Vitamin D status and hypertension: a review

Association between fat-soluble vitamin co-exposure patterns and blood pressure in people with hypertension: a cross-sectional study

Background

Existing epidemiological studies investigated the association between a single vitamin and hypertension. However, the potential relationship between the level of circulating multivitamins and blood pressure has not been explored. We aimed to investigate the association between multiple fat-soluble vitamin levels and blood pressure.

Methods

A total of 2052 participants with essential hypertension were sampled nationwide. The plasma concentrations of fat-soluble vitamins (A, E, D, and K) were assessed using liquid chromatography coupled with the mass spectrometry method. Participants were categorized into different co-exposure patterns using the unsupervised K-means clustering method. The multiple linear regression model was used for subsequent analyses.

Results

Participants were classified into two co-exposure patterns of fat-soluble vitamins. The levels of vitamins were relatively low in pattern 1, compared to pattern 2. Participants in pattern 2 had no significantly different blood pressure levels compared to pattern 1. However, the plasma 25-hydroxyvitamin D3 (VD3) levels were negatively associated with SBP (logarithmic 10 transformed) (β = -0.002, 95% CI: -0.004, 0); participants in the fourth α-tocopherol quartile had mean SBP levels that were 1.02% (95% CI: 0.43, 1.61%) greater than those in the lowest quartile (p for trend <0.01). In addition, no significant relationships were found between plasma VA/VK concentrations and blood pressure.

Discussion

Although no significant association between fat-soluble vitamin co-exposure patterns and blood pressure was found, further analyses could imply that plasma α-tocopherol levels may offset the potential protective effect of plasma VD3 on blood pressure among hypertensive adults. This provided a novel perspective for exploring the joint effects of fat-soluble vitamins on blood pressure. Further studies are warranted to better understand the implications.

Vitamin D and its associations with blood pressure in the Chronic Kidney Disease in Children (CKiD) cohort

BACKGROUND

Vitamin D (25OHD) can modulate pathways and mechanisms that regulate blood pressure (BP). Observational studies in children and adults have shown an inverse association between 25OHD and BP. Studies evaluating associations between 25OHD and BP in pediatric chronic kidney disease are limited.

METHODS

We evaluated the associations between 25OHD and BP using data from the Chronic Kidney Disease in Children (CKiD) study. Clinic or ambulatory BP index was defined as participant's BP divided by 95th age-sex-height-specific BP percentile, an index > 1 suggests hypertension. Primary outcomes of interest were changes in systolic and diastolic clinic and ambulatory BP indices over follow-up. Linear mixed-effects models were used to evaluate associations between BP indices and 25OHD.

RESULTS

The study cohort consisted of 370 participants who contributed 970 person-visits. A subset of 194 participants with ambulatory BP data contributed 465 person-visits. There was an association between baseline 25OHD levels and clinic systolic BP index such that for every 10 ng/ml lower 25OHD, clinic systolic BP index was 1.0% higher (95%CI: 0.2-1.8, p = 0.016) between participants. The association between clinic diastolic BP index with baseline 25OHD was not significant. For within-person changes, longitudinal decreases in 25OHD were not significantly associated with concomitant increases in clinic systolic or diastolic BP index. There were no significant associations between 25OHD levels at baseline or longitudinally with 24-h ABPM indices.

CONCLUSIONS

Low 25OHD levels were associated with higher clinic systolic BP in children with CKD. Vitamin D supplementation to maintain normal 25OHD levels might be a useful adjunctive treatment in optimizing BP control in these high-risk patients.

Blood Pressure Decreases in Overweight Elderly Individuals on Vitamin D: A Randomized Trial

Context

Evidence for a beneficial role of vitamin D on blood pressure (BP) outcomes is inconclusive.

Objective

This work aimed to investigate the effect of 2 doses of cholecalciferol (vitamin D3) supplementation coadministered with calcium on systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Methods

Exploratory analyses were conducted from a 1-year, multicenter, double-blind, randomized controlled trial (RCT). Total of 221 ambulatory older overweight individuals received calcium dose and oral vitamin D3, at the equivalent of 600 IU/day or 3750 IU/day.

Results

SBP and DBP decreased significantly in the overall group, and in the high-dose group at 6 and 12 months. Similar trends were observed in the low-dose group, but did not achieve statistical significance. In participants with a body mass index (BMI) greater than 30, SBP decreased significantly in both treatment groups whereas DBP significantly decreased in the high-dose group only. In the subgroups of hypertensive participants (N = 143), there was a decrease in SBP and DBP at 6 and 12 months, with both vitamin D doses and independently of BMI levels. Using multivariate linear mixed models with random effects in the overall group of participants, SBP at 6 and 12 months was significantly predicted by BMI (β = .29; P = .05) and by baseline SBP (β = .16; P < .001), but not by vitamin D treatment dose.

