Relationship Between Vitamin D Deficiency and Nondipper Hypertension

The relationship between vitamin D and short-term blood pressure variability

OBJECTIVES

This study aimed to evaluate the relationships between serum levels of 25-hydroxyvitamin D (25(OH)D) and short-term blood pressure variability (BPV) in newly diagnosed hypertensive patients.

METHODS

One hundred newly diagnosed patients with stage one essential hypertension were included and divided into two groups, the deficient and non-deficient groups, according to their 25(OH)D level. The blood pressure was recorded automatically by a portable ambulatory blood pressure monitor for 24 h.

RESULTS

In the present study, there was no significant relationship between vitamin D levels and short-term BPV or other parameters derived from ambulatory blood pressure monitoring (ABPM) (P > 0.05). Age (r = 0.260, P = 0.009), serum phosphorus (r = 0.271, P = 0.007), and cholesterol levels (r = 0.310, P = 0.011) were positively correlated with 25(OH)D levels, while glomerular filtration rate (r = -0.232, P = 0.021) negatively correlated with vitamin D levels. There was no crude or adjusted relationship between the levels of 25(OH)D and any parameters of ABPM in multiple linear regression analysis.

CONCLUSION

Although the relationship between vitamin D levels and cardiovascular diseases has been confirmed, vitamin D deficiency does not cause an increase in cardiovascular risk by influencing the short-term BPV or other parameters derived from ABPM.

Relationship between 25-hydroxyvitamin D and microalbuminuria in patients with newly diagnosed essential hypertension

Purpose: Vitamin D deficiency is known that associated with hypertension. Microalbuminuria (MAU) is associated with increased cardiovascular morbidity and mortality. This study aimed to evaluate the relationship between 25-hydroxyvitamin D (25(OH)D) and MAU in newly diagnosed essential hypertension (NDEH) patients. Methods: A total of 116 patients with a diagnosis of NDEH were enrolled in the study. The diagnosis of hypertension was based on ABPM. Patients were divided into 2 groups according to 25(OH)D levels: Group 1: (25(OH)D)>20 ng/mL was defined as Vitamin D sufficiently (VDS), while Group 2: (25(OH)D)<20 ng/mL was defined Vitamin D deficiently (VDD). The relationship between 25(OH)D and MAU was analyzed. The results were analyzed using the SPSS program version 21. Results: The mean age of the patients was 58.4 ± 14.7 years and 60 (51.7%) of them were female. The prevalence of MAU was 18.9% and Vitamin D deficiency was 61.2% in NDEH. Linear regression analysis showed that 25(OH)D was independently related to MAU [β 0.643, 95% confidence interval 1.173-1.631, p = .011]. Besides, male gender, C-reactive protein, non-dipper hypertension, and diastolic blood pressure were independent risk factors associated with MAU in the multivariate analysis (p < .05). Conclusion: Vitamin D deficiency is highly prevalent in NDEH patients. This study showed that the level of microalbuminuria was significantly higher in patients with 25(OH)D deficiency compared to patients with normal 25(OH)D levels. Vitamin D deficiency is independently related to microalbuminuria in NDEH.

Serum parathyroid hormone levels in patients with chronic right heart failure

Parathyroid hormone (PTH) is a novel cardiovascular biomarker which is particularly useful for detection and assessment of heart failure (HF). However, previous studies examining PTH in heart failure have primarily focused on left HF; thus, the relationship between PTH and right HF remains unclear. The aim of the present study was to evaluate the serum PTH levels in patients with chronic right HF. A total of 154 patients with chronic right HF were enrolled in the present study. A binary logistic regression analysis model was used to assess the independent predictive value of PTH levels in chronic right HF. Partial correlative analysis was used to demonstrate the relevance of PTH levels on the parameters of assessment of right heart function. A multiple linear regression analysis model was used to evaluate the independent factors of PTH levels in patients with right HF. The results showed that the serum PTH levels in the right HF group were significantly higher compared with the control group. After adjusting for predictors of right HF, serum PTH levels were associated with right HF with an odds ratio of 1.066 (95% confidence interval: 1.030-1.102, P<0.001. Serum PTH levels were independently correlated with plasma N-terminal pro-B-type natriuretic peptide levels, right ventricular end-diastolic diameter and severity of lower extremity edema (all P<0.05). Therefore, based on the results of the present study, PTH may be a useful biomarker for detection and assessment of right HF.

