Parathyroid hormone and calcium are independently associated with subclinical vascular disease in a community-based cohort

Survival in primary hyperparathyroidism over five decades (1965-2010) a population-based retrospective study

CONTEXT

Survival in patients with primary hyperparathyroidism (PHPT) remains uncertain.

OBJECTIVE

To update survival in patients with PHPT in a United States community population.

DESIGN

Retrospective cohort study.

SETTING

Community population in Rochester, Minnesota.

PARTICIPANTS

Residents who met criteria for PHPT from 1965 to 2010.

INTERVENTIONS

Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death.

MAIN OUTCOME MEASURE

The overall age and gender-adjusted survival compared to white Minnesota residents.

RESULTS

We identified 1139 PHPT individuals, 76% female, with a median age of 58 years. Most were observed without parathyroidectomy (69%). The relative risk of death among the entire cohort was 0.996 (95% CI: 0.91-1.09, P = 0.935) which was not different compared to Minnesota residents. Those with maximum serum calcium level ≥ 10.8 mg/dL (0.7 mg/dL above the reference range) had an increase in mortality (RR 1.32, 95% CI: 1.10-1.58, P = 0.002). Survival among all PHPT individuals after parathyroidectomy was no different from expected (RR = 1.06, 95% CI 0.89-1.28; P = 0.508). Mortality was significantly decreased after parathyroidectomy in those with serum calcium levels ≥10.8 mg/dL (HR 0.47, 95% CI: 0.36-0.61, P < 0.001).

CONCLUSIONS

Mortality in the entire cohort was not different from expected. PHPT patients with a maximum serum calcium level ≥ 10.8 mg/dL had increased mortality. Survival was improved after parathyroidectomy in those with this degree of hypercalcemia.

Endurance exercise and the risk of cardiovascular pathology in men: a comparison between lifelong and late-onset endurance training and a non-athletic lifestyle - rationale and design of the Master@Heart study, a prospective cohort trial

Introduction

Low and moderate endurance exercise is associated with better control of cardiovascular risk factors, a decreased risk of coronary artery disease and atrial fibrillation (AF). There is, however, a growing proportion of individuals regularly performing strenuous and prolonged endurance exercise in which the health benefits have been challenged. Higher doses of endurance exercise have been associated with a greater coronary atherosclerotic plaque burden, risk of AF and myocardial fibrosis (MF).

Methods and analysis

Master@Heart is a multicentre prospective cohort study aiming to assess the incidence of coronary atherosclerosis, AF and MF in lifelong endurance athletes compared to late-onset endurance athletes (initiation of regular endurance exercise after the age of 30 years) and healthy non-athletes.

The primary endpoint is the incidence of mixed coronary plaques. Secondary endpoints include coronary calcium scores, coronary stenosis >50%, the prevalence of calcified and soft plaques and AF and MF presence. Tertiary endpoints include ventricular arrhythmias, left and right ventricular function at rest and during exercise, arterial stiffness and carotid artery intima media thickness.

Two hundred male lifelong athletes, 200 late-onset athletes and 200 healthy non-athletes aged 45–70 will undergo comprehensive cardiovascular phenotyping using CT, coronary angiography, echocardiography, cardiac MRI, 12-lead ECG, exercise ECG and 24-hour Holter monitoring at baseline. Follow-up will include online tracking of sports activities, telephone calls to assess clinical events and a 7-day ECG recording after 1 year.

Ethics and dissemination

Local ethics committees approved the Master@Heart study. The trial was launched on 18 October 2018, recruitment is complete and inclusions are ongoing.

Trial registration number

NCT03711539.

Association of serum uromodulin with mortality and cardiovascular disease in the elderly-the Cardiovascular Health Study

BACKGROUND

Uromodulin (UMOD) is released by renal tubular cells into the serum (sUMOD) and urine. Lower urine UMOD has been linked to mortality and cardiovascular disease but much less is known about sUMOD. We evaluated the association of sUMOD with these outcomes in community-dwelling older adults.

