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Abstract

Background:

Low levels of 25(OH) vitamin D [25(OH)VitD] have been recognized as a new cardiovascular disease (CVD) risk factor. Statins seem to increase 25(OH)VitD concentration.

Aim:

To investigate whether combined treatment with the usual dose of rosuvastatin plus fenofibrate or omega-3 fatty acids would increase 25(OH)VitD levels compared with the high-dose rosuvastatin monotherapy in participants with mixed dislipidemia.

Methods:

We randomly allocated 60 patients with mixed dyslipidemia (low-density lipoprotein cholesterol: >160 mg/dL plus triglycerides: >200 mg/dL) to receive rosuvastatin 40 mg (n = 22), rosuvastatin 10 mg plus fenofibrate 200 mg (n = 21), or rosuvastatin 10 mg plus omega-3 fatty acids 2 g (n = 17) daily for 3 months. Our primary end point was changes in the levels of serum 25(OH)VitD.

Results:

Rosuvastatin monotherapy was associated with a 53% increase in 25(OH)VitD (from 14.6 [1.0-38.0] to 17.8 [5.3-49.6] ng/mL; P = .000). Rosuvastatin plus micronized fenofibrate and rosuvastatin plus omega-3 fatty acids were associated with increases of 64% (from 14.1 [1.0-48.0] to 18.4 [6.7-52.4] ng/mL, P = .001) and 61% (from 10.4 [6.6-38.4] to 14.0 [9.6-37.6] ng/mL, P = .04), respectively. The changes in 25(OH)VitD after treatment were comparable in the 3 groups.

Conclusion:

High-dose rosuvastatin monotherapy and the usual dose of rosuvastatin plus fenofibrate or omega-3 fatty acids are associated with significant and similar increases in the 25(OH)VitD levels. This increase may be relevant in terms of CVD risk prevention.

Keywords

vitamin D cardiovascular disease rosuvastatin fenofibrate omega-3 fatty acids

Introduction

During the last 10 years, the role of vitamin D (VitD) has been upgraded from just regulating bone metabolism and calcium homeostasis to participating in the normal function of numerous tissues and organs. In particular, low levels of 25(OH)VitD could be a novel risk factor for cardiovascular disease (CVD), the metabolic syndrome and its components (ie, hypertension, atherogenic dyslipidemia, impaired glucose tolerance, and central obesity), diabetes mellitus, and even for cancer, autoimmune diseases, infections, and overall mortality.^1,2

Statin use has been associated with fewer hip fractures and improved hip bone mineral density.³ Also, there are some data showing that statins, such as lovastatin,⁴ simvastatin,⁵ atorvastatin,⁶ and especially rosuvastatin,^7,8 may be associated with an increase in 25(OH)VitD levels.

So far there is no information as to whether the usual dose of a statin plus a fibrate or omega-3 fatty acids is associated with increases in 25(OH)VitD levels in participants with mixed dyslipidemia, and whether this compares with a high dose of statin alone. Therefore, we aimed to compare the effect of monotheraphy with high-dose rosuvastatin (40 mg) versus combination treatments with either 10 mg rosuvastatin plus micronized 200 mg fenofibrate or 10 mg rosuvastatin plus 2 g omega-3 fatty acids on serum 25(OH)VitD levels in participants with mixed dyslipidemia. Our primary end point was changes in serum 25(OH)VitD levels after 3 months of treatment, while secondary end points were alterations in lipid profile and glucose levels.

Patients and Methods

Patients

Patients who visited the Outpatient Lipid and Obesity Clinic of the University Hospital of Ioannina, Greece, were included in the present study. Patients were considered eligible if they had low-density lipoprotein cholesterol (LDL-C) >160 mg/dL and triglycerides (TGs) >200 mg/dL at baseline. Exclusion criteria were known coronary heart disease or other atherosclerotic diseases, TGs >500 mg/dL, renal disease (serum creatinine levels >1.6 mg/dL or proteinuria >300 mg/d), diabetes (fasting blood glucose >126 mg/dL or treatment with hypoglycemic agents), hypothyroidism (thyroid-stimulating hormone >5 IU/mL), and liver disease (alanine transaminase and/or aspartate transaminase levels >3-fold the upper limit of normal in more than 2 consecutive measurements). Patients with hypertension were included in the study if they were on stable medication for at least 3 months before study entry and their blood pressure was adequately controlled (no change in their treatment was allowed during the study period). Patients currently taking lipid-lowering drugs or having stopped them less than 4 weeks before study entry were excluded. After the initial screening, all study participants gave a written informed consent.