The mechanism of adaptation of the organism of patients with chronic heart failure combined with vitamin D deficiency and the morphofunctional state of peripheral blood erythrocytes

The problem of structural changes in peripheral blood erythrocytes in patients with chronic heart failure in combination with vitamin D deficiency during exercise stress remains insufficiently studied. Vitamin receptors are located on smooth myocytes, endothelial cells, cardiomyocytes and blood cells. It affects the state of the cell membrane, the contractile function of the myocardium, the regulation of blood pressure, cardiac remodeling and reduction of left ventricular hypertrophy. Therefore, it is important to assess the level of vitamin D in blood plasma in individuals with chronic heart failure and to identify the effect of its deficiency on the state of peripheral red blood cells when performing a 6-minute walk test. A total of 75 patients of the main group with chronic heart failure stage II A, I–II functional class with different levels of vitamin D deficiency were examined. The control group included 25 patients with chronic heart failure stage II A, functional class I–II without signs of vitamin D deficiency. The average age of patients was 57.5 ± 7.5 years. All patients were asked to undergo the 6 minutes walking test. The level of total vitamin D in plasma was determined by enzyme immunoassay. Morphological studies of erythrocytes were performed on the light-optical and electron-microscopic level. The obtained results showed that patients of the main group with chronic heart failure had a decrease in vitamin D by 2.2 times compared with the control group. Correlation analysis showed a directly proportional relationship between vitamin D deficiency and the number of red blood cells of a modified form and red blood cells with low osmotic resistance. Dosed exercise stress in patients with chronic heart failure against a background of vitamin D deficiency leads to an increase in the number of reversibly and irreversibly deformed erythrocytes and a decrease in their osmotic stability. This indicates a disorder in the structural integrity of their membrane and can have negative consequences for the somatic health of such patients.

Relationship of vitamin D and parathyroid hormone with the nocturnal blood pressure decline in hypertension

OBJECTIVES

Vitamin D deficiency and high parathyroid hormone (PTH) levels have been linked with hypertension. Nondipper hypertension is associated with increased morbidity and mortality. We aimed to investigate the relationship of vitamin D and PTH levels with nondipper hypertension and nocturnal decline in untreated hypertensive patients.

PATIENTS AND METHODS

This cross-sectional study included a total of 73 hypertensive and 34 normotensive participants. Each patient underwent 24-hour ambulatory blood pressure monitoring, routine biochemical tests, vitamin D, and PTH analysis.

RESULTS

The study population was divided into three groups according to ambulatory blood pressure monitoring records: 40 nondippers (mean age; 59.8±10.8 years, 24 women and 16 men), 33 dipper hypertensives (mean age; 58±11.8 years, 13 women and 20 men), and 34 normotensives (mean age; 56.9±11.7 years, 19 women and 15 men). Nondipper hypertensives showed lower levels of vitamin D than dippers and normotensives (9.7±6.1 vs. 14.9±10.1 vs. 16.4±9.5 ng/ml, P=0.001, for both) and higher levels of PTH than dippers (74.8±34.7 vs. 53.3±19.9 ng/ml, P=0.001). A significant positive correlation was observed between vitamin D and nocturnal decline (r=0.34, P=0.001), whereas a significant negative correlation was present between PTH and nocturnal decline(r=-0.26, P=0.006). In multivariate analysis, PTH level was correlated independently with nocturnal decline (β=-0.07, 95% confidence interval: -0.114-0.025, P=0.003).

CONCLUSION

In this study, vitamin D levels were significantly lower and PTH levels were significantly higher in nondippers. The vitamin D level was correlated positively and the PTH level was correlated negatively with nocturnal decline. In addition, PTH level was associated independently with nocturnal decline in hypertension.

Nocturnal diastolic blood pressure decline is associated with higher 25-hydroxyvitamin D level and standing plasma renin activity in a hypertensive population

Patients with nondipper hypertension are known to carry a high risk of cardiovascular complications. Vitamin D deficiency is associated with hypertension. Because vitamin D deficiency activates the renin-angiotensin-aldosterone system (RAAS), we hypothesized that this vitamin would interact with the RAAS to influence blood pressure (BP) in nondipper hypertensive patients. We performed a cross-sectional analysis of 1,007 outpatients with hypertension (HTN). Dipper and nondipper patterns were detected, and the two groups were matched for clinical, laboratory, 25-hydroxyvitamin D (25OHD) levels, and ambulatory blood pressure recording. Plasma renin activity (PRA), angiotensin II, and plasma aldosterone concentration (PAC) were assessed in 174 patients treated with calcium channel blockers or no medication. The mean 25OHD concentration in the entire study population was 12.3ng/dL, and the prevalence of vitamin D deficiency was 87.0%. Dipper and nondipper HTN were noted in 187 patients (24.6%) and 573 patients (75.4%). 25OHD levels were similar between nondipper and dipper HTN groups. Forward stepwise logistic regression analysis showed that BMI and age were independent predictors of nondipper HTN. Neither 25OHD levels nor RAAS components were included in the model. In correlation analyses, nocturnal decline of diastolic BP was positively associated with 25OHD levels and standing PRA (r = 0.152 p = 0.045, r = 0.165 p = 0.038, respectively). The present study showed that vitamin D deficiency was astonishingly prevalent in hypertensive subjects residing in Xinjiang, China. There may be a weakly association of nocturnal DBP decline with 25OHD levels and standing PRA levels. We found no association between vitamin D deficiency and nondipper HTN.