METHODS

We measured sUMOD in a random subcohort of 933 participants enrolled in the Cardiovascular Health Study. The associations of sUMOD with all-cause mortality, incident heart failure (HF) and incident cardiovascular disease (CVD; myocardial infarction, stroke and mortality due to coronary disease or stroke) were evaluated using multivariable Cox regression, adjusting for study participants' demographics, estimated glomerular filtration rate (eGFR), albuminuria and CVD risk factors. Generalized additive models with splines were used to address the functional form of sUMOD with outcomes. Due to nonlinear associations of sUMOD with all outcomes, 2.5% of the values on either end of the sUMOD distribution were excluded from the analyses, limiting the range of sUMOD to 34.3-267.1 ng/mL.

RESULTS

The mean age was 78 ± 5 years, 40% were male, sUMOD level was 127 ± 64 ng/mL, eGFR was 63 mL/min/1.73 m2 and 42% had CKD defined as eGFR <60 mL/min/1.73 m2. Patients in the lower sUMOD quartiles had lower eGFR and higher albuminuria (P < 0.01, respectively). During a median follow-up of 9.9 years, 805 patients died, 283 developed HF and 274 developed CVD. In multivariable analysis, higher sUMOD was significantly associated with a lower hazard for mortality {hazard ratio [HR] 0.89 [95% confidence interval (CI) 0.80-0.99] per 1 standard deviation (SD) higher sUMOD}, CVD [HR 0.80 (95% CI 0.67-0.96)] and the composite endpoint [HR 0.88 (95% CI 0.78-0.99)]; the association with HF was not statistically significant [HR 0.84 (95% CI 0.70-1.01)].

CONCLUSION

Higher sUMOD is independently associated with a lower risk for mortality and CVD in older adults.

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.

Hyperparathyroidism in men - morbidity and mortality during 21 years' follow-up

Hyperparathyroidism (HPT), including normocalcaemic, vitamin D sufficient (Serum (S)-25(OH)D ≥ 50 nmol/L) hyperparathyroidism (nHPT), has increasingly been diagnosed in the last few decades due to the more common use of the serum parathyroid hormone (S-PTH) assay. We investigated if men with HPT had higher morbidity and mortality than men without HPT during 21 years' follow-up.A random population sample of 750 men, all 50 years of age, was examined in 1993. Endpoints were retrieved 21 years later at 71 years of age.Albumin-corrected serum (S) calcium, S-25-hydroxyvitamin D and S-PTH were assessed along with data on cardiovascular risk factors and medication. Outcome data on fractures, stroke, myocardial infarction, cancer and death were retrieved in 2014; 21 years after primary assessment. The prevalence of HPT at 50 years of age was 9.3%; nHPT 2.8%, primary HPT 0.4%, secondary HPT 0.4%, and HPT with vitamin D insufficiency 6%. Fracture rate, myocardial infarction, stroke, cancer and death occurred similarly in men with or without HPT, as well as in men with nHPT as compared with men without calcium/PTH aberrations during 21 years' follow-up. S-PTH was evenly distributed in the univariable analyses for each outcome. Cox regression analyses showed no increase in serious morbidity or in mortality in men with HPT, irrespective of cause, compared with men with normal S-PTH over a 21-year period. None had HPT at a S-25(OH)D level of 100 nmol/L.

Effect of Parathyroidectomy on Cardiovascular Risk Factors in Primary Hyperparathyroidism: A Randomized Clinical Trial

CONTEXT

It remains unclear whether risk of cardiovascular diseases is increased in patients with mild (<1.45 mmol/L) to moderate (≥1.45 to 1.60 mmol/L) primary hyperparathyroidism (PHPT).

OBJECTIVE

We aimed to determine the short-term effect of parathyroidectomy (PTX) on arterial stiffness, cholesterol levels, and blood pressure (BP).

DESIGN

This study was a clinical trial randomly allocating patients to either PTX or a control group (no surgery). Follow-up was performed 3 months after surgery in the PTX group and 3 months after baseline in the control group.

SETTING

University hospital.

PARTICIPANTS

We recruited 79 patients with PHPT; 69 participants completed the study.

MAIN OUTCOMES

Office and ambulatory 24-hour BP, pulse wave velocity (PWV), augmentation index, and fasting plasma cholesterol levels.