Conclusion

Vitamin D and calcium decrease SBP and DBP in overweight older individuals, but more is not necessarily better. This effect is seen in individuals with BMI greater than 30, in hypertensive patients, and seems to be largely independent of dose.

Vitamin D improves hepatic alterations in ACE1 and ACE2 expression in experimentally induced metabolic syndrome

Metabolic Syndrome (MetS) is a term used to describe a cluster of pathophysiological, biochemical, and metabolic criteria; including high Blood Pressure (BP), high cholesterol, dyslipidaemia, central obesity and Insulin Resistance (IR). The Renin Angiotensin System (RAS) has a regulatory function in BP, hydroelectrolyte balance, and cardiovascular function. RAS is composed of angiotensinogen (AGT), (Ang I), (Ang II), (ACE1), (ACE2), (AT1R), (AT2R), and (Ang 1-7). Vitamin D had been proved to act as a protective factor against MetS. Therefore, the study is pursued to explore vitamin D supplementation roles on hepatic RAS in MetS experimental model. At first, 36 males Albino rats were separated into 4 groups and induced to MetS under controlled circumstances for 3 months. Then, data were collected from blood samples, whereas RNA extracted from liver were analyzed using biochemical and statistical analysis tests. As a result, the major finding was proving that vitamin D can balance the expression of ACE1 and ACE2. Also, confirming that it can improve MetS components by elevating HDL and insulin levels while reducing the levels of BP, cholesterol, LDL, TG, GLU, ALT, AST, and IR. These outcomes may give a new insight into the RAS pathways associated with MetS.

Vitamin D supplementation and major cardiovascular events: D-Health randomised controlled trial

OBJECTIVE

To investigate whether supplementing older adults with monthly doses of vitamin D alters the incidence of major cardiovascular events.

DESIGN

Randomised, double blind, placebo controlled trial of monthly vitamin D (the D-Health Trial). Computer generated permuted block randomisation was used to allocate treatments.

SETTING

Australia from 2014 to 2020.

PARTICIPANTS

21 315 participants aged 60-84 years at enrolment. Exclusion criteria were self-reported hypercalcaemia, hyperparathyroidism, kidney stones, osteomalacia, sarcoidosis, taking >500 IU/day supplemental vitamin D, or unable to give consent because of language or cognitive impairment.

INTERVENTION

60 000 IU/month vitamin D₃ (n=10 662) or placebo (n=10 653) taken orally for up to five years. 16 882 participants completed the intervention period: placebo 8270 (77.6%); vitamin D 8552 (80.2%).

MAIN OUTCOME MEASURES

The main outcome for this analysis was the occurrence of a major cardiovascular event, including myocardial infarction, stroke, and coronary revascularisation, determined through linkage with administrative datasets. Each event was analysed separately as secondary outcomes. Flexible parametric survival models were used to estimate hazard ratios and 95% confidence intervals.

RESULTS

21 302 people were included in the analysis. The median intervention period was five years. 1336 participants experienced a major cardiovascular event (placebo 699 (6.6%); vitamin D 637 (6.0%)). The rate of major cardiovascular events was lower in the vitamin D group than in the placebo group (hazard ratio 0.91, 95% confidence interval 0.81 to 1.01), especially among those who were taking cardiovascular drugs at baseline (0.84, 0.74 to 0.97; P for interaction=0.12), although the P value for interaction was not significant (<0.05). Overall, the difference in standardised cause specific cumulative incidence at five years was -5.8 events per 1000 participants (95% confidence interval -12.2 to 0.5 per 1000 participants), resulting in a number needed to treat to avoid one major cardiovascular event of 172. The rate of myocardial infarction (hazard ratio 0.81, 95% confidence interval 0.67 to 0.98) and coronary revascularisation (0.89, 0.78 to 1.01) was lower in the vitamin D group, but there was no difference in the rate of stroke (0.99, 0.80 to 1.23).

CONCLUSIONS

Vitamin D supplementation might reduce the incidence of major cardiovascular events, although the absolute risk difference was small and the confidence interval was consistent with a null finding. These findings could prompt further evaluation of the role of vitamin D supplementation, particularly in people taking drugs for prevention or treatment of cardiovascular disease.

TRIAL REGISTRATION

ACTRN12613000743763.

