Serum calcium levels and hypertension among U.S. adults

Cross-sectional association between blood cholesterol and calcium levels in genetically diverse strains of mice

Genetically diverse outbred mice allow for the study of genetic variation in the context of high dietary and environmental control. Using a machine learning approach, we investigated clinical and morphometric factors that associate with serum cholesterol levels in 840 genetically unique Diversity Outbred mice of both sexes (n = 417 male and 423 female), and on both a control chow (% kcals in diet: protein 22%, carbohydrate 62%, fat 16%, no cholesterol) and high fat high sucrose (% kcals in diet: protein 15%, carbohydrate 41%, fat 45%, 0.05% cholesterol). We find expected elevations of cholesterol in male mice, as well as in mice with elevated serum triglycerides and/or fed a high fat high sucrose diet. The third strongest predictor was serum calcium which correlated with serum cholesterol across both diets and sexes (r = 0.39-0.48) in both Diversity Outbred (P = 3.0 × 10-43 ) and BXD (P = 0.005) mice. This is in-line with several human cohort studies which show associations between calcium and cholesterol, and calcium as an independent predictor of cardiovascular events.

Interactive Effects of Obesity and Hypertension on Patterns of Hair Essential Trace Element and Mineral Content in Adult Women

The objective of the present study was to evaluate potential similar patterns and interactive effects of obesity and hypertension on hair essential trace element and mineral content in adult women. In this cross-sectional study, a total of 607 adult women divided into controls (n = 101), groups with obesity without hypertension (n = 199), hypertension without obesity (n = 143), and both obesity and hypertension (n = 164) were included in the study. Assessment of hair mineral and trace element levels was performed by inductively-coupled plasma mass-spectrometry. Hair Ca, Mg, Co, and Mn levels in women with obesity, hypertension, and both diseases were significantly lower, compared to controls. Hair Mg levels in women with obesity and hypertension were significantly lower, whereas hair Na and K were found to be higher when compared to other groups. Hair Fe and V content in obese patients was lower than in other groups. Obesity was associated with lower hair Cu levels, whereas patients with hypertension had higher hair Cu content. Hypertension was also associated with higher hair Cr and Se content irrespective of body weight. Hair Zn levels in obese women with and without hypertension were significantly lower than those in healthy controls and normal-weight women with hypertension. In multiple regression models hair Mg was considered as a significant negative predictor of both systolic and diastolic blood pressure values. The observed alterations in hair trace element and mineral content provide an additional link between obesity and hypertension, although further detailed studies are required.

Association of the serum calcium level with metabolic syndrome and its components among adults in Taiwan

Objective

An increasing amount of literature indicates that the serum calcium level may be related to metabolic syndrome (MetS) and obesity. This study aimed to examine the relationship between the serum calcium level and MetS in adults in Taiwan.

Subjects and methods

We conducted a crosssectional study and enrolled 1,580 participants (54.4% women; mean age, 33.28 ± 12.21 years) who underwent health examinations in northern Taiwan between 2012 and 2016. Logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of MetS and its components in groups of patients in the tertiles of the serum calcium level.

Results

In total, 167 participants (10.6%) had MetS. The odds of high systolic blood pressure (BP), blood glucose, and triglyceride (TG) levels significantly increased as the serum calcium level increased. Compared with the participants in the lowest tertile of the serum calcium level (tertile 1), those in the second tertile (OR = 1.47, 95% CI: 0.97-2.23) and third tertile (OR = 1.63, 95% CI: 1.06-2.53) had a significantly higher risk of MetS. Further analyses revealed a significant association between MetS and an increased serum calcium level in those in the overweight and obese groups. However, there was no association between the serum calcium levels and MetS in those in the normal weight group.

Conclusion

This study demonstrated that a higher serum calcium level is associated with an increased risk of MetS and its components in adults with overweight and obesity.

Association of dietary calcium with mortality from all causes, cardiovascular disease and cancer in people with hypertension

Association between calcium intake and premature mortality in the general population has been well studied, but little is known about the association among specific populations. The authors aim to evaluate the association among people with hypertension and to provide a proper reference range of dietary calcium intake. This prospective cohort study included 8534 US adults with hypertension from National Health and Nutrition Examination Survey cycles 2003-2014. Dietary calcium intakes were self-reported and mortality status was ascertained by National Death Index records. During a median follow-up of 5.9 years, 1357 death occurred. Compared with participants of dietary calcium intake in quintile 1, participants in quintiles 2 and 4 had a 27% (HR: 0.73, 95% CI: 0.60-0.89) and a 29% lower risk (HR: 0.71, 95% CI: 0.57-0.88) of all-cause mortality respectively. The authors also observed a 34% lower risk (HR: 0.66, 95% CI: 0.45-0.97) of CVD death among participants in quintile 3 and a 37% lower risk (HR: 0.63, 95% CI: 0.40-0.99) of cancer-related death in participants in quintile 4 respectively. Restricted cubic spline (RCS) regression revealed a consistent protective effect of dietary calcium in participants with a daily intake of over 1000 mg, but a daily intake over 1200 mg fails to show further protective effect. Our findings suggest that elevated dietary calcium was associated with lower mortality risk from all-causes, cardiovascular disease (CVD) and cancer, and supplying sufficient dietary calcium intake, between 1000 and 1200 mg per day, in people with hypertension may be considered cost-effective to decrease risk of premature death.

Cross-sectional association between blood cholesterol and calcium levels in genetically diverse strains of mice

Genetically diverse outbred mice allow for the study of genetic variation in the context of high dietary and environmental control. Using a machine learning approach we investigated clinical and morphometric factors that associate with serum cholesterol levels in 840 genetically unique mice of both sexes, and on both a control chow and high fat high sucrose diet. We find expected elevations of cholesterol in male mice, those with elevated serum triglycerides and/or fed a high fat high sucrose diet. The third strongest predictor was serum calcium which correlated with serum cholesterol across both diets and sexes (r=0.39-0.48). This is in-line with several human cohort studies which show associations between calcium and cholesterol, and calcium as an independent predictor of cardiovascular events.

High manganese and nickel concentrations in human hair and well water and low calcium concentration in blood serum in a pristine area with sulphide-rich bedrock

We report the trace element status of residents living in areas with naturally sulphide-rich bedrock and soil in two municipalities in Finland, Sotkamo and Kaavi. Altogether, 225 people from these sparsely populated regions participated voluntarily by providing hair and blood samples. The concentrations of calcium, zinc and copper in serum as well as selenium and cadmium in whole blood did not show correlation with those concentrations in hair samples. Calcium concentration in serum was slightly lower in the sulphide-rich areas (median value 91.4 mg/l, n = 103) than in the areas with adjacent sulphur-poor bedrock (median value 93.6 mg/l, n = 82). The concentrations of Ni and Mn in hair correlated with those in drinking water. The highest Mn and Ni concentrations in the water samples from private wells were 1620 µg/l and 51 µg/l and the highest concentrations in human hair samples 36.44 mg/kg and 12.3 mg/kg, respectively. The challenge with elevated trace element concentrations in some well waters is well documented. In northern countries (Finland, Sweden, Norway and Canada), only 10% of the population depend on private well water, and 90% have access to monitored municipal water supplies. Compared with data available from sulphide mine sites globally, the nickel and manganese concentrations in human hair samples were high in our sulphide-rich study area at Sotkamo representing the trace element status of residents under natural conditions.

