Does Vitamin D Deficiency Lead to Hypertension?

Serum Vitamin D Levels Mediate the Association Between Physical Activity and Blood Pressure in Adolescents

Individuals with low levels of vitamin D are associated with cardiovascular risks, such as elevated blood pressure (BP), and are; therefore, more likely to develop hypertension. Patients with vitamin D deficiency may face an increased risk of cardiovascular events. In this study, a multicenter, cross-sectional, and school-based investigation was conducted as part of the ERICA project. The sample comprised 1152 adolescents aged 12-17 years from 4 Brazilian cities. Anthropometric variables, BP measurements, and hydroxyvitamin D concentrations were assessed. A 2-level linear regression was fitted to examine the relationship between each level of BP and independent variables. Our findings indicate that movement behaviors were not associated with BP levels, with the exception of sleep time, which demonstrated a positive association. However, after adjustment, this association was found to be nonsignificant. Our study's mediation analysis revealed that vitamin D mediates up to 12.9% of the association between physical activity and systolic BP. Vitamin D is inversely associated with BP in adolescents. In addition to mediating the physical activity and systolic BP association, engaging in physical activity, particularly outdoors, can provide a dual benefit for adolescents by increasing serum vitamin D levels and assisting in the control of BP levels.

The association of 25 (OH) D3 serum level with ischemic cerebrovascular accident risk, severity and outcome in Iranian population

OBJECTIVES

The role of combined presence of vitamin D deficiency and other risk factors of stroke in ischemic cerebrovascular accident (CVA) development in Iranian adults has been unclear, so far. The association of vitamin D status at admission with ischemic CVA severity and outcome in this community is not yet well elucidated. This study aimed to clarify these ambiguities.

METHODS

In a cross-sectional study 104 hospitalized ischemic CVA patients and 104 healthy controls participated. The serum level of 25 (OH) D3 and baseline biochemical parameters were measured in ischemic patients within the first 24 h of admission, as well as healthy controls. The severity of CVA and clinical outcome were assessed using National Institutes Health Stroke Scale and Modified Rankin Scale, respectively. Data were analyzed using the Chi-square test, independent t-test, and multiple logistic regression.

RESULTS

There was a significant difference between patients and controls regarding the presence of vitamin D3 deficiency, hypertension, smoking, and baseline level of LDL and FBS. Vitamin D3 deficiency boosted the risk of ischemic in males and those having family history of CVA. A low serum level of 25 (OH) D3 was associated with more severity and poor outcome of CVA. The CVA severity, vitamin D3 deficiency, and hypertension were predictors of poor outcome.

CONCLUSIONS

The study highlights the increased risk of ischemia in Iranians by cooccurrence of vitamin D3 deficiency and other risk factors of CVA. Clinical significance of vitamin D3 deficiency control may be suggested in those at risk of CVA and functional poor outcomes.

Age-dependent changes in fat- and water-soluble vitamins—National Health and Nutrition Examination Surveys study

Aging is an independent risk factor for the development of various diseases associated, among others, with detrimental blood levels of fat- and water-soluble vitamins. Thus, the objective of this study is to investigate age-related changes in blood levels of vitamin A, B12, C, D, and E. Subject serum vitamin levels were obtained from the combined National Health and Nutrition Examination Surveys (NHANES). NHANESIII and NHANES 1999–2000, 2001–2002, 2003–2004, and 2005–2006. The raw data set was stratified into five age groups G1- G5: 20 ≤ G1 < 30, 30 ≤ G2 < 40, 40 ≤ G3 < 50, 50 ≤ G4 < 60, and 60 ≤ G5 < 70 years of age. Age stratified data was cleaned using the modified Horn algorithm. The reference range for the vitamin level of a specific age group was defined as data between the first and third quartile of the subject defined by normal blood pressure and normal bone density. Age-dependent changes in serum/plasma vitamin levels were assessed using the bootstrap technique with 10,000 repeats and Bonferroni adjustment. There was a continuous increase in vitamin A, B12, D, and E levels in the blood. However, the vitamin C concentration remained virtually constant in all age groups. There was a lack of cross-correlations between lipid and water-soluble vitamin levels and blood pressure and bone health. The following reference levels for vitamin A, B12, C, D, and E in subjects older than 20 years of age were established: vitamin A: 1.32–2.8 mmol/L, vitamin B12: 257.94–498.33 pmol/L, vitamin C: 38.18–79.2 mmol/L, vitamin D: 76.33–199.36 nmol/L and vitamin E: 3.65–41.12 μmol/L.