Vitamin D Deficiency Association with Comorbid Diseases in Palestine: "A Cross-Sectional Observation Study"

BACKGROUND

Vitamin D deficiency (VDD) is a global health concern. This study aimed to determine the prevalence of vitamin D deficiency and its associated comorbidities in Palestine, such as diabetes mellitus, hypertension, hyperlipidemia, and cardiovascular and autoimmune diseases.

METHODS

A retrospective, descriptive study retrieved medical data from the Nat Health insurance processor database from 2014 to 2020. Patient information included age, sex, vitamin D laboratory order, symptoms, and comorbidities. This study included patients prescribed vitamin D at a dose of 50000IU for vitamin D deficiency confirmed by a serum vitamin D laboratory test. The collected data were analyzed using IBM SPSS. In addition, a chi-square test was conducted to assess the association between vitamin D deficiency, symptoms, and comorbidities.

RESULTS

Data of 3011 patients were collected; 639 patients were diagnosed with osteoporosis, and 39 patients prescribed vitamin D without a laboratory test were excluded. Approximately, 1837 (78%) participants had vitamin D deficiency. A total of 1330 women (81.3%) were significantly more likely to have vitamin D deficiency than males, 507 (72.7%; P < 0.001). Joint pain, back pain, and cervicalgia were significantly associated with vitamin D deficiency (P < 0.001). Asymptomatic participants (2.1%) were significantly less likely to have vitamin D deficiency than symptomatic participants (9.5%, p < 0.001). Hypothyroidism is significantly associated with vitamin D deficiency (p = 0.048).

CONCLUSION

In this retrospective study, the prevalence of vitamin D was high and alarming. There was a significant association between VDD, patients who presented with back pain, arthritis, and cervicalgia symptoms, and patients diagnosed with hypothyroidism. Therefore, health initiative programs are warranted to increase awareness regarding screening, prevention, and treatment. Further studies are needed to confirm the relationship between vitamin D supplementation and the reduced risk of comorbid diseases.

Vitamin D and family history of hypertension in relation to hypertension status among college students

Hypertension and vitamin D concentrations have heritable components, although these factors remain uninvestigated in young adults. The objective of this study was to investigate hypertension risk among young adults with respect to family history of hypertension, adjusting for vitamin D status. Resting blood pressure (BP) was measured in 398 individuals aged 18-35 and classified according to the 2017 American Heart Association criteria. Plasma vitamin D metabolite (25(OH)D3; 24,25(OH)2D3; 1,25(OH)2D3) concentrations were determined using liquid chromatography tandem mass spectrometry (LC-MS/MS). Stepwise logistic regression was used to select covariates. Participants' mean age was 21, 30.3% had hypertension, and nearly all unaware of their hypertensive status (90.7%). Compared with no parental history, the adjusted odds ratio (AOR) for hypertension was elevated among participants with two parents having hypertension (AOR = 4.5, 95% CI: 1.70-11.76), adjusting for sex, body mass index, physical activity, and plasma 25(OH)D3. Results for systolic hypertension (SH) were similar but more extreme (two parents AOR = 7.1, 95% CI: 2.82, 17.66), although dihydroxy metabolites (1,25(OH)2D3 and 24,25(OH)2D3) were significant. There was a strong, independent association with dual parental history and hypertension status, regardless of vitamin D status. Hypertension was prevalent in nearly one-third of the sample and underscores the need for targeted prevention for young adults.

Vitamin D supplementation at different doses affects the vagal component of the baroreceptor reflex and the Bezold-Jarisch reflex in eutrophic rats