Association of urine phthalate metabolites, bisphenol A levels and serum electrolytes with 24-h blood pressure profile in adolescents

BACKGROUND

Among the possible causes of hypertension in adolescence, electrolyte imbalances and environmental pollutants are drawing increasing attention. We aimed to examine the relationship between bisphenol A (BPA), phthalate metabolites, and serum electrolytes and blood pressure.

METHODS

Eighty-six participants aged 12-15 years were included in the study. Body mass index (BMI), office blood pressure and 24-h ambulatory blood pressure measurements (ABPM), and carotid intima-media thickness were determined. Blood samples were taken for hemogram, renal function tests, and serum electrolytes. Free- and total-BPA and phthalate metabolites were analyzed from urine samples.

RESULTS

Of the participants, 34 were evaluated as normal blood pressure profile, 33 as white-coat hypertension (WCHT), and 19 as ABPM-hypertension. Adolescents in ABPM- hypertension groups had higher BMI-standard deviation score (SDS), leucocyte, platelet count; but lower serum chloride, compared to the normal blood pressure profile group. The percentage of adolescents with detectable urinary mono-benzyl phthalate (MBzP) was higher in ABPM-hypertension (42.1%) and WCHT groups (33.3%), compared to the normal blood pressure profile group (5.9%, p = 0.004). Associations between MBzP and ABPM- hypertension and WCHT were remained after confounding factor adjustment. Adolescents with detectable MBzP levels had also higher "albumin-corrected calcium" and lower serum phosphate and "albumin-corrected calcium x phosphate product" compared to others. Adolescents with detectable urinary MBzP levels had higher blood pressure profiles in some 24-h (mean arterial pressure-SDS, systolic blood pressure-SDS), daytime (systolic blood pressure-SDS), and night-time (mean arterial pressure-SDS, systolic blood pressure-SDS, and diastolic blood pressure-SDS) measurements, compared to others. WCHT was found to be associated negatively with monomethyl phthalate and the sum of dibutyl phthalate metabolites and ABPM-HT with MCPP. There was no significant association between blood pressure profiles and free- and total-BPA status.

CONCLUSION

MBzP was associated with adverse blood pressure profiles in adolescence. Additive follow-up studies are necessary for cause-effect relations.

Serum Calprotectin Level as an Inflammatory Marker in Newly Diagnosed Hypertensive Patients

Background

Hypertension is one of the leading causes of cardiovascular mortality. Although the pathogenetic process involved is not yet fully understood, the disease involves endothelial damage and inflammation. Calprotectin is an inflammatory marker that rises in parallel with disease activity in conditions such as systemic inflammatory diseases, infection, and atherosclerosis. The purpose of this study was to evaluate inflammation through serum calprotectin levels in newly diagnosed primary hypertension patients.

Methods

Forty-nine newly diagnosed hypertensive patients and 38 healthy adults were included in the study. Patients' office blood pressure values, biochemical findings, and demographic characteristics were recorded. Serum calprotectin levels were measured using ELISA. Parameters affecting serum calprotectin levels and determinants of hypertension were evaluated.

Results

Serum calprotectin levels were 242.8 (72.4–524) ng/mL in the control group and 112.6 (67.4–389.8) ng/mL in the hypertensive patient group, the difference being statistically significant (p=0.001). There was no correlation between serum calprotectin levels and other parameters (blood pressure values, age, gender, serum creatinine, uric acid, and calcium levels) in the hypertensive group. A lower serum calprotectin level was found to be independently related to hypertension (β = −0.009, p=0.005). Serum calprotectin at a cutoff level of 128.6 ng/mL differentiated hypertensives from healthy controls with a sensitivity of 69.4% and specificity of 68.4% (AUC = 0.767).

Conclusions

The results of this study were the opposite of our hypothesis that a higher calprotectin level may reflect subclinical endothelial damage in newly diagnosed hypertensive patients. Further comparative studies involving patients at different stages of hypertension may contribute to clarifying the relationship between calprotectin and hypertension. We conclude that molecular studies seem essential for understanding the place of calprotectin in hypertension-associated inflammation, a complex process.

Association Between Serum Calcium and the Prevalence of Hypertension Among US Adults

Background: Hypertension is a significant risk factor of cardiovascular diseases, posing a serious threat to global health. Calcium plays an important role in regulating body homeostasis. The association of calcium with hypertension remains uncertain in the general population.

Methods and Results: Cross-sectional data from the 2007–2018 National Health and Nutrition Examination Survey (NHANES) were analyzed. Adjusted multivariable logistic regression analysis and restricted cubic spline were used to investigate the association of serum calcium with the prevalence of hypertension. A total of 26,778 participants were included. The increase in calcium levels showed a positive association with the prevalence of hypertension in all three models with ORs of 1.347 (1.249–1.454), 1.522 (1.401–1.654), and 1.438 (1.306–1.583). The further subgroup analysis demonstrated a robust trend across all categories by sex, age, race, BMI, and eGFR. The restricted cubic spline plot exhibited an S-curve relationship between calcium and hypertension.

Conclusion: Our cross-sectional study demonstrated a positive association between higher serum calcium level and the prevalence of hypertension. Our findings highlighted serum calcium level in hypertensive patients.

Association of Serum Magnesium with Blood Pressure in Patients with Hypertensive Crises: A Retrospective Cross-Sectional Study

The role of magnesium in blood pressure has been studied among hypertensive patients; however, there is a dearth of studies exploring the role of magnesium in hypertensive crises. The primary objective of this study was to evaluate the relationship between serum magnesium and blood pressure in patients with hypertensive crises. This was a single-center, retrospective, chart review, cross-sectional study of patients with hypertensive crises. Patients were included if they were eighteen years of age or older, with an international classification disease ninth revision (ICD-9) code of 401.9 (hypertensive crises: emergency or urgency) and a documented magnesium level on their electronic medical record. The primary outcome of the study was the correlation between serum magnesium and blood pressure (systolic blood pressure and diastolic blood pressure) in patients with hypertensive crises. Two hundred and ninety-three patients were included in the study. The primary outcome result showed that serum magnesium was positively correlated with systolic blood pressure (r = 0.143, p = 0.014), but not diastolic blood pressure. Conclusion: This study found a significant positive association between magnesium and systolic blood pressure, but not diastolic blood pressure, among patients with hypertensive crises. This positive association of serum magnesium with systolic blood pressure was maintained after adjusting for covariates. This study's findings suggest a potential role of magnesium in blood pressure among patients with hypertensive crises.