RESULTS

At baseline, participants had a median level of ionized calcium of 1.41 mmol/L (range, 1.33 to 1.60 mmol/L) and PTH of 10.4 pmol/L (4.5 to 30.4 pmol/L). Median age was 64 years (range, 18 to 81) and 72% were females. Following PTX, plasma total cholesterol levels decreased significantly compared with the controls (P = 0.04). Changes in PWV, augmentation index, and ambulatory 24-hour BP did not differ between groups, except for an increase in ambulatory diastolic BP following PTX. However, in patients with baseline levels of ionized calcium ≥1.45 mmol/L, PWV decreased significantly in response to PTX compared with the control group (P = 0.03).

CONCLUSION

PTX may decrease risk of cardiovascular diseases in PHPT by lowering total cholesterol levels, although ambulatory diastolic BP increases in response to surgery. Patients with moderate to severe hypercalcemia may benefit from PTX by a decrease in PWV.

Effect of parathyroid hormone on cardiac function in rats with cardiomyopathy

The present study investigated the role of parathyroid hormone (PTH) in non-ischemic cardiomyopathy (CM) and its underlying mechanism. A total of 30 Sprague-Dawley male rats were randomly divided into a control group (n=6) and an experimental group (n=24). To induce CM in the rats of the experimental group, 2 mg/kg Adriamycin (ADR) was administered intraperitoneally with 5 equal injections every third day followed by 5 weekly injections resulting in a cumulative dose of 20 mg/kg. Following establishment of the model, rats in the experimental group were subdivided into a PTH-untreated CM group that received daily normal saline subcutaneous injections for 7 days and three treated CM groups that received daily subcutaneous injections of 5, 10, or 20 µg/kg of recombinant PTH for 7 days. Rats in the control group accordingly received intraperitoneal and subcutaneous injections of normal saline. Blood sample analysis revealed that B-type natriuretic peptide (BNP), troponin T, C-reactive protein (CRP), creatinine and phosphorus concentrations were increased in the PTH-untreated CM group compared with that in the control group, whereas PTH and calcium concentrations were decreased. Administration of PTH dose-dependently decreased BNP, CRP, creatinine and phosphorus levels, and increased PTH and calcium levels. Notably, there were significant differences in PTH, BNP, troponin T, CRP, creatinine, calcium, and phosphorus levels among the rats in the five groups (P<0.01). Cardiac ultrasonography results indicated that the left ventricular ejection fraction (LVEF) was significantly decreased in rats treated with ADR compared with the rats from the control group (P<0.01). However, the LVEF gradually recovered with elevated PTH treatment doses. The overall differences of LVEF and left ventricular end-systolic volume in the five experimental groups were statistically significant (P<0.01). Furthermore, there were dose-dependent increases in LV mass and left ventricular end-diastolic volume in PTH-treated rats; however, the differences between any two groups did not reach statistical significance (P>0.05). Immunohistochemical staining and western blot analysis using an anti-PTH polyclonal antibody was performed to evaluate the protein expression levels of PTH in myocardial tissues. The mRNA expression levels of PTH and BNP were measured using reverse transcription-quantitative polymerase chain reaction. The results demonstrated that the mRNA and protein expression levels of PTH in myocardial tissues were significantly decreased in ADR-treated rats compared with the levels in the control group rats. Injection of recombinant PTH significantly increased PTH expression and reduced BNP expression in dose-dependent manners (P<0.05). These findings demonstrated that PTH can improve cardiac function in rats with ADR-induced CM, suggesting a potential therapeutic application for PTH in non-ischemic CM.