The association between vitamin D deficiency and metabolic syndrome in Ukrainian adolescents with overweight and obesity

PURPOSE

This work aims to determine the association between vitamin D deficiency and metabolic syndrome in overweight and obese adolescents from Ukraine.

METHODS

Anthropometric measurements were taken and general and biochemical examinations were performed on 136 obese and overweight adolescents and 60 adolescents with normal body weight. The vitamin D status was determined using 25-hydroxyvitamin D (25(OH)D) (calcidiol) levels in blood serum. To establish the factors influencing vitamin D status, the subjects were asked to answer a questionnaire and 2007 International Diabetes Federation diagnostic criteria were used to determine the incidence of metabolic syndrome. All research results were processed statistically.

RESULTS

A calcidiol sufficiency level was found in 3.9% of obese adolescents and 6.7% of overweight adolescents. Metabolic syndrome was found in 64.4% of obese adolescents with vitamin D deficiency, and in 26.2% of overweight adolescents. Factors associated with an increased risk of developing vitamin D deficiency in adolescents with metabolic syndrome included male sex (p=0.042), low income per family member (p=0.040), daily milk consumption of up to 1 cup per day (p=0.001), physical activity (p=0.001), duration of outdoor stays (p=0.001), and passive rest in front of a computer or television (p=0.001). Adolescents with metabolic syndrome were found predominance of body mass index (p<0.001), waist circumference (p<0.001), fasting blood glucose level (Р<0.001), and decreased calcidiol level (p=0.022). Among metabolic syndrome components, vitamin D deficiency was strongly associated with waist circumference and increased fasting blood glucose (p<0.05).

CONCLUSION

Vitamin D deficiency is prevalent in overweight and obese adolescents from Ukraine. Vitamin D deficiency is associated with metabolic syndrome criteria in overweight and obese adolescents.

Prevalence of Vitamin D Deficiency Between Type 2 Diabetes Mellitus Patients and Non-Diabetics in the Arab Gulf

BACKGROUND

The link between the risk of type 2 diabetes mellitus (T2DM) and vitamin D deficiency has perplexed the medical society due to the controversy in the data available. Saudi Arabia (SA) is a sunny region; however, ample amount of data reported the increased prevalence of vitamin D deficiency along with T2DM. Thus, this study aimed to compare vitamin D deficiency between healthy and T2DM patients in SA, alongside with the risk factors associated with that.

METHODS

A cross-sectional study was conducted in the Medical Unit, Taibah University in Al-Madinah Al-Munawarah, SA, from November 2017 to May 2018. The involved participants were non-diabetics and T2DM men. Measuring vitamin D for T2DM and non-diabetics group was done by trained technicians. Data analysis was done via SPSS.

RESULTS

Sixty-four participants (T2DM group = 32; non-diabetics group = 32) were recruited, and the mean age of T2DM patients was 48.6 ± 10.4, while that of the non-diabetics was 42.4 ± 6.5. The mean of vitamin D level was found higher in the non-diabetic participants than in diabetic patients. There was statistically significant association between vitamin D deficiency and T2DM (P = 0.001). Besides, duration of diabetes was the only factor, found to be positively correlated with vitamin D deficiency in T2DM patients.

CONCLUSION

Early screening for vitamin D serum-level is recommended for T2DM patients in Saudi Arabia. Therefore, early correction of vitamin D levels should be considered, and medical and scientific societies, along with other sectors such as the media, should highlight and increase the awareness of the importance of vitamin D and the seriousness of its deficiency.

