Association of 25-hydroxyvitamin D and parathyroid hormone with incident hypertension: MESA (Multi-Ethnic Study of Atherosclerosis)

Review Article on Molecular Mechanism of Regulation of Hypertension by Macro-elements (Na, K, Ca and Mg), Micro-elements/Trace Metals (Zn and Cu) and Toxic Elements (Pb and As)

Hypertension (HT) is a medical condition arising due to increase in blood pressure (BP) prevalent worldwide. The balanced dietary intakes of macro-elements and micro-elements including Na, K, Ca, Mg, Zn, and Cu have been described to maintain BP in humans by regulating the osmolarity of blood, cells/tissues, prevention of generation of oxidative and nitrosative stress (OANS), and endothelial damage through their functioning as important components of renin-angiotensin-aldosterone system (RAAS), antioxidant enzyme defense system, and maintenance of blood vascular-endothelial and vascular smooth muscle cell (VSMC) functions. However, inadequate/excess dietary intakes of Na/K, Ca/Mg, and Zn/Cu along with higher Pb and As exposures recognized to induce HT through common mechanisms including the followings: endothelial dysfunctions due to impairment of vasodilatation, increased vasoconstriction and arterial stiffness, blood clotting, inflammation, modification of sympathetic activity and higher catecholamine release, increased peripheral vascular resistance, and cardiac output; increased OANS due to reduced and elevated activities of extracellular superoxide dismutase and NAD(P)H oxidase, less nitric oxide bioavailability, decrease in cGMP and guanylate cyclase activity, increase in intracellular Ca2+ ions in VSMCs, and higher pro-inflammatory cytokines; higher parathyroid and calcitriol hormones; activation/suppression of RAAS resulting imbalance in blood Na+, K+, and water regulated by renin, angiotensin II, and aldosterone through affecting natriuresis/kaliuresis/diuresis; elevation in serum cholesterol and LDL cholesterol, decrease in HDL cholesterol due to defect in lipoprotein metabolism. The present study recommends the need to review simple dietary mineral intervention studies/supplementation trials before keeping their individual dietary excess intakes/exposures in consideration because their interactions lead to elevation and fall of their concentrations in body affecting onset of HT.

Association of parathyroid hormone with risk of hypertension and type 2 diabetes: a dose-response meta-analysis

BACKGROUND

Despite an increase in parathyroid hormone (PTH) has been reported to be associated with a higher risk of hypertension and type 2 diabetes (T2D), the comprehensive evaluation of the dose-response relationship between PTH and hypertension and T2D remains ambiguous. Therefore, a dose-response meta-analysis was performed to quantitatively investigate this association.

METHODS

PubMed, Web of Science, and Embase were systematically searched up to May 2023. Random-effect models were used to estimate the summary odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines were used to model the dose-response association.

RESULTS

Ten articles (including 13 studies) were identified, with a total of 11,878 cases and 51,234 participants in the meta-analysis. Of these studies, eight (five cohort and three cross-sectional) studies investigated the association of PTH with hypertension; five (two cohort and three cross-sectional) studies assessed the association of PTH with T2D. The results showed a positive relationship between PTH and the risk of hypertension (OR,1.24, 95% CI: 1.16-1.33). We found a linear association between PTH and hypertension (Pnon-linearity= 0.222). In the dose-response analysis, the risk of hypertension increased 5% for every 10 pg/ml increase in PTH (OR,1.05, 95% CI: 1.02-1.08). The pooled OR of T2D risk for a 10 pg/ml increase in PTH was 1.00 (95% CI: 0.98-1.02).

CONCLUSIONS

Elevated PTH is associated with an increased risk of hypertension. However, the evidence of the association between PTH and T2D is limited, and more well-designed studies need to be explored.

Development and Validation of Vitamin D- Food Frequency Questionnaire for Moroccan Women of Reproductive Age: Use of the Sun Exposure Score and the Method of Triad's Model

This cross-sectional study aimed to develop and validate a vitamin D food frequency questionnaire (VitD-FFQ) to assess vitamin D intake in Moroccan women of reproductive age. Using the method of triads, the VitD-FFQ was validated against seven-day dietary records (7d-FR) and 25-hydroxyvitamin D (25(OH)D) as a biomarker of vitamin D status in 152 women (aged 18-45 years). Participants' sun exposure scores (SES) were assessed using a specific questionnaire (SEQ). Predictors of vitamin D status were identified via linear regression models. Several statistical tests were applied to evaluate the criterion validity of the FFQ against two references methods (7d-FR and the biomarker-serum 25(OH)D). Median (Interquartile range) intakes were 7.10 ± 6.95 µg /day and 6.33 ± 5.02 µg/ day, respectively, for VitD-FFQ and 7d-FR. Vitamin D status was mainly determined by SES (R = 0.47) and vitamin D absolute food intakes derived by the VitD-FFQ (R = 0.56), which demonstrated a more significant prediction ability compared to 7d-FR (R = 0.36). An agreement was observed between the VitD-FFQ and 7d-FR (BA index of 3.29%) with no proportional bias (R² = 0.002, p = 0.54). <10% of participants were incorrectly classified, and weighted kappa statistics showed that VitD-FFQ had an acceptable ranking ability compared to the 7d-FR and the biomarker. The validity coefficient for the VitD-FFQ was high: ρQR = 0.90 (95%CI: 0.89-0.92), and a range from 0.46 to 0.90. Adjustment for the participants' SES and BMI (body mass index) improved the biomarker's validity coefficient (ρRB 0.63 (95% CI 0.39-0.82). Our results indicate that the VitD-FFQ is valid for estimating absolute vitamin D intake in Moroccan women of reproductive age.

Effects of Vitamin D on Cardiovascular Risk and Oxidative Stress

INTRODUCTION

Vitamin D has been primarily studied as an important factor influencing bone and calcium metabolism. Metabolites of vitamin D are essential for whole-body calcium homeostasis, maintaining serum calcium levels within a narrow range by regulating this process in the bones and gut. Nevertheless, its deficiency is also related to increased risk of type 2 diabetes mellitus (T2DM), metabolic syndrome (MS), and cardiovascular disease (CVD)-with increased visceral adipose tissue and body mass index (BMI), as well as the frequently associated hypercholesterolemia. It has been reported that vitamin D levels are inversely related to cardiovascular (CV) risk in men and women. However, the effects of vitamin D on distinct outcomes in women and the dose of supplementation needed to improve clinical endpoints have not been established. 25-Hydroxyvitamin D [25(OH)D] reduces systemic inflammatory mediators in CVD and favors the release of anti-inflammatory cytokines from the immune system. In addition, 25(OH)D can be primarily converted into calcitriol (1,25-dihydroxycholecalciferol [1,25(OH)2D]) in the kidneys through the action of the 1-α-hydroxylase enzyme. Calcitriol, through the downregulation mechanism of renin expression, renin-angiotensin-aldosterone system (RAAS) activity, and its interaction with the vitamin D receptor, can bring CV benefits. The calcitriol form also lowers parathyroid hormone (PTH) levels by indirectly causing a reduction in aldosterone and mineralocorticoid synthesis. Elevated plasma aldosterone is related to endothelial dysfunction and CVD in hypovitaminosis D status.

CONCLUSION

Vitamin D supplementation may benefit certain risk groups, as it improves metabolic variables, reducing oxidative stress and CV outcomes. More studies are needed to define interventions with vitamin D in men and women.

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.

25-hydroxyvitamin D insufficiency and inflammation increase cardiovascular risk in older people

PURPOSE

The objective of this study was to identify an association between serum levels of 25(OH) D, inflammation and cardiovascular disease risk in older adults.

METHODS

This was a cross-sectional study, with older adults of both sexes, investigating variables on lifestyle, anthropometric assessments (weight, height, waist circumference, BMI), and systemic arterial hypertension (systolic blood pressure, SBP, and diastolic blood pressure DBP), serum levels of 25(OH)D, serum high-sensitive C-reactive protein (hs-CRP), serum lipid profile and fasting blood glucose. Cardiovascular disease risk was assessed using the global risk score for cardiovascular events, the Framingham criteria.

RESULTS

The sample consisted of 124 participants, 50.8% of whom were at high risk for cardiovascular events. Older adults with 25(OH)D insufficiency presented higher levels of blood sugar (p < 0.01), LDL-c (p = 0.03) SBP (p < 0.01) and hs-CRP (p < 0 0.01). When grouped by serum concentrations hs-CRP, it was observed that higher hs-CRP levels were associated with higher blood glucose (p = 0.02), SBP (p = 0.04) and lower HDL-c concentrations (p = 0.02). It was also observed that 25(OH)D insufficiency increased the chance of a high risk for cardiovascular events by 2.8 times (OR = 2.80; p = 0.01), which with high hs-CRP concentrations increased to 4.75 times (OR = 4.75; p < 0.01).

CONCLUSION

Low concentrations of 25(OH)D and the presence of inflammation in older adults are associated with a high risk for cardiovascular diseases.