Novel Approaches to Investigate One-Carbon Metabolism and Related B-Vitamins in Blood Pressure

Hypertension, a major risk factor for heart disease and stroke, is the world's leading cause of preventable, premature death. A common polymorphism (677C→T) in the gene encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR) is associated with increased blood pressure, and there is accumulating evidence demonstrating that this phenotype can be modulated, specifically in individuals with the MTHFR 677TT genotype, by the B-vitamin riboflavin, an essential co-factor for MTHFR. The underlying mechanism that links this polymorphism, and the related gene-nutrient interaction, with hypertension is currently unknown. Previous research has shown that 5-methyltetrahydrofolate, the product of the reaction catalysed by MTHFR, appears to be a positive allosteric modulator of endothelial nitric oxide synthase (eNOS) and may thus increase the production of nitric oxide, a potent vasodilator. Blood pressure follows a circadian pattern, peaking shortly after wakening and falling during the night, a phenomenon known as 'dipping'. Any deviation from this pattern, which can only be identified using ambulatory blood pressure monitoring (ABPM), has been associated with increased cardiovascular disease (CVD) risk. This review will consider the evidence linking this polymorphism and novel gene-nutrient interaction with hypertension and the potential mechanisms that might be involved. The role of ABPM in B-vitamin research and in nutrition research generally will also be reviewed.

Correlation between serum parathyroid hormone levels and coronary artery calcification in patients without renal failure

The aim of the present study was to investigate the correlation between serum parathyroid hormone (PTH) levels and coronary artery calcification (CAC) in patients without renal failure, as well as to determine independent risk factors of CAC score (CACS). A total of 157 patients who underwent coronary computed tomography angiographic examination at the 101th Hospital of the People's Liberation Army between December 2013 and February 2015 were retrospectively evaluated. The correlation between PTH levels and CACS was determined using a Pearson correlation analysis. A receiver operating characteristic (ROC) curve was drawn to determine the best cutoff PTH level for prediction of CAC. The independent association between serum PTH levels and CAC was analyzed by using a logistic regression analysis model with the response variable Be binary class. The results revealed that PTH levels in patients in the CAC group were significantly higher than those of patients in the non-calcification group. PTH levels were positively correlated with CACS (r=0.288, P<0.001). The ROC curve suggested that a PTH level of ≥31.05 pg/ml was the best cut-off point for the prediction of CAC, with a sensitivity of 80.88%, specificity of 60.67% and an area under the curve of 0.761. After including predictive factors for CAC (gender, age, smoking status, diabetes, hypertension, hyperlipidemia, body mass index, glomerular filtration rate and calcium, phosphorus, calcium-phosphorus product, magnesium, PTH, total cholesterol, low-density lipoprotein cholesterol, triglyceride, high-density lipoprotein cholesterol and C-reactive protein levels), the odds ratio of the serum PTH levels regarding the prediction of CAC was 1.050 (95% confidence interval, 1.027-1.074; P<0.001). In conclusion, the present study suggested that serum PTH levels are correlated with CAC in patients without renal failure and may thus be used as a reliable predictor of CAC.

Serum Parathyroid Hormone Levels Predict Discharge and Readmission for Heart Failure

AIMS

Parathyroid hormone (PTH) levels are useful as a prognostic factor of chronic heart failure (HF) and can predict hospitalization for HF. It is unknown whether serum PTH levels in hospitalized patients with HF can predict discharge and if admission, discharge, or change from admission to discharge PTH measure is the most important predictor of readmission and/or death.

METHODS

A total of 125 consecutive hospitalized patients with HF were enrolled into this study. The receiver operating characteristic (ROC) curves indicated the predicted values of PTH for readmission due to HF and the optimal cutoff points of PTH levels for discharge. The binary logistic regression model indicated an association between PTH levels and readmission due to HF.

RESULTS

The PTH level on admission was positively correlated with the New York Heart Association class and N-terminal pro-B-type natriuretic peptide level. The ROC curves showed that the PTH level at discharge (PTHdis) was of predictive value for readmission within 1 year due to HF. A PTHdis level <45.2 pg/mL was the best cutoff point for discharge, with a sensitivity of 72.1%, specificity of 61.5%, and area under the ROC curve of 0.693 (95% confidence interval [CI] 0.598-0.788). The results of logistic regression analysis showed that PTHdis had an odds ratio of 1.035 for readmission due to HF (95% CI 1.005-1.067).