All participants were given individualized dietary instructions by a clinical nutritionist, based on each ones basal energy requirements and on an estimation of the participant’s typical activity level according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) guidelines.⁹ The treatment groups did not differ in their nutrient intake at baseline, and there were no differences in diet composition between the study groups. All patients were asked to attend the clinic monthly during the treatment in order to assess diet compliance. Patients who remained hyperlipidemic (LDL-C >160 mg/dL plus TGs >200 mg/dL) after a dietary intervention period of approximately 3 months were considered eligible for randomization. We followed a simple randomization method using a table of random numbers. Patients were allocated to open-label 40 mg rosuvastatin, 10 mg rosuvastatin plus micronized 200 mg fenofibrate, or 10 mg rosuvastatin plus 2 g omega-3 fatty acids (each gram of the preparation contains approximately 465 mg of eicosapentaenoic acid and 375 mg of docosahexaenoic acid ) daily for 3 months. Blood pressure was measured in triplicate in the right arm after patients had rested for 10 minutes at a sitting position. Measurements were performed by trained clinicians using an electronic sphygmomanometer (WatchBP Office, Microlife WatchBP AG, Widnau, Switzerland). The study was approved by the ethics committee of the University Hospital of Ioannina and adheres to the principles of the declaration of Helsinki.

Biochemical Parameters

All laboratory determinations were carried out after an overnight fast and were blindly assessed with regard to treatment allocation. Serum concentrations of fasting glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and TGs were determined enzymatically on an Olympus AU600 Clinical Chemistry analyzer (Olympus Diagnostica, Hamburg, Germany). Serum apolipoproteins (Apo) A-I and B were measured by immunonephelometry on a BN ProSpec nephelometer (Dade-Behring, Lieberbach, Germany). Non-HDL-C was calculated by the equation: non-HDL-C = TC − HDL-C. Low-density lipoprotein cholesterol was calculated using the Friedewald formula (provided that TGs were <400 mg/dL). Serum 25(OH)VitD was determined quantitatively by an enzyme immunoassay method using the reagents from DRG Instruments GmbH kit (Germany). The sensitivity of the method was 3.2 nmol/L (1.28 ng/mL) and the intra- and inter-assay variation was 7% for each at the level of 72 and 84 nmol/L (28.8 and 33.6 ng/mL), respectively. In order to exclude the confounding effect of the seasonal variation in 25(OH)VitD serum levels, we collected all specimens from early spring to late summer. During this period, sunshine in Greece is of the same duration and therefore we can largely exclude confounding sunlight effect on 25(OH)VitD levels.

Statistical Analyses

We used G*Power 3.0.10 to calculate the sample size. Based on previous studies, we estimated that rosuvastatin would result in a 160% increase in 25(OH)VitD. Power analysis revealed that a sample size of 21 patients per group would give a 90% power to detect a 15% difference between groups at an α level of .05.

Preliminary analyses were performed to ensure no violation of the assumptions of normality and linearity. The Kolmogorov-Smirnoff test was used to evaluate whether each variable followed a Gaussian distribution. Data are presented as mean and standard deviation except for non-Gaussian distributed variables, which are presented as median (range). For variables that did not follow the normal distribution, appropriate nonparametric tests were used. The paired samples t test (or the Wilcoxon signed ranks test, when required) was used for assessing the effect of treatment in each group. Analysis of covariance (ANCOVA) or the Kruskal-Wallis test for nonparametric variables, adjusted for baseline values, was used for comparisons between treatment groups. Significance was defined as P < .05. Analyses were performed using the SPSS 18.0 statistical package for Windows (SPSS Inc, 1989-2004, Chicago, Illinois).