Vitamin D has been used to prevent several diseases. The 1,25 (OH) 2D3, the active form of vitamin D (VitD), participates in calcium metabolism, and has direct action in various tissues as those of the cardiovascular system binding to the VitD receptor. We investigated whether the supplementation with different doses of VitD affect or not the resting mean arterial pressure (MAP) and heart rate (HR), heart rate variability (HRV), baroreceptor and Bezold-Jarisch reflexes in eutrophic rats. Adult male Wistar rats were randomly assigned in 4 groups (Control, VitD 15, 250, and 3,750 IU/day, n = 6/group). After 3 days of supplementation, MAP and HR recordings were performed in freely moving rats. Baseline (resting) MAP, HR, and HRV showed no difference in Control and VitD groups. Nevertheless, the index of the baroreceptor reflex showed that the bradycardic component of the baroreflex evoked by a pressor dose of phenylephrine (3 μg/kg of b.w.) in bolus injection had a significant increase in rats supplemented with VitD 15 IU/day for 3 days compared to Control animals. No difference was observed in the index of the baroreflex evaluated with phenylephrine in rats treated with VitD 250 and 3,750 IU/day for 3 days in comparison to the Control group. The index of the baroreceptor reflex evaluated with an intravenous bolus injection of a depressor dose of sodium nitroprusside (30 μg/kg of b.w.) showed that the tachycardic component of the baroreflex is not different comparing all groups supplemented with VitD and Control animals. Rats supplemented with VitD 15 IU/day presented exaggerated bradycardic responses to the intravenous injection of phenylbiguanide (PBG, 5 μg/kg of b.w.) compared to Control animals, despite the similar hypotension in both groups. Higher doses of supplementation of VitD (250 and 3,750 IU/day for 3 days) abolished the hypotension and bradycardia induced by PBG. The findings suggest that the supplementation with different doses of VitD (15, 250, and 3,750 IU/day) for 3 days did not affect the resting arterial pressure, heart rate and autonomic modulation on the heart in rats. Despite that, the supplementation with a low dose of VitD (15 IU/day for 3 days) improved the sensitivity of the bradycardic component of the baroreflex, whereas higher doses of supplementation with VitD (250 and 3,750 IU/day for 3 days) were unable to cause such effect. In addition, the Bezold-Jarisch reflex responses can be affected regardless the dose of VitD (15, 250 or 3,750 IU/day) supplementation for 3 days in rats.

Efficacy of single-dose cholecalciferol in the blood pressure of patients with type 2 diabetes, hypertension and hypovitaminoses D

Observational and experimental data reinforce the concept that vitamin D is associated with the pathogenesis of arterial hypertension. We investigated the effect of a single dose of 100,000 IU of cholecalciferol, in office blood pressure (BP), and 24-h ambulatory blood pressure monitoring (ABPM) in patients with type 2 diabetes mellitus (DM), hypertension, and hypovitaminosis D. Forty-three patients were randomized to a placebo or cholecalciferol group. BP was assessed by office measurements and 24-h ABPM, before and after intervention. At week 8, a greater decrease in median ABPM values was observed in cholecalciferol supplementation than in the placebo group for systolic 24-h (− 7.5 vs. − 1; P = 0.02), systolic daytime (− 7 vs. − 1; P = 0.007), systolic nighttime (− 7.0 vs. 3; P = 0.009), diastolic 24-h (− 3.5 vs. − 1; P = 0.037), and daytime DBP (− 5 vs. 0; P = 0.01). Office DBP was also reduced after vitamin D supplementation. A single dose of vitamin D₃ improves BP in patients with type 2 diabetes, hypertension, and vitamin D insufficiency, regardless of vitamin D normalization. Vitamin D supplementation could be a valuable tool to treat patients with type 2 DM, hypertension, and hypovitaminosis D.

Trial registration: Clinicaltrials.gov NCT 02204527.

Effects of vitamin D supplementation on 25(OH)D levels and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) levels and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D level changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D levels and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Effects of vitamin D supplementation on 25(OH)D levels and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) levels and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D level changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D levels and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Effects of vitamin D supplementation on 25(OH)D concentrations and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) concentrations and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D concentrations changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D concentrations and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Association of Serum Levels of Vitamin D with Blood Pressure Status in Northern Iranian Population: The PERSIAN Guilan Cohort Study (PGCS)

Background

Evidence in the last decades has indicated an association between vitamin D and cardiovascular risk factors including blood pressure. The present study aimed to determine whether serum 25-hydroxyvitamin D is independently associated with blood pressure in a large population-based study.

Methods

The study was based on subjects from PERSIAN Guilan Cohort Study (PGCS), a prospective, population-based cohort study in Guilan, Iran. In 9520 men and women, aged 35-70 years, serum 25-hydroxyvitamin D, systolic and diastolic blood pressure were measured. Multiple logistic and linear regression analyses were conducted with adjustments for demographic factors (age and gender), anthropometric characteristics (waist circumference and body mass index), lifestyle variables (physical activity, alcohol, and smoking consumption), and renal function (serum creatinine).

Results

Fully adjusted linear regression analyses revealed a weak but statistically significant negative association between serum 25-hydroxyvitamin D levels and systolic blood pressure (β = -0.02, 95% CI= -0.052 to -0.0001, P-value=0.04), whereas vitamin D status was not significantly associated with diastolic blood pressure (β = -0.01, 95% CI= -0.026 to 0.009, P-value=0.3). Serum 25-hydroxyvitamin D status showed no significant association with the presence of hypertension (OR 1.09, 95% CI=0.94 to 1.25 for the lowest (25OHD <12 ng/mL) versus the highest (25OHD ≥20 ng/mL) category).