CONCLUSION

Serum PTH levels in hospitalized patients with HF were shown to be an independent predictor of discharge and PTHdis was the best predictor of readmission and/or death within 1 year due to HF.

The Relationship between Vitamin D Deficiency and Pulmonary Hypertension

Vitamin D deficiency actives renin-angiotensin-aldosterone system (RAAS) which affects cardiovascular system. Activation of RAAS is associated with pulmonary hypertension (PHT). Relation between vitamin D deficiency and PHT could be therefore suggested. In  our study we compared pulmonary artery pressure between vitamin D deficiency and control groups. 115 consecutive patients (average age: 61.86 ± 5.86) who have detected very low vitamin D (vitamin D levels < 10 ng/ml) were enrolled. 117 age matched persons (average age: 61.74 ± 5.99) were selected as the control group. All groups underwent transthoracic echocardiography. Routine biochemical measurement of 25-OH vitamin D and parathormon (PTH) levels were performed. Baseline characteristics of the study groups were comparable. Systolic pulmonary artery pressure (SPAP) of patients in  the low vitamin D group was higher than the control groups. As a  result our study, a  relation between vitamin D deficiency and pulmonary artery hypertension was revealed.

Vitamin D and nifedipine in the treatment of Chinese patients with grades I-II essential hypertension: a randomized placebo-controlled trial

OBJECTIVES

Low vitamin D status has been shown to be associated with hypertension. We planned to research the effect of vitamin D and nifedipine in the treatment of patients with essential hypertension.

METHODS

Patients with grades I-II essential hypertension were enrolled in this single-center, double-blind, placebo-controlled trial in Beijing. All patients received a conventional antihypertensive drug (nifedipine, 30 mg/d). One hundred and twenty-six patients were randomly assigned to receive vitamin D (n=63, 2000 IU/d) or a placebo (n=63) as an add-on to nifedipine, by the method of permutated block randomization. Ambulatory blood pressure monitoring was performed at baseline (month 0), at month 3 and at month 6.

RESULTS

In vitamin D supplementation group, there was a significant increase in mean 25-hydroxyvitamin D levels from baseline (19.4 ± 11.6 ng/ml) to 6 months (34.1 ± 12.2 ng/ml; p<0.001). At 6 months, the primary end points, a difference in the fall of 24-h mean blood pressure, between the groups was -6.2 mmHg (95% CI -11.2; -1.1) for systolic blood pressure (p<0.001) and -4.2 mmHg (95% CI -8.8; -0.3) for diastolic blood pressure (p<0.001) under intention to treat analysis. In patients with vitamin D <30 ng/ml at baseline (n=113), 24-h mean blood pressure decreased by 7.1/5.7 mmHg (p<0.001). Safety and tolerability were similar among the two groups.

CONCLUSIONS

Vitamin D supplementation can reduce blood pressure in patients with hypertension, it can be an adjuvant therapy for patients with grades I-II essential hypertension.

CLINICAL TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry, it is available in Website: http://www.chictr.org/cn/;

REGISTRATION NUMBER

ChiCTR-ONC-13003840.

Sphingomyelin levels in nondipper and dipper hypertensive patients

A number of studies have focused on the association between sphingomyelin (SM) levels and atherosclerosis, however, there are few data concerning the correlation of SM with nondipper hypertension. The present study aimed to investigate the correlation between plasma SM levels and nondipper status in patients with hypertension. A total of 200 hypertensive patients were enrolled and divided into two groups according to their ambulatory blood pressure monitoring (AMBP) results: Dipper group (84 patients) and nondipper group (116 patients). All patients were subjected to transthoracic echocardiography examination and laboratory tests. No statistically significant difference was observed between the two groups in terms of basic clinical characteristics. However, the plasma SM levels in the dipper group were significantly lower than those of the nondipper group (41.9±17.5 vs. 96.4±14.3 mg/dl, P=0.003). The left ventricular mass index (LVMI) was higher in the nondipper patients than in the dipper patients and the diastolic function parameters in the nondipper patients were less favorable. Correlation analysis showed that the SM level was negatively correlated with the magnitude of systolic blood pressure (SBP) fall at night (r=−0.42, P<0.01) and diastolic blood pressure (DBP) fall at night (r=−0.31, P<0.01). The nondipper status had contributory effects on hypertensive concentric hypertrophy and diastolic function impairment. In addition, the plasma SM level was associated with a nondipper pattern of hypertension.