Circulating 25-hydroxyvitamin D levels and hypertension risk after adjusting for publication bias

BACKGROUND

Previous systematic reviews reported that serum vitamin D deficiency was associated with risk of hypertension. The aim was to conduct a meta-epidemiological analysis for evaluating the potential effects of publication bias.

METHODS

The selection criterion was defined as a follow-up study for evaluating the association between circulating 25-hydroxyvitam D level and hypertension risk in adults. A funnel plot and Egger's test were used to detect a publication bias. If a publication bias was identified, trim-and-fill analysis (TFA) with linear estimator was performed to estimate a summary relative risk (sRR).

RESULTS

The meta-analysis of 13 cohorts resulted in the lower the vitamin D, the higher the risk of hypertension statistically significant (sRR, 1.22; 95% confidence interval [CI], 1.05 to 1.41). But The P-value of Egger's test (=0.015) and asymmetry of the funnel plot showed that there was a publication bias. TFA resulted in that statistical significance disappeared in the association between vitamin D level and hypertension risk in total cohorts (filled sRR, 1.03; 95% CI, 0.89 to 1.18) as well as men and women cohorts.

CONCLUSIONS

The publication bias-adjusted results by TFA had no statistically significant association between vitamin D levels and the risk of hypertension. The significant results in previous systematic reviews might be interpreted as due to publication bias.

Serum Vitamin D Levels in Relation to Hypertension and Pre-hypertension in Adults: A Systematic Review and Dose–Response Meta-Analysis of Epidemiologic Studies

Background

Findings of observational studies that evaluated the association of serum vitamin D status and high blood pressure were contradictory. This meta-analysis of epidemiologic studies assessed the relation of serum vitamin D levels to hypertension (HTN) and pre-hypertension in adults.

Methods

We conducted a systematic search of all published articles up to March 2021, in four electronic databases (MEDLINE (PubMed), Web of Science (ISI), Embase and Scopus), and Google scholar. Seventy epidemiologic studies (10 prospective cohort, one nested case–control, and 59 cross-sectional investigations) that reported relative risks (RRs), odds ratios (ORs), hazard ratios, or prevalence ratios with 95% CIs for HTN or pre-hypertension in relation to serum vitamin D concentrations in adults were included in the analysis.

Results

In prospective studies, a 16% decrease in risk of hypertension was observed in participants with high levels of serum vitamin D compared to low levels (RR: 0.84; 95%CI: 0.73, 0.96; 12 effect sizes). Dose–response analysis in prospective studies revealed that each 25 nmol/L increase in serum vitamin D concentrations resulted in 5% reduced risk of HTN (RR: 0.95; 95% CI: 0.90, 1.00). Also, a significant nonlinear relationship between serum vitamin D levels and HTN was found (P_nonlinearity < 0.001). In cross-sectional investigations, highest vs. lowest level of serum vitamin D was related to reduced odds of HTN (OR: 0.84; 95%CI: 0.79, 0.90; 66 effect sizes) and pre-hypertension (OR: 0.75; 0.95%CI: 0.68, 0.83; 9 effect sizes). Dose–response analysis in these studies showed that each 25 nmol/L increase in serum vitamin D levels was related to a significant 6% reduction in odds of hypertension in all populations (RR: 0.94; 95%CI: 0.90, 0.99) and 3% in studies with representative populations (RR: 0.97; 95%CI: 0.95, 0.99).

Conclusion

This meta-analysis of epidemiologic studies disclosed that serum vitamin D concentrations were inversely related to the risk of HTN in adults, in a dose–response manner in both prospective cohort and cross-sectional studies.

Systematic Review Registration:http://www.crd.york.ac.uk/Prospero, identifier: CRD42021251513.

Effect of Vitamin D Supplementation on the Regulation of Blood Pressure in Iranian Patients with Essential Hypertension: A Clinical Trial

BACKGROUND

Low serum vitamin D level is associated with both high blood pressure and incidence of primary hypertension. Experimental studies suggest that vitamin D supplements may reduce blood pressure.

OBJECTIVE

The aim of this study was to investigate whether vitamin D supplementation reduces systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) in Iranian patients with essential hypertension.

METHOD

A total of 173 patients with essential hypertension participated in this open-label clinical trial. SBP, DBP, and serum vitamin D levels were measured at baseline and at the end of the study. Vitamin D was administered at a dose of 50,000 IU/week, and 1000 IU/day in patients with serum vitamin D levels <20 ng/mL and 20-30 ng/mL, respectively, for 8 weeks.

RESULTS

Based on serum vitamin D levels, 45.1%, 17.3%, and 29.5% of patients were deficient, insufficient, and sufficient for vitamin D intake, respectively. Baseline serum levels of vitamin D were not correlated with SBP, DBP, and MAP at the beginning of the study (p = ns). Multiple logistic regression analysis revealed that the risk of vitamin D deficiency was 2.5-fold times higher in women than in men (p = 0.03). After 8 weeks of supplementation with vitamin D, mean SBP and MAP were significantly reduced by 5.5 ± 16.16 (p = 0.01) and 3.7 ± 9.24 (p = 0.004) mmHg, respectively. Neither sex nor age could significantly predict BP response to vitamin D supplementation.

CONCLUSION

Vitamin D supplementation may significantly reduce SBP and MAP but not DBP in patients with essential hypertension.

Environmental Factors That Affect Parathyroid Hormone and Calcitonin Levels

Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied. In this review, we analyzed the literature discussing the influence of environmental factors (lifestyle factors and pollutants) on PTH and calcitonin levels. Among lifestyle factors, smoking, body mass index (BMI), diet, alcohol, and exercise were analyzed; among pollutants, heavy metals and chemicals were analyzed. Lifestyle factors that showed the clearest association with PTH levels were smoking, BMI, exercise, and micronutrients taken from the diet (vitamin D and calcium). Smoking, vitamin D, and calcium intake led to a decrease in PTH levels, while higher BMI and exercise led to an increase in PTH levels. In terms of pollutants, exposure to cadmium led to a decrease in PTH levels, while exposure to lead increased PTH levels. Several studies have investigated the effect of chemicals on PTH levels in humans. Compared to PTH studies, a smaller number of studies analyzed the influence of environmental factors on calcitonin levels, which gives great variability in results. Only a few studies have analyzed the influence of pollutants on calcitonin levels in humans. The lifestyle factor with the clearest relationship with calcitonin was smoking (smokers had increased calcitonin levels). Given the importance of PTH and calcitonin in maintaining calcium and phosphate homeostasis and bone mineral metabolism, additional studies on the influence of environmental factors that could affect PTH and calcitonin levels are crucial.

The activity of the renin-angiotensin-aldosterone system before and after parathyroidectomy in patients with primary hyperparathyroidism

Background. The relationships between renin-angiotensin-aldosterone system (RAAS) and elevated parathyroid hormone levels in primary hyperparathyroidism (PHPT) is being actively discussed. But the way how parathyroid hormone interacts with renin and aldosterone currently is not clear. Materials and methods. Forty patients aged 18 to 70 years with a confirmed diagnosis of PHPT were involved in the study. All patients were tested for the main parameters of phosphorus-calcium metabolism and the RAAS parameters (plasma renin, plasma aldosterone) before and 2 weeks after parathyroidectomy. Results. Sixty percent of patients had any cardiovascular disease (CVD) and hypertension was the most common. Patients CVD in comparison with patients without CVD were older (61 and 41 years, respectively; p0.001), had a higher body mass index (28.9 and 21.9 kg/m2, respectively; p0.001) and had a lower aldosterone-to-renin ratio ARR (1.78 and 5.42, respectively; p=0.030). Patients with hypertension were older than patients with normal blood pressure (63 and 41 years, respectively; p0.001), had a higher body mass index (28.1 and 23.5 kg/m2, respectively; p=0.005), a lower ARR (1.46 and 5.82, respectively; p=0.001), as well higher levels of plasma renin (109.2 and 20.3 pg/ml, respectively; p=0.007) and serum total calcium (2.84 and 2.71 mmol/l, respectively; p=0.041). Correlation analysis showed that in patients with PHPT and CVD, the concentration of aldosterone is associated with the level of 24-hour urinary calcium (r=0.829, p=0.042), and in patients with symptomatic PHPT and CVD, the level of aldosterone correlated with the level of ionized calcium (r=-0.812, p=0.05). We found no significant differences between the levels of renin, aldosterone and ARR before and 2 weeks after parathyroidectomy. However, in the postoperative period, there were no differences in the levels of renin and ARR among patients with hypertension and without hypertension. Conclusion. In our study we found that the levels of plasma renin and serum total calcium were higher in patients with PHPT and hypertension compared to patients with normal blood pressure. Also, we found the associations between plasma aldosterone and levels of ionized calcium and 24-hour urinary calcium. But the relationships between RAAS parameters and parameters of phosphorus-calcium metabolism need further investigations.