Role of Magnesium Deficiency in Promoting Atherosclerosis, Endothelial Dysfunction, and Arterial Stiffening as Risk Factors for Hypertension

Arterial hypertension is a disease with a complex pathogenesis. Despite considerable knowledge about this socially significant disease, the role of magnesium deficiency (MgD) as a risk factor is not fully understood. Magnesium is a natural calcium antagonist. It potentiates the production of local vasodilator mediators (prostacyclin and nitric oxide) and alters vascular responses to a variety of vasoactive substances (endothelin-1, angiotensin II, and catecholamines). MgD stimulates the production of aldosterone and potentiates vascular inflammatory response, while expression/activity of various antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase) and the levels of important antioxidants (vitamin C, vitamin E, and selenium) are decreased. Magnesium balances the effects of catecholamines in acute and chronic stress. MgD may be associated with the development of insulin resistance, hyperglycemia, and changes in lipid metabolism, which enhance atherosclerotic changes and arterial stiffness. Magnesium regulates collagen and elastin turnover in the vascular wall and matrix metalloproteinase activity. Magnesium helps to protect the elastic fibers from calcium deposition and maintains the elasticity of the vessels. Considering the numerous positive effects on a number of mechanisms related to arterial hypertension, consuming a healthy diet that provides the recommended amount of magnesium can be an appropriate strategy for helping control blood pressure.

Hypertension and other cardiovascular risk factors are associated with vitamin D deficiency in an urban Chinese population: A short report

There is debate concerning the association of 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) with cardiovascular disease (CVD) risk factors. As both hypertension and vitamin D deficiency are increasingly important public health concerns in China, we investigated these associations in 566 Macao residents. The aim was to investigate the association of serum 25OHD and PTH concentrations with CVD risk factors (hypertension, high pulse rate, abnormal blood lipids). The data were stratified by age, sex, and blood pressure (BP) medication use. Multiple linear regression analyses were performed to assess associations, adjusting for appropriate confounders. Lower 25OHD concentrations were significantly associated with higher systolic BP (SBP) mmHg (β=-0.07), diastolic BP (DBP) mmHg (β=-0.06) and pulse rate beats/min (β=-0.12), lower high-density lipoprotein (HDL) concentrations nmol/L (β=10.51) and higher triglycerides (TG) nmol/L (β=-2.38). However, the inverse associations with lower 25OHD for higher SBP, DBP, pulse rate and TG were much stronger in those using BP medications, in those who were older, and in females. Higher PTH concentrations were significantly associated with higher low-density lipoprotein (LDL) nmol/L (β=0.77) in the total population and with higher SBP mmHg (β=0.08) in males and those who were older (β=0.09). In conclusion, our major new finding is that lower 25OHD is associated with higher BP especially in those who use BP medications. These results might explain past discrepancies in findings regarding the association of BP and vitamin D and suggest that prospective studies and randomized control trials, in otherwise healthy Chinese populations taking blood pressure medications, are needed to confirm these cross-sectional results.

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.

Electronegative low-density lipoprotein increases the risk of ischemic lower-extremity peripheral artery disease in uremia patients on maintenance hemodialysis

Electronegative low-density lipoprotein (LDL) has been shown to increase coronary artery disease risk in hemodialysis patients, but its effect on the risk of peripheral artery disease (PAD) remains unclear. We separated plasma LDL from 90 uremia patients undergoing hemodialysis into 5 subfractions (L1-L5) according to charge by using fast-protein liquid chromatography with an anion-exchange column and examined the distribution of L5-the most electronegative LDL subfraction-in total LDL (i.e. L5%). During a 5-year period, we followed up with these patients until the occurrence of ischemic lower-extremity PAD. During the follow-up period, ischemic lower-extremity PAD developed in 24.4% of hemodialysis patients. L5% was higher in hemodialysis patients in whom ischemic lower-extremity PAD occurred (3.03% [IQR, 2.36-4.54], n = 22) than in hemodialysis patients in whom PAD did not occur (1.13% [IQR, 0.90-1.83], n = 68) (p < 0.001). Furthermore, L5% significantly increased the adjusted hazard ratio of ischemic lower-extremity PAD (1.54 [95% CI, 1.14-2.10]) (p = 0.005). Flow-mediated dilation was negatively associated with L5% (p < 0.001). Additionally, in vivo experiments from mice showed that L5 compromised endothelium-dependent vascular relaxation through a nitric oxide-related mechanism. Our findings indicate that increased L5% may be associated with the occurrence of ischemic lower-extremity PAD in hemodialysis patients.