The effect of imatinib and nilotinib on blood calcium and blood potassium levels in chronic myeloid leukemia patients: a literature review

Imatinib and nilotinib are first-line treatments for chronic myeloid leukemia (CML) patients, which act specifically against target cells. However, these drugs may cause side effects, such as electrolyte disturbances. This literature review aimed to provide a comparison of the effects of imatinib and nilotinib on blood potassium and calcium levels. It also summarized their hypothetical mechanism. A comprehensive electronic search of the different databases was conducted using ‘chronic myeloid leukemia’, ‘tyrosine kinase inhibitors’, ‘imatinib’, ‘nilotinib’, ‘potassium’, ‘calcium’, ‘electrolytes’ as keywords. This review used PubMed- MEDLINE, Cochrane Library, and Google Scholar as the source databases. Sixteen articles published from 2006 to 2020 were reviewed. Changes in blood potassium levels range from increased to decreased levels, while changes in blood calcium levels range from the lower normal values to below normal values (hypocalcemia). Tyrosine kinase inhibitors (TKIs), including imatinib and nilotinib, have a non-specific target, namely plateletderived growth factor receptor (PDGFR), which indirectly affects blood potassium and calcium levels in CML patients. The clinical manifestations of these changes vary from being visible only in laboratory tests to displaying a variety of clinical signs and symptoms.

Evaluation of serum calcium differences in hypertensive crises and control patients: A randomly matched case-control study

The role of calcium in blood pressure has been widely studied among hypertensive patients; however, no study has explored the role of calcium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum calcium levels between hypertensive crises patients and a 1:1 random matched controls (age‐, sex‐, race‐, diabetes, and body mass index matched). This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented calcium level. The control group patients were required to be 18 years of age or older, have a documented calcium level, and have no diagnosis of hypertensive crises. The primary outcome of the study was to compare the mean serum calcium in patients with hypertensive crises vs patients without hypertensive crises. Five hundred and sixty‐six patients were included in the study: 283 patients in both the case group and control group. The primary outcome results showed that serum calcium concentration was not significantly different between the case group (8.99 ± 0.78 mg/dL) and control group (8.96 ± 0.75 mg/dL) (P = .606). This study found no significant difference in serum calcium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of calcium on blood pressure in hypertensive crises.

Evaluation of serum magnesium differences in hypertensive crises and control patients: A randomly matched case-control study

Although the role of magnesium in blood pressure has been well studied among hypertensive patients, no study has explored the role of magnesium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum magnesium levels between hypertensive crises patients and matched controls (age‐, sex‐, race‐, and diabetes‐matched) in a 1:1 random match. This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented magnesium level. The control group patients were required to be 18 years of age or older, have no diagnosis of hypertensive crises, and have a documented magnesium level. The primary outcome of the study was to compare the mean serum magnesium in patients with hypertensive crises versus patients without hypertensive crises. Three hundred and fifty‐eight patients were included in the study: 179 patients in both the case group and control group. The primary outcome results showed that serum magnesium concentration was not significantly different between the case group (1.89 ± 0.29 mg/dl) and control group (1.90 ± 0.31 mg/dl) (p = .787). This study found no significant difference in serum magnesium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of magnesium on blood pressure in hypertensive crises.

Protection of the neurovascular unit from calcium-related ischemic injury by linalyl acetate

Calcium-related ischemic injury (CRII) can damage cells of the neurovascular unit (NVU). Here, we investigate the protective effects of linalyl acetate (LA) against CRII-induced NVU damage and evaluate the underlying mechanisms. The protective effects of LA in cell lines representative of NVU components (BEND, SH-SY5Y, BV2, and U373 cells) were evaluated following exposure to oxygen-glucose deprivation/reoxygenation alone (OGD/R-only) or OGD/R in the presence of 5 mM extracellular calcium ([Ca²⁺]_o) to mimic CRII. LA reversed damage under OGD/R-only conditions by blocking p47^phox/NADPH oxidase (NOX) 2 expression, reactive oxygen species (ROS) production, nitric oxide (NO) abnormality, and lactate dehydrogenase (LDH) release only in the BEND cells. However, under CRII-mimicking conditions, LA reversed NO abnormality and matrix metalloproteinase (MMP)-9 activation in the BEND murine brain endothelial cells; inhibited p47^phox expression in the human SH-SY5Y neural-like cells; decreased NOX2 expression and ROS generation in the BV2 murine microglial cells; and reduced p47^phox expression in the U373 human astrocyte-like cells. Importantly, LA protected against impairment of the neural cells, astrocytes, and microglia, all of which are cellular components of the NVU induced by exposure to CRII-mimicking conditions, by reducing LDH release. We found that LA exerted a protective effect in the BEND cells that may differ from its protective effects in other NVU cell types, following OGD/R-induced damage in the context of elevated [Ca²⁺]_o.

Associations of Plasma Copper, Magnesium, and Calcium Levels with Blood Pressure in Children: a Cross-sectional Study

Studies of the relationship of copper (Cu), magnesium (Mg), and calcium (Ca) levels with blood pressure in children are limited. This cross-sectional study included 443 children aged 6-9 years from Guangzhou, China. Plasma concentrations of Cu, Mg, and Ca were measured by inductively coupled plasma mass spectrometry. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured with an electronic sphygmomanometer. Elevated SBP and DBP were defined as the 90th percentile or greater (age and sex specific) of reference values for Chinese children. Abnormal blood pressure (ABP) was defined as an elevated SBP and/or DBP. The plasma Cu concentration was positively correlated with blood pressure, body mass index (BMI), and the C-reactive protein (CRP) level, whereas the plasma Mg and Ca concentrations were negatively correlated with SBP. A higher Cu concentration (T3 vs. T1) was associated with a higher risk of ABP (odds ratio (OR) 2.55, 95% confidence interval (CI) 1.20 to 5.40). In contrast, children in the top tertiles of Mg (OR 0.42, 95% CI 0.18 to 0.98) and Ca (OR 0.28, 95% CI 0.11 to 0.70) concentrations showed lower risks of ABP than those in the bottom tertiles. Path analysis showed that the CRP levels and BMI mediated the associations between the Cu concentration and ABP. We found that higher plasma Mg and Ca concentrations were negatively related to blood pressure in children aged 6-9 years. In contrast, a higher plasma Cu concentration was positively correlated with the risk of ABP, and the association was mediated by CRP and BMI.

Increased serum calcium levels are associated with carotid atherosclerotic plaque in normocalcaemic individuals with type 2 diabetes

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have an elevated risk of atherosclerotic cardiovascular disease. Although previous data have suggested that serum calcium levels could be involved in T2DM and cardiovascular disease, whether this applies in T2DM patients with atherosclerosis remains unclear. This study therefore aimed to investigate the relationship between serum calcium levels within the physiological ranges and carotid atherosclerotic plaque in T2DM patients.

METHODS

A total of 594 normocalcaemic in-patients with T2DM were recruited, of whom 231 had carotid atherosclerotic plaque. Serum calcium levels were measured and carotid ultrasonography was performed.

RESULTS

Patients with plaque had significantly higher serum albumin-corrected calcium than those without plaque [9.02 (8.78-9.34) mg/dL versus 8.86 (8.66-9.06) mg/dL, p < 0.001]. As serum albumin-corrected calcium levels increased across tertiles, the percentage of plaque increased (27.6%, 35.5%, and 55.7%; p < 0.001). Logistic regression showed that serum albumin-corrected calcium levels were independently and positively correlated with the presence of plaque, but not parathyroid hormone levels. Compared with patients in the lowest serum calcium tertiles, the odds ratio for plaque in patients in the upper quartile was 2.47 (95% confidence interval 1.51-4.03, p < 0.001) after adjustment for potential confounders.

