[Vitamin D deficiency and cardiovascular diseases]

Serum Cortisol, 25 (OH)D, and Cardiovascular Risk Factors in Patients with Type 2 Diabetes Mellitus

BACKGROUND AND AIMS

The effects of cortisol on cardiovascular diseases (CVD) and CVD risk are unknown, especially in patients with type 2 diabetes mellitus (T2DM). Furthermore, it is unclear whether 25 (OH)D can alter the associations of cortisol with CVD and CVD risk factors. Thus, the present study was to investigate the associations of serum cortisol with CVD and CVD risk factors and whether 25 (OH)D altered these associations among patients with T2DM. Materials and methods. A total of 762 patients diagnosed with T2DM were recruited. The levels of serum cortisol and 25 (OH)D were measured with a liquid chromatography-tandem mass spectrometry. Logistic regression and linear regression were used to assess the association of cortisol with CVD and multiple cardiovascular risk factors. Modification analyses were performed to identify whether 25 (OH)D altered the above associations.

RESULTS

A 1 SD increase in cortisol was associated with a higher prevalence of stroke (odds ratio (OR): 1.25, 95% confidence interval (CI): 1.05, 1.50). Elevated cortisol was associated with related cardiovascular risk factors, including deceased ß cell function, high-density lipoprotein-cholesterol (HDL-C), and fasting insulin, as well as increased triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C), fasting plasma glucose (FPG), and glycated hemoglobin (HbA1c). In addition, modification analyses suggested that the associations of cortisol with ß cell function, fasting insulin, FPG, and HbA1c were modified by 25 (OH)D.

CONCLUSIONS

Serum cortisol was associated with the prevalence of stroke and cardiovascular risk factors, and the associations of cortisol with cardiovascular risk factors were moderated by 25 (OH)D, suggesting that T2DM patients with exposure to lower 25 (OH)D levels and higher cortisol levels were more susceptible to have higher cardiovascular risk factors.

The Effect of Three-Month Vitamin D Supplementation on the Levels of Homocysteine Metabolism Markers and Inflammatory Cytokines in Sera of Psoriatic Patients

Psoriasis is an autoimmune and inflammatory skin disease. Psoriatic patients express higher levels of plasma homocysteine (Hcy) concentration and pro-inflammatory mediators than healthy people; this is frequently associated with vitamin D deficiency. The aim of this clinical study was to investigate the effects of high doses of vitamin D supplementation on the parameters of Hcy metabolism and cytokines in sera of psoriatic patients. This prospective study was conducted on 40 psoriatic patients who had the vitamin D deficiency. All patients received vitamin D 5000 IU/day for three months. Clinical and biochemical measurements were taken at baseline and at follow up (3 months). The results showed that the severity of clinical features, measured by the psoriasis area severity index (PASI) score, were considerably improved in patients after vitamin D supplementation. After vitamin D supplementation, most of the patients (n = 25 or 62.5%) had mild clinical form (p < 0.001). After twelve weeks of intervention period, there were significant increases in vitamin D and B₁₂ serum levels in comparison to the levels that had been measured at the beginning of the study (56.77 ± 14.66 nmol/L and 301.08 ± 95.02 pg/mL vs. 103.85 ± 32.20 nmol/L and 362.81 ± 118.56 pg/mL, respectively; p < 0.001). Moreover, serum levels of Hcy and folate were significantly lower at the end of the study in comparison with the initial levels (12.45 ± 1.92 µmol/L and 8.01 ± 3.88 mg/mL vs. 10.38 ± 1.66 µmol/L and 6.27 ± 2.60 mg/mL, respectively). High doses of vitamin D supplementation led to a significant decrease in pro-inflammatory cytokines (IFN-ɤ, TNF-α, IL-1β, IL-6, IL-8, and IL-17) and high-sensitivity C-reactive protein (hsCRP), whereas the production of anti-inflammatory cytokines (IL-10, IL-5) was up-regulated. In conclusion, supplementation with high doses of vitamin D could be one of the possible preventive and therapeutic measures to reduce systemic inflammation in psoriatic patients.