Vitamin D Deficiency Is a Potential Risk for Blood Pressure Elevation and the Development of Hypertension

Background and objectives: Hypertension is a global health problem and a major risk factor for cardiovascular diseases. Vitamin D deficiency is closely related to high blood pressure and the development of hypertension. This study investigated the relationship between the vitamin D and blood pressure status in healthy adults, and their 8-year follow-up was added. Materials and Methods: A total of 491 healthy middle-aged participants without any chronic illness, ages 21 to 67 at baseline, were divided into two groups as non-optimal blood pressure (NOBP) and optimal blood pressure (OBP). NOBP group was divided into two subgroups: normal (NBP) and high normal blood pressure (HNBP). Serum 25-hydroxy vitamin D levels were measured with the immunoassay method. 8-year follow-up of the participants was added. Results: The average vitamin D level was detected 32.53 ± 31.50 nmol/L in the OBP group and 24.41 ± 14.40 nmol/L in the NOBP group, and a statistically significant difference was found (p < 0.001). In the subgroup analysis, the mean vitamin D level was detected as 24.69 ± 13.74 and 24.28 ± 14.74 nmol/L in NBP and HNBP, respectively. Together with parathyroid hormone, other metabolic parameters were found to be significantly higher in the NOBP. During a median follow-up of 8 years, higher hypertension development rates were seen in NOBP group (p < 0.001). Conclusions: The low levels of vitamin D were significantly associated with NBP and HNBP. The low levels of vitamin D were also associated with the development of hypertension in an 8-year follow-up.

Vitamin D and Vascular Disease

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Vitamin D deficiency has been identified as a potential risk factor for a number of diseases unrelated to the classical skeletal pathophysiology, such as cancer and CVD, but the effects of vitamin D supplementation are less clear. Purpose of this narrative review is to discuss the evidence suggesting an association between vitamin D status and CVD as well as the results of supplementation studies. Vitamin D deficiency has been associated with CVD risk factors such as hypertension, dyslipidemia and diabetes mellitus as well as with cardiovascular events such as myocardial infarction, stroke and heart failure. While vitamin D deficiency might contribute to the development of CVD through its association with risk factors, direct effects of vitamin D on the cardiovascular system may also be involved. Vitamin D receptors are expressed in a variety of tissues, including cardiomyocytes, vascular smooth muscle cells and endothelial cells. Moreover, vitamin D has been shown to affect inflammation, cell proliferation and differentiation. While observational studies support an association between low plasma vitamin D levels and increased risk of CVD, Mendelian randomization studies do not support a causal association between the two. At present, high quality randomized trials do not find evidence of significant effects on CVD endpoints and do not support supplementation of vitamin D to decrease CVD events.

The relationship between Vitamin D deficiency and polycystic ovary syndrome

BACKGROUND

Vitamin D deficiency is frequently seen in patients with polycystic ovary syndrome (PCOS) and has been shown to exhibit multiple effects on the disease process. The purpose of this study was to investigate the role of vitamin D deficiency in complex PCOS pathophysiological pathways.

METHODS

Two hundred sixty-seven patients with PCOS were divided into two groups Group 1 with 25(OH)D3 deficiency, and Group 2 with normal 25(OH)D3. Biochemical and hormonal parameters (androgen hormones, gonadotropins, and thyroid function tests) were compared between the two groups.

RESULTS

Eighty-six percent of the patients (n=231) were in Group 1 and 14% (n=36) in Group 2. Statistically significantly higher concentrations of serum testosterone, dehydroepiandrosterone-sulfate and LH were determined in Group 1 (p<0.05). 25(OH)D3 concentrations were negatively correlated with body mass index (r=-0.459), serum testosterone (r =-0.374) and dehydroepiandrosterone-sulfate levels (r=-0.418); (all; p< 0.05).

CONCLUSION

The study findings show that low 25(OH)D3 levels are associated with high androgen levels in women with PCOS. Vitamin D deficiency should be considered as an additional risk factor in the development of PCOS. We think that providing vitamin D supplementation for women from identified deficiency areas can reduce the risk of PCOS development.

Primary hyperparathyroidism and hypertension

Although untreated primary hyperparathyroidism is associated with increased cardiovascular mortality, controversy exists regarding the therapeutic effects of parathyroidectomy on cardiovascular health. This review will examine the evidence linking primary hyperparathyroidism (PHPT) and cardiovascular disease, specifically hypertension, and evaluate the available literature regarding the natural history of hypertension after successful parathyroidectomy.

Effect of Vitamin D on Blood Pressure and Hypertension in the General Population: An Update Meta-Analysis of Cohort Studies and Randomized Controlled Trials

Background

The effect of vitamin D supplementation on blood pressure has been explored in previous meta-analyses, but whether the association is causal in the general population is still unknown. We evaluated the association comprehensively and quantitatively.

Methods

We searched PubMed and Embase for relevant cohort studies and randomized controlled trials (RCTs). We used a 2-step generalized least-squares method to assess the dose–response association of circulating 25-hydroxyvitamin D (25[OH]D) and hypertension and a fixed-effects model to pool the weighted mean differences (WMDs) and corresponding 95% confidence intervals (95% CIs) of blood pressure across RCTs.

Results

We identified 11 cohort studies and 27 RCTs, with 43,320 and 3,810 participants, respectively. The dose–response relationship between circulating 25(OH)D levels and hypertension risk was approximately L-shaped (P_nonlinearity = .04), suggesting that the risk of hypertension increased substantially below 75 nmol/L as 25(OH)D decreased, but it remained significant over the range of 75–130 nmol/L. However, pooled results of RCTs showed that there was no significant reduction in systolic blood pressure (WMD, −0.00 mm Hg; 95% CI, −0.71 to 0.71) or diastolic blood pressure (WMD, 0.19 mm Hg; 95% CI, −0.29 to 0.67) after vitamin D intervention.

Conclusions

The results of this meta-analysis indicate that supplementation with vitamin D does not lower blood pressure in the general population. RCTs with long-term interventions and a sufficient number of participants who have low levels of vitamin D are needed to validate these findings.

Higher concentration of serum C-terminal cross-linking telopeptide of type I collagen is positively related with inflammatory factors in postmenopausal women with H-type hypertension and osteoporosis

OBJECTIVE

To investigate the changes of inflammatory factors and bone metabolism markers in postmenopausal women with H-type hypertension and to assess the relationship between them.

METHODS

Postmenopausal women who were diagnosed with osteoporosis were selected as observation objects. Participants were divided into three groups: only osteoporosis group (osteoporosis group), hypertension combined with osteoporosis group (hypertension group), and H-type hypertension combined with osteoporosis group (H-type hypertension group). The changes in bone mineral density and bone metabolic markers (osteocalcin [OC], procollagen type I N-terminal propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen [CTX]) and inflammatory factors (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]) were compared among three groups.

RESULTS

In the hypertension group and the H-type hypertension group, the bone mineral density of the lumbar spine (0.647 ± 0.038 vs 0.638 ± 0.034 vs 0.668 ± 0.047, P < 0.05) and the femoral neck (0.567 ± 0.047 vs 0.552 ± 0.053 vs 0.618 ± 0.059, P < 0.05) was significantly lower than that in the osteoporosis group. The concentrations of CTX (266.61 ± 64.65 vs 293.09 ± 72.34 vs 235.48 ± 62.85, P < 0.05), IL-6 (44.36 ± 6.45 vs 48.05 ± 8.04 vs 39.06 ± 7.95, P < 0.05) and TNF-α (30.53 ± 6.28 vs 34.52 ± 7.15 vs 28.66 ± 6.19, P < 0.01) in the hypertension group and in the H-type hypertension group were significantly higher than those in the osteoporosis group. The concentrations of OC (30.59 ± 6.43 vs 27.10 ± 6.51, P < 0.05) and PINP (36.36 ± 6.16 vs 33.16 ± 6.77, P < 0.05) in the H-type hypertension group were increased dramatically. The concentration of CTX was positively correlated with the concentration of IL-6 (r = 0.587, P < 0.01) and TNF-α (r = 0.474, P < 0.01) and negatively related with the concentration of OC (r = -0.591, P < 0.01) and PINP (r = -0.646, P < 0.01) and the bone mineral density of the lumbar spine (r = -0.470, P < 0.01) and the femoral neck (r = -0.509, P < 0.01).

CONCLUSION

Higher concentration of serum CTX is found in postmenopausal women with H-type hypertension, which is positively correlated with inflammatory factors. Besides, H-type hypertension could further enhance the activity of osteoclasts and increase the expressions of inflammatory factors, resulting in the aggravation of osteoporosis.

