Parathyroid hormone and arterial dysfunction in the multi-ethnic study of atherosclerosis

Ethnic and seasonal variations in FGF-23 and markers of chronic kidney disease-mineral and bone disorder

Background

Fibroblast growth factor 23 (FGF-23) and other markers of chronic kidney disease-mineral and bone disorder (CKD-MBD) provide valuable insights into disease processes, treatment options and patient prognosis. However, limited research has explored potential associations with ethnicity or season, particularly in multi-ethnic populations residing in high-latitude regions.

Methods

We evaluated CKD-BMD markers in a diverse cohort of CKD patients, who were participants of The CANADIAN AIM to PREVENT (the CAN AIM to PREVENT) study. FGF-23, calcium, phosphate, 25-hydroxyvitamin D (25-OHD) and intact parathyroid hormone (iPTH) in 1234 participants with pre-dialysis CKD (mean estimated glomerular filtration rate: 41.8 ± 14.3 mL/min) were analyzed. Mixed-effects general linear regression models adjusted for demographic and biological factors were used to compare repeated measurements across patient groups categorized by ethnicity (East Asian, White, South Asian, Black, Southeast Asian) and seasons.

Results

Compared with other groups, White participants exhibited 8.0%-18.5% higher FGF-23 levels, Black participants had 0.17-0.32 mg/dL higher calcium levels, White participants had 10.0%-20.1% higher 25-OHD levels, South Asian participants had 7.3%-20.1% lower 25-OHD levels and Black participants had 22.1-73.8% higher iPTH levels, while East Asian participants had 10.7%-73.8% lower iPTH levels. Seasonal variations were also observed. FGF-23 levels were 11.9%-15.5% higher in summer compared with other seasons, while calcium levels were 0.03-0.06 mg/dL lower in summer. 25-OHD levels were 5.6%-10.6% higher in summer and autumn compared with other seasons.

Conclusions

This study shows that FGF-23 and CKD-MBD markers in a Canadian pre-dialysis CKD cohort vary independently by ethnicity and season. Further research is needed to understand the reasons and clinical significance of these findings.

A Delicate Balance: Challenges in the Management of Primary Hyperparathyroidism and Congestive Heart Failure

Primary hyperparathyroidism (PHPT) is an excessive parathyroid hormone (PTH) production disorder, causing increased calcium levels. Commonly, these cases are asymptomatic and detected incidentally on routine labs. These patients are usually conservatively managed and monitored periodically, including bone and kidney health evaluation. Medical management of severe hypercalcemia secondary to PHPT includes IV fluids, cinacalcet, bisphosphonates, and dialysis, while the surgical treatment is parathyroidectomy. Patients suffering from heart failure with reduced ejection fraction (HFrEF) on diuretics and PHPT require a delicate balance of their volume status to prevent exacerbation of either condition. In patients with these two comorbidities on the opposite ends of the volume spectrum, it can lead to challenges in managing these patients. We present a case of a woman with repeated hospitalizations due to poor volume status control.  An 82-year-old female with primary hyperparathyroidism (diagnosed 17 years ago), HFrEF due to non-ischemic cardiomyopathy, sick sinus syndrome with a pacemaker, and persistent atrial fibrillation presented to the emergency department with worsening bilateral lower limb swelling for several months. The remaining review of systems was largely negative. Her home medication regimen included carvedilol, losartan, and furosemide. Vitals were stable, and the physical exam revealed bilateral lower extremity pitting edema. Chest x-ray revealed cardiomegaly with mild pulmonary vascular congestion. Relevant labs were NT pro-BNP at 2190 pg/mL, calcium at 11.2 mg/dL, creatinine at 1.0 mg/dL, PTH at 143 pg/mL, and Vitamin D, 25-hydroxy at 48.6 ng/mL. The echocardiogram showed an ejection fraction (EF) of 39%, grade III diastolic dysfunction, severe pulmonary hypertension, and mitral and tricuspid regurgitation. The patient received IV diuretics and guideline-directed treatment for congestive heart failure exacerbation. She was managed conservatively for her hypercalcemia and advised to maintain hydration at home. Spironolactone and Dapagliflozin were added to her regimen, and the Furosemide dose was increased at discharge.  The patient was re-admitted three weeks later with fatigue and decreased fluid intake. Vitals were stable; however, the physical exam revealed dehydration. Pertinent labs were calcium at 13.4 mg/dL, potassium at 5.7 mmol/L, creatinine at 1.7 mg/dL (baseline 1.0), PTH at 204 pg/mL, and Vitamin D, 25-hydroxy at 54.1 ng/mL. Repeat ECHO showed an ejection fraction (EF) of 15%. She was started on gentle IV fluids to correct the hypercalcemia while preventing volume overload. Hypercalcemia and acute kidney injury improved with hydration. She was put on Cinacalcet 30 mg, and home medications were adjusted for better volume control at discharge. This case highlights the complications of balancing the volume status with primary hyperparathyroidism and CHF. Worsening HFrEF resulted in a higher diuretic requirement, thereby worsening her hypercalcemia. With emerging data on the correlation between PTH and cardiovascular risks, it is becoming necessary to assess the risks and benefits of conservative management in asymptomatic patients. Current research has also shown that various patient demographics and comorbidities prevent the surgical management of PHPT. Hence, in suitable candidates, parathyroidectomy must be considered early in patients with asymptomatic hyperparathyroidism.

Biomarkers of Vitamin D Metabolism and Hip and Vertebral Fracture Risk: The Multi-Ethnic Study of Atherosclerosis

Studies on associations between biomarkers of vitamin D metabolism and fracture risk have focused predominantly on White or elderly populations and may not be generalizable to relatively healthy multiethnic populations. We tested associations of total 25-hydroxyvitamin D (25[OH]D), the ratio of 24,25-dihydroxyvitamin D3 to 25-hydroxyvitamin D3 (vitamin D metabolite ratio, VDMR), parathyroid hormone (PTH), and fibroblast growth factor-23 (FGF-23) concentrations measured in serum with risk of hip and vertebral fractures in the Multi-Ethnic Study of Atherosclerosis (MESA). Serum 25-hydroxyvitamin D2 and D3 and 24,25-dihydroxyvitamin D3 were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The study cohort of 6466 participants was without clinically apparent cardiovascular disease and was 39% White, 27% Black, 22% Hispanic, and 12% Chinese. The mean age was 62 years, and 53% were female. There were 128 hip and vertebral fractures over a mean follow-up of 14.2 years. 25(OH)D, the VDMR, PTH, and FGF-23 were not significantly associated with fracture risk after adjustment for demographics, diabetes, smoking, systolic blood pressure, body mass index, medication use, albuminuria, and estimated glomerular filtration rate. Principal component analysis did not suggest differences in linear combinations of 25(OH)D, the VDMR, PTH, and FGF-23 between participants who experienced fractures and those who did not. We did not observe significant interaction between race and ethnicity and any biomarker of vitamin D metabolism on fracture risk. In conclusion, none of the four serum biomarkers of vitamin D metabolism investigated showed a significant association with fracture risk in relatively healthy multiethnic populations. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Plasma Levels of Intact Parathyroid Hormone and Congestion Burden in Heart Failure: Clinical Correlations and Prognostic Role