CONCLUSION

Serum albumin-corrected calcium levels are elevated in patients with T2DM and carotid atherosclerotic plaques.

Association between Serum Calcium and Risk of Cardiometabolic Disease among Community-dwelling Adults in Taiwan

Serum calcium, although only comprising 1% of total body calcium, is involved in intracellular signal pathways, vascular dilatation/constriction, and muscle contraction, which are crucial for insulin secretion, cholesterol catabolism, and blood pressure regulation. As far as we know, research on the relationship between serum calcium level and metabolic syndrome (MetS), diabetes, and hypertension in one longitudinal study is rare. Owing to the crucial role of serum calcium in human cardiometabolic physiology and lack of related study so far, this study aims to describe the relationship between serum calcium level and the incidence of MetS, diabetes, and hypertension. During the period 2010-2016, there are two parts to our study: cross-sectional analysis and longitudinal analysis. Logistic regression was applied for cross-sectional analysis of the association between serum calcium level or albumin-corrected calcium (ACCA) and the prevalence of MetS, diabetes, or hypertension. Receiver operating characteristic (ROC) curve analysis was used for calculating of optimal cut-off value of serum calcium and ACCA. Cox proportional regression for development of MetS, diabetes, and hypertension according to different cut-off values of serum calcium level and ACCA were conducted. At baseline, there were 27,364 participants in our study. Serum calcium level had positive association with diabetes in the total population, male, and female. ACCA level had positive association with diabetes in the total population, male, and female. In unadjusted and multivariate Cox proportional hazard models, serum calcium level was associated with increased risk of incident MetS in the total population and male. ACCA was associated with increased risk of incident MetS in the total population and male. ACCA was associated with increased risk of incident diabetes in the total population and male participants. This study describes the relationship between serum calcium level and the incidence of MetS, diabetes, and hypertension. Higher serum calcium level is associated with increased risk of MetS, diabetes, and hypertension.

Association of Serum Calcium and Insulin Resistance With Hypertension Risk: A Prospective Population-Based Study

Background

The temporal sequence between serum calcium and insulin resistance (IR) and their effects on hypertension are unclear. We studied the association between serum calcium and IR, with risk of hypertension events in a longitudinal cohort conducted in China.

Methods and Results

Data from 8653 subjects aged 20 to 74 years with an average follow‐up of 5.3 years were analyzed. Serum calcium, and fasting and 2‐hour serum glucose and insulin were measured at baseline and follow‐up. Cross‐lagged panel and mediation analysis were used to examine the temporal relationship between serum calcium and IR and its impact on hypertension incidence. The conjoint effects of serum calcium and IR at baseline on hypertension at follow‐up were observed (P=0.029 for HOMA_IR [hepatic IR] and P=0.009 for Gutt index [peripheral IR]). The cross‐lagged path coefficient (β₂) from baseline serum calcium to follow‐up peripheral IR were significantly greater than path coefficient (β₁) from baseline peripheral insulin resistance to follow‐up serum calcium (β₂ =−0.354 versus β₁=−0.005; P=0.027). However, no directional relationships were observed in the serum calcium↔hepatic IR analysis. The mediation effect of peripheral IR on the association of serum calcium at baseline with hypertension at follow‐up was estimated at 16.4% (P<0.001).

Conclusions

Our findings demonstrate that higher serum calcium levels probably precede peripheral IR, and this 1‐directional relation plays a role in the development of hypertension.

Pseudomonas aeruginosa β-carbonic anhydrase, psCA1, is required for calcium deposition and contributes to virulence

Calcification of soft tissue leads to serious diseases and has been associated with bacterial chronic infections. However, the origin and the molecular mechanisms of calcification remain unclear. Here we hypothesized that a human pathogen Pseudomonas aeruginosa deposits extracellular calcium, a process requiring carbonic anhydrases (CAs). Transmission electron microscopy confirmed the formation of 0.1-0.2 μm deposits by P. aeruginosa PAO1 growing at 5 mM CaCl₂, and X-ray elemental analysis confirmed they contain calcium. Quantitative analysis of deposited calcium showed that PAO1 deposits 0.35 and 0.75 mM calcium/mg protein when grown at 5 mM and 10 mM CaCl₂, correspondingly. Fluorescent microscopy indicated that deposition initiates at the cell surface. We have previously characterized three PAO1 β-class CAs: psCA1, psCA2, and psCA3 that hydrate CO₂ to HCO₃^-, among which psCA1 showed the highest catalytic activity (Lotlikar et. al. 2013). According to immunoblot and RT-qPCR, growth at elevated calcium levels increases the expression of psCA1. Analyses of the deletion mutants lacking one, two or all three psCA genes, determined that psCA1 plays a major role in calcium deposition and contributes to the pathogen's virulence. In-silico modeling of the PAO1 β-class CAs identified four amino acids that differ in psCA1 compared to psCA2, and psCA3 (T59, A61A, A101, and A108), and these differences may play a role in catalytic rate and thus calcium deposition. A series of inhibitors were tested against the recombinant psCA1, among which aminobenzene sulfonamide (ABS) and acetazolamide (AAZ), which inhibited psCA1 catalytic activity with K_Is of 19 nM and 37 nM, correspondingly. The addition of ABS and AAZ to growing PAO1 reduced calcium deposition by 41 and 78, respectively. Hence, for the first time, we showed that the β-CA psCA1 in P. aeruginosa contributes to virulence likely by enabling calcium salt deposition, which can be partially controlled by inhibiting its catalytic activity.

Association of abnormal serum electrolyte levels with hypertension in a population with high salt intake

Objective

The present epidemiological study aimed to evaluate the association of serum electrolyte levels with hypertension in a population with a high-salt diet.

Design

Secondary analysis of epidemiology data from the Northeast China Rural Cardiovascular Health Study conducted in 2012–2013. Blood pressure and hypertension status were analysed for association with serum sodium, potassium, chloride, total calcium, phosphate and magnesium levels using regression models.

Setting

High-salt diet, rural China.

Participants

Adult residents in Liaoning, China.

Results

In total 10 555 participants were included, of whom 3287 had incident hypertension (IH) and 1655 had previously diagnosed hypertension (PDH). Fifty-six per cent of participants had electrolyte disturbance. Sixty-two per cent of hypercalcaemic participants had hypertension, followed by hypokalaemia (56 %) and hypernatraemia (54 %). Only hypercalcaemia showed significant associations with both IH (OR=1·70) and PDH (OR=2·25). Highest serum calcium quartile had higher odds of IH (OR=1·58) and PDH (OR=1·64) than the lowest quartile. Serum sodium had no significant correlation with hypertension. Serum potassium had a U-shaped trend with PDH. Highest chloride quartile had lower odds of PDH than the lowest chloride quartile (OR=0·65). Highest phosphate quartile was only associated with lower odds of IH (OR=0·75), and the higher magnesium group had significantly lower odds of IH (OR=0·86) and PDH (OR=0·77).

Conclusions

We have shown the association of serum calcium, magnesium and chloride levels with IH and/or PDH. In the clinical setting, patients with IH may have concurrent electrolyte disturbances, such as hypercalcaemia, that may indicate other underlying aetiologies.