Plasma total calcium concentration is associated with blood pressure and systemic vascular resistance in normotensive and never-treated hypertensive subjects

Purpose: The underlying causes of primary hypertension are not fully understood. Evidence on the relation of plasma calcium concentration with blood pressure (BP) is inconsistent and relies largely on studies utilizing office BP measurements in populations using cardiovascular drugs. In many studies adjustment for confounders was not optimal. In this cross-sectional study we examined the association of plasma total calcium concentration with the haemodynamic determinants of blood pressure.Subjects and methods: Supine haemodynamics were recorded using pulse wave analysis, whole-body impedance cardiography, and heart rate variability analysis in 618 normotensive or never-treated hypertensive subjects (aged 19-72 years) without diabetes, cardiovascular or renal disease, or cardiovascular medications. Linear regression analysis was used to investigate factors associated with haemodynamic variables.Results: Mean age was 45.0 years, body mass index 26.8 kg/m², seated office BP 141/89 mmHg, and 307 subjects (49.7%) were male. Mean values of routine blood and plasma chemistry analyses were within the reference limits of the tests except for low-density lipoprotein cholesterol (3.05 mmol/l). In the laboratory, mean supine radial BP was 131/75 mmHg, and both systolic and diastolic BP correlated directly with plasma total calcium concentration (r = 0.25 and r = 0.22, respectively, p < 0.001 for both). In regression analysis plasma total calcium concentration was an independent explanatory variable for radial and aortic systolic and diastolic BP, and systemic vascular resistance, but not for cardiac output, pulse wave velocity, or any of the heart rate variability parameters.Conclusion: Plasma total calcium concentration was directly associated with systolic and diastolic BP and systemic vascular resistance in normotensive or never-treated hypertensive subjects without comorbidities and cardiovascular medications. Higher plasma calcium concentration potentially plays a role in primary hypertension via an effect on vascular resistance.

Elevated parathyroid hormone levels and cognitive function: A systematic review

OBJECTIVE

To systematically estimate the association between elevated parathyroid hormone (PTH) levels and cognitive function.

METHODS

This review was conducted on ten papers identified through database searches from inception to 31 October 2018. The quality of studies was assessed using the Downs and Black checklist.

RESULTS

There is a low volume of data reporting on the impact of elevated PTH levels on cognitive impairment. The quality of the identified studies ranged from poor (37 %) to good (76 %). Although the results from studies were mixed, one cross-sectional study and one prospective study suggested a link between elevated PTH levels and a decrease in the Mini-Mental State Examination (MMSE) score. Three cross-sectional studies that assessed other cognitive domain in specific domains, such as language, memory and executive function provided mixed results for an association between elevated PTH levels and cognitive function. Two studies showed mixed evidence for a link between elevated PTH levels and poor executive function. One prospective study, one cross-sectional study and three case-control studies provide mixed evidence for an association between higher PTH levels and Alzheimer´s disease (AD). Two studies showed limited evidence for an association between elevated PTH levels and vascular dementia.

CONCLUSION

This review presented that the level of evidence available to support an association between elevated PTH levels and cognitive function was generally weak and inconsistent. Future studies with more better methodological quality are needed.

Serum level vitamin D and parathyroid hormone, and mortality, with or without chronic kidney disease

Levels of vitamin D and parathyroid hormone (PTH) are closely associated with renal function. We evaluated the associations among 25-hydroxyvitamin D (25OHD) levels, PTH levels, and mortality, and whether these associations varied by renal function. We used data from the Dong-gu Study, a population-based cohort in Korean adults. We analyzed the associations among intact PTH, 25OHD levels and mortality in 8580 participants. Hazard ratios (HRs) for mortality were calculated using Cox proportional hazards regression after adjusting for age, sex, month of sampling, lifestyle, and comorbidities. We also evaluated the effects of chronic kidney disease (CKD). A total of 860 deaths occurred during the follow-up period of 7.6 years. Compared to the first 25OHD quartile, the HRs of the second, third, and fourth quartiles were 0.96 [95% confidence interval (CI) 0.79-1.16], 0.84 (95% CI 0.68-1.02), and 0.71 (95% CI 0.57-0.89), respectively. The association between intact PTH levels and mortality varied by renal function, and was both nonlinear and significant only in subjects with CKD. Compared to the second intact PTH quartile in such subjects, the HRs for the first, third, and fourth quartiles were 1.61 (95% CI 0.92-2.81), 1.97 (95% CI 1.17-3.31), and 2.19 (95% CI 1.33-3.59), respectively. In conclusion, we demonstrated that low serum levels of 25OHD are associated with an increased risk of mortality. Serum levels of intact PTH are nonlinearly associated with mortality only in subjects with CKD, with the lowest risk for mortality being evident in the second quartile.

Impact of uric acid on incident hypertension: Sex-specific analysis in different age groups

The aim of the present study is to evaluate the association of serum uric acid (UA) levels with the risk of incident hypertension among different age groups in men and women using a single large Japanese general cohort. The present study is based on annual health check-up program in Gunma, Japan. We studied 12,029 participants (mean age, 48 ​± ​9 years old; 31% women) free of prevalent cardiovascular disease and hypertension at baseline (2009). Hypertension was defined by self-report, hypertensive medication use, or measured BP ​> ​140/90 ​mmHg ​at each visit. Discrete proportional hazards regression model was used to evaluate the association of UA level at baseline with incident hypertension through 2012 adjusted for age, gender, baseline blood pressure, and other CVD risk factors among different age decade groups in men and women. During follow-up of 3 years, 12% of the cohort (n ​= ​1457) developed hypertension. UA was strongly associated with incident hypertension in the multivariable model in all participants. In age-stratified analysis, participants below 50 years of age in men had the significant association of UA with incident hypertension, whereas participants above 50 years did not. In women, participants above 40 years had the significant association, whereas participants below 40 years did not. The present data suggest that UA level is an independent predictor for incident hypertension among middle aged men below 50 years old and middle aged and the elderly women above 40 years.

Mechanisms Involved in the Relationship between Low Calcium Intake and High Blood Pressure

There is increasing epidemiologic and animal evidence that a low calcium diet increases blood pressure. The aim of this review is to compile the information on the link between low calcium intake and blood pressure. Calcium intake may regulate blood pressure by modifying intracellular calcium in vascular smooth muscle cells and by varying vascular volume through the renin-angiotensin-aldosterone system. Low calcium intake produces a rise of parathyroid gland activity. The parathyroid hormone increases intracellular calcium in vascular smooth muscles resulting in vasoconstriction. Parathyroidectomized animals did not show an increase in blood pressure when fed a low calcium diet as did sham-operated animals. Low calcium intake also increases the synthesis of calcitriol in a direct manner or mediated by parathyroid hormone (PTH). Calcitriol increases intracellular calcium in vascular smooth muscle cells. Both low calcium intake and PTH may stimulate renin release and consequently angiotensin II and aldosterone synthesis. We are willing with this review to promote discussions and contributions to achieve a better understanding of these mechanisms, and if required, the design of future studies.

Tongxinluo may stabilize atherosclerotic plaque via multiple mechanisms scanning by genechip

BACKGROUND

Chinese traditional medicine Tongxinluo capsule (TXL) has been widely used for cardiovascular diseases. Both clinical and basic studies showed that TXL had effective effects on atherosclerosis. However, the mechanism researches were relatively scattered. This study was aimed to fully evaluate the potential mechanisms of TXL on atherosclerosis as a whole.

METHOD

One hundred apoE-/- mice (male, 12 weeks old) were randomly divided into five groups (n = 20 each group) Mice in the control group were fed normal diet and mice in the other four groups (intervention groups) were fed high fat diet. The intervention groups were randomly divided into normal saline (NS) group and TXL treatment groups, and the latter were further divided into three subgroups: low-dose TXL (TXL-L), medium-dose TXL (TXL-M) and high-dose TXL (TXL-H), with TXL dosage at 0.38, 0.75, 1.5 g/kg/d by gavage, respectively. After sixteen weeks of intervention, all mice underwent euthanasia. Gene expression profiles with aortic tissues were determined by genechip. A Gene Ontology (GO) analysis was performed to interpret the functional implications of altered genes.

RESULT

Histological and morphological analysis demonstrated that TXL at different doses all reduced plaque burden and plaque size. The expressions of IL-6, TNF-ɑ and MMP-2 were significantly decreased in the TXL intervention groups compared with control. In atherosclerotic lesions of TXL groups 3284 genes altered compared with control, and 632 genes changed in the TXL-H group compared with the NS group. Of these genes, 48 showed a decrease which were high in atherosclerosis, and 56 showed a increase which were low in atherosclerosis after TXL intervention. Significantly altered genes were found to be involved in the aspects of hormone secretion, protein binding, lipid metabolic, fatty acid metabolic immune system process, and inflammatory response.

CONCLUSION

TXL has effects on inhibiting atherosclerosis development and stablizing plaque. The comprehensive mechanisms, in addition to inflammation and lipid metabolism, might also involve cell physical function, hormone secretion, protein binding, and immune response process.