Circulating parathyroid hormone (PTH) concentrations increase in heart failure (HF) and are related to disease severity. The relationship between PTH and congestion is still a matter of debate. The objective of this analysis was to evaluate the role of PTH as a marker of congestion and prognosis in HF. We enrolled 228 patients with HF. Intact PTH concentrations and HYDRA score (constituted by: B-type natriuretic peptide, blood urea nitrogen−creatinine ratio, estimated plasma volume status, and hydration status) were evaluated. The study endpoint was all-cause mortality. PTH levels were higher in acute compared with chronic HF and in patients with clinical signs of congestion (i.e., peripheral oedema and orthopnea). PTH concentrations significantly correlated with NYHA class and HYDRA score. At multivariate analysis of HYDRA score, estimated glomerular filtration rate (eGFR), and corrected serum calcium were independently determinants of PTH variability. Fifty patients (22%) died after a median follow-up of 408 days (interquartile range: 283−573). Using univariate Cox regression analysis, PTH concentrations were associated with mortality (hazard ratio [HR]: 1.003, optimal cut-off: >249 pg/mL—area under-the-curve = 0.64). Using multivariate Cox regression analysis, PTH was no longer associated with death, whereas HYDRA score, left ventricular ejection fraction, and eGFR acted as independent predictors for mortality (HR: 1.96, 0.97, and 0.98, respectively). Our study demonstrated that intact PTH was related to clinical and subclinical markers of congestion. However, intact PTH did not act as an independent determinant of all-cause death in HF patients.

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.

The association between Hba1c and arterial stiffness among non-diabetic patients with chronic kidney disease

Background

Cardiovascular events are seen more frequently after the age of 60 and they are a significant cause of morbidity and mortality. Arterial stiffness is a property that can be expressed by pulse wave velocity and this value is assumed to be a predictor of cardiovascular events. Patients with chronic kidney disease and dysregulated blood sugar have increased atherosclerosis and arterial stiffness, but the relationship between physiological levels of Hba1c and arterial stiffness is less clear in chronic kidney disease patients without diabetes mellitus.

Objectives

Here, we aimed to investigate the degree of arterial stiffness among non-diabetic, non-dialysis dependent chronic kidney disease patients with physiological HbA1c levels.

Methods

We enrolled 51 patients who were followed up at Ege University Hospital Nephrology Department between February and June 2015. Non-diabetic, non-dialysis dependent chronic kidney disease patients were included in the study. Blood pressure and pulse wave velocity were measured with an applanation tonometry device (Sphygmocor Vx Software Atcor Medical, Australia). Correlations between pulse wave velocity and the aforementioned parameters were investigated (see below).

Results

We detected a significant correlation between pulse wave velocity and systolic blood pressure (p=0.0001) and Hba1c (p=0.044) separately. There was an inverse correlation with creatinine clearance (p=0.04). We also detected a significant correlation with serum phosphorus level (p=0.0077) and furosemide use (p=0.014). No correlations were found among the other parameters.

Conclusions

Arterial stiffness is an important predictor of cardiovascular events and measuring it is an inexpensive method for estimating morbidity and mortality. Our study supports the importance of measuring arterial stiffness and of controlling blood glucose levels, even at physiological Hba1c values, especially for chronic kidney disease patients.

Prognostic value of lower bone mineral density in predicting adverse cardiovascular disease in Asian women

OBJECTIVE

We investigated whether the evaluation of bone mineral density (BMD) provides independent and incremental prognostic value for predicting atherosclerotic cardiovascular disease (ASCVD) in women.

METHODS

A total of 12 681 women aged 50-80 years (mean, 63.0±7.8 years) who underwent dual-energy X-ray absorptiometry were retrospectively analysed. We assessed the hazard ratio (HR) for ASCVD events (ASCVD death, non-fatal myocardial infarction and ischaemic stroke) according to the BMD or a clinical diagnosis of osteopenia or osteoporosis, with adjustment for clinical risk factors, including age, body mass index, hypertension, type 2 diabetes, hyperlipidaemia, current smoking and previous fracture. We also evaluated whether the addition of BMD or a clinical diagnosis of osteopenia or osteoporosis to clinical risk factors improved the prediction for ASCVD events.

RESULTS

In total, 468 women (3.7%) experienced ASCVD events during follow-up (median, 9.2 years). Lower BMD at the lumbar spine, femur neck and total hip was independently associated with higher risk for ASCVD events (adjusted HR per 1-standard deviation decrease in BMD: 1.16, p<0.001; 1.29, p<0.001; 1.38, p<0.001; respectively). A clinical diagnosis of osteoporosis was also independently associated with higher risk for ASCVD events (adjusted HR: 1.79, p<0.001). The addition of BMD or a clinical diagnosis of osteopenia or osteoporosis to clinical risk factors demonstrated significant incremental value in discriminating ASCVD events (addition of total hip BMD, p for difference <0.001).

CONCLUSION

The evaluation of BMD provides independent and incremental prognostic value for ASCVD in women and thus may improve risk stratification in women.

The Multi-Ethnic Study of Atherosclerosis individual response to vitamin D trial: Building a randomized clinical trial into an observational cohort study

The INdividual response to VITamin D (INVITe) trial was a randomized, placebo-controlled, parallel group trial of vitamin D3 supplementation (2000 IU daily) designed to determine clinical and genetic characteristics that modify the response to vitamin D supplementation. To enhance internal and external validity and reduce cost, the INVITe trial was nested within the Multi-Ethnic Study of Atherosclerosis (MESA), an ongoing prospective observational cohort study. The INVITe trial enrolled a community-based population of 666 racially and ethnically diverse participants from January 2017 to April 2019. This represents 30% of 2210 MESA participants approached for screening, and 96% of those found to be eligible. Barriers to enrollment included delayed initiation of the trial relative to scheduled MESA study visits, a lower number of available MESA participants than expected, and a high prevalence (18%) of high-dose vitamin D supplementation (>1000 IU daily, an exclusion criterion). The final study visit was attended by 611 participants (92%), and median adherence was 98%. Our experience suggests that integration of a randomized trial into an existing observational cohort study may leverage strengths of the source population and enhance enrollment, retention, and adherence, although with limited enrollment capacity. The INVITe trial will use rigorously-collected data to advance understanding of individual determinants of vitamin D response.