The Relationship between Low 25-Hydroxyvitamin D and Cardio-Metabolic Risk Factors among Ellisras Young Adults

Introduction: 25-hydroxyvitamin D (25(OH)D) is found in circulating blood and is regarded as an estimate of vitamin D status. Low circulating 25(OH)D levels are associated with a high body mass index (BMI), increased weight and the increased development of adipose tissue. This study aimed to determine the relationship between low 25(OH)D and cardio-metabolic risk factors among Ellisras young adults. Materials and methods: This is a cross-sectional study that took place in a rural area at Ellisras in Limpopo Province South Africa. The study included 631 young adults (327 females and 304 males) aged between 20 and 29 years. Anthropometric measurements including height, weight and waist circumference were measured following standard procedures. Blood pressure, pulse pressure and blood parameters including fasting plasma glucose, total cholesterol and triglycerides were also measured. Correlations and linear regression were performed to determine the relationship between low 25(OH)D and cardio-metabolic risk factors. Results: Descriptive statistics showed significant (p < 0.05) mean difference of LDL, HDL and blood pressure between males and females. There was a significant association between low 25(OH)D and WC (p = 0.010) based on Spearman correlation. There was no association found between low 25(OH)D and HDL in all models (B ranges from 0.072 to 0.075). There was also no association found between low 25(OH)D and systolic blood pressure (SBP) in all models (B ranges from −0.009 to −0.024). Conclusion: Low 25(OH)D was correlated with WC, and therefore with adiposity. Knowledge of the associations between 25(OH)D deficiency and cardio-metabolic risk before the development of the disease is therefore important to establish whether 25(OH)D supplementation can be used for the prevention of these conditions. Educational programmes should be implemented to educate the communities and the nation at large on how to prevent 25(OH)D deficiency.

Vitamin D Supplementation and Blood Pressure in Children and Adolescents: A Systematic Review and Meta-Analysis

Suboptimal vitamin D status is associated with elevated blood pressure (BP) in children and adolescents. Whether vitamin D supplementation reduces BP remains unclear. To systematically review whether vitamin D supplementation reduces BP in children and adolescents, we conducted a literature review according to the PRISMA statement. We included vitamin-D supplementation human interventions studies that reported on BP as an outcome. We searched PUBMED, MEDLINE, CINAHL, EMBASE, the Cochrane Library, and the clinical trials website. We also hand searched the references of the included articles and previous reviews of vitamin D therapy. No language or time restrictions were applied. We extracted data on population characteristics, baseline and endline vitamin D and BP values, and assessed the risk of bias of the included studies. We performed a narrative review of the findings, conducted a meta-analysis when possible, and performed sensitivity analyses to test the robustness of our results. We assessed the overall quality of the evidence produced in the meta-analysis. We included eight studies in our review and five studies in the meta-analysis, none of which included hypertensive only participants. The risk of bias was variable. In non-randomized studies, no effect of vitamin D supplementation was seen on systolic BP (SBP) (mean difference: 0.39 (95% confidence interval (CI): −0.9; 1.68) mmHg; p = 0.55; I² = 0%). Only a significant decrease in diastolic BP (DBP) (mean difference: −1.87 (95% CI: −3.02; −0.72) mmHg; p = 0.001; I² = 0%) was noted. Both analyses had a low quality of evidence. In randomized controlled trials (RCTs), no effect was noted on SBP (mean difference: −2.04 (95% CI: −5.12; 1.04) mmHg; p = 0.19; I² = 71%) nor DBP (mean difference: 0.01 (95% CI: −1.09; 1.12) mmHg; p = 0.98; I² = 0%). The final quality of evidence ranged between low and moderate. Sensitivity analyses did not affect the results. Vitamin D supplementation was found to be ineffective in lowering SBP and DBP in children and adolescents.

Cerebrovascular disease: how serum phosphorus, vitamin D, and uric acid levels contribute to the ischemic stroke

Background

Associations between serum phosphorus level and the incidence of ischemic stroke are not clear. This study aimed to measure serum phosphorus, vitamin D3, and uric acid levels in ischemic stroke patients compared to a population without ischemic stroke.

Methods

In this cross-sectional study, 133 patients admitted to a neurology ward with the diagnosis of ischemic stroke were compared with a control group comprising 133 age- and gender-matching individuals. The presence of ischemic stroke was confirmed by a neurologist based on clinical signs, symptoms, brain CT scan, and MRI. Blood samples were taken from all patients in the first 24 h of admission to measure serum phosphorus, vitamin D3, calcium, and uric acid levels.