Parathyroid Hormone Causes Endothelial Dysfunction by Inducing Mitochondrial ROS and Specific Oxidative Signal Transduction Modifications

Vitamin D deficiency contributes to cardiovascular risk (CVR), with hyperparathyroidism advocated as a putative mechanism. Indeed, mounting evidence supports the hypothesis that parathyroid hormone (PTH) impairs endothelial function, even though mechanisms are not fully elucidated. The present study was designed to verify in vitro the ability of sustained exposure to PTH to cause endothelial dysfunction, exploring the underlying mechanisms. In bovine aortic endothelial cells (BAECs), we evaluated the effects of PTH exposure (0.1 nM–24 hours) on both endothelial response to vasodilators, such as bradykinin (Bk (30 nM)) and acetylcholine (Ach (1 μM)), and angiogenic competence. Pretreatment with PTH impaired endothelial response to Bk but not to Ach, in terms of cytosolic calcium fluxes and NO production. In order to explore the underlying mechanisms, we assessed the production of total and mitochondrial ROS (tROS and mROS, respectively) in response to PTH (at 1 and 3 hours). PTH increased ROS generation, to an extent high enough to determine oxidation of Bk receptor B2. Conversely, the oxidation levels of M1 and M3 Ach receptors were not affected by PTH. A mROS selective scavenger (MitoTEMPO (5 μM)) restored the endothelial responsiveness to Bk while the well-known antioxidant properties of vitamin D (100 nM) failed to counteract PTH-mediated oxidative stress. PTH determined mitochondrial calcium fluxes ([Ca²⁺]_mt) and the mitochondrial calcium uniporter inhibitor Ru360 (10 μM) reduced mROS production and prevented the PTH-mediated endothelial dysfunction. Angiogenic competence was evaluated as tubular formations in the endothelial Matrigel assay and showed a significant impairment in PTH-pretreated cells (0.1 nM–24 hours), despite the increase in VEGF transcriptional levels. VEGFR2 oxidation occurred in response to PTH, suggesting that even the impairment of angiogenesis was due to the ROS surge. These results indicate that PTH affects endothelial function through ROS production, driven by mitochondrial calcium overload. PTH-induced oxidative stress might act as signaling modifiers, altering specific pathways (Bk and VEGF) and preserving others (Ach).

Biomarker Differences between Controlled and Uncontrolled Hypertension among US Adults: National Health and Nutrition Examination Survey 2005-2010

This study aims to determine biomarker differences between controlled and uncontrolled hypertension using nationally representative samples. Those in the uncontrolled hypertension group were more likely to have CVD (p=0.0258) and diabetes (p=0.0004), less likely to meet the recommended waist circumference (p=0.0039) and BMI (p=0.0209), and less likely to drink alcohol (p=0.0002) than those in the controlled hypertension group, after controlling for demographic variables. Upon controlling for demographic variables, risk factors and diseases related to hypertension, those in the uncontrolled hypertension group had higher total cholesterol (p<.0001), HDL (p=0.0702, marginally significant), LDL (p<.0001), triglycerides (p=0.0702, marginally significant), apolipoprotein B (p<.0001), transferrin receptor (p=0.0692, marginally significant), and ACR (p<.0001) than those in the controlled hypertension group.

CONCLUSION

Our study found that ACR, total cholesterol, HDL, LDL, triglycerides, apolipoprotein B, and transferrin receptor are biomarkers associated with the risk of uncontrolled hypertension compared to controlled hypertension. Since uncontrolled hypertension is linked to very high risks of cardiovascular disease and chronic kidney disease, our findings may provide a partial answer to why antihypertensive treatment is ineffective for certain groups of patients. Further studies are warranted to examine the cause of uncontrolled hypertension.

Association of vitamin D status with metabolic syndrome and its components: A cross-sectional study in a population of high educated Iranian adults

AIM

We aimed to assess the association of vitamin D status with metabolic syndrome and its components among high educated Iranian adults.

METHOD

In this cross-sectional study, 352 faculty members with age of 35 years or more, belong to Tarbiat Modares University, Tehran, Islamic Republic of Iran, were recruited during 2016 and 2017. Fasting blood samples were obtained to quantify serum 25(OH)D concentrations, glycemic indicators and lipid profile. Metabolic syndrome was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Multivariate logistic regression adjusted for potential confounders was used to evaluate the association between vitamin D status and metabolic syndrome.

RESULT

Metabolic syndrome and vitamin D insufficiency were prevalent among 26% and 60.2% of subjects, respectively. There was no statistically significant difference in the prevalence of metabolic syndrome across quartiles of 25(OH)D levels either before or after adjusting for potential confounders (OR: 0.94, 95% CI: 0.43-1.95). In terms of metabolic syndrome components, subjects in the highest quartile of vitamin D levels had 59% decreased risk of abdominal obesity compared with those in the lowest quartile (OR: 0.41, 95% CI: 0.17-0.99), after adjusting for potential confounders. Such inverse relationship was also seen for elevated blood pressure (OR: 0.37, 95% CI: 0.14-0.99), and abnormal glucose homeostasis (OR: 0.40, 95% CI: 0.19-0.85).

CONCLUSION

Serum levels of 25(OH)D was inversely associated with the risk of abdominal obesity, hypertension, and abnormal glucose homeostasis. However, no significant relationship was seen for metabolic syndrome.

Circulating parathyroid hormone and risk of hypertension: A meta-analysis

OBJECTIVES

To examine the relationship between circulating parathyroid hormone (PTH) level and risk of hypertension (HTN).

METHODS

The electronic databases of PubMed, Web of Science and Embase were searched up to December 2017, for prospective cohort studies on the relationship between circulating PTH level and risk of HTN. The pooled relative risk (RR) of HTN for the highest versus lowest category of circulating PTH level as well as their corresponding 95% confidence interval (CI) were calculated.

RESULTS

A total of six prospective cohort studies, which involved 18,994 participants and 5040 HTN cases, were included in this meta-analysis. The overall multi-variable adjusted RR showed a positive relationship between circulating PTH level and risk of HTN (RR = 1.35, 95%CI: 1.09 to 1.67; P = 0.006). A substantial level of heterogeneity was observed among the studies (P < 0.001, I² = 77.6%). No evidence of publication bias was observed among the studies according to Begg's rank-correlation test (P = 0.452).

CONCLUSIONS

The existing evidence suggests that an increase in circulating PTH level may be associated with a higher risk of HTN. However, due to the limited number of included studies, more well-designed prospective cohort studies are needed to further elaborate the issues examined in this study.

Vitamin D Deficiency and Supplementation in Cardiovascular Disorders

Cardiovascular disease (CVD) is the leading cause of death in developed countries. Similarly, the frequency of vitamin D deficiency is increasing, and a number of epidemiologic and clinical studies have suggested that there is an increased risk of CVD among people with depletion of this vitamin. This has raised much interest in the potential pathogenic and therapeutic role of vitamin D in CVD. However, randomized trials and meta-analyses have not shown a clear benefit of vitamin D supplementation with respect to cardiovascular events. Herein, we provide a comprehensive review of the most relevant evidence to date regarding vitamin D deficiency and supplementation, and their respective impact on CVD prevention and treatment.

Independent effects of blood pressure and parathyroid hormone on aortic pulse wave velocity in untreated Chinese patients

OBJECTIVE

Whether or not calcium-regulating hormones stiffen arteries independent of blood pressure (BP) is uncertain. We investigated the independent associations of carotid-femoral pulse wave velocity (PWV) with 25-hydroxy-vitamin D [25(OH)D], parathyroid hormone (PTH) and 24-h ambulatory BP in untreated Chinese patients.

METHODS

Consecutive untreated patients referred for ambulatory BP monitoring were recruited. PWV was measured with a high-fidelity micromanometer and the SphygmoCor software (AtCor Medical, West Ryde, New South Wales, Australia). Serum 25(OH)D and PTH were determined by electrochemiluminescence immunoassay. Analysis of variance, single and multiple regressions were applied for analyses.

RESULTS

In 1052 untreated patients (50.7% women; mean age, 51 years), PWV averaged 7.8 m/s, 24-h SBP/DBP 126.5/81.7 mmHg, serum 25(OH)D and PTH 36.0 nmol/l and 61.6 pg/ml, respectively. In multivariable-adjusted analyses, BP (P < 0.001) and PTH (P = 0.012) increased from less than 25th to at least 75th percentile of the PWV distribution. In continuous analyses, PWV independently increased by 0.40/0.23 m/s per 1-SD increment in SBP/DBP (P < 0.001) and by 0.14 m/s for a doubling of serum PTH (P = 0.029). Associations of PWV with BP were tighter than with PTH (P < 0.001). In pathway analysis, the effect of PTH on PWV did not run via serum or urinary calcium (P = 0.65), but PTH had both a direct (P = 0.026) and a BP-mediated indirect effect (P = 0.043) on PWV. In none of our analyses were PWV associated with serum 25(OH)D.

CONCLUSION

Arterial stiffness, as assessed by PWV, independently increased both with BP and with PTH, but BP remains the main driver of arterial stiffening.