Conclusion

Lower serum vitamin 25 (OH) D levels were associated with higher systolic blood pressure; however, it was not associated with diastolic blood pressure and presence of hypertension.

Association of serum 25-hydroxyvitamin D levels with primary hypertension: a study from south India

Hypertension is a major risk factor for cardiovascular and cerebrovascular disease. Recent studies have identified an association between low vitamin D levels and hypertension. We investigated the association between vitamin D levels and hypertension in the general population. We recruited 400 hypertensive subjects and compared them with 400 age- and sex-matched normotensive subjects. This study was carried out at Yashoda Hospital, Hyderabad, India from January 2015 to December 2017. Both groups underwent risk factor evaluation, estimation of serum 25-hydroxyvitamin D levels, and C-reactive protein (CRP) and liver function tests. Out of the 400 hypertensive subjects, 164 (40.2%) had serum 25-hydroxyvitamin D deficiency, compared with 111 (27.7%) normotensive subjects (p = 0.0001). Deficiency of serum 25-hydroxyvitamin D in hypertensive subjects was significantly associated with CRP positivity, low levels of mean serum calcium, low levels of mean serum phosphorous, high levels of mean alkaline phosphatase (p < 0.0001), and abnormal alanine transaminase (ALT) (p = 0.0015) compared with the same parameters in the normotensive subjects. After adjustment in the multiple logistic regression analysis, serum 25-hydroxyvitamin D deficiency (odds: 1.78; 95% CI: 1.31-2.41), CRP positivity (odds: 1.48; 95% CI: 1.48-2.32) and abnormal ALT (odds: 1.2; 95% CI: 0.98-1.94) were significantly associated with hypertension. Serum 25-hydroxyvitamin D deficiency was significantly associated with hypertension.

Association of circulating 25-hydroxyvitamin D levels with hypertension and blood pressure values in Korean adults: A Mendelian randomization study on a subset of the Korea National Health and Nutrition Survey 2011-2012 population

BACKGROUND/OBJECTIVES

Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach.

SUBJECTS/METHODS

Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method.

RESULTS

In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence.

CONCLUSIONS

We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.

Vitamin D and cardiovascular disease in chronic kidney disease

Chronic kidney disease (CKD) is considered an independent risk factor for cardiovascular disease, with increased cardiovascular morbidity and mortality seen even in the early stages of CKD. Several studies have shown a high prevalence of vitamin D deficiency in individuals with CKD. Low vitamin D levels upregulate the renin-angiotensin-aldosterone system (RAAS), cause endothelial dysfunction, and increase inflammation. Epidemiological studies show an association between vitamin D deficiency and risk factors for cardiovascular disease, but a causal relationship has not been established. The high cardiovascular morbidity and mortality associated with CKD in adults requires therapies to decrease this elevated risk. However, results from several meta-analyses and randomized clinical trials in adults have not shown convincing evidence for the use of vitamin D therapy in improving cardiovascular outcomes. Lack of high-quality evidence from randomized clinical trials in children regarding the effectiveness and long-term safety of vitamin D treatment precludes any recommendations on its use to mitigate the cardiovascular burden of CKD.

Telomere length and associated factors in older adults with hypertension

Telomeres and telomerase play important roles in the occurrence and development of hypertension. This review was performed to clarify the factors that influence telomere length and telomerase activity in older patients and elucidate the association of these factors with hypertension. A PubMed search and critical review of studies assessing the risk factors underlying the association of hypertension with telomere length and telomerase activity was performed. Telomere length and telomerase activity were found to be associated with hypertension. The factors that influence telomere length and telomerase activity in older patients with hypertension include genetics, demographics, social and environmental factors, chronic disease, psychological factors, and antihypertensive drug treatment. A better understanding of the molecular mechanisms underlying the association of hypertension with telomere length and telomerase activity may help to reduce the incidence of hypertension.