Association of physical activity on body composition, cardiometabolic risk factors, and prevalence of cardiovascular disease in the Korean population (from the fifth Korea national health and nutrition examination survey, 2008-2011)

BACKGROUND

Data regarding associations among physical activity (PA) level, body composition, and prevalence of cardiovascular diseases in Asian populations are rare.

METHODS

The International Physical Activity Questionnaire (IPAQ) was utilized to estimate PA levels and analyze the association of PA level with various body composition parameters and the prevalence of cardiovascular diseases by using data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011.

RESULTS

Moderate and high PA levels were associated with lower prevalence of hypertension and diabetes mellitus, and lower concentrations of serum ferritin, parathyroid hormone, and alkaline phosphatase. Sarcopenia (low vs. moderate vs. high PA group: 14.3% vs. 10.5% vs. 7.3%, p = 0.001), underweight (5.7% vs. 4.9% vs. 3.5%, p = 0.001), and central obesity (7.8% vs. 6.9% vs. 6.3%, p = 0.002) were more often observed in the low PA group. The prevalence rates of cardiovascular diseases were lower in the moderate (odds ratio [OR], 0.822; 95% confidence interval [CI], 0.737-0.916; p = 0.001) and high activity groups (OR, 0.663; 95% CI, 0.589-0.748; p = 0.001) than in the low activity group, even after adjusting for age, sex, smoking, underlying disease, and general or abdominal obesity and muscle mass.

CONCLUSION

Regular physical activity was associated with a low prevalence of cardiovascular diseases (stroke, myocardial infarction, stable angina, and chronic renal disease), which was independent of body composition and conventional risk factors in the Korean population, with a positive dose-response relationship.

Endocrine Hypertension: A Practical Approach

Elevated blood pressure resulting from few endocrine disorders (endocrine hypertension) accounts for a high proportion of cases of secondary hypertension. Although some features may be suggestive, many cases of endocrine hypertension remain silent until worked up for the disease. A majority of cases result from primary aldosteronism. Other conditions that can cause endocrine hypertension are: congenital adrenal hyperplasia, Liddle syndrome, pheochromocytomas, Cushing's syndrome, acromegaly, thyroid diseases, primary hyperparathyroidism and iatrogenic hormone manipulation. Early identification and treatment of the cause of endocrine hypertension may help to reduce morbidity and mortality related to these disorders. This article gives a comprehensive and practical approach to the diagnosis and management of endocrine hypertension.

Parathyroid hormone reflects adiposity and cardiometabolic indices but not bone density in normal men

Hyperparathyroidism may be associated with skeletal and cardiovascular abnormalities, but it is unclear whether these associations exist for high-normal levels of parathyroid hormone (PTH). We assessed relationships between PTH and anthropometric, skeletal and cardiometabolic indices in normal men. Body composition, blood pressure, biochemistry and bone mineral density (BMD) were evaluated in 151 healthy men. BMD was reassessed at 2 years, and coronary artery calcium (CAC) was measured at 3.5 years. Relationships between PTH and other baseline characteristics, CAC scores and change in BMD were evaluated. PTH correlated positively with baseline body mass index, fat mass, diastolic blood pressure, triglycerides, total and low-density lipoprotein (LDL) cholesterol, (r=0.19-0.25, P=0.02-0.002), and with category of CAC score. Relationships between PTH and cardiometabolic indices remained significant after adjustment for age, 25-hydroxyvitamin D and estimated glomerular filteration rate. Men in the top PTH tertile (⩾4.4 pmol l^-1, n=51) were more likely to have LDL cholesterol ⩾3.5 mmol l^-1, diastolic blood pressure ⩾85 mm Hg, and CAC score >0 than men in lower tertiles. PTH was not associated with history of fracture, baseline BMD, or change in BMD over 2 years. In summary, in this cohort of healthy men, PTH levels are linearly related to adiposity and to cardiometabolic indices, but not to BMD or bone loss. These findings suggest that adiposity should be considered as an independent cause of secondary hyperparathyroidism, and they may be relevant to patients with normocalcemic hyperparathyroidism, in whom high PTH levels may be a marker of adiposity and cardiometabolic risk rather than always indicating parathyroid autonomy.