Biomarkers of Key Biological Pathways in CVD

This review provides background on the laboratory design for MESA (Multi-Ethnic Study of Atherosclerosis) as well as the approach used in MESA to select biomarkers for measurement. The research related to the multitude of circulating and urinary biomarkers of inflammation and other novel and emerging biological pathways in MESA is summarized by domain, or pathway, represented by the biomarker. The contributions of MESA biomarkers to our knowledge of these key pathways in the development and progression of atherosclerosis, cardiovascular disease, diabetes, kidney disease, and pulmonary disease are highlighted, as are the contributions of MESA to recommendations for clinical use of several of these biomarkers. In addition, contributions of MESA to multicohort genomics consortia and current collaborations in transomics and metabolomics are noted.

Serum Phosphate and Retinal Microvascular Changes: The Multi-Ethnic Study of Atherosclerosis and the Beaver Dam Eye Study

PURPOSE

Higher levels of serum phosphate are strongly linked to increased risk of cardiovascular disease and therapies aimed to lower serum phosphate are employed in the management of patients with chronic kidney disease (CKD). Data are limited, however, on serum phosphate as a risk factor for microvascular disease in community-based populations. It is important to determine the impact of novel risk factors, such as phosphate, on the microvasculature.

METHODS

We conducted a prospective study of 3919 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and 3544 individuals in the Beaver Dam Eye Study (BDES) to test the associations of serum phosphate with retinopathy and retinal vessel caliber, and change in retinopathy severity and change in retinal vessel caliber.

RESULTS

Mean (standard deviation) serum phosphate was 3.66 (0.52) mg/dl in the MESA and 3.77 (0.55) mg/dl in the BDES. In multivariable adjusted models, phosphate was significantly associated with prevalent retinopathy in the MESA (Odds Ratio [OR] per 1 mg/dl increase in phosphate, 1.22; Confidence Interval [CI] 1.02-1.47) and the BDES (OR 1.06; CI 1.01-1.11). In stratified analyses, these relationships were even stronger and only seen in individuals with diabetes in both the MESA (OR 1.81; CI 1.30-2.53) and the BDES (OR 1.16; CI 1.05-1.29). Phosphate was not associated with incident or change in retinopathy severity, nor any retinal caliber outcome.

CONCLUSIONS

Among community-living individuals with low prevalence of CKD, higher serum phosphate was associated with prevalent retinopathy in individuals with diabetes. Further longitudinal assessments in patients with diabetes necessitate further investigation.

Association of parathyroid hormone and vitamin D with untreated hypertension: Is it different in white-coat or sustained hypertension?

BACKGROUND

Previous reports about the relationship between a high parathyroid hormone (PTH) and low vitamin D levels with blood pressure in different hypertension groups are conflicting.

OBJECTIVE

We studied serum PTH and vitamin D levels in white-coat (WCHT) and sustained hypertension (SHT) patients who had not been on antihypertensive treatment. We also investigated the association between serum PTH and vitamin D levels with respect to blood pressure in SHT and WCHT patients.

METHODS

We included 52 SHT patients (54.06 ± 9.2 years, 32 newly diagnosed and 20 previously diagnosed with SHT who had not been treated with antihypertensive medication for 3 months or more), 48 WCHT patients (53.64 ± 9.5 years), and 50 normotensive (NT) healthy controls (53.44 ± 8.4 years) in our study. In addition to routine tests, PTH and vitamin D levels were measured.

RESULTS

Serum PTH levels were significantly higher in SHT patients not taking antihypertensive medications than in WCHT patients and NT controls (p = 0.004). Although PTH levels were higher in WCHT than in NT groups, the difference was not statistically significant. In SHT patients, PTH levels showed a positive correlation with office systolic (r = 0.363, p = 0.008), office diastolic (r = 0.282, p = 0.038), home systolic (r = 0.390, p = 0.004), and home diastolic blood pressures (r = 0.397, p = 0.003). Serum vitamin D levels were similar in SHT, WCHT and NT groups. Vitamin D levels were not associated with blood pressures in the entire study group. Furthermore, no significant relation was found between vitamin D and PTH levels in SHT and WCHT groups.

CONCLUSION

PTH levels are significantly higher in untreated SHT patients than WCHT patients and NT subjects. However, vitamin D levels are similar in SHT, WCHT and NT groups. There is a significant association between PTH levels and blood pressures suggesting PTH has a role in increase of blood pressure in SHT.

Vitamin D and Blood Pressure Among U.S. Adults: A Cross-sectional Examination by Race/Ethnicity and Gender

INTRODUCTION

The cross-sectional association of serum vitamin D levels with blood pressure and hypertension status among a representative sample of U.S. adults was examined.

METHODS

Participants of the National Health and Nutrition Examination Survey from 2001 to 2010 were included in these analyses. Harmonizing of the vitamin D levels from 2001 to 2006 with vitamin D measurement from 2007 to 2010 was done using regression equations released by the Centers for Disease Control and Prevention. Use of vitamin D supplements was assessed for all participants. Statistical analyses included examination of linear association of vitamin D levels with blood pressure and non-linear cubic splines with hypertension in overall population, by gender, and by race/ethnicity.

RESULTS

With every 10 nmol/L higher vitamin D, systolic blood pressure decreased by 0.19 mmHg in this population (p<0.01). In fully adjusted stratified analyses, this association was present among females (-0.25 mmHg, p<0.01) and non-Hispanic whites (0.22 mmHg, p<0.01). After race/ethnic and gender stratification, this association was observed among non-Hispanic white females (0.26 mmHg, p=0.01), non-Hispanic black females (0.65 mmHg, p=0.02), and marginally significant among Hispanic males (0.33 mmHg, p=0.07). Non-parametric assessment with cubic splines show that vitamin D has an inverse association with odds of hypertension up to 100 nmol/L with no apparent benefit at higher levels in overall population, and even lower threshold levels of vitamin D in non-Hispanic blacks (50 nmol/L) and Hispanic Americans (70 nmol/L).

CONCLUSIONS

Significant race/ethnic and gender differences exist in the association of vitamin D and systolic blood pressure. Odds for hypertension are reduced significantly at higher vitamin D levels, but this benefit plateaus at very high vitamin D levels.

The Role of Toll-Like Receptors and Vitamin D in Cardiovascular Diseases-A Review

Cardiovascular diseases are the leading cause of mortality worldwide. Therefore, a better understanding of their pathomechanisms and the subsequent implementation of optimal prophylactic and therapeutic strategies are of utmost importance. A growing body of evidence states that low-grade inflammation is a common feature for most of the cardiovascular diseases in which the contributing factors are the activation of toll-like receptors (TLRs) and vitamin D deficiency. In this article, available data concerning the association of cardiovascular diseases with TLRs and vitamin D status are reviewed, followed by a discussion of new possible approaches to cardiovascular disease management.

Association of parathyroid hormone with 20-year cognitive decline: The ARIC study

OBJECTIVE

We hypothesized that elevated parathyroid hormone (PTH) levels will be independently associated with 20-year cognitive decline in a large population-based cohort.

METHODS

We studied 12,964 middle-aged white and black ARIC participants without a history of prior stroke who, in 1990-1992 (baseline), had serum PTH levels measured and cognitive function testing, with repeat cognitive testing performed at up to 2 follow-up visits. Cognitive testing included the Delayed Word Recall, the Digit Symbol Substitution, and the Word Fluency tests, which were summed as a global Z score. Using mixed-effects models, we compared the relative decline in individual and global cognitive scores between each of the top 3 quartiles of PTH levels to the reference bottom quartile. We adjusted for demographic variables, education, vascular risk factors, and levels of calcium, phosphate, and vitamin D. We imputed missing covariate and follow-up cognitive data to account for attrition.

RESULTS

The mean (SD) age of our cohort was 57 (6) years, 57% were women, and 24% were black. There was no cross-sectional association of elevated PTH with cognitive global Z score at baseline (p > 0.05). Over a median of 20.7 years, participants in each PTH quartile showed a decline in cognitive function. However, there was no significant difference in cognitive decline between each of the top 3 quartiles and the lowest reference quartile (p > 0.05). In a subset, there was also no association of higher mid-life PTH levels with late-life prevalent adjudicated dementia (p > 0.05).

CONCLUSIONS

Our work does not support an independent influence of PTH on cognitive decline in this population-based cohort study.

Vitamin D and hypertension: Prospective study and meta-analysis

OBJECTIVES

The study sought to determine the link between vitamin D concentrations and incident hypertension in prospective study and meta-analysis.

METHODS

The study was embedded in the Kailuan Study, a population-based cohort of adults that contains underground miners. In 2012, we studied 2,456 men and women free of prevalent hypertension, age 21 to 67 at baseline. Serum 25-hydroxyvitamin D was measured from previously frozen baseline samples using ELISA (Enzyme-Linked ImmunoadSorbent Assay). We use the logistic regression analysis to estimate the odd radio (ORs) 95% confidence intervals (CIs) for 25-hydroxyvitamin D [25(OH)D] concentrations with incident hypertension. To help place our new data in context, we conducted a systemic review and meta-analysis of previous prospective reports of vitamin D and hypertension.