Parathyroid hormone may play a role in the pathophysiology of primary hypertension

Parathyroid hormone has been related with the risk of hypertension, but the matter remains controversial. We examined the association of parathyroid hormone with central blood pressure and its determinants in 622 normotensive or never-treated hypertensive subjects aged 19-72 years without diabetes, cardiovascular or renal disease, or cardiovascular medications. The methods were whole-body impedance cardiography and analyses of pulse wave and heart rate variability. Cardiovascular function was examined in sex-specific tertiles of plasma parathyroid hormone (mean concentrations 3.0, 4.3 and 6.5 pmol/L, respectively) during head-up tilt. Explanatory factors for haemodynamics were further investigated using linear regression analyses. Mean age was 45.0 (s.d. 11.7) years, BMI 26.8 (4.4) kg/m2, seated office blood pressure 141/90 (21/12) mmHg, and 309 subjects (49.7%) were male. Only five participants had elevated plasma parathyroid hormone and calcium concentrations. Highest tertile of parathyroid hormone presented with higher supine and upright aortic diastolic blood pressure (P < 0.01) and augmentation index (P < 0.01), and higher upright systemic vascular resistance (P < 0.05) than the lowest tertile. The tertiles did not present with differences in pulse wave velocity, cardiac output, or measures of heart rate variability. In linear regression analyses, parathyroid hormone was an independent explanatory factor for aortic systolic (P = 0.005) and diastolic (P = 0.002) blood pressure, augmentation index (P = 0.002), and systemic vascular resistance (P = 0.031). To conclude, parathyroid hormone was directly related to central blood pressure, wave reflection, and systemic vascular resistance in subjects without cardiovascular comorbidities and medications. Thus, parathyroid hormone may play a role in the pathophysiology of primary hypertension.

Race, Ancestry, and Vitamin D Metabolism: The Multi-Ethnic Study of Atherosclerosis

CONTEXT

A comprehensive characterization of racial/ethnic variations in vitamin D metabolism markers may improve our understanding of differences in bone and mineral homeostasis and the risk of vitamin D-related diseases.

OBJECTIVE

Describe racial/ethnic differences in vitamin D metabolism markers and their associations with genetic ancestry.

DESIGN, SETTING, PARTICIPANTS

In a cross-sectional study within the Multi-Ethnic Study of Atherosclerosis (MESA), we compared a comprehensive panel of vitamin D metabolism markers across self-reported racial/ethnic groups of Black (N = 1759), White (N = 2507), Chinese (N = 788), and Hispanic (N = 1411). We evaluated associations of proportion African and European ancestry with this panel of markers in Black and Hispanic participants using ancestry informative markers. Latent class analysis evaluated associations between patterns of vitamin D measurements with race/ethnicity.

RESULTS

Compared with Black participants, White participants had significantly higher serum concentrations of 25-hydroxyvitamin D and fibroblast growth factor-23; lower concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D; circulating vitamin D metabolite ratios suggesting lower CYP27B1 and higher CYP24A1 activity; higher urinary concentrations of calcium and phosphorus with higher urinary fractional excretion of phosphorus; and differences in vitamin D binding globulin haplotypes. Higher percent European ancestry was associated with higher 25-hydroxyvitamin D and lower parathyroid hormone concentrations among Black and Hispanic participants. Latent classes defined by vitamin D measurements reflected these patterns and differed significantly by race/ethnicity and ancestry.

CONCLUSIONS

Markers of vitamin D metabolism vary significantly by race/ethnicity, may serve to maintain bone and mineral homeostasis across ranges of 25-hydroxyvitamin D production, and be attributable, at least partly, to genetic ancestry.

Impact of Race on the Association of Mineral Metabolism With Heart Failure: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Alterations in mineral metabolism, such as high phosphorus, high parathyroid hormone (PTH), and high fibroblast growth factor-23 (FGF-23) have been identified as potential risk factors for heart failure (HF). Important differences in the prevalence of mineral metabolism abnormalities and in the risk of HF have been reported across race and/or ethnic groups. In this study, we evaluated whether the associations of mineral metabolism markers with HF differed by race and/or ethnicity.

METHODS

We included participants free of cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis to quantify rates of HF overall and across race and/or ethnic groups. Using Cox models, we tested associations of baseline higher phosphorus (>4 mg/dL), PTH greater than 65 pg/mL, and FGF-23 greater than 46.5 pg/mL with incident HF, and for interactions by race and/or ethnicity, adjusting for sociodemographic and cardiovascular risk factors.

RESULTS

Among the 6413 participants, median follow-up time was 14.9 years. The incidence rate for HF was highest for African Americans and lowest for Chinese (4.71 and 2.42 per 1000 person-years, respectively). The prevalence of elevated PTH (18.8% vs 7.4%) but not FGF-23 (23.1% vs 28.8%) was higher in African Americans vs Whites. In multivariable models, the associations of elevated PTH (hazard ratio [HR] 1.50, 95% CI: 1.13-1.99) and FGF-23 (HR 1.37, 95% CI: 1.07-1.75) with incident HF were statistically significant. However, the interactions by race and/or ethnicity were not statistically significant.

CONCLUSIONS

In a multiethnic population, higher PTH and FGF-23 were associated with risk of HF in African American and Hispanic individuals. There is no evidence that race and/or ethnicity modifies the association of altered mineral metabolism with risk of HF.

Serum parathyroid hormone levels in patients with chronic right heart failure

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

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.

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.

Low dietary magnesium intake alters vitamin D-parathyroid hormone relationship in adults who are overweight or obese

Vitamin D metabolism is dependent on magnesium (Mg) as a cofactor; therefore, poor Mg status may alter the relationship between vitamin D metabolite serum 25-hydroxyvitamin D (s25OHD) and serum parathyroid hormone (sPTH). We hypothesized that low dietary Mg intake may alter sPTH response to s25OHD in a population with excess body weight, thereby leading to a worsening of cardiometabolic health. To explore this hypothesis, we conducted a cross-sectional study on adults who were either overweight or obese (owt/ob). Dietary Mg intake was measured using a Mg food frequency questionnaire (MgFFQ). Body composition information was measured using Dual Energy X-ray Absorptiometry (DXA). Blood samples were obtained for all biochemical analyses. A total of 57 participants, 22 to 65 years of age, with a body mass index between 25 to 45 kg/m² were divided into 3 groups, according to dietary Mg intake percentiles (Low Mg Group = <33 percentile, Medium Mg Group = 33 to 66 percentile, High Mg Group = >66 percentile). Higher s25OHD was negatively associated with lower sPTH in the High Mg Intake group (r = -0.472, P = .041), but not in other groups. A positive relationship between s25OHD and serum high-molecular weight adiponectin concentrations was observed in the High Mg Group (r = 0.532, r = 0.022), but not in other groups. Serum Interleukin-6 concentrations were negatively associated with s25OHD (r = -0.316, P = .017) for the entire study group. Based on these results, our study demonstrated that a low dietary Mg intake may alter PTH response to 25OHD.