Results

According to the results of this study, uric acid medians in patients with stroke and controls were 4.9 [3.8–6.4] and 3.9 [3.5–4.9] mg/dL, respectively (p < 0.001). Median phosphorus and vitamin D levels were significantly lower in stroke patients than the controls (3.6 [3.02–4.21] vs. 4.2 [3.8–4.6]) and (15.1 [8.2–27.9] vs. 22.7 [10.4–39.2]), respectively. Multiple logistic regression analysis showed that the ischemic stroke was positively associated with the vitamin D level and negatively correlated with the uric acid level. The phosphorus level was not significantly predictive of ischemic stroke.

Conclusion

Lower serum levels of vitamin D3 and higher levels of uric acid were associated with ischemic stroke. There are still unknowns about the role of these indicators on ischemic stroke and it requires further studies.

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.

The Association between Cardiovascular Disease Risk Factors and 25-Hydroxivitamin D and Related Analytes among Hispanic/Latino Adults: A Pilot Study

Although the association of vitamin D levels with cardiovascular risk profiles among Hispanics/Latinos has been studied, little is known about this association among Hispanics/Latinos with chronic conditions. This pilot study determined serum vitamin D and parathyroid hormone (PTH) levels in a sample of participants from the University of Illinois at the Chicago Cohort of Patients, Family and Friends (UIC Cohort) and examined their association with traditional cardiovascular disease risk factors. From July 2012 to June 2016, the UIC Cohort study enrolled and conducted clinical examinations on men and women ages 18 years and older, who had one or more diagnosed chronic diseases/conditions (excluding cancer). This pilot study sample included 40 participants from the six main Hispanic/Latino background groups in the United States, namely Dominican, Cuban, Puerto Rican, Mexican, Central American, and South American, and were grouped by Caribbean or mainland origin. No substantial differences were noted in the vitamin D-related measures by Hispanic/Latino background, but the PTH levels were somewhat higher in the Caribbean vs. mainland group (43.0 ± 4.6 vs. 38.6 ± 2.7 pg/mL). The associations between selected CVD risk factors (systolic and diastolic blood pressure (SBP, DBP), total cholesterol, glucose) and PTH and vitamin D-related analytes were investigated using interval-censored multivariate regression models adjusted for age, sex, percent body fat, serum albumin/calcium, and Hispanic/Latino background. A negative association between total 25[OH]D and blood pressure was corroborated (SBP: β = -1.2, 95%CI = -2.0, -0.3; DBP: β = -0.7, 95% CI = -1.2, -0.1), whereas a positive association with total cholesterol was observed (β = 1.9, 95% CI = 0.02, 3.7). Levels of 1, 25[OH]2D were not associated with CVD risk factors, whereas 24, 25[OH]2D3 was associated with blood pressure (SBP: β = -13.0, 95% CI = -20.7, -5.2; DBP: β = -6.3, 95% CI = -11.6, -1.0). Estimated free 25[OH]D was inversely associated with both SBP (β = -3.5, 95% CI = -6.1, -0.9) and DBP (β = -2.1, 95% CI = -3.8, -0.3). Similarly, calculated bioavailable 25[OH]D was inversely associated with both SBP (β = -9.2, 95% CI = -15.9, -2.4) and DBP(β = -5.3, 95% CI = -9.8, -0.8). In conclusion, a negative association between 25[OH]D with BP was observed and a positive association with lipids is suggested. Due to the small sample size, most associations did not reach statistical significance.

Genetic Epidemiologic Analysis of Hypertensive Retinopathy in an Underrepresented and Rare Federally Recognized Native American Population of the Intermountain West