Relationship between the serum levels of Vitamin D and inflammatory markers in ESRD patients

BACKGROUND AND AIM

In patients with End-stage renal disease (ESRD), 25-(OH)-Vitamin D3 deficiency is a common problem and also the inflammatory responses increase in these patients. The present study aims to evaluate the relation of 25-(OH)-Vitamin D3 with the indirect inflammatory markers in patients on hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

This study was done by cross-sectional method on 85 ESRD patients receiving renal replacement therapy (RRT), from one geographical area. 64 patients on HD and 21 patients on PD who were matched for age and sex were studied. Serum level of 25-(OH) Vitamin D3 was measured in each patient. ESR, CRP and the other routine blood tests were measured as well.

RESULTS

The level of 25-OH Vitamin D3 was significantly lower in PD group in comparison to HD group (P: 0/0012, 2/70±0/10 vs 2/05±0/14). Platelet (195/40 ± 7/6 vs 265/52 ± 15/6, P: 0/001) and ESR (46/80 ± 6/89 vs 23/53 ± 1/96, P: 0/003) were significantly higher in PD group. Considering total population of the study (PD and HD), there was a significant association between ESR and serum level of 25-(OH)-Vitamin D3 (r: 0.26, P: 0.036) but no correlation was seen between 25-(OH)-Vitamin D3 and hemoglobin (Hb) or duration of dialysis. On the other hand, in patients on HD, multiple regression analysis revealed a significant relationship between duration of dialysis (P: 0.02), Hb (P: 0.01) and ESR (P: 0.001) with 25-(OH)-Vitamin D3 level. Moreover, there was a relationship between vitamin D3 levels and inflammatory markers as well.

CONCLUSIONS

The deficiency of 25-(OH)-Vitamin D3 was followed with increase of ESR as an inflammatory marker in patients on HD. Key words: Inflammation; 25-hydroxy vitamin D; Renal replacement; Dialysis.

Discrepant association of serum C-3 epimer of 25-hydroxyvitamin D versus non-epimeric 25-hydroxyvitamin D with serum lipid levels

Background

Low vitamin D status has been associated with a number of chronic diseases. For dyslipidemia, vitamin D deficiency has been associated with higher low density lipoprotein-cholesterol (LDL-C) in a number of studies, but with inconsistent results in clinical trials. The purpose of the present study is to explore the relative importance of 3-epi-25-hydroxyvitamin D (25(OH)D) as compared with the non-epimeric form in relation to serum lipid.

Method

This study used data from 1068 randomly selected volunteers in the Thai 4^th National Health Examination Survey (NHES IV). Serum 25(OH)D₂, 25(OH)D₃, 3-epi-25(OH)D₂ and 3-epi-25(OH)D₃ were analyzed by liquid chromatography–tandem mass spectrometry.

Results

There was no association between serum total 25(OH)D and serum LDL-C. However, circulating 3-epi-25(OH)D₃ was negatively related to serum LDL-C (r = −0.077, P <0.05), while no such association was found for non-epimeric 25(OH)D₃ (r =0.030, P = 0.33). On the other hand, both 3-epi-25(OH)D₃ (r = 0.175, P <0.001) and non-epimeric 25(OH)D₃ (r = 0.142, P <0.001) were positively related to serum triglyceride (TRIG) levels. In multiple linear regression models with age, gender, body mass index , urban residence, education, hypertension and education as covariates, it was found that 3-epi-25(OH)D₃ was independently associated with serum LDL-C (beta = −0.12, P <0.01), while non-epimeric 25(OH)D₃ was positively related to LDL-C (beta = 0.13, P = 0.002). For TRIG, there were positive association with 3-epi-25(OH)D₃ (beta = 0.27, P <0.001) and negative association with non-epimeric 25(OH)D₃ (beta = − 0.10, P = 0.011) independent of age, gender, urban resident and education.

Conclusions

There is a discrepant association of 25(OH)D levels with serum lipids according to 25(OH)D epimeric forms.