Mineral Metabolism Disturbances and Arteriovenous Fistula Maturation

BACKGROUND

The arteriovenous fistula (AVF) is central to haemodialysis treatment, but up to half of surgically created AVF fail to mature. Chronic kidney disease often leads to mineral metabolism disturbances that may interfere with AVF maturation through adverse vascular effects. This study tested associations between mineral metabolism markers and vein histology at AVF creation and unassisted and overall clinical AVF maturation.

METHODS

Concentrations of fibroblast growth factor 23, parathyroid hormone, calcium, phosphate, and vitamin D metabolites: 1,25(OH)₂D, 24,25(OH)₂D, 25(OH)D, and bioavailable 25(OH)D were measured in pre-operative serum samples from 562 of 602 participants in the Haemodialysis Fistula Maturation Study, a multicentre, prospective cohort study of patients undergoing surgical creation of an autologous upper extremity AVF. Unassisted and overall AVF maturation were ascertained for 540 and 527 participants, respectively, within nine months of surgery or four weeks of dialysis initiation. Study personnel obtained vein segments adjacent to the portion of the vein used for anastomosis, which were processed, embedded, and stained for measurement of neointimal hyperplasia, calcification, and collagen deposition in the medial wall.

RESULTS

Participants in this substudy were 71% male, 43% black, and had a mean age of 55 years. Failure to achieve AVF maturation without assistance occurred in 288 (53%) participants for whom this outcome was determined. In demographic and further adjusted models, mineral metabolism markers were not significantly associated with vein histology characteristics, unassisted AVF maturation failure, or overall maturation failure, other than a biologically unexplained association of higher 24,25(OH)₂D with overall failure. This exception aside, associations were non-significant for continuous and categorical analyses and relevant subgroups.

CONCLUSIONS

Serum concentrations of measured mineral metabolites were not substantially associated with major histological characteristics of veins in patients undergoing AVF creation surgery, or with AVF maturation failure, suggesting that efforts to improve AVF maturation rates should increase attention to other processes such as vein mechanics, anatomy, and cellular metabolism among end stage renal disease patients.

Association of circulating 25-hydroxyvitamin D and parathyroid hormone with carotid intima media thickness in children and adolescents with excess weight

Evidence on the association of vitamin D and parathyroid hormone (PTH) with cardiovascular risk factors in the young is limited. We therefore assessed the relationships of circulating vitamin D and PTH concentrations and subclinical atherosclerosis in overweight or obese children and adolescents. This was a cross-sectional study, investigated the association of 25-hydroxyvitamin D (25(OH)D), intact PTH (iPTH), and iPTH/25(OH)D ratio with carotid intima-media thickness (cIMT) in 368 Iranian children and adolescents with a body mass index (BMI) ≥1 z-score based on WHO criteria. Ultrasound measurement of cIMT was performed. Multivariable linear and logistic regressions were used to test associations between 25(OH)D, iPTH, and iPTH/25(OH)D ratio using one-ln-unit increment with cIMT. Median (25-75 interquartile range) 25(OH)D and iPTH concentrations were 11.8 (8.2-18.6) ng/ml and 38.2 (25.0-61.4) pg/ml, respectively. Among boys, each one-ln-unit increase of iPTH and iPTH/25(OH)D ratio was significantly associated with 0.194 mm and 0.147 mm increase, respectively, in cIMT, after adjustment for confounders. A similar pattern of association was observed between iPTH (β = 0.143, p = 0.037) and iPTH/25(OH)D ratio (β=0.172, p = 0.007) with cIMT among obese participants. Furthermore, among obese participants in the fully adjusted model, each one-ln-unit increase of iPTH and 25(OH)D/iPTH ratio was significantly associated with 53% and 39% increased odds of having high cIMT, respectively. Girls and those who were overweight did not show any significant association of 25(OH)D, iPTH, and iPTH/25(OH)D ratio with cIMT. High iPTH and iPTH/25(OH)D ratio were associated with increased cIMT in boys and those who are obese.

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).

Retinal micro-vascular and aortic macro-vascular changes in postmenopausal women with primary hyperparathyroidism

Aim of the study was to evaluate the micro and macro-vascular changes in patients with primary hyperparathyroidism (PHPT) compared to controls. 30 postmenopausal PHPT women (15 hypertensive and 15 normotensive) and 30 normotensive controls underwent biochemical evaluation of mineral metabolism and measurements of arterial stiffness by 24 hour ambulatory blood pressure monitoring. Retinal microcirculation was imaged by a Retinal Vessel Analyzer. PHPT patients also underwent bone mineral density measurements and kidney ultrasound. PHPT patients had higher mean calcium and parathyroid hormone values compared to controls. Evaluating macro-vascular compartment, we found higher values of 24 hours-systolic, diastolic blood pressure, aortic pulse wave velocity (aPWV) and aortic augmentation index (Aix) in hypertensive PHPT, but not in normotensive PHPT compared to controls. The eye examination showed narrowing arterial and venular diameters of retinal vessels in both hypertensive and normotensive PHPT compared to controls. In hypertensive PHPT, 24 hours systolic blood pressure was associated only with parathyroid hormone (PTH) levels (beta = 0.36, p = 0.04). aPWV was associated with retinal diameter (beta = -0.69, p = 0.003), but not with PTH. Retinal artery diameter was associated with PTH (beta = -0.6, p = 0.008). In the normotensive PHPT, only PTH was associated with retinal artery diameter (beta = -0.60, p = 0.01) and aortic AIx (beta = 0.65, p = 0.02). In conclusion, we found macro-vascular impairment in PHPT and that micro-vascular impairment is negatively associated with PTH, regardless of hypertension in PHPT.

Diet-induced vitamin D deficiency has no effect on acute post-stroke outcomes in young male mice

Recent observational studies have reported that patients with low circulating levels of vitamin D experience larger infarct volumes and worse functional outcomes after ischemic stroke compared to those with sufficient levels. However, it is unknown whether a causal relationship exists between low vitamin D levels and poor stroke outcome. This study aimed to assess the effect of vitamin D deficiency on acute outcomes post-stroke. Male C57Bl6 mice (six week old) were assigned to either a control or vitamin D deficient diet for four weeks prior to stroke. Stroke was induced by 1 h middle cerebral artery occlusion (MCAO) with reperfusion. At 24 h, we assessed functional outcomes, infarct volume, quantified immune cells in the brain by immunofluorescence and examined susceptibility to lung infection. ELISAs showed that the plasma level of hydroxyvitamin D₃ was 85% lower in mice fed the vitamin D-deficient diet compared with the control group. Despite this, vitamin D deficiency had no impact on functional outcomes or infarct volume after stroke. Further, there were no differences in the numbers of infiltrating immune cells or bacterial load within the lungs. These data suggest that diet-induced vitamin D deficiency has no effect on acute post-stroke outcomes.