Vitamin D and cardiovascular disorders

Vitamin D is necessary for bone health but may also have many extra-skeletal effects. The vitamin D endocrine system has major effects on gene and protein expression in many cells and tissues related to the cardiovascular system. In addition, many preclinical studies in animals with vitamin D deficiency or genetically silenced expression of the vitamin D receptor or vitamin D metabolizing enzymes suggest that the absence of vitamin D action may result in cardiovascular events. This includes dysfunctions of endothelial cells, thereby accelerating the process of atherosclerosis, hypertension or abnormal coagulation, ultimately resulting in higher risks for all major cardiovascular or cerebrovascular events. A wealth of observational studies in different parts of the world have fairly consistently found a strong association between a poor vitamin D status and surrogate markers or hard cardiovascular events. A few Mendelian randomization studies did, however, not find a link between genetically lower serum 25OHD concentrations and cardiovascular events. Finally, many RCTs could not demonstrate a consistent effect on surrogate markers, and a limited number of RCTs did so far not find whatever effect on hard cardiovascular endpoints such as myocardial ischemia or infarction, stroke, or cardiovascular death. In conclusion, preclinical data generated a plausible hypothesis of a link between vitamin D status and extra-skeletal events, including cardiovascular endpoints. Whether the vitamin D endocrine system is redundant for the human vascular system or whether the RCTs have not been optimally designed to answer the research question is thus not yet settled.

The relationship between Plasma Markers and Essential Hypertension in Middle-aged and Elderly Chinese Population: A Community Based Cross-sectional Study

Plasma markers have been continuously advocated as pointers to estimate the long-term risk of cardiovascular disease in the general population. We examined the relationship between plasma high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), high-sensitivity cardiac troponin T (hs-cTnT), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), 25-Hydroxyvitamin D (25OHD), glycosylated hemoglobin A1c (HbA1c), and serum uric acid (SUA) levels and hypertension in middle and old aged population. A total of 2624 Chinese (62.02 ± 5.73 years old) were recruited into a population-based, cross-sectional study. Plasma hs-CRP, Hcy, HbA1c, and SUA levels were significantly higher in the hypertension group compared with control in the entire population and men (P = 0.05 for all). We observed a positive association between the highest quartiles of Hcy, NT-proBNP, HBA1c concentrations, and the prevalence of hypertension, OR (95% CI) = 1.48 (1.16–1.90), 1.62 (1.27–2.07) and 1.94 (1.49–2.52), respectively. The multivariable-adjusted OR of hypertension for the fourth versus the first quartile of homocysteine were 2.00 and 1.39 in men and women, respectively. In conclusion, our study found an independent and robust association between elevated Hcy, NT-ProBNP, and HBA1c levels and prevalence of hypertension in the middle-aged and elderly Chinese population. A follow-up study is necessary to endorse the observed association.

The Mechanism of Acupuncture in Treating Essential Hypertension: A Narrative Review

Essential hypertension has a high incidence worldwide, and patients with essential hypertension endure a lifetime of medication, leading to a heavy economic burden on the patient's family and causing serious impacts on the patient's quality of life. Much evidence has demonstrated that acupuncture as an adjunctive therapy can lower blood pressure in patients with hypertension, but the mechanism of its action is unclear. This article reviews the research from 2000 to 2018 regarding the mechanism of acupuncture for hypertension, and we summarize the current knowledge about using acupuncture for hypertension. We found that the mechanism whereby acupuncture lowers blood pressure is related to the regulation of renin-angiotensin-aldosterone system, vascular endothelium, oxidative stress, neuroendocrine system, and so on. Besides, there may be cross-talk between multiple systems and multiple targets. We also investigate the influence factors of acupuncture for hypertension. These results may provide evidence and research ideas for the treatment of hypertension via acupuncture.

Effect of Vitamin D Supplementation on Weight Loss, Glycemic Indices, and Lipid Profile in Obese and Overweight Women: A Clinical Trial Study

Introduction

Vitamin D (vit D) deficiency has defined as a health problem worldwide. World Health Organization (WHO) has declared that obesity is an epidemic of the 21^st century. Previous studies have shown that obesity may increase the risk of Vit D deficiency. Furthermore, other studies have demonstrated that vit D insufficiency was accompanied with higher risk of type 2 diabetes, cardiovascular diseases, hypertension, and obesity. The aim of this study was to survey the effect of vit D supplementation on weight loss among overweight and obese women aged 20-40 years in Isfahan.

Methods

This double-blind clinical trial was done on 50 overweight and obese women who were divided into two groups, in which one group received vit D supplements and the other group received placebo. Intervention group received vit D with dozes 50,000 IU/w for 6 weeks. The levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), fasting blood sugar (FBS), insulin (ins), homeostasis model assessment of ins resistance (IR), C-reactive protein (CRP), height, weight (WT), waist circumference (WC), hip circumference (HC), and blood pressure (BP) were measured before and after intervention.

Results

After using vit D supplementation for 6 weeks, WT, WC, and body mass index (BMI) were decreased significantly and serum vit D increased significantly compared to control group (P < 0.001). Other factors including TC, TG, LDL-c, HDL-c, FBS, CRP, ins, IR, and waist to hip ratio (WHR) did not change significantly (P > 0.05).