Association of serum calcium and heart failure with preserved ejection fraction in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a recognized trigger factor for heart failure with preserved ejection fraction (HFpEF). Recent studies show that higher serum calcium level is associated with greater risk of both T2DM and heart failure. We speculate that increased serum calcium is related to HFpEF prevalence in patients with T2DM.

METHODS

In this cross-sectional echocardiographic study, 807 normocalcemia and normophosphatemia patients with T2DM participated, of whom 106 had HFpEF. Multinomial logistic regression was carried out to determine the variables associated with HFpEF. The associations between serum calcium and metabolic parameters, as well as the rate of HFpEF were examined using bivariate linear correlation and binary logistic regression, respectively. The predictive performance of serum calcium for HFpEF was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

Patients with HFpEF have significantly higher serum calcium than those without HFpEF. Serum calcium was positively associated with total cholesterol, triglycerides, low-density lipoprotein cholesterol, serum uric acid, HOMA-IR and fasting plasma glucose. Compared with patients in the lowest serum calcium quartile, the odds ratio (OR) for HFpEF in patients in the highest quartile was 2.331 (95 % CI 1.088-4.994, p = 0.029). When calcium was analyzed as a continuous variable, per 1 mg/dL increase, the OR (95 % CI) for HFpEF was [2.712 (1.471-5.002), p = 0.001]. Serum calcium can predict HFpEF [AUC = 0.673, 95 % CI (0.620-0.726), p < 0.001].

CONCLUSIONS

An increase in serum calcium level is associated with an increased risk of HFpEF in patients with T2DM.

Circulating calcium concentrations, vascular disease and mortality: a systematic review

Associations between serum calcium and vascular disease have been reported, but the consistency of these findings is unknown. We conducted a systematic review to determine whether circulating calcium concentrations are associated with risks of cardiovascular disease and death in normocalcaemic populations. We conducted PubMed searches up to 18 December 2014 and scrutinized reference lists of papers. Eligible studies related serum calcium to mortality or cardiovascular events in humans. A follow-up of at least one year was required for longitudinal studies. Studies in populations selected on the basis of renal disease or abnormal serum calcium were excluded. Two investigators performed independent data extraction. The results were tabulated and, where possible, meta-analysed. Five of 11 studies reported a statistically significant positive association between serum calcium and mortality. Meta-analysis of eight of these studies showed a hazard ratio of death of 1.13 (1.09, 1.18) per standard deviation of serum calcium. Eight of 13 studies reported a statistically significant positive association between serum calcium and cardiovascular disease. Meta-analysis of eight studies showed a hazard ratio of cardiovascular disease of 1.08 (1.04, 1.13) per standard deviation of serum calcium. For two studies reporting odds ratios, the pooled odds ratio per standard deviation was 1.22 (1.11, 1.32). When hazard ratios adjusted for cardiovascular risk factors were meta-analysed, the pooled hazard ratio was 1.04 (1.01, 1.08). Other studies demonstrated associations between serum calcium and stroke and between serum calcium and direct measurements of arterial disease and calcification. These observational data indicate that serum calcium is associated with vascular disease and death, but they cannot determine causality.

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.

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.

Relationship Between Parathormone and Obesity-Linked Disorders

BACKGROUND

In this study, we aimed to investigate whether high parathormone (PTH) levels in obese patients contribute to the metabolic complications of obesity.

METHODS

A total of 400 obese subjects aged 18-65 years were included. Anthropometric bioelectrical bioimpedance measures, blood tests, and 75 gram oral glucose tolerance test results were evaluated.