Exploring the concept of functional vitamin D deficiency in pregnancy: impact of the interaction between 25-hydroxyvitamin D and parathyroid hormone on perinatal outcomes

Background

Associations of vitamin D with perinatal outcomes are inconsistent and few studies have considered the wider calcium metabolic system.

Objectives

We aimed to explore functional vitamin D deficiency in pregnancy by investigating associations between vitamin D status, parathyroid hormone (PTH), and perinatal outcomes.

Design

SCOPE (Screening for Pregnancy Endpoints) Ireland is a prospective cohort study of low-risk, nulliparous pregnant women. We measured serum 25-hydroxyvitamin D [25(OH)D] and PTH at 15 wk of gestation in 1754 participants.

Results

Mean ± SD 25(OH)D was 56.6 ± 25.8 nmol/L (22.7 ± 10.3 ng/mL) and geometric mean (95% CI) PTH was 7.84 pg/mL (7.7, 8.0 pg/mL) [0.86 pmol/L (0.85, 0.88 pmol/L)]. PTH was elevated in 34.3% of women who had 25(OH)D <30 nmol/L and in 13.9% of those with 25(OH)D ≥75 nmol/L. Whereas 17% had 25(OH)D <30 nmol/L, 5.5% had functional vitamin D deficiency, defined as 25(OH)D <30 nmol/L with elevated PTH. Elevated mean arterial pressure (MAP), gestational hypertension, pre-eclampsia, and small-for-gestational-age (SGA) birth were confirmed in 9.2%, 11.9%, 3.8%, and 10.6% of participants, respectively. In fully adjusted regression models, neither low 25(OH)D nor elevated PTH alone increased the risk of any individual outcome. The prevalence of elevated MAP (19.1% compared with 9.7%) and SGA (16.0% compared with 6.7%) were highest (P < 0.05) in those with functional vitamin D deficiency compared with the reference group [25(OH)D ≥75 nmol/L and normal PTH]. The adjusted prevalence ratio (PR) and RR (95% CIs) for elevated MAP and SGA were 1.83 (1.02, 3.27) and 1.53 (0.80, 2.93), respectively. There was no effect of functional vitamin D deficiency on the risk of gestational hypertension (adjusted RR: 1.00; 95% CI: 0.60, 1.67) or pre-eclampsia (adjusted RR: 1.17; 95% CI: 0.32, 4.20).

Conclusion

The concept of functional vitamin D deficiency, reflecting calcium metabolic stress, should be considered in studies of vitamin D in pregnancy. The SCOPE pregnancy cohort is registered at http://www.anzctr.org.au as ACTRN12607000551493.

[Imaging of parathyroid adenomas with F‑18 choline PET-CT]

BACKGROUND

Ultrasound and sestamibi scintigraphy are the recommended standard procedures for initial diagnosis in primary hyperparathyroidism (pHPT). Recently, F‑18 choline positron emission tomography computed tomography (choline PET/CT) has been shown promising results for the diagnostic work up of primary hyperparathyroidism (pHPT) suggesting superiority over conventional scintigraphy using Tc99m sestamibi based protocols using planar dual-phase imaging, SPECT or SPECT/CT.

METHODS

This review presents the results of F‑18 choline PET/CT on the basis of a literature search using the keywords "primary hyperparathyroidism and choline", "primary hyperparathyroidism and PET", "parathyroid adenoma and choline" und "parathyroid adenoma and PET".

RESULTS

6 studies were identified dealing with the diagnostic impact of choline PET/CT. The studies included 5 to 151 patients. Localization of single gland adenomas can be achieved with choline PET/CT in 80 up to 96% of cases. A high sensitivity and accuracy of choline PET/CT imaging is documented even in cases of repeated surgery for recurrent pHPT, in coexistant nodular goiter or in the detection of adenoma in atypical localization.

CONCLUSIONS

Using choline PET/CT parathyroid adenoma and probably parathyroid hyperplasia can be exactly localized in most patients with pHPT. Thus, a minimal-invasive surgical procedure is feasible with decreased risk of complications but high success rate in terms of biochemical cure. The diagnostic accuracy in multiglandular disease remains to be established.

Markers of vitamin D metabolism and incidence of clinically diagnosed abdominal aortic aneurysm: The Atherosclerosis Risk in Communities Study

Little is known about whether markers of vitamin D metabolism are associated with the development of abdominal aortic aneurysm (AAA), though these markers have been linked to other cardiovascular diseases. We tested the hypotheses that risk of AAA is higher among individuals with low serum concentrations of 25-hydroxy vitamin D [25(OH)D], and among those with elevated concentrations of calcium, fibroblast growth factor 23 (FGF23), phosphorus, and parathyroid hormone (PTH) using data from a cohort of black and white individuals with long-term follow-up. Markers of vitamin D metabolism were measured using serum collected in 1990-1992 from ARIC study participants (mean ± SD age 56.9 ± 5.7 years, 43.2% male, 23.9% black). A total of 12,770 participants were followed until 2011 for incident AAA. Multivariable-adjusted Cox regression models were used. A total of 449 incident AAA events occurred over a median follow-up of 19.7 years. For the association between serum calcium and risk of incident AAA there was evidence of interaction by sex ( p-interaction 0.02). Among women, in the fully adjusted model, the hazard ratio (95% confidence interval) comparing the highest to lowest quartile was 2.43 (1.25-4.73), whereas in men it was 1.01 (0.72-1.43). Not associated with risk of incident AAA were 25(OH)D, FGF23, phosphorus, and PTH. In this large prospective cohort, there was little evidence that markers of vitamin D metabolism are associated with risk of incident AAA. The positive association of calcium with AAA among women may warrant further investigation and replication in other populations.