Body Composition and Serum Total Calcium Were Associated With Blood Pressure Among Children and Adolescents Aged 7-18 in China: A Cross-Sectional Study

Background: This study aimed to assess the prevalence of childhood pre-hypertension and hypertension (elevated blood pressure, EBP) and explore their risk factors, especially the role of body composition and serum total calcium on EBP. Methods: From Nov 2013 to Jul 2014, a cross-sectional study was conducted in Hainan and Shaanxi Provinces in China. Two thousand two hundred eighty-three children and adolescents aged 7-18 underwent anthropometric and blood pressure measurements. Fasting blood was collected and serum total calcium was tested. Blood pressure standards from the updated Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents were used to classify BP groups based on age, sex and stature. Results: The overall prevalence of pre-hypertension and hypertension were 8.36 and 7.06%, respectively. Boys, older age, living in Hainan Province, excess adiposity and higher level of serum total calcium were found to be associated with EBP. Lean subjects had an average 3.87 mmHg decrease in systolic blood pressure (SBP) than normal weight groups. In contrary, overweight/obesity had increased SBP (3.69 mmHg) and diastolic blood pressure (DBP) (2.58 mmHg) than the normal weight group. Participants with high-level serum total calcium had a 1.60 mmHg increased SBP and 1.77 mmHg increased DBP than the low-level group. Compared with normal weight individuals, lean subjects appeared to have decreased odds of EBP (OR = 0.65, 95% CI: 0.43-0.98) but overweight/obese individuals were more likely to have EBP (OR = 2.67, 95% CI: 1.68-4.25). High-level of serum total calcium was associated with increased odds of EBP, the OR (95% CI) was 1.51 (1.17-1.94). The restrict cubic spline presented a linear relationship between serum total calcium and OR of EBP (P < 0.001). Conclusions: Body composition and serum total calcium were positively associated with blood pressure in children and adolescents. Serum calcium could be considered as an untraditional risk factors for high blood pressure screening along with other body composition indexes in clinical settings.

Calcium, magnesium, zinc and lead concentrations in the structures forming knee joint in patients with osteoarthritis‬

The aim of the study was to investigate the relationships between the concentrations of calcium (Ca), magnesium (Mg), zinc (Zn), and lead (Pb) in cartilage, anterior cruciate ligament, and meniscus samples obtained following knee joint surgery in patients with osteoarthritis in northwestern Poland.‬ Furthermore, we examined the relationships between the concentrations of these metals in the studied parts of the knee joint and the influences of gender, age, BMI and hypertension. We found significantly higher concentrations of Ca, Mg, and Zn in the cartilage of men than in women and a significantly higher Pb concentration in the meniscus of the men. We also found a higher concentration of Pb in the cartilage of patients over 65 years of age.‬ There were no differences in the concentrations of the studied metals between patients with and without hypertension.‬ There was no relationship between Ca, Mg, Zn, and Pb levels in analyzed materials and BMI. Furthermore, we noted some new interactions between metals in the studied structures of the knee joint. The results reported in the study shows the influence of age, gender and BMI on the Ca, Mg, Zn and Pb in the studied structures of the knee joint.

Update on Chronic Kidney Disease Mineral and Bone Disorder in Cardiovascular Disease

Chronic kidney disease mineral and bone disorder (MBD) encompasses changes in mineral ion and vitamin D metabolism that are widespread in the setting of chronic kidney disease and end-stage renal disease. MBD components associate with cardiovascular disease in many epidemiologic studies. Through impacts on hypertension, activation of the renin-angiotensin-aldosterone system, vascular calcification, endothelial function, and cardiac remodeling and conduction, MBD may be a direct and targetable cause of cardiovascular disease. However, assessment and treatment of MBD is rife with challenges owing to biological tensions between its many components, such as calcium and phosphorus with their regulatory hormones fibroblast growth factor 23 and parathyroid hormone; fibroblast growth factor 23 with its co-receptor klotho; and vitamin D with control of calcium and phosphorus. These complex interactions between MBD components hinder the simple translation to clinical trials, which ultimately are needed to prove the benefits of treating MBD. Deeper investigation using precision medicine tools and principles, including genomics and individualized risk assessment and therapy, may help move the field closer toward clinical applications. This review provides a high-level overview of conventional and precision epidemiology in MBD, potential mechanisms of cardiovascular disease pathogenesis, and guiding therapeutic principles for established and emerging treatments.

Age-related Disease: A Revolution is Coming, Part 2-Dietary Acid Load, Hypertension, and Cardiovascular Disease

We are starting to develop the analytical tools to examine damage to our DNA and screen for the presence of clonal hematopoiesis of indeterminate potential. This type of technology will soon support the personalization of approaches to both the prevention and treatment of age-related diseases, which have historically been characterized as beyond our control. We are at the start of an era that will one day be looked upon as the age of precision personalized lifestyle health care. This article is the second in a series in which I will be examining new tools and research that I believe is paving the path forward and leading to exciting times ahead.

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.

Serum fibroblast growth factor-23 and incident hypertension: the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

Elevated serum fibroblast growth factor-23 (FGF23), an endogenous hormone, is associated with disturbed mineral homeostasis, cardiovascular disease, and chronic kidney disease. It is unclear whether FGF23 impacts the development of incident hypertension. We examined the association between elevated FGF23 and incident hypertension in a community-based cohort.

METHOD

We investigated the association of serum FGF23, measured at baseline (1990-1992), with incident hypertension at two follow-up visits (1993-1995 and 1996-1998) in 7948 middle-aged men and women without hypertension at baseline participating in the Atherosclerosis Risk in Communities Study. Incident hypertension was determined by measured blood pressure (DBP ≥ 90 mmHg or SBP ≥ 140 mmHg) and/or self-reported hypertension medication use at follow-up exams. Complementary log-log models that accounted for interval censoring were used to model the association between FGF23 and incident hypertension.

RESULTS

During a median follow-up of 5.9 years, 27% (2152/7948) participants developed hypertension. A nonlinear association between serum FGF23 and incident hypertension was observed; only persons in the highest decile of serum FGF23 had an increased risk of incident hypertension. After adjustment for demographics, behaviors, and adiposity, the hazard ratio for incident hypertension was 1.24 (95% confidence interval: 1.11, 1.39) for the highest decile of FGF23 compared with the lowest quintile. The association was further attenuated in the final model after adjusting for renal function (hazard ratio: 1.21, 95% confidence interval: 1.08, 1.35).

CONCLUSION

High levels (≥60.6 pg/ml) of FGF23 are associated with a modestly increased risk of incident hypertension in the general population, independent of kidney function.

Associations between serum calcium, phosphorus and mortality among patients with coronary heart disease

PURPOSE

Serum calcium and phosphorus abnormalities are associated with cardiovascular disorders in general population, but evidence among patients with established coronary heart disease (CHD) is limited and controversial. This study aimed to investigate the associations of baseline serum calcium and phosphorus levels with long-term mortality risk among patients with CHD.

METHODS

We conducted a prospective cohort study among 3187 patients with CHD from October 2008 and December 2011 in China. Cox proportional hazards model was used to assess the associations of serum calcium and phosphorus at baseline with the risk of death.