Conclusions

After 6 weeks of intervention, the means of WT, BMI, WC, and HC decreased significantly. Previous studies have shown that vit D deficiency was more prevalence in obese people and there was an inverse association among vit D with BMI and WC. The relationship between vit D and lipid profiles such as glycemic indexes, anthropometric indexes, CRP, and BP is not clear and needs more study in the future.

The Impact of Vitamin D in the Treatment of Essential Hypertension

The aim of this review is to investigate, whether there is a possible link between vitamin D supplementation and the reduction of blood pressure in hypertensive patients. The renin-angiotensin-aldosterone system is known for being deeply involved in cardiovascular tonus and blood pressure regulation. Hence, many of the pharmaceutical antihypertensive drugs inhibit this system. Interestingly, experimental studies in mice have indicated that vitamin D supplementation significantly lowers renin synthesis and blood pressure. It is conceivable that similar mechanisms may be found in the human organism. Regarding this, large-scale cross-sectional studies suggest the serum 25(OH)D-level to be inversely correlated to the prevalence of hypertension. However, randomized controlled trials (RCTs) have not found a clear association between vitamin D supplementation and improvements in hypertension. Nevertheless, the missing association of vitamin D and hypertension in clinical trials can be due to suboptimal study designs. There are hints that restoration of serum 25(OH)D levels during vitamin D therapy is essential to achieve possible beneficial cardiovascular effects. It is important to perform long-term trials with a short dose interval and a high bioavailability of supplementation. Taken together, more RCTs are required to further investigate if vitamin D can be beneficial for the reduction of blood pressure.

Evaluation of vitamin D relationship with type 2 diabetes and systolic blood pressure

OBJECTIVE

To investigate whether relationships exist among vitamin D, type 2 diabetes mellitus (T2DM), and blood pressure in Trinidadian subjects with T2DM.

RESEARCH DESIGN AND METHODS

This was a case-controlled study to determine if vitamin D levels were lower in patients with T2DM. After data analysis, an exploratory hypothesis of vitamin D relationship to systolic blood pressure (SBP) was developed. Plasma calcifediol (25(OH)D) concentrations were used as a measurement for vitamin D levels and were determined by ELISA. Cholesterol levels were measured by an automated dry chemistry analyzer and blood pressure was measured using an automatic blood pressure monitor.

RESULTS

There was no significant difference (p=0.139, n=76) in 25(OH)D levels between patients with T2DM and controls. Subjects with SBP above 130 mm Hg were 8 times more likely to have a 25(OH)D plasma concentration above 25 ng/mL (OR 7.9 (2.2 to 28.7)), and were 5 times (OR 4.7 (1.7 to 15.1)) more likely to have a 25(OH)D plasma concentration above 30 ng/mL (OR 7.5 (2.3-24.2)). Vitamin D levels moderately and positively correlated with SBP (rs=0.38, p=0.001).

CONCLUSIONS

There was no significant difference in the 25(OH)D levels between patients with T2DM and controls (p=0.139). Patients with SBP under 130 mm Hg were 8 times more likely to have a vitamin D level above 25 ng/mL (OR 7.9 (2.2 to 28.7)). Further investigations are required to examine the relationship between vitamin D and SBP.

The association between Vitamin D and health outcomes in women: A review on the related evidence

BACKGROUND

Vitamin D has a wide range of physiological functions in skeletal and nonskeletal tissues which may play a role in many diseases. The aim of this study was to evaluate the recent evidence regarding the effects of Vitamin D on several health outcomes in women including breast cancer, ovarian and endometrial cancers, hypertension, and osteoporosis.

MATERIALS AND METHODS

We searched PubMed and Google Scholar databases through March 2016. We included the most current systematic reviews and meta-analyses assessing the associations of Vitamin D intake and/or serum 25-hydroxyvitamin D (25(OH)D) levels with the risk of incidence of breast cancer, ovarian and endometrial cancers, hypertension, and osteoporosis.

RESULTS

Many studies have represented that Vitamin D supplementation and high 25(OH)D levels can decrease the risk of breast cancer occurrence or mortality. However, there is no strong evidence to support the existence of a relationship between Vitamin D and ovarian or endometrial cancers. Furthermore, the results regarding the effects of Vitamin D on hypertension were inconsistent. Although observational studies have shown an association between Vitamin D and hypertension, there is no evidence regarding effectiveness of Vitamin D in lowering blood pressure in several clinical trials. On the other hand, the findings associating the impact of Vitamin D on osteoporosis were more definitive and most studies have represented that Vitamin D may have beneficial effects on osteoporosis.