Association of bone metabolism markers with coronary atherosclerosis and coronary artery disease in postmenopausal women

This study aimed to evaluate the association of bone metabolism markers with coronary atherosclerosis and coronary artery disease (CAD) in postmenopausal women. Based on the findings of coronary angiography, 111 women with CAD and 116 women without CAD were recruited. Serum calcium, phosphate, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), osteocalcin, N-terminal propeptide of type I procollagen (P1NP) and C-terminal cross-linked telopeptide of type I collagen (CTX) were measured. The Gensini score was used to assess the severity of coronary atherosclerosis. Compared with women with serum calcium ≤2.29 mmol/L, women with serum calcium >2.29 mmol/L had a 2.63-fold increased risk of CAD after adjusting for multiple cardiovascular risks, PTH and 25OHD [odds ratio (OR) = 2.91, 95% confidence interval (CI) 1.35-6.28]. In the fully adjusted model plus PTH and 25OHD, the risk of CAD increased 1.87-fold with every 1-SD increment of serum calcium (OR = 1.87, 95% CI 1.21-2.88). To further analyze the potential strong confounding effect of albumin, the absolute levels of calcium were replaced by their albumin-corrected values in the regression model. Compared with women with albumin-corrected calcium ≤2.27 mmol/L, women with albumin-corrected calcium >2.27 mmol/L had a 2.36-fold increased risk of CAD in the fully adjusted model plus PTH and 25OHD (OR = 2.36, 95% CI 1.13-4.92). The risk of coronary atherosclerosis as defined by Gensini score >0 increased 1.73-fold with every 1-SD increment of serum calcium in the fully adjusted model plus PTH and 25OHD (OR = 1.73, 95% CI 1.09-2.73). However, albumin-corrected calcium was not associated with coronary atherosclerosis either as a categorical variable or as a continuous variable in all models. No significant association of PTH, 25OHD, osteocalcin, CTX and P1NP with CAD or coronary atherosclerosis was found in this study. Higher serum calcium levels were independently associated with CAD in postmenopausal women.

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.

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.

Parathyroid hormone promotes osteoblastic differentiation of endothelial cells via the extracellular signal-regulated protein kinase 1/2 and nuclear factor-κB signaling pathways

Vascular calcification (VC) occurs in patients with chronic kidney disease (CKD) and contributes to cardiovascular dysfunction and mortality. Parathyroid hormone (PTH) is a crucial regulator of VC. High PTH serum levels constitute as a major risk factor for patients with CKD. However, the effect and mechanism of PTH on osteoblastic differentiation in endothelial cells have not been fully elucidated. In the present study, the role of PTH in VC was investigated using an in vitro calcification model. Endothelial cells were stimulated with PTH in the femto- to picomolar range. As determined by western blot analysis and ELISA, osteoblastic differentiation, as indicated by the BMP2 marker, occurred with maximum effect at 1×10^-10 mmol/l PTH. The results indicate that PTH promotes osteoblastic differentiation of endothelial cells, as demonstrated by the increased expression of bone morphogenetic protein (BMP) 2 and BMP4. In addition, western blot analysis revealed that PTH activated the extracellular signal-regulated protein kinase (Erk)1/2 and nuclear factor (NF)-κB signaling pathways. However, reverse transcription-quantitative polymerase chain reaction demonstrated that inhibitors specific to Erk1/2 and NF-κB eradicated the effect of PTH treatment on BMP2, BMP4, ALP and RUNX2 expression. These results demonstrate that PTH promotes the osteoblastic differentiation of endothelial cells via the Erk1/2 and NF-κB signaling pathways, which suggests a potential role of PTH in the promotion of VC. These findings provide an insight into the association between PTH and cardiovascular disease.

Association of serum vitamin D and parathyroid hormone with subclinical atherosclerotic phenotypes: The Dong-gu Study

Background

Although previous studies reported an association between serum vitamin D and parathyroid hormone (PTH) with carotid atherosclerosis or arterial stiffness, these were inconsistent. We examined the independent association between serum vitamin D and PTH with multiple subclinical markers of atherosclerosis.

Methods

A total of 8,217 subjects who participated in the Dong-gu Study in Korea were included in the final analysis. The carotid artery structure, including intima-media thickness (IMT), plaques, and luminal diameter, was evaluated using a high-resolution B-mode ultrasound. The brachial-ankle pulse wave velocity (baPWV) was determined using an automatic waveform analysis device, and the mean of the left and right baPWV was used.

Results

The PTH concentration was positively associated with carotid luminal diameter and baPWV, but not with carotid IMT and plaques. The mean carotid luminal diameter of individuals with PTH levels in the second, third, and fourth quartiles was significantly larger compared with those in the first quartile (P-trend < 0.01). The mean baPWV of individuals with PTH levels in the fourth quartile was significantly greater than those with PTH levels in the first quartile (P-trend = 0.01). However, there was no significant association between vitamin D and any atherosclerotic phenotypes, including carotid IMT, plaques, luminal diameter, and baPWV.

Conclusion

This suggests that PTH might affect the development of atherosclerosis by altering vascular compliance.

Parathyroid hormone is related to QT interval independent of serum calcium in patients with coronary artery disease

BACKGROUND

Elevated serum parathyroid hormone (PTH) is associated with increased risk of cardiovascular death, including sudden cardiac death, in patients with and without parathyroid disease. In small studies, PTH levels have been associated with changes in cardiac conduction and repolarization. Changes in the corrected QT interval (QTc) in particular are thought to be mediated by the effect of PTH on serum calcium. There is limited evidence to suggest PTH may affect cardiac physiology independent of its effects on serum calcium, but there is even less data linking PTH to changes in electrical conduction and repolarization independent of serum calcium.

METHODS

ECG data were examined from the PULSE database-an observational cohort study designed to examine depression after acute coronary syndromes (ACS) at a single, urban American medical center. In all, 407 patients had PTH and ECG data for analysis.

RESULTS

The QTc was longer in patients with elevated PTH levels compared with those without elevated PTH levels (451 ± 38.6 ms vs. 435 ± 29.8 ms; p < .001). The difference remained statistically significant after controlling for calcium, vitamin D, and estimated glomerular filtration rate (p = .007). Inclusion of left ventricular ejection fraction in the model attenuated the association (p = .054), suggesting that this finding may be partly driven by changes in cardiac structure.

CONCLUSIONS

In one of the largest series to examine PTH, calcium, and QT changes, we found that elevated PTH is associated with longer corrected QT interval independent of serum calcium concentration in ACS survivors.

Diagnostic performance of bone metabolic indexes for the detection of stroke

Objectives:

To explore the diagnostic performance of 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), bone alkaline phosphatase (BALP), and osteocalcin (OC) in predicting stroke.

Methods:

This retrospective survey was conducted in The Second Affiliated Hospital to Nanchang University, Nanchang, Jiangxi Province, China. involved 121 cerebral infarction patients and 103 cerebral hemorrhage patients as the experimental groups, 100 volunteers as the healthy control group and 80 brain trauma patients as the disease control group. The 25(OH)D, PTH, BALP, and OC levels of all participants were measured by electrochemiluminescence immunoassay.

Results:

The serum concentration of 25(OH)D in stroke patients was appreciably lower than that of the control groups (p<0.05), and subsequently, the deficiency level of 25(OH)D in the stroke population was considerably higher than that of the control groups (p<0.05). The serum concentrations of PTH and OC in stroke patients exceeded those found in the control groups (p<0.05), and the abnormal level in the stroke patients was also higher than that of the control. Compared with the control group, BALP concentrations in cerebral infarction patients were increased significantly. Additionally, abnormal levels of BALP in stroke patients were found to be higher than those in the control groups. However, concentrations and abnormal levels of BALP in cerebral hemorrhage patients were not found to be significantly different than those found in cerebral infarction and the control groups, There were no substantial differences between the 2 control groups.