RESULTS

During a median follow-up of 2 years, 42.6% of the cohort (n = 1047) developed hypertension. Compared with the 25-hydroxyvitamin D >30ng/ml, 25-hydroxyvitamin D <20 ng/ml was associated with a greater hypertension risk (OR: 1.225 [95% CI: 1.010 to 1.485] p = 0.04), although the association was attenuated and not statistically significant after adjusting for potential confounders (OR: 1.092 [95% CI: 0.866 to 1.377] p = 0.456). This meta-analysis included seven prospective studies for 53,375 participants using adjusted HR founded a significant association between vitamin D deficiencies and incident hypertension (HRs = 1.235 (95% CI: 1.083 to 1.409, p = 0.002)).

CONCLUSION

Lower serum 25-hydroxyvitamin D concentrations were not associated with a greater risk of incident hypertension. More research is needed to further determine the role of 25-hydroxyvitamin D in hypertension prevention and therapy.

Serum Parathyroid Hormone Responses to Vitamin D Supplementation in Overweight/Obese Adults: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Obesity is often associated with vitamin D deficiency and secondary hyperparathyroidism. Vitamin D supplementation typically leads to the reductions in serum parathyroid hormone (PTH) levels, as shown in normal weight individuals. Meanwhile, the dose of vitamin D supplementation for the suppression of PTH may differ in overweight and obese adults. We conducted a systematic review and meta-analysis of randomized controlled trials to determine the dose of vitamin D supplementation required to suppress PTH levels in overweight/obese individuals. We identified 18 studies that examined overweight or obese healthy adults who were supplemented with varying doses of vitamin D3. The primary outcomes examined were changes in PTH and serum 25-hydroxyvitamin D (25OHD) levels from baseline to post-treatment. The results of the meta-analysis showed that there was a significant treatment effect of vitamin D supplementation on PTH, total standardized mean difference (SMD) (random effects) = -0.38 (95% CI = -0.56 to -0.20), t = -4.08, p < 0.001. A significant treatment effect of vitamin D supplementation was also found on 25OHD, total SMD (random effects) = 2.27 (95% CI = 1.48 to 3.06) t = 5.62, p < 0.001. Data from available clinical trials that supplemented adults with D3 ranging from 400 IU to 5714 IU, showed that 1000 IU of vitamin D supplementation best suppressed serum PTH levels, total SMD = -0.58, while vitamin D supplementation with 4000 IU showed the greatest increase in serum 25OH levels. Vitamin D and calcium supplementation of 700 IU and 500 mg, respectively, also showed a significant treatment effect on the suppression of PTH with a total SMD = -5.30 (95% CI = -9.72 to -0.88). In conclusion, the meta analysis of available clinical trials indicates that 1000 IU vitamin D supplementation can suppress serum PTH levels, while 4000 IU of vitamin D was associated with the largest increase in serum 25OHD levels in the overweight and obese population.

Primary Hyperparathyroidism: Effects on Bone Health

Primary hyperparathyroidism (PHPT) is the most common cause of chronic hypercalcemia. With the advent of routine calcium screening, the classic presentation of renal and osseous symptoms has been largely replaced with mild, asymptomatic disease. In hypercalcemia caused by PHPT, serum parathyroid hormone levels are either high, or inappropriately normal. A single-gland adenoma is responsible for 80% of PHPT cases. Less frequent causes include 4-gland hyperplasia and parathyroid carcinoma. Diminished bone mineral density and nephrolithiasis are the major current clinical sequelae. Parathyroidectomy is the only definitive treatment for PHPT, and in experienced hands, cure rates approach 98%.

Angiotensin-Converting Enzyme Inhibition and Parathyroid Hormone Secretion

BACKGROUND

Prior studies suggest that renin-angiotensin-aldosterone system (RAAS) inhibitors decrease parathyroid hormone (PTH) secretion.

OBJECTIVE

To evaluate the effect of angiotensin-converting enzyme inhibitors (ACEi) on serum PTH in participants with and without primary hyperparathyroidism (P-HPT).

METHODS

An open-label, single-arm, pilot study whereby participants with and without P-HPT had PTH were evaluated before and after 1 week of maximally tolerated lisinopril therapy.

RESULTS

A total of 12 participants with, and 15 participants without, P-HPT successfully completed the protocol. Following 1 week of lisinopril, participants with P-HPT had a decrease in systolic blood pressure (SBP) (-6.4 mmHg, P < 0.01), an increase in plasma renin activity (PRA) (+1.50 ng/mL/h, P = 0.06), and a decrease in PTH (79.5 (21.6) to 70.9 (19.6) pg/mL, ∆ = -8.6 pg/mL, P = 0.049); however, serum and urine calcium did not change. In contrast, although 1 week of lisinopril significantly decreased SBP and increased PRA among participants without P-HPT, there were no changes in PTH or calcium.

CONCLUSION

In this short pilot investigation, 1 week of maximally titrated ACEi did not impact PTH in participants without P-HPT, but resulted in a modest and marginally significant reduction of PTH but not calcium, among participants with P-HPT. This trial is registered with ClinicalTrials.gov NCT01691781.

Vitamin D, PTH and the risk of overall and disease-specific mortality: Results of the Longitudinal Aging Study Amsterdam

Observational studies suggest that low concentrations of serum 25-hydroxyvitamin D (25(OH)D) and high concentrations of parathyroid hormone (PTH) are associated with a higher risk of mortality. The aim of this study was to examine whether 25(OH)D and PTH concentrations are independently associated with overall and disease-specific (cardiovascular and cancer-related) mortality in a large, prospective population-based cohort of older adults. Data from 1317 men and women (65-85 years) of the Longitudinal Aging Study Amsterdam were used. Cox proportional hazard analyses were used to examine whether 25(OH)D and PTH at baseline were associated with overall mortality (with a follow-up of 18 years) and disease-specific mortality (with a follow-up of 13 years). Compared to persons in the reference category of ≥75nmol/L, persons with serum 25(OH)D <25nmol/L (HR 1.46; 95% CI: 1.12-1.91) and 25-49.9nmol/L (HR 1.24; 95% CI: 1.01-1.53) had a significantly higher risk of overall mortality, as well as men with baseline PTH concentrations ≥7pmol/L (HR 2.54 (95% CI: 1.58-4.08)), compared to the reference category of <2.33pmol/L. The relationship of 25(OH)D with overall mortality was partly mediated by PTH. Furthermore, men with PTH concentrations of ≥7pmol/L (HR 3.22; 95% CI: 1.40-7.42) had a higher risk of cardiovascular mortality, compared to the reference category. No significant associations of 25(OH)D or PTH with cancer-related mortality were observed. Both 25(OH)D and PTH should be considered as important health markers.

Parathyroid hormone and the risk of incident hypertension: the Atherosclerosis Risk in Communities study

BACKGROUND

Recent evidence suggests that parathyroid hormone (PTH) has effects on vascular smooth muscle cells, the rennin-angiotensin system and kidney function, but less is known about its role in the development of hypertension. The distribution of serum PTH also varies by race.

METHODS AND RESULTS

Therefore, we examined the relation between PTH and incident hypertension and tested for interaction by race among 7504 Atherosclerosis Risk in Communities participants (1264 black, 6240 white, median age 56 years) without initial hypertension in 1990-1992. During a median follow-up of 6 years, 1487 white and 509 black participants developed hypertension. In the overall study population, PTH was not associated with incident hypertension after adjustment for demographics and behavioral risk factors [hazard ratio highest vs. lowest quintiles, 95% confidence interval: 1.11 (0.96-1.28); P for linear trend 0.02]. Although the interaction was not statistically significant (P = 0.60), there was some evidence that the PTH-hypertension association differed by race. Among blacks, PTH was positively associated with incident hypertension, independent of demographics, and behavioral risk factors (P for linear trend 0.003). Among whites, PTH was not associated with hypertension risk. Results were similar when comparing participants with elevated versus nonelevated PTH (≥65 vs. <65 pg/ml): hazard ratio in blacks: 1.24 (1.02-1.54); hazard ratio in whites: 0.95 (0.78-1.16).

CONCLUSIONS

In this large community-based cohort, PTH levels, overall, were not independently associated with the risk of hypertension. However, we found some evidence that PTH may be associated with hypertension in blacks. Future research should continue to explore potential race differences in the PTH-hypertension association.

Parathyroid hormone and risk of heart failure in the general population: A meta-analysis of prospective studies

Inconsistent findings have been reported on the association between the parathyroid hormone (PTH) level and risk of heart failure. We aimed to systematically evaluate the association between circulating level of PTH and risk of heart failure in the general population by conducting a meta-analysis. We made a comprehensive literature search in PubMed, Embase, VIP, CNKI, and Wanfang databases published until January 2016. Only prospective observational studies reporting the association between circulating level of PTH and risk of heart failure in the general population were selected. Pooled adjusted hazard ratio (HR) and corresponding 95% confidence intervals (CIs) were calculated for the highest versus lowest PTH category. Six studies with 25,207 participants identified. Higher circulating level of PTH was associated with an increased risk of heart failure (HR: 1.38; 95% CI 1.09-1.74) in a random effect model. Subgroup analyses revealed that the risk of heart failure was more pronounced among men (HR: 1.75; 95% CI 1.38-2.22) than in both genders. However, the risk increment was not statistically significant (HR: 1.12; 95% CI 0.76-1.66) in the middle-aged population. Higher PTH level is independently associated with an exacerbated risk of heart failure in the general population.