Understanding disease risk is challenging in multifactorial conditions as it can differ by environment, ethnicity and race. The Confederated Tribes of the Goshute Reservation are one of the most isolated populations in the United States. Retinal changes are a reliable indicator for systemic disease. We conducted a cross-sectional study to identify correlations between genetic data and epidemiological risk factors for blinding retinal disease in this tribe. As part of the "Supporting Prediction and Prevention Blindness Project (SPBPP)" in the Native American Population of the Intermountain West, we found that hypertensive retinopathy was the most prevalent retinal disease. We found that forty-two percent of the Goshute population was affected. Blood samples, fundus photos and intraocular pressure were obtained for all participants. In addition, a standardized questionnaire was administered. DNA and total cholesterol, HDL, LDL, VLDL, triglycerides and HbA1c were also evaluated. Our study interrogated genetic variants from the PAGE study (ARMS2 rs10490924, CFH rs800292, rs1061170) and additional studies that looked at previously associated genetic variants with retinal disease associated with cardiovascular disease. We conducted univariate and multivariate logistic regression in Stata v15.0. We found an association between hypertriglyceridemia and HTR (adjp = .05) within the Goshute population. To the best of our knowledge, this is the first study to demonstrate the prevalence of hypertensive retinopathy in a Native American population. Moreover, our study is the first to demonstrate an independently predictive relationship between hypertriglyceridemia and hypertensive retinopathy in an American Indian population. This study furthers our knowledge about prevalent blinding eye disease within the most geographically isolated federally recognized native United States American tribe, for which nothing has been published with respect to any disease. Although, this study furthers our understanding about the prevalence of genetic epidemiological risk factors within this population, it has greater implications for the screening of blinding diseases in underserved populations in general. This study can inform public health on planning and delivering of quality, accessible and relevant care to this population.

The association between the serum level of vitamin D and ischemic heart disease: a study from Jordan

Background

Decreased levels of vitamin D were associated with increased risk of multiple diseases, including cardiovascular diseases. However, there seem to be some discrepancies among the results obtained from different studies. The aim of the present study was to explore the importance of having sufficient serum levels of vitamin D in reducing the incidence and the progression of coronary artery stenosis and ischemic heart disease (IHD).

Methods

Serum levels of vitamin D were measured using radioimmunoassay in 186 Jordanian patients who underwent investigative coronary catheterization. Of these patients, 133 were suffering from coronary artery stenosis. The association between vitamin D levels, coronary stenosis and many risk factors was determined using SPSS software.

Results and conclusions

Interestingly, the current results did not show an association between vitamin D abnormalities and the incidence or the reoccurrence of coronary artery stenosis. Moreover, significant differences were detected in the prevalence of vitamin D abnormalities based on the patient’s gender, and there was a significant association between vitamin D abnormalities and both body mass index and dyslipidemia. However, current results did not show any significant association with other risk factors for IHD. For instance, no association was found with smoking, hypertension, diabetes mellitus, stable and unstable angina or with acute recent myocardial infarction.

Vitamin D deficiency causes inward hypertrophic remodeling and alters vascular reactivity of rat cerebral arterioles

Background and purpose

Vitamin D deficiency (VDD) is a global health problem, which can lead to several pathophysiological consequences including cardiovascular diseases. Its impact on the cerebrovascular system is not well understood. The goal of the present work was to examine the effects of VDD on the morphological, biomechanical and functional properties of cerebral arterioles.

Methods

Four-week-old male Wistar rats (n = 11 per group) were either fed with vitamin D deficient diet or received conventional rat chow with per os vitamin D supplementation. Cardiovascular parameters and hormone levels (testosterone, androstenedione, progesterone and 25-hydroxyvitamin D) were measured during the study. After 8 weeks of treatment anterior cerebral artery segments were prepared and their morphological, biomechanical and functional properties were examined using pressure microangiometry. Resorcin-fuchsin and smooth muscle actin staining were used to detect elastic fiber density and smooth muscle cell counts in the vessel wall, respectively. Sections were immunostained for eNOS and COX-2 as well.

Results

VDD markedly increased the wall thickness, the wall-to-lumen ratio and the wall cross-sectional area of arterioles as well as the number of smooth muscle cells in the tunica media. As a consequence, tangential wall stress was significantly lower in the VDD group. In addition, VDD increased the myogenic as well as the uridine 5’-triphosphate-induced tone and impaired bradykinin-induced relaxation. Decreased eNOS and increased COX-2 expression were also observed in the endothelium of VDD animals.

Conclusions

VDD causes inward hypertrophic remodeling due to vascular smooth muscle cell proliferation and enhances the vessel tone probably because of increased vasoconstrictor prostanoid levels in young adult rats. In addition, the decreased eNOS expression results in endothelial dysfunction. These morphological and functional alterations can potentially compromise the cerebral circulation and lead to cerebrovascular disorders in VDD.

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.