Conclusion:

Lack of 25(OH)D and excessive PTH, BALP, and OC could indicate a high risk of stroke.

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.

Associations of Vitamin D-Binding Globulin and Bioavailable Vitamin D Concentrations With Coronary Heart Disease Events: The Multi-Ethnic Study of Atherosclerosis (MESA)

CONTEXT

Low 25-hydroxyvitamin D [25(OH)D] is associated with coronary heart disease (CHD) in people who are white and Chinese but not black or Hispanic. Vitamin D binding globulin (VDBG) avidly binds 25(OH)D, reducing its bioavailability, and differs in isoform and concentration by race.

OBJECTIVE

Evaluate associations of VDBG with CHD and whether accounting for VDBG or estimating bioavailable 25(OH)D explains the heterogeneity of the association of 25(OH)D with CHD.

DESIGN AND SETTING

We conducted a case-cohort study within the Multi-Ethnic Study of Atherosclerosis. Participants with an incident CHD event over 12 years of follow-up (n = 538) and a randomly assigned subcohort (n = 999) were included. We measured baseline 25(OH)D, VDBG, and isoforms using mass spectrometry and estimated bioavailable 25(OH)D from published equations.

RESULTS

VDBG was associated with an increased risk of CHD [hazard ratio, 1.77 (95% confidence interval, 1.46 to 2.14) per standard deviation increment, P < 0.0001], without evidence of heterogeneity by race or isoform (each P for interaction > 0.1). Low total 25(OH)D was differentially associated with CHD events, by race, with or without adjustment for VDBG (P for interaction = 0.04 or 0.05, respectively). Associations of 25(OH)D with CHD were strengthened with adjustment for VDBG among participants who were white or Chinese, and bioavailable 25(OH)D was associated with CHD events only among white participants.

CONCLUSIONS

High VDBG concentration was associated with CHD events in all racial and ethnic groups. Incorporation of VDBG strengthened existing associations of 25(OH)D with CHD but did not explain racial heterogeneity in associations of 25(OH)D with CHD.

Fibroblast Growth Factor 23, Mineral Metabolism, and Adiposity in Normal Kidney Function

Context

Obesity is associated with poor bone mineralization and quality. Fibroblast growth factor 23 (FGF23) plays an important role in skeletal physiology.

Objective

To test hypothesis that greater adiposity results in higher FGF23 levels among individuals with normal estimated glomerular filtration rate (eGFR).

Design, Setting, Participants

Cross-sectional analyses among participants with eGFR ≥60 mL/min/1.73m2. We assessed the association between crude [body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR); n = 5610] and refined (abdominal adipose tissue area by computed tomography; n = 1313) measures of adiposity and FGF23 using multivariable linear regression.

Main Outcome Measure

Serum FGF23.

Results

FGF23 was higher across BMI categories (BMI <25: 37.7; BMI 25 to 29.99: 38.7; BMI 30 to 39.99: 39.8; BMI ≥40: 40.9 pg/mL, unadjusted P trend < 0.0001). The association between BMI and FGF23 was independent of known confounders of FGF23 (adjusted β = +7.2% higher FGF23 per 10 kg/m2; P < 0.0001). Similar results were observed using WC and WHR. Abdominal adipose tissue area was also independently associated with higher FGF23 (P < 0.01). Notably, the positive associations between FGF23 and adiposity were observed despite the fact that eGFR did not decline and serum phosphate levels did not increase with adiposity.

Conclusion

In a large cohort with normal kidney function, adiposity was associated with higher FGF23 levels independent of known confounders, including eGFR and phosphate. Further studies are needed to evaluate the causes of higher FGF23 in settings of greater adiposity and the potential impact on skeletal health.

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.

Parathyroid Hormone Levels in the Prediction of Ischemic Stroke Risk

Objective. It was examined whether PTH and 25-dihydroxyvitamin D (25(OH)D) levels, together or separately, are indicators of the risk of stroke. Materials and Methods. This prospective study was performed at two centers. In the study, 100 patients diagnosed with acute ischemic stroke and 100 control individuals in the same age range were examined. In addition to neurological examination, cranial imaging, extensive routine blood chemistry, PTH, and 25(OH)D levels were evaluated in all cases. Stroke risk factors were determined. Logistic regression was used for statistical analysis. Results. A total of 60 patients and 79 control individuals were included in the study. Different estimation models were designed in order to examine the relationship between PTH and 25(OH)D levels with stroke. According to modeling results, it was determined that the most effective predictor for risk of stroke was 25(OH)D levels, followed by hypertension and PTH levels, respectively. Conclusion. PTH and 25(OH)D levels together can make important contributions to determination of stroke risk, and further investigations are needed to understand this relationship more fully.

Vitamin D Metabolism and the Implications for Atherosclerosis

Vitamin D levels and metabolism may play a role in the pathogenesis and treatment of atherosclerosis and subsequent cardiovascular health. Herein, we discuss both normal and disordered vitamin D metabolism as it pertains to atherosclerosis, and we review major clinical trials regarding vitamin D levels and effects of supplementation. Although there are no official recommendations for vitamin D as it applies to atherosclerosis, it is clear that these two entities are linked. Further study of the complex association between vitamin D and atherosclerosis, as well as the effects of supplementation, are recommended.

Serum Bicarbonate Is Associated with Heart Failure in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Low serum bicarbonate concentrations are associated with mortality and kidney disease progression. Data regarding associations between bicarbonate and cardiovascular disease (CVD) are scarce.

METHODS

We performed a cohort study of 6,229 adult participants from the Multi-Ethnic Study of Atherosclerosis, a community-based cohort free of CVD at baseline. Serum bicarbonate was measured at baseline. Cardiovascular outcomes were defined as: (1) subclinical CVD (left ventricular mass [LVM] and aortic pulse pressure [PP] measured at baseline), (2) incident atherosclerotic cardiovascular events (CVE; composite of myocardial infarction, resuscitated cardiac arrest, stroke, coronary heart disease death, and stroke death), and (3) incident heart failure.

RESULTS

During a median (interquartile range) follow-up of 8.5 (7.7-8.6) years, 331 (5.3%) participants had an incident CVE and 174 (2.8%) developed incident heart failure. We stratified analyses by use of diuretics because we observed a significant interaction between diuretic use and bicarbonate with study outcomes. Among diuretic nonusers, with adjustment, bicarbonate ≥25 mEq/L was associated with an estimated 3.0 g greater LVM (95% CI 0.5-5.0) and 1.0 mm Hg higher aortic PP (95% CI 0.4-2.0) compared to bicarbonate 23-24 mEq/L. Each 1 mEq/L of bicarbonate increase was associated with a 13% higher risk of incident heart failure (hazards ratio 1.13, 95% CI 1.01-2.11). Among diuretic users, higher bicarbonate was not associated with CVD. Bicarbonate was not associated with incident atherosclerotic CVE irrespective of diuretic use.