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.

Parathyroid Hormone and the Use of Diuretics and Calcium-Channel Blockers: The Multi-Ethnic Study of Atherosclerosis

Thiazide diuretic (TZ) use is associated with higher bone mineral density, whereas loop diuretic (LD) use is associated with lower bone density and incident fracture. Dihydropyridine-sensitive calcium channels are expressed on parathyroid cells and may play a role in parathyroid hormone (PTH) regulation. The potential for diuretics and calcium-channel blockers (CCBs) to modulate PTH and calcium homeostasis may represent a mechanism by which they influence skeletal outcomes. We hypothesized that the use of LD and dihydropyridine CCBs is associated with higher PTH, and TZ use is associated with lower PTH. We conducted cross-sectional analyses of participants treated for hypertension in the Multi-Ethnic Study of Atherosclerosis who did not have primary hyperparathyroidism or chronic kidney disease (n = 1888). We used adjusted regression models to evaluate the independent association between TZ, LD, and CCB medication classes and PTH. TZ use was associated with lower PTH when compared with non-TZ use (44.4 versus 46.9 pg/mL, p = 0.02), whereas the use of LD and CCBs was associated with higher PTH when compared with non-users of each medication class (LD: 60.7 versus 45.5 pg/mL, p < 0.0001; CCB: 49.5 versus. 44.4 pg/mL, p < 0.0001). Adjusted regression models confirmed independent associations between TZ use and lower PTH (β = -3.2 pg/mL, p = 0.0007), and LD or CCB use and higher PTH (LD: β = +12.0 pg/mL, p < 0.0001; CCB: +3.7 pg/mL, p < 0.0001). Among CCB users, the use of dihydropyridines was independently associated with higher PTH (β = +5.0 pg/mL, p < 0.0001), whereas non-dihydropyridine use was not (β = +0.58 pg/mL, p = 0.68). We conclude that in a large community-based cohort with normal kidney function, TZ use is associated with lower PTH, whereas LD and dihydropyridine CCB use is associated with higher PTH. These associations may provide a mechanistic explanation linking use of these medications to the development of skeletal outcomes. © 2016 American Society for Bone and Mineral Research.

Parathyroid hormone, cardiovascular and all-cause mortality: A meta-analysis

BACKGROUND

Inconsistent findings have reported on parathyroid hormone (PTH) concentration and cardiovascular or all-cause mortality.

OBJECTIVE

To investigate whether elevated PTH concentration was an independent predictor for cardiovascular or all-cause mortality in the general population by conducting a meta-analysis based on prospective studies.

METHOD

We searched Cochrane Library, Pubmed, and Embase databases up to June 2015. Only prospective studies evaluating serum PTH concentration and cardiovascular or all-cause mortality were included. Pooled adjust risk ratio (RR) and corresponding 95% confidence intervals (CI) were calculated for the highest vs. lowest PTH concentration.

RESULTS

Ten studies with 31,616 subjects were identified and analyzed. Compared the highest to the lowest PTH concentration, elevated serum PTH concentration increased the risk of all-cause mortality (RR 1.19; 95% CI 1.08-1.30) but not for cardiovascular mortality (RR 1.26; 95% CI 0.96-1.66). Subgroup analyses indicated that cardiovascular mortality risk appeared to be more pronounced among men (RR 1.68; 95% CI 1.05-2.67).

CONCLUSIONS

Elevated PTH concentration is an independent predictor of all-cause mortality. Elevated serum PTH concentration appears to increase risk of cardiovascular mortality among men.

Parathyroid Hormone and Subclinical Cerebrovascular Disease: The Atherosclerosis Risk in Communities Brain Magnetic Resonance Imaging Study

BACKGROUND

Elevated parathyroid hormone (PTH) levels have been associated with cardiovascular disease risk factors and events. We hypothesized that elevated PTH levels would also be associated with subclinical cerebrovascular disease. We examined the relationship between elevated PTH level and white matter hyperintensities (WMHs) and subclinical infarcts measured on brain magnetic resonance imaging (MRI).

METHODS

PTH was measured at baseline (1993-1994) among participants free of prior clinical stroke who underwent a brain MRI at baseline (n = 1703) and a second brain MRI 10 years later (n = 948). PTH levels of 65 pg/mL or higher were considered elevated (n = 204). Participants who did not return for a follow-up MRI had, at baseline, higher PTH and a greater prevalence of cardiovascular risk factors (P < .05 for all); therefore, multiple imputation was used. The cross-sectional and prospective associations of PTH levels with WMH and MRI-defined infarcts (and their progression) were investigated using multivariable regression models.

RESULTS

At baseline, the participants had a mean age of 62 years and were 60% female and 49% black. Cross-sectionally, after adjusting for demographic and lifestyle factors, elevated PTH level was associated with higher WMH score (β = .19, 95% confidence interval [CI] .04-.35) and increased odds of prevalent infarcts (odds ratio 1.56, 95% CI 1.02-2.36). Results were attenuated after adjustment for potential mediators of this association (i.e., hypertension). No prospective associations were found between PTH and incident infarcts or change in estimated WMH volume, although estimates were imprecise.

CONCLUSIONS

Although associated cross-sectionally, we did not confirm any association between elevated PTH level and progression of cerebrovascular changes on brain MRIs obtained 10 years apart. The relationship of PTH with subclinical brain disease warrants further study.

Parathyroid hormone is associated with incident diabetes in white, but not black adults: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

Accumulating evidence has linked elevated parathyroid hormone (PTH) with insulin resistance, beta cell dysfunction and dysglycaemia, however, its role in the development of diabetes is largely unclear, particularly among non-whites. We sought to examine the association of PTH with the incidence of diabetes.

METHODS

We studied 8066 white and 2034 black adults aged 46-70 years at baseline (1990-92) from the ARIC Study with follow-up for incident diabetes ascertained during study visits conducted in 1993-95 and 1996-98. Hazard ratios (HR) and their 95% CIs for diabetes adjusted for demographics, lifestyle, and 25-hydroxyvitamin D were estimated according to PTH measured at baseline.

RESULTS

PTH was higher among blacks than whites (median [IQR], 43.8 [35.0-55.8] vs. 37.9 [30.4-47.3] pg/mL; P<0.001). During a median follow-up of 6 years, 498 white and 167 black participants developed diabetes. The association of PTH with diabetes varied significantly by race (P-interaction 0.02). PTH was not associated with risk for diabetes among black adults. Among whites, HRs according to quintiles of PTH were 1 (referent), 0.95 (0.71, 1.29), 0.95 (0.70, 1.28), 1.12 (0.84, 1.51), and 1.31 (0.98, 1.76) (P-trend 0.03). When a clinical cut-point for PTH was applied (≥65pg/mL; 5.7% of whites), the HR for diabetes among whites was 1.38 (1.01, 1.88). Results were similar when restricted to participants with normal baseline kidney function.

CONCLUSION

In this large, population-based study, elevated PTH was independently associated with risk for diabetes among white, but not black adults. Further studies are needed to elucidate the mechanisms that may underlie this differential association of PTH with diabetes across race groups.

Association of Serum 25-Hydroxyvitamin D and Parathyroid Hormone With Hypertension in Middle-Aged and Older Korean Adults

BACKGROUND

Previous studies have suggested that serum 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) levels are associated with hypertension. However, the associations have yet to be studied in Koreans. This study explored the relationship among serum 25(OH)D, PTH concentrations, and the presence of hypertension in middle-aged and older Korean adults using the most recent nationally representative survey data.

METHODS

A population-based, cross-sectional study was conducted with data collected from 5,260 Korean adults (aged ≥50 years) who participated in the 2010 and 2011 Korean National Health and Nutrition Examination Surveys. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or current use of antihypertensive medication.

RESULTS

The prevalence of hypertension significantly increased according to the quartiles of serum PTH levels (P < 0.0001), but not of serum 25(OH)D levels. In multivariable logistic analysis, the adjusted odds ratios (ORs) for hypertension were significantly higher among participants in the highest quartile than among those in the lowest quartile of serum PTH level, after adjusting for potential confounders (OR = 1.26, 95% confidence interval: 1.02-1.56, P = 0.03). The adjusted ORs for hypertension tended to decrease across the quartiles of serum 25(OH)D level, but the associations were not significant.

CONCLUSION

Serum 25(OH)D was not associated with the presence of hypertension, whereas serum PTH was positively associated, suggesting that serum PTH may be an independent risk factor for hypertension in middle-aged and older Korean adults.