Results

Sixty patients (23 men and 37 women) with a mean age of 55 ± 12 years were enrolled for the study and were divided into 3 treatment groups: 40 mg rosuvastatin (group R, n = 22) 10 mg rosuvastatin plus micronized 200 mg fenofibrate (group RF, n = 21), and 10 mg rosuvastatin plus 2 g omega-3 fatty acids (group RN, n = 17). No significant differences in baseline characteristics were noted between the 3 groups (Table 1).

Table 1.

Baseline Characteristics of Study Participants^a

Characteristics	Group R	Group RF	Group RN	P
N (males/females)	22 (7/15)	21 (11/10)	17 (5/12)	NS
Age, years	58 ± 13	54 ± 10	53 ± 15	NS
Current smokers, %	41	28	53	NS
Body weight, kg	76 ± 12	84 ± 12	82 ± 16	NS
BMI, kg/m²	29 ± 4	31 ± 3	30 ± 3	NS
WC, cm	98 ± 8	104 ± 9	101 ± 10	NS
SBP, mm Hg	131 ± 21	127 ± 10	129 ± 10	NS
DBP, mm Hg	81 ± 10	84 ± 8	82 ± 7	NS
TC, mg/dL	318 ± 75	300 ± 45	287 ± 11	NS
LDL-C, mg/dL	228 ± 76	191 ± 44	186 ± 46	NS
TGs, mg/dL	203 (162-299)	279 (209-340)	238 (143-349)	NS
HDL-C, mg/dL	54 ± 9	53 ± 9	50 ± 12	NS
Non-HDL-C, mg/dL	264 ± 70	247 ± 39	236 ± 39	NS
Apo AI, mg/dL	153 ± 22	155 ± 23	149 ± 28	NS
Apo B, mg/dL	140 ± 42	144 ± 26	129 ± 22	NS
Glucose, mg/dL	94 ± 9	94 ± 10	94 ± 10	NS
25(OH)VitD, ng/mL	14.6 (1-38)	14.1 (1-48)	10.4 (6.6-38.4)	NS

Abbreviations: BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; WC, waist circumference; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TGs, triglycerides; Apo, apolipoprotein; HOMA index, homeostasis model assessment insulin resistance index; 25(OH)Vit D, 25-hydroxy vitamin D; R, rosuvastatin 40 mg; RF, rosuvastatin 10 mg plus micronized fenofibrate 200 mg; RN, rosuvastatin 10 mg plus omega-3 fatty acids 2 g.

^aTo convert values for triglycerides to millimoles per liter multiply by 0.01129. To convert values for cholesterol to millimoles per liter multiply by 0.02586. To convert values for glucose to millimoles per liter multiply by 0.05551. To convert values for 25(OH)Vit D to nanomoles per liter multiply by 2.5.

Serum 25(OH)VitD levels were significantly increased in all study groups (Table 2). Specifically, in the 40-mg rosuvastatin group, there was a 53% increase (P = .000). The usual dose of rosuvastatin plus fenofibrate was associated with a 64% increase (P = .001), while the usual dose of rosuvastatin plus omega-3 fatty acids with a 61% rise (P = .04) in serum 25(OH)VitD concentrations. The observed increase in the 25(OH)VitD levels after treatment did not differ significantly between the 3 groups. We found no significant correlations between the changes in 25(OH)VitD levels and those of any other metabolic parameter (data not shown).

Table 2.