CONCLUSION

Among nonusers of diuretics in a large community-based study, higher serum bicarbonate concentrations are associated with subclinical CVD and new heart failure.

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.

Serum Parathyroid Hormone Levels Predict Discharge and Readmission for Heart Failure

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Association between parathyroid hormone levels and the extensiveness of coronary artery disease

Objective:

Previous studies have suggested that there is a relationship between coronary artery disease (CAD) and parathyroid hormone (PTH) levels. Here, we aimed to evaluate the association between PTH levels and severity of CAD.

Methods:

Patients were divided into two groups based on their serum PTH values. Patients with PTH levels ≤72 pg/mL were accepted as Group 1 (n=568) and >72 pg/mL as Group 2 (n=87). Gensini score system and >50% stenosis in any coronary artery with conventional coronary angiography were used to determine the extensiveness of CAD. This study was designed as a prospective and cross-sectional study.

Results:

Baseline characteristics except for age, gender, and blood pressure were similar between groups. Mean serum PTH levels of the entire cohort was 43.4±29.5 pg/mL. Median Gensini score was 19.5 in Group 1 and 14.5 in Group 2 (p=0.75). On the other hand, PTH levels were weakly correlated with Gensini score (Spearman’s Rho=0.11, p=0.003). Additionally, we did not observe a statistically significant difference between PTH levels and the number of stenotic vessels (p=0.14). This study was designed as a prospective and cross-sectional study.

Conclusion:

There is no association between serum PTH levels and extensiveness of CAD.

Aortic Arch Calcification Predicts Patency Loss of Arteriovenous Fistula in End-Stage Renal Disease Patients

Aortic arch calcification (AAC) is recognized as an important cardiovascular risk factor in patients with end-stage renal disease (ESRD). The aim of the study was to evaluate the impact of AAC grade on patency rates of arteriovenous fistula (AVF) in this specific population. The data of 286 ESRD patients who had an initial AVF placed were reviewed. The extent of AAC identified on chest radiography was divided into four grades (0–3). The association between AAC grade, other clinical factors, and primary patency of AVF was then analyzed by Cox proportional hazard analysis. The multivariate analysis demonstrated that the presence of AAC grade 2 (hazard ratio (95% confidence interval): 1.80 (1.15–2.84); p = 0.011) and grade 3 (3.03 (1.88–4.91); p < 0.001), and higher level of intact-parathyroid hormone (p = 0.047) were associated with primary patency loss of AVF. In subgroup analysis, which included AVF created by a surgeon assisted with preoperative vascular mapping, only AAC grade 3 (2.41 (1.45–4.00); p = 0.001), and higher intact-parathyroid hormone (p = 0.025) level were correlated with AVF patency loss. In conclusion, higher AAC grade and intact-parathyroid hormone level predicted primary patency loss of AVF in an ESRD population.

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.

Vitamin D metabolites and bone mineral density: The multi-ethnic study of atherosclerosis

Previous studies demonstrate associations of low 25-hydroxyvitamin D (25(OH)D) concentrations with low bone mineral density (BMD) and fractures, motivating widespread use of vitamin D supplements for bone health. However, previous studies have been limited to predominantly White populations despite differences in the distribution and metabolism of 25(OH)D by race/ethnicity. We determined associations of serum 25(OH)D, 24,25-dihydroxyvitamin D (24,25(OH2)D3), and parathyroid hormone (PTH) with BMD among 1773 adult participants in the Multi-Ethnic Study of Atherosclerosis (MESA) in a staggered cross-sectional study design. Vitamin D metabolites were measured using liquid chromatography-mass spectroscopy and PTH using a 2-site immunoassay from serum collected in 2000-2002. Volumetric trabecular lumbar BMD was measured from computed tomography scans performed in 2002-2005 expressed as g/cm(3). We used linear regression and graphical methods to compare associations of vitamin D metabolite and PTH concentrations with BMD as the outcomes measure among White (n=714), Black (n=353), Chinese (n=249), and Hispanic (n=457) participants. Serum 25(OH)D and 24,25(OH2)D3 concentrations were highest among Whites and lowest among Blacks. BMD was greatest among Black participants. Higher serum 25(OH)D was only associated with higher BMD among Whites and Chinese participants (P-for-interaction=0.054). Comparing the lowest category of 25(OH)D (<20 ng/ml) to the highest (≥30 ng/ml), the adjusted mean difference in BMD was -8.1g/cm3 (95% CI -14.8, -1.4) for Whites; -10.2g/cm3 (-20.4, 0.0) for Chinese vs. 8.8 g/cm3 (-2.8, 20.5) for Black and -1.1g/cm3 (-8.3, 6.2) for Hispanic. Similar results were observed for serum 24,25(OH2)D3. Serum PTH was not associated with BMD. In a multi-ethnic population, associations of 25(OH)D with BMD were strongest among White and Chinese participants and null among Black and Hispanic participants. Further studies are needed to determine optimal biomarkers for bone health for multiple ethnic groups.

[Localization of parathyroid adenomas with C11-methionine PET-CT]

BACKGROUND AND OBJECTIVES

In primary hyperparathyroidism (pHPT) preoperative localization of parathyroid adenomas enables focussed unilateral parathyroidectomy. Ultrasound and sestamibi scintigraphy are the recommended standard procedures for primary diagnostics of pHPT and C-11 methionine positron emission tomography computed tomography (Met-PET/CT) is the latest technique for localization of hyperfunctioning parathyroid glands.

METHODS

This review presents the results of Met-PET/CT on the basis of a selective literature search using the keywords "primary hyperparathyroidism and methionine", "primary hyperparathyroidism and PET", "parathyroid adenomas and methionine" and "parathyroid adenomas and PET".

RESULTS

Localization of single gland adenomas can be achieved with Met-PET/CT in 79-91 % of cases. The advantages of this procedure are a high sensitivity even in operations for recurrencies or concomitant thyroid nodules and an accurate detection even with atypical localizations. In multiglandular disease a localization of more than one hyperfunctioning gland remains difficult. Potential limitations of the method include the restricted availability and the relatively high costs of Met-PET/CT.

CONCLUSIONS

Using Met-PET/CT hyperfunctioning parathyroid glands can be exactly localized in most patients with pHPT. Indications for this procedure are mostly when preoperative standard tests are negative and in parathyroid surgery for recurrencies.