4, 65% female).

MEASUREMENTS

In all three trials, 25(OH)D status and statin use were assessed repeatedly over time (baseline, 6 and 12 months). Repeated-measures analysis was used to compare 25(OH)D response to vitamin D treatment at baseline and 6 and 12 months of statin users and nonusers, controlling for age, sex, body mass index, Charlson Comorbidity Index, vitamin D dose, trial, and season.

RESULTS

At baseline, 17.5% were statin users, and 65% were vitamin D deficient (25(OH)D < 20 ng/mL). Baseline 25(OH)D levels did not differ significantly between groups at baseline (18.8 for statin users, 17.2 ng/mL for nonusers, P = .07), but according to the longitudinal analyses, the total increase over 12 months in 25(OH)D concentration was significantly lower in statin users (13.1 ng/L) than nonusers (15.9 ng/mL; 21.4% difference; P = .009).

CONCLUSION

Of persons aged 60 and older at high risk of vitamin D deficiency, statin users had a 21.4% smaller increase in 25(OH)D serum concentrations over time than nonusers, independent of vitamin D dose and other covariates.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Vitamin D deficiency may predict a poorer outcome of IgA nephropathy

Background

Experimental studies showed that 25-hydroxy-vitamin D [25(OH)D] deficiency (defined as 25-hydroxy-vitamin D < 15 ng/ml) has been associated with CKD progression. Patients with IgA nephropathy have an exceptionally high rate of severe 25(OH)D deficiency; however, it is not known whether this deficiency is a risk factor for progression of IgA nephropathy. We conducted this study to investigate the relationship between the plasma level of 25(OH)D and certain clinical parameters and renal histologic lesions in the patients with IgA nephropathy, and to evaluate whether the 25(OH)D level could be a good prognostic marker for IgA nephropathy progression.

Methods

A total of 105 patients with biopsy-proven IgA nephropathy were enrolled between 2012 and 2015. The circulating concentration of 25(OH)D was determined using serum samples collected at the time of biopsy. The primary clinical endpoint was the decline of estimated glomerular filtration rate (eGFR; a 30 % or more decline compared to the baseline).

Results

Mean eGFR decreased and proteinuria worsened proportionally as circulating 25(OH)D decreased (P < 0.05). The 25(OH)D deficiency was correlated with a higher tubulointerstitial score by the Oxford classification (P = 0.008). The risk for reaching the primary endpoint was significantly higher in the patients with a 25(OH)D deficiency compared to those with a higher level of 25(OH)D (P = 0.001). As evaluated using the Cox proportional hazards model, 25(OH)D deficiency was found to be an independent risk factor for renal progression [HR 5.99, 95 % confidence intervals (CIs) 1.59–22.54, P = 0.008].

Conclusion

A 25(OH)D deficiency at baseline is significantly correlated with poorer clinical outcomes and more sever renal pathological features, and low levels of 25(OH)D at baseline were strongly associated with increased risk of renal progression in IgAN.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0378-4) contains supplementary material, which is available to authorized users.

Vitamin D deficiency as adverse drug reaction? A cross-sectional study in Dutch geriatric outpatients

PURPOSE

Adverse drug reactions as well as vitamin D deficiency are issues of public health concern in older people. However, relatively little is known about the impact of drug use on vitamin D status. Our primary aim is to explore associations between drug use and vitamin D status in older people. Furthermore, prevalences of drug use and vitamin D deficiency are estimated.

METHODS

In a population of 873 community-dwelling Dutch geriatric outpatients, we explored the cross-sectional relationships of polypharmacy (≥5 medications concomitantly used), severe polypharmacy (≥10 medications), and use of twenty-one specific drug groups, with serum 25-hydroxyvitamin D (25(OH)D) by analysis of covariance.