RESULTS

During follow-up (mean, 4.9 years), 295 patients died, 193 of which resulted from cardiovascular causes. Multivariable-adjusted hazard ratios (HR) for each 1 mmol/L increase in serum calcium at baseline were 0.27 (95% confidence interval (CI) 0.14-0.51) for all-cause mortality and 0.26 (95% CI 0.12-0.54) for cardiovascular mortality. Patients in the highest compared to the lowest quartile of serum calcium were at lower risk of all-cause mortality (HR, 95% CI 0.57, 0.40-0.82) and cardiovascular mortality (0.50, 0.32-0.79) (both P _trend < 0.001). This inverse association between serum calcium and the risk of mortality did not change when participants were stratified by sex, age groups, level of overweight, types of CHD, and history of diabetes. We also observed a graded positive association between baseline serum phosphorus and the risks of mortality.

CONCLUSIONS

The present study is the first to report that lower serum calcium at baseline is associated with an increased risk of all-cause and cardiovascular mortality in a Chinese coronary heart disease cohort. Further studies are required to investigate the causal relationship and actual mechanisms.

Increasing extracellular Ca2+ sensitizes TNF-alpha-induced vascular cell adhesion molecule-1 (VCAM-1) via a TRPC1/ERK1/2/NFκB-dependent pathway in human vascular endothelial cells

Increasing circulating Ca²⁺ levels within the normal range has been reported to positively correlate with the incidence of fatal cardiovascular diseases (CVDs). However, limited studies have been able to delineate the potential mechanism(s) linking circulating Ca²⁺ to CVD. In this study, we exposed primary human umbilical vein endothelial cells (HUVECs) and human umbilical vein cell line (EA.hy926) to different extracellular Ca²⁺ to mimic the physiological state. Our data revealed that increasing extracellular Ca²⁺ significantly enhanced susceptibility to tumor necrosis factor (TNF)-alpha-stimulated vascular cell adhesion molecule (VCAM)-1 expression and monocytes adhesion. Knocking-down VCAM-1 by siRNA abolished calcium-induced monocytes adhesion on HUVECs. Follow up mechanistic investigations identified that extracellular Ca²⁺-increased calcium influx contributed to the activation of VCAM-1. This was mediated via upregulation of transient receptor potential channel (TRPC)1 in a nuclear factor (NF)κB-dependent manner. Most importantly, we found that a novel TRPC1-regulated extracellular signal-regulated kinase 1/2 (ERK1/2) pathway exclusively contributed to calcium-induced NFκB activation. This study provided direct evidence that increasing extracellular Ca²⁺ enhanced TNF-alpha-induced VCAM-1 activation and monocytes adhesion. Moreover, we identified a novel TRPC1/ERK1/2/NFκB signaling pathway mediating VCAM-1 activation and monocyte adhesion in this pathological process. Our studies indicate that blood calcium levels should be strictly monitored to help prevent CVD, and that TRPC1 might act as a potential target for the treatment and prevention against increased circulating calcium-enhanced CVDs.

Circulating active serum calcium reduces the risk of hypertension

Purpose Calcium, which is one the most abundant mineral elements in the body, has been suggested to be involved in blood pressure regulation. We aimed to assess the association of active serum calcium (which is the ionised and physiologically active form of serum calcium) with the future risk of hypertension. Methods The active serum calcium concentration was assessed at baseline in the Finnish Kuopio Ischemic Heart Disease population-based prospective cohort study of 1562 normotensive men aged 42-61 years at baseline. Cox proportional hazard models were used to assess the hazard ratios (95% confidence intervals (CIs)) for incident hypertension. Results During a median follow-up of 24.9 years, 247 men developed new-onset hypertension. Active serum calcium was inversely associated with incident hypertension in an approximately linear fashion. In age-adjusted analysis, the hazard ratio for hypertension per 1 standard deviation increase in active serum calcium was 0.86 (95% CI 0.76-0.98), which remained consistent after adjustment for several established risk factors and potential confounders 0.82 (0.71-0.94). In a comparison of extreme quintiles of active serum calcium levels, the corresponding adjusted hazard ratios were 0.59 (95% CI 0.39-0.90) and 0.54 (95% CI 0.35-0.82), respectively. Conclusion Active serum calcium is protective of future hypertension in a middle-aged male Caucasian population. Further research is needed to confirm these findings and help unravel the mechanistic pathways of calcium in the pathogenesis of hypertension.

No difference in acute effects of supplementalv.dietary calcium on blood pressure and microvascular function in obese women challenged with a high-fat meal: a cross-over randomised study

Recent studies suggest that supplemental Ca (SC) increases the risk of cardiovascular events, whereas dietary Ca (DC) decreases the risk of cardiovascular events. Although frequently consumed with meals, it remains unclear whether Ca can mitigate or aggravate the deleterious effects of a high-fat meal on cardiovascular risk factors. This study aimed to evaluate the effects of SC or DC on blood pressure (BP) and microvascular function (MVF) in the postprandial period in obese women challenged with a high-fat meal. In this cross-over controlled trial, sixteen obese women aged 20–50 years were randomly assigned to receive three test meals (2908 kJ (695 kcal); 48 % fat): high DC (HDCM; 547 mg DC), high SC (HSCM; 500 mg SC–calcium carbonate) and low Ca (LCM; 42 mg DC). BP was continuously evaluated from 15 min before to 120 min after meals by digital photoplethysmography. Before and 120 min after meals, participants underwent evaluation of serum Ca and microvascular flow after postocclusive reactive hyperaemia (PORH) by laser speckle contrast imaging. Ionised serum Ca rose significantly only after HSCM. Systolic BP increased after the three meals, whereas diastolic BP increased after LCM and HDCM. Hyperaemia peak, hyperaemia amplitude and AUC evaluated after PORH decreased with LCM. After HDCM, there was a reduction in hyperaemia peak and hyperaemia amplitude, whereas HSCM decreased only hyperaemia peak. However, comparative analyses of the effects of three test meals on serum Ca, BP and MVF revealed no significant meal×time interaction. This study suggests that in obese women SC and DC do not interfere with the effects of a high-fat meal on BP and MVF.

Role of Dietary Components in Modulating Hypertension

Hypertension is a major health issue, particularly in medically underserved populations that may suffer from poor health literacy, poverty, and limited access to healthcare resources. Management of the disease reduces the risk of adverse outcomes, such as cardiovascular or cerebrovascular events, vision impairment due to retinal damage, and renal failure. In addition to pharmacological therapy, lifestyle modifications such as diet and exercise are effective in managing hypertension. Current diet guidelines include the DASH diet, a low-fat and low-sodium diet that encourages high consumption of fruits and vegetables. While the diet is effective in controlling hypertension, adherence to the diet is poor and there are few applicable dietary alternatives, which is an issue that can arise from poor health literacy in at-risk populations. The purpose of this review is to outline the effect of specific dietary components, both positive and negative, when formulating a dietary approach to hypertension management that ultimately aims to improve patient adherence to the treatment, and achieve better control of hypertension.