Serum Metabolic Parameters at Baseline and After 3 Months of Drug Treatment^a

	Baseline	3 Months	P vs Baseline	Change, %
TC, mg/dL
Group R	318 ± 75	176 ± 38	.000	–44^b
Group RF	300 ± 45	197 ± 41	.000	–33
Group RN	287 ± 11	196 ± 39	.000	–31
TGs, mg/dL
Group R	203 (162-299)	137 (62-309)	.009	–30
Group RF	279 (209-340)	131 (67-244)	.000	–54^c
Group RN	238 (143-349)	169 (106-327)	.004	–26
HDL-C, mg/dL
Group R	54 ± 9	55 ± 8	NS	+1.0
Group RF	53 ± 9	57 ± 12	.020	+7.7^c
Group RN	50 ± 12	52 ± 12	NS	+4.8
LDL-C, mg/dL
Group R	228 ± 76	97 ± 38	.000	–58^b
Group RF	191 ± 44	122 ± 47	.000	–44
Group RN	186 ± 46	108 ± 33	.000	–41
Non-HDL-C, mg/dL
Group R	264 ± 70	125 ± 34	.000	–52^b
Group RF	247 ± 39	141 ± 39	.000	–42
Group RN	236 ± 39	144 ± 34	.000	–39
Apo AI, mg/dL
Group R	153 ± 22	155 ± 18	NS	+1.0
Group RF	155 ± 23	162 ± 30	.040	+4.0^c
Group RN	149 ± 28	152 ± 25	NS	+2.0
Apo B, mg/dL
Group R	140 ± 42	77 ± 22	.000	–52^b
Group RF	144 ± 26	83 ± 24	.000	–45
Group RN	129 ± 22	98 ± 30	.000	–37
Glucose, mg/dL
Group R	94 ± 9	94 ± 11	NS	+0.5
Group RF	94 ± 10	93 ± 7	NS	–0.7
Group RN	94 ± 10	95 ± 9	NS	+1.0
25(OH)VitD, ng/mL
Group R	14.6 (1.0-38.0)	17.8 (5.3-49.6)	.000	+53
Group RF	14.1 (1.0-48.0)	18.4 (6.7-52.4)	.001	+64
Group RN	10.4 (6.6-38.4)	14 (9.6-37.6)	.040	+61

Abbreviations: TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TGs, triglycerides; Apo, apolipoprotein; HOMA index, homeostasis model assessment insulin resistance index; 25(OH)Vit D, 25-hydroxy vitamin D.

^aGroup R: rosuvastatin 40 mg monotherapy, group RF: rosuvastatin 10 mg plus micronized fenofibrate 200 mg, and group RN: rosuvastatin 10 mg plus omega-3 fatty acids 2 g.

^b P < .05 versus RF and RN groups.

^c P < .05 versus R and RN groups.

There were significant reductions in the plasma levels of TC, LDL-C, non-HDL-C, and TGs in all study groups (Table 2). The reductions in the levels of TC, LDL-C, non-HDL-C, and ApoB were significantly greater in the high-dose rosuvastatin monotherapy group compared with either of the 2 other therapies (P for the comparison between groups <.05). On the contrary, the reduction in TGs was significantly higher in the usual-dose rosuvastatin plus fenofibrate group compared with the high-dose rosuvastatin monotherapy and the usual-dose rosuvastatin plus omega-3 fatty acids groups (P for the comparison between groups <.05). HDL-C and ApoAI levels were significantly increased in the usual-dose rosuvastatin plus fenofibrate group and nonsignificantly increased in the usual-dose rosuvastatin plus omega-3 fatty acids group and the high-dose rosuvastatin monotherapy group (P for the comparison between groups <.05; Table 2).

Discussion

In this randomized study, we show, for the first time, that high-dose rosuvastatin monotherapy and usual-dose rosuvastatin plus micronized fenofibrate and usual-dose rosuvastatin plus omega-3 fatty acids are associated with significant and to a similar degree increases in serum 25(OH)VitD levels.

The idea that there may be a relationship between statins and 25(OH)VitD levels came about when some studies showed that statin use was associated with fewer hip fractures and improved hip bone mineral density.³ Grimes proposed that since the unexpected and unexplained clinical benefits of statins have also been shown to be the properties of 25(OH)VitD, and therefore mimic many of the actions of 25(OH)VitD, they may be considered as VitD analogues.¹⁰

Several statins, such as lovastatin,⁴ simvastatin,⁵ atorvastatin,⁶ and especially rosuvastatin,^7,8 appear to increase 25(OH)VitD serum levels contrary to the initial concern that statins would impair the formation of steroids dependent on cholesterol synthetic pathway, including vitamin D synthesis.¹¹ Several potential mechanisms have been proposed to explain the observed increase in 25(OH)VitD concentrations after statin therapy. Since 25(OH)VitD is catabolized in liver and intestine by CYP3A4,¹² which also extensively metabolizes statins (along with CYP3A5), the competition in this common catabolic pathway could be the cause for the increased 25(OH)VitD levels observed in patients under statin treatment. Another attractive mechanism is that when 3-hydroxy-3 methylglutaryl coenzyme A reductase is inhibited by statins, 7-hydrocholesterol levels (the common precursor of cholesterol and 25(OH)VitD) may increase, thereby providing an abundance of substrate for the synthesis of 25(OH)VitD by ultraviolet sun radiation of the skin.¹³