RESULTS

Of the 400 obese subjects, 335 were female. The mean age was 39 ± 10 years. The median body mass index was 36 (interquartile range 34-41). Subjects were divided into quartiles according to blood PTH levels. Groups included quartile 1 [n = 100, median PTH; 42 (range 36-45)], quartile 2 [n = 100, median PTH; 55 (51-59)], quartile 3 [n = 100, median PTH; 73 (68-78)], and quartile 4 [n = 100, median PTH; 99 (89-125)]. Quartiles were evaluated with a generalized linear model adjusted for age, sex, and season of recruitment. Systolic and diastolic blood pressure, fasting glucose, homeostatic model assessment-estimated insulin resistance, insulin sensitivity index, triglyceride level, and high-density lipoprotein cholesterol (HDL-C) were not different among quartiles. PTH and 25 hydroxyvitamin D (25(OH)D) were not associated with higher odds of prevalent metabolic syndrome in obese subjects (odds ratio, OR, 0.99 [95% confidence interval, CI, 0.981.00], P = 0.38 and 0.99 95% CI 0.96-1.01], P = 0.46, respectively). Decreased 25(OH)D levels were significantly correlated with higher odds of low HDL-C (OR 0.96 [95% CI 0.93-0.99], P = 0.04).

CONCLUSIONS

PTH does not contribute to the occurrence of metabolic components of obesity, but there is a positive correlation between 25(OH)D and HDL-C.

Acute effects of calcium supplements on blood pressure and blood coagulation: secondary analysis of a randomised controlled trial in post-menopausal women

Recent evidence suggests that Ca supplements increase the risk of cardiovascular events, but the mechanism(s) by which this occurs is uncertain. In a study primarily assessing the effects of various Ca supplements on blood Ca levels, we also investigated the effects of Ca supplements on blood pressure and their acute effects on blood coagulation. We randomised 100 post-menopausal women to 1 g/d of Ca or a placebo containing no Ca. Blood pressure was measured at baseline and every 2 h up to 8 h after their first dose and after 3 months of supplementation. Blood coagulation was measured by thromboelastography (TEG) in a subgroup of participants (n 40) up to 8 h only. Blood pressure declined over 8 h in both the groups, consistent with its normal diurnal rhythm. The reduction in systolic blood pressure was smaller in the Ca group compared with the control group by >5 mmHg between 2 and 6 h (P≤0·02), and the reduction in diastolic blood pressure was smaller at 2 h (between-groups difference 4·5 mmHg, P=0·004). Blood coagulability, assessed by TEG, increased from baseline over 8 h in the calcium citrate and control groups. At 4 h, the increase in the coagulation index was greater in the calcium citrate group compared with the control group (P=0·03), which appeared to be due to a greater reduction in the time to clot initiation. These data suggest that Ca supplements may acutely influence blood pressure and blood coagulation. Further investigation of this possibility is required.

Teriparatide Therapy Reduces Serum Phosphate and Intima-Media Thickness at the Carotid Wall Artery in Patients with Osteoporosis

Although cross-sectional and longitudinal studies report a relationship between osteoporosis and cardiovascular disorders (known as the bone-cardiovascular axis), the benefits of osteoporosis treatment on atherosclerosis are largely unclear. Teriparatide is a bone-forming agent that increases urinary phosphate excretion. Because elevated serum phosphate is associated with the development of atherosclerosis, the purpose of our study was to examine the relationship among lumbar spine bone mineral density (LS-BMD), intima-media thickness at the carotid artery (CA-IMT), and phosphate metabolism in response to daily teriparatide therapy. Osteoporotic patients (n = 28) with low LS-BMD (T-score < -2.5) and/or at least one vertebral fracture were treated with teriparatide (20 μg/day) for 12 months. Metabolic bone markers, LS-BMD, and CA-IMT were measured over the course of treatment. The LS-BMD significantly increased by 0.046 ± 0.038 g/cm(2) over the 12-month period (P < 0.001). CA-IMT decreased from 0.701 mm (interquartile range: 0.655-0.774 mm) at baseline to 0.525 mm (0.477-0.670 mm) at 12 months (P < 0.05); however, CA-IMT change was not significantly associated with LS-BMD change. Serum phosphate decreased after 1 month of teriparatide administration, and the change in serum phosphate at 1 months was associated with the change in CA-IMT at 12 months (ρ = 0.431, P = 0.025). Teriparatide improved LS-BMD and CA-IMT, suggesting the existence of the bone-cardiovascular axis. The association between serum phosphate and CA-IMT suggests that the teriparatide decreased CA-IMT in part by reducing serum phosphate, a well-known vascular toxin, in addition to the improvement of bone-cardiovascular axis.