Risk Factors in Adolescent Hypertension

Hypertension is a complex and multifaceted disease, with many contributing factors. While diet and nutrition are important influences, the confounding effects of overweight and obesity, metabolic and genetic factors, racial and ethnic predispositions, socioeconomic status, cultural influences, growth rate, and pubertal stage have even more influence and make diagnosis quite challenging. The prevalence of hypertension in adolescents far exceeds the numbers who have been diagnosed; studies have found that 75% or more go undiagnosed. This literature review summarizes the challenges of blood pressure classification in adolescents, discusses the impact of these confounding influences, and identifies actions that will improve diagnosis and treatment outcomes.

Serum Calcium Concentration Is Inversely Associated With Radiographic Knee Osteoarthritis: A Cross-Sectional Study

To examine the relationship between serum calcium (Ca) concentration and radiographic knee osteoarthritis (OA).This study covered a total of 2855 subjects. The serum Ca concentration was detected by the Arsenazo III method. The radiographic OA of the knee was defined as changes equivalent to Kellgren-Lawrence grade 2 on 1 side at least. The serum Ca concentration was categorized into 4 quartiles, which are ≤2.27, 2.28-2.34, 2.35-2.41, and ≥2.42 mmol/L, respectively. The relationship between serum Ca and radiographic knee OA was examined using the multivariable logistic analysis after adjusting a series of potential confounding factors. For each quartile of the relationship between serum Ca concentration and radiographic knee OA, the OR with 95% CI was calculated, and the one with the lowest value was considered to be the reference.An inverse association existed between serum Ca concentration and radiographic OA of the knee in the multivariable model and the model where the factors of age, sex, and BMI were adjusted. The multivariable-adjusted OR (95% CI) for radiographic knee OA in the second, third, and fourth quartiles of serum Ca concentration were 1.05 (95% CI: 0.83-1.31), 1.01 (95% CI: 0.80-1.27), and 0.79 (95% CI: 0.62-1.00), respectively, in comparison with the reference (first) quartile. A trend approaching to statistical significant (P = 0.06) was observed. Meanwhile, the relative odds of radiographic OA of the knee were decreased by 0.79 times in the fourth quartile in comparison with the reference.There is likely to be an inverse association between serum Ca concentration and radiographic OA of the knee.

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.

The association between circulating IGF1, IGFBP3, and calcium: results from NHANES III

BACKGROUND

Despite mounting evidence linking both calcium and IGF1, there is a lack of studies investigating any association between circulating levels of IGF1 and serum calcium.

METHODS

Serum calcium, IGF1, and IGF-binding protein 3 (IGFBP3) were measured for 5368 participants in NHANES III. We calculated multivariable-adjusted geometric means of serum concentrations of IGF1, IGFBP3, and IGF1/IGFBP3 by categories of calcium (lowest 5% (<1.16 mmol/l), mid 90%, and top 5% (≥1.31 mmol/l)). We also performed stratified analyses by sex, age, ethnicity, BMI, serum levels of vitamin D, and bone mineral density (BMD).

RESULTS

Overall, we found that circulating calcium was positively associated with circulating levels of IGF1 and IGFBP3, but not their molar ratio (i.e., geometric mean of IGF1 by increasing calcium categories: 237.63, 246.51, and 264.22 ng/nl; Ptrend: 0.43; Pfirst vs third category: 0.01). In particular, these associations were observed in women, people aged <60, non-Hispanic whites, those with vitamin D levels above the mean, and those with low BMD. In contrast, there was an inverse association with the molar ratio for those with BMI ≥30 kg/m(2).

CONCLUSION

We found an overall positive association between circulating levels of IGF1 and IGFBP3 and serum calcium. However, stratification by potential effect-modifiers did not support all suggested hypotheses. Our findings provide more insight into the interplay between calcium and IGF1, which in the future can be investigated in larger observational studies allowing for additional stratifications based on a combination of the different effect-modifiers investigated here.

Dietary intake of calcium and phosphorus and serum concentration in relation to the risk of coronary artery calcification in asymptomatic adults

OBJECTIVE

The current data regarding the association between calcium and phosphorus and cardiovascular disease are lacking. The aim of this study was to explore whether dietary calcium and phosphorus intake and their serum levels are associated with the prevalence of coronary artery calcification (CAC) using cardiac computed tomography in asymptomatic participants without a history of chronic kidney disease or cardiovascular disease.

APPROACH AND RESULTS

A cross-sectional study was performed in 23 652 Korean participants (40.8±7.3 years, male 83.5%) without chronic kidney disease (estimated glomerular filtration rate≥60 mL/min per 1.73 m(2)) or clinically overt cardiovascular disease, who underwent cardiac computed tomographic estimation of CAC scores as part of a general health checkup in addition to completing a self-administered food frequency questionnaire. We assessed the relationship of dietary calcium and phosphorus intake and serum levels with CAC scores using both multivariate-adjusted Tobit models and multinomial logistic regression models. Neither dietary calcium nor phosphorus intake was consistently associated with CAC scores. However, the serum calcium, phosphorus, and calcium-phosphorus product levels were significantly associated with the CAC score ratios. In multivariable-adjusted models, the CAC score ratios (95% confidence intervals) comparing the highest quartiles of serum calcium, phosphorus, and calcium-phosphorus product levels to the lowest quartiles were 1.89 (1.36-2.64), 3.33 (2.55-4.35), and 3.98 (3.00-5.28), respectively (P for trend <0.001).

CONCLUSIONS

Elevated serum levels of calcium, phosphorus, and calcium-phosphorus product, but not dietary consumption, are associated with increased CAC scores. Our findings should be explored in further research.

Association of calcium concentration with pulse pressure in older women: data from a large population-based multicentric study

OBJECTIVE

High arterial pulse pressure is a predictor of cardiovascular morbimortality. Mineral metabolism has been associated with blood pressure regulation. Our objective was to determine which variable among serum calcium, parathyroid hormone and 25-hydroxyvitamin D concentrations, was associated with pulse pressure among older adults.

DESIGN

Cross-sectional study corresponding to the baseline assessment of the EPIDOS study.

SETTING

Five French cities including Amiens, Lyon, Montpellier, Paris and Toulouse.

PARTICIPANTS

Randomized sample of 610 community-dwelling older women (mean age 80.2±3.5years) using no antihypertensive drugs.

MEASUREMENTS

Serum calcium, parathyroid hormone and 25-hydroxyvitamin D concentrations; supine pulse pressure after 15 minutes of rest (hypertension defined as pulse pressure >50mmHg). Age, body mass index, the number of morbidities and of drugs daily taken, diabetes mellitus, dysthyroidy, the use of estrogenic drugs, smoking, alcohol consumption, practice of a regular physical activity, creatinine clearance, and the effects of season and study centers were used as potential confounders.

RESULTS

Hypertensive participants (n=539) had higher calcium concentrations than normotensive ones (94.33±4.12mg/L versus 93.28±3.36mg/L respectively, P=0.040). There were no between-group differences for serum parathyroid hormone and 25-hydroxyvitamin D concentrations. The multiple logistic regressions examining the serum calcium, parathyroid hormone and 25-hydroxyvitamin D concentrations as predictors of hypertension found an association only with calcium (adjusted odds ratio=1.19, P=0.015), but not with parathyroid hormone (adjusted OR=1.01, P=0.349) or 25-hydroxyvitamin D concentration (adjusted OR=0.99, P=0.971).