RESULTS

Overall prevalence of polypharmacy was 65 %, of severe polypharmacy 22 %. Depending on the cut-off value, prevalence of vitamin D deficiency was 49 % (<50 nmol/l) or 77 % (<75 nmol/l). Of the patients using a vitamin D supplement, 17 % (<50 nmol/l) or 49 % (<75 nmol/l) were still deficient. In non-users of supplemental vitamin D, after adjustment for age and gender, negative associations were found for severe polypharmacy, metformin, sulphonamides and urea derivatives (SUDs), vitamin K antagonists, cardiac glycosides, loop diuretics, potassium-sparing diuretics, ACE inhibitors, and serotonin reuptake inhibitors; for non-selective monoamine reuptake inhibitors (NSMRIs) the association was positive. The most extreme impacts of drug use on adjusted mean 25(OH)D were -19 nmol/l for SUDs and +18 nmol/l for NSMRIs.

CONCLUSION

Drug use should be considered a risk factor for vitamin D deficiency amongst geriatric outpatients.

Markers of subclinical atherosclerosis in premenopausal women with vitamin D deficiency and effect of vitamin D replacement

BACKGROUND

Recent studies have revealed a relationship between vitamin D deficiency and atherosclerosis. This study aims to investigate the impact of vitamin D deficiency and replacement on markers of subclinical atherosclerosis in young premenopausal women in whom vitamin D deficiency is prevalent.

METHODS

Thirty-one premenopausal vitamin D deficient women and 27 age and gender-matched control subjects were enrolled in this study. Markers of subclinical atherosclerosis including carotid intima-media thickness (cIMT), flow-mediated dilatation (FMD), endothelial progenitor cell (EPC) count and cytokine levels were determined at baseline. All measurements were repeated at 6-month follow-up in vitamin D-deficient subjects after vitamin D replacement.

RESULTS

Vitamin D deficient premenopausal women had lower FMD (9.9 ± 1.3 vs. 13.8 ± 1.7%, p < 0.001) and EPC counts at baseline. This population also had lower IL-10 and higher IL-17 levels. A 6-month vitamin D replacement therapy resulted in a significant increase in FMD (9.9 ± 1.3 vs. 11.4 ± 1.4%, p < 0.001) and EPC counts. Furthermore, cytokine profile shifted toward a more anti-inflammatory phenotype including elevated IL-10 and decreased IL-17 levels. cIMT was not different between patient and control groups and did not change following vitamin D replacement. Change in 25(OH)D and IL-17 levels were independent predictors of the change in FMD measurements following vitamin D replacement.

CONCLUSION

This study demonstrates that endothelial function is impaired in otherwise healthy vitamin D deficient young premenopausal women and improves with 6-month replacement therapy. Immune-modulatory effects of vitamin D may, at least partly, be responsible for its beneficial effects on vascular health.

Comparative Effect of Atorvastatin and Rosuvastatin on 25-hydroxy-Vitamin D Levels in Non-diabetic Patients with Dyslipidaemia: A Prospective Randomized Open-label Pilot Study

AIMS

Low 25-hydroxy-vitamin D [25(ΟΗ)D] levels have been associated with increased risk for cardiovascular disease. Conflicting data exist regarding the effect of statins on [25(OH)D] levels. The aim of this study was to compare the effect of atorvastatin and rosuvastatin on 25(OH)D levels in non-diabetic patients with dyslipidaemia.

METHODS

This was a prospective randomized open-label study. Patients were assigned to atorvastatin 20 mg⁄day (n=28, age: 56.1±2.2 years, 22 females) or rosuvastatin 10 mg⁄day (n=24, age: 57.4±1.9 years, 20 females). Total cholesterol (TC), low- (LDL-C) and high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), fasting plasma glucose, insulin, glycosylated haemoglobin A1c (HbA1c) and high sensitivity C-reactive protein (hsCRP) levels were measured, and homeostatic model of assessment insulin resistance (HOMA-IR) was calculated at baseline and 12 weeks post-treatment.

RESULTS

There were no within or between group significant differences in 25(OH)D levels (atorvastatin: 21.7±1.9 ng/ml at baseline and 23.5±2.3 ng/ml at week 12; rosuvastatin: 25.3±1.8 and 27.0±2.4 ng/ml, respectively; p=0.172 and p=0.306 for between groups, respectively). Both statins significantly reduced TC, TG and LDL-C levels, with a greater LDL-C reduction being observed by rosuvastatin.

CONCLUSION

Atorvastatin and rosuvastatin did not significantly affect 25(OH)D levels in this study.