In our study, high-dose rosuvastatin monotherapy was associated with a 53% increase in 25(OH)VitD levels after 3 months of treatment. Previous studies of Yavuz et al⁷ and Ertugrul et al⁸ have also examined the effect of rosuvastatin at 10 and 20 mg daily on 25(OH)VitD levels after 8 weeks of treatment and found significant increases in 25(OH)VitD concentrations by 159% and 198%, respectively, which are substantially higher than ours. The reasons for this difference are mainly unknown. Differences in baseline 25(OH)VitD concentration, study population, and study duration may account for this inconsistency. Nevertheless, this increase in 25(OH)VitD levels may represent a novel pleiotropic effect of statins.¹⁴

We also found that combinations of the usual-dose rosuvastatin with fenofibrate 200 mg or omega-3 fatty acids 2 g were associated with significant increases in 25(OH)VitD levels of 64% and 61%, respectively. These increases occurred to the same degree with the high-dose rosuvastatin monotherapy. Based on our study design, we cannot conclude whether fenofibrate or omega-3 fatty acids has synergistic effects in increasing 25(OH)VitD concentrations or if this increase is only associated with rosuvastatin, independently of dose. To our knowledge, there are no published data concerning the possible effects of fibrates or omega-3 fatty acids on 25(OH)VitD serum levels.

The increase in 25(OH)VitD seen with the 3 treatment regimens may be clinically important, since low levels of 25(OH)VitD have been recognized as an independent CVD risk factor.¹⁵ Results from large, cross-sectional studies (NHANES),¹⁶ as well as from prospective studies,¹⁷ associated 25(OH)VitD deficiency (<15 ng/mL) with increased rate of myocardial infarction. Moreover, VitD deficiency seems to have a negative association with survival, while supplementation may decrease overall mortality.¹⁸ ^, ¹⁹ Currently, the Vitamin D and Omega-3 Trial (VITAL), a 5-year, randomized, placebo-controlled trial involving 20 000 US people, examines whether VitD (2000 IU/d) with or without the addition of omega-3 fatty acids prevents CVD and cancer, in people who do not have a prior history of these illnesses.²⁰ Its results will be of great interest.

Furthermore, we found that high-dose rosuvastatin was more effective in reducing TC, LDL-C, and non-HDL-C compared with combination treatments. On the other hand, the combination of rosuvastatin plus fenofibrate was more potent in reducing TGs and increasing HDL-C compared with the other 2 treatment groups.

Study Limitations and Strengths

There are certain limitations in our study. We included no group receiving monotherapy with fenofibrate or omega-3 fatty acids, as statin use must be a component of any lipid-lowering treatment. Subsequently, we cannot distinguish whether fenofibrate or omega-3 fatty acids may by themselves increase 25(OH)VitD levels, or whether it is rosuvastatin independently of dosage (ie, usual dose [10 mg] and maximum dose [40 mg]) that leads to similar increases in 25(OH)VitD levels. Additional limitations include the open-label design and the relatively short period of follow-up (3 months). The number of patients in each treatment group is rather small. However, this was an adequately powered study based on a priori power calculations.

On the other hand, this is a clinically relevant study, since we tested the efficacy of treatments used in everyday clinical practice in the management of combined dyslipidaemia on altering 25(OH)VitD levels. Additionally, this was a randomized, adequately powered study, with all comparisons being adjusted for baseline levels and end points being blindly assessed.

Conclusions

High-dose rosuvastatin, usual-dose rosuvastatin plus fenofibrate, and usual-dose rosuvastatin plus omega-3 fatty acids are similarly capable of increasing 25(OH)VitD levels in participants with mixed dyslipidemia. The clinical relevance of improving vitamin D status in this population, even indirectly, remains to be determined but should not be ignored.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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