CONCLUSION

Increased serum calcium concentration was independently and positively associated with high pulse pressure in our study, possibly due to increased arterial stiffness. Interventions aimed at normalizing calcaemia may be attractive to prevent hypertension and cardiovascular risk in older adults.

Association of serum calcium with serum sex steroid hormones in men in NHANES III

BACKGROUND

Bone is a positive regulator of male fertility, which indicates a link between regulation of bone remodeling and reproduction or more specifically a link between calcium and androgens. This possibly suggests how calcium is linked to prostate cancer development through its link with the reproductive system. We studied serum calcium and sex steroid hormones in the Third National Health and Nutrition Examination Survey (NHANES III).

METHODS

Serum calcium and sex steroid hormones were measured for 1262 men in NHANES III. We calculated multivariable-adjusted geometric means of serum concentrations of total and estimated free testosterone and estradiol, androstanediol glucuronide (AAG), and sex hormone binding globulin (SHBG) by categories of calcium (lowest 5% [<1.16 mmol/L], mid 90%, top 5% [≥1.30 mmol/L]).

RESULTS

Levels of total and free testosterone, total estradiol or AAG did not differ across categories of serum calcium. Adjusted SHBG concentrations were 36.4 for the bottom 5%, 34.2 for the mid 90% and 38.9 nmol/L for the top 5% of serum calcium (Ptrend = 0.006), free estradiol levels were 0.88, 0.92 and 0.80 pg/ml (Ptrend = 0.048).

CONCLUSIONS

This link between calcium and sex steroid hormones, in particular the U-shaped pattern with SHBG, may, in part, explain why observational studies have found a link between serum calcium and risk of prostate cancer.

Association of serum calcium and hypertension among adolescents aged 12-17 years in the rural area of Northeast China

Calcium plays an important role in regulating body homeostasis. Several studies have reported the association between serum calcium and cardiovascular disease in adults. However, studies assessing the relationship between serum calcium and hypertension were limited, especially in subject populations of adolescents. The aim of the present study was to examine the association of serum calcium levels and blood pressure levels among adolescents in the rural area of Northeast China. A total of 2,023 students participated in this study, including 894 boys and 1,129 girls, aged from 12 to 17 years old. We measured the body weight, height, systolic blood pressure (SBP), diastolic blood pressure (DBP), and serum calcium concentrations of all eligible subjects, and the body mass index (BMI) was calculated from body weight and height. Childhood hypertension was defined as SBP and/or DBP ≥95th percentile for age and gender. According to the results of multivariable linear and logistic regression analysis, we found that higher serum calcium levels were positively associated with childhood hypertension. In comparison with serum calcium levels ≤2.37 mmol/L, the multivariable odds ratio (95 % confidence interval) of hypertension among adolescents with serum calcium levels ≥2.53 mmol/L was 1.89 (1.41-2.53; P trend < 0.001). In addition, higher serum calcium levels were also positively associated with average difference in SBP and DBP; the average differences (95 % confidence interval) were 4.22 (2.74-5.83; P trend < 0.001) and 2.23(1.00-3.46; P trend < 0.001), respectively. In conclusion, higher serum calcium concentrations were found to have an association with higher blood pressure levels and higher prevalence of hypertension in the young population.

Serum calcium levels are not associated with coronary heart disease

Background

Numerous studies have reported that low calcium intake is related to a higher prevalence of cardiovascular disease. However, the relationship between serum calcium and coronary heart disease is unclear. The purpose of this study was to compare serum calcium levels in patients with coronary heart disease and those in healthy individuals.

Methods

This retrospective, case-control study conducted in the People’s Republic of China comprised 380 cases and 379 controls. Serum calcium levels, blood lipids, and anthropometric measurements were measured in both groups. The Student’s unpaired t-test or Chi-square test was used to compare differences between cases and controls. Pearson’s partial correlation coefficient was used to determine the association between serum calcium, blood lipids, and blood pressure in both groups.

Results

Our results indicate that the average level of serum calcium in cases was higher than in controls. Serum calcium levels showed no correlation with any parameter except for triglycerides in either group.

Conclusion

Overall, these data suggest that serum calcium has no influence on coronary heart disease or triglyceride levels in the general population.

The relationship between serum calcium level, blood lipids, and blood pressure in hypertensive and normotensive subjects who come from a normal university in east of China

Previous studies revealed that low calcium intake is related to high prevalence of cardiovascular diseases such as hypertension. However, the relationship between serum calcium and blood pressure was unclear. The prevalence of hypertension is high in China. Thus, the aim of this study was to evaluate the serum calcium level between hypertensive and normotensive groups and to investigate the correlation between serum calcium, blood pressure, and blood lipid parameters. A total of 1,135 adult subjects participated in this study and were divide into two study groups: a hypertensive group (n = 316) who had 140 mmHg or higher in systolic blood pressure (SBP) or 90 mmHg or higher in diastolic blood pressure (DBP) and an age- and sex-matched normotensive group (n = 819, 120 mmHg or less SBP and 80 mmHg or less DBP). Our results indicate a significant trend for men (60 years old or older) in the direction of decreasing blood pressure with increasing serum calcium level, but no trend for women was indicated. In the normotensive group, a significant positive correlation was found between DBP and total cholesterol (P < 0.01) and triglyceride (P < 0.01), Likewise, triglyceride was positively correlated with SBP (P < 0.01). Overall, these data suggest that serum calcium may have an influence in the blood pressure of older male subjects with hypertension and in blood lipid profiles of normotensive subjects.

Calcium intake and serum concentration in relation to risk of cardiovascular death in NHANES III

Background

Evidence for an association between calcium intake and risk of cardiovascular death remains controversial. By assessing dietary intake, use of supplements, and serum levels of calcium, we aimed to disentangle this link in the third National Health and Nutrition Examination Survey (NHANES III).

Methods

Mortality linkage of NHANES III to death certificate data for those aged 17 years or older (n = 20,024) was used to estimate risk of overall cardiovascular death as well as death from ischemic heart disease (IHD), acute myocardial infarction (AMI), heart failure (HF), and cerebrovascular disease (CD) with multivariate Cox proportional hazards regression analysis.

Results

About 10.0% of the population died of cardiovascular disease and the majority (5.4%) died of IHD. There was increased risk of overall CVD death for those in the bottom 5% of serum calcium compared to those in the mid 90% (HR: 1.51 (95% CI: 1.03–2.22)). For women there was a statistically significant increased risk of IHD death for those with serum calcium levels in the top 5% compared to those in the mid 90% (HR: 1.72 (95%CI: 1.13–2.61)), whereas in men, low serum calcium was related to increased IHD mortality (HR: 2.32 (95% CI 1.14–3.01), P_interaction: 0.306). No clear association with CVD death was observed for dietary or supplemental calcium intake.

Conclusions

Calcium as assessed by serum concentrations is involved in cardiovascular health, though differential effects by sex may exist. No clear evidence was found for an association between dietary or supplementary intake of calcium and cardiovascular death.