CONCLUSION

Although the adequate Vitamin D level can play a protective role in the incidence and development of breast cancer, hypertension, and osteoporosis, there is limited evidence regarding ovarian and endometrial cancers.

The Effect of High Dose Cholecalciferol on Arterial Stiffness and Peripheral and Central Blood Pressure in Healthy Humans: A Randomized Controlled Trial

Background

Low levels of serum 25-hydroxy vitamin D are associated with increased arterial stiffness and hypertension. Supplementation with vitamin D precursors has been proposed as a treatment option for these conditions. We examined the effect of oral cholecalciferol on arterial stiffness and blood pressure in healthy normotensive adults.

Methods

40 healthy adults were randomised in this double-blinded study to either oral cholecalciferol 3000 IU/day or matching placebo and were followed for 16 weeks to examine any effects on pulse wave velocity (PWV), augmentation index (AIx), peripheral and central blood pressure and 24-hour ambulatory blood pressure.

Results

22 subjects in the cholecalciferol arm and 18 subjects in the placebo arm completed the 16 weeks of follow-up. There was no difference in changes in PWV, AIx corrected for heart rate or central or peripheral blood pressure between the two groups. There was no correlation between serum 25-hydroxy vitamin D and any of these parameters.

Conclusions

Oral cholecalciferol 3000 IU/day does not affect arterial stiffness or blood pressure after 16 weeks of treatment in healthy normotensive adults.

Trial Registration

ClinicalTrials.gov NCT00952562

Serum 25-hydroxyvitamin D as a predictor of hospitalization-free survival in predialysis and dialysis patients with chronic kidney disease: a single-center prospective observational analysis

Background

Vitamin D has pleiotropic effects important for the proper functioning of multiple organ systems. We investigated whether serum 25-hydroxyvitamin D [25(OH)D] levels influenced hospitalization-free survival in patients with chronic kidney disease (CKD).

Methods

In this prospective study, serum levels of 25(OH)D were measured in 210 patients with CKD in the winter of 2009. Data regarding hospitalizations were collected over the subsequent 3 years.

Results

Vitamin D deficiency, as defined by a serum 25(OH)D level below 15 ng/mL, was observed in 76.7% of the patients. The mean 25(OH)D serum level was 13.6 ± 7.8 ng/mL in predialysis patients (n = 62) and 11.3 ± 6.7 ng/mL in dialysis patients (n = 148). During the follow-up, 107 patients (28 predialysis and 79 dialysis) were hospitalized because of infectious (33.6%) or cardiovascular diseases (23.4%). Predialysis and dialysis groups were divided into 2 subgroups based on the median 25(OH)D serum level. Kaplan–Meier analysis revealed that the risk of hospitalization was significantly lower in both predialysis and dialysis patients with above-median serum 25(OH)D levels (log-rank test; P = 0.043 and 0.002, respectively). Multivariate Cox proportional hazards models also demonstrated that the risk of hospitalization was significantly lower for patients with higher serum 25(OH)D levels in both the predialysis (hazard ratio, 0.963; 95% confidence interval, 0.93–0.99) and dialysis groups (hazard ratio, 0.955; 95% confidence interval, 0.91–0.99).

Conclusion

A lower serum 25(OH)D level predicted poorer hospitalization-free survival in both predialysis and dialysis CKD patients.

The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D

Using a variety of approaches, researchers have studied the health effects of solar ultraviolet (UV) radiation exposure and vitamin D. This review compares the contributions from geographical ecological studies with those of observational studies and clinical trials. Health outcomes discussed were based on the author's knowledge and include anaphylaxis/food allergy, atopic dermatitis and eczema, attention deficit hyperactivity disorder, autism, back pain, cancer, dental caries, diabetes mellitus type 1, hypertension, inflammatory bowel disease, lupus, mononucleosis, multiple sclerosis, Parkinson disease, pneumonia, rheumatoid arthritis, and sepsis. Important interactions have taken place between study types; sometimes ecological studies were the first to report an inverse correlation between solar UVB doses and health outcomes such as for cancer, leading to both observational studies and clinical trials. In other cases, ecological studies added to the knowledge base. Many ecological studies include other important risk-modifying factors, thereby minimizing the chance of reporting the wrong link. Laboratory studies of mechanisms generally support the role of vitamin D in the outcomes discussed. Indications exist that for some outcomes, UVB effects may be independent of vitamin D. This paper discusses the concept of the ecological fallacy, noting that it applies to all epidemiological studies.