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

Figures & data

Table 1. Demographics, clinical characteristics and laboratory results per tertile of plasma total calcium concentration.

Demographics and clinical characteristics	Tertile 1 (n = 201)	Tertile 2 (n = 218)	Tertile 3 (n = 199)
Males (%)	49.3	53.2	48.2
Age (years)	44.9 (10.7)	45.8 (12.1)	44.4 (12.5)
Body mass index (kg/m^2)	26.7 (4.4)	26.9 (4.3)	26.8 (4.3)
Extracellular water volume (l)	13.02 (1.75)	12.87 (1.90)	12.84 (1.90)
Extracellular water balance	1.00 (0.11)	0.98 (0.09)	0.97 (0.11)**
Current smokers (%)	10.9	11.0	16.1
Alcohol consumption (standard drinks/week)	3.7 (5.2)	4.4 (6.0)	5.4 (6.1)*
Dairy product consumption (standard dose/day)	3.0 (1.8)	3.0 (1.9)	3.4 (2.6)
Calcium supplement users (%)	1.5	2.3	5.5
Vitamin D supplement users (%)	11.9	17.0	20.1
Seated brachial office blood pressure measured by physician (mmHg)	139 (22)/88 (13)	142 (21)/90 (12)	142 (20)/90 (12)
Supine brachial blood pressure measured by nurse (mmHg)	127 (17)/78 (12)	134 (20)**/81 (12)	135 (18)**/83 (11)**
Supine radial laboratory blood pressure (mmHg)	127 (19)/72 (12)	133 (20)**/76 (13)**	135 (19)**/77 (13)**
Supine finger laboratory blood pressure (mmHg)	118 (17)/68 (12)	124 (19)*/69 (13)	124 (20)**/70 (13)

Results shown as mean (standard deviation). *p < 0.05 vs. Tertile 1; **p < 0.01 vs. Tertile 1.

Figure 1. Radial systolic blood pressure (a), radial diastolic blood pressure (b), aortic pulse pressure (c), and pulse wave velocity (d) in tertiles of plasma total calcium concentration adjusted for sex; mean (circle) with 95% confidence intervals of the mean (whiskers), one-way ANOVA with the Bonferroni correction in post-hoc analyses.

Figure 2. Heart rate (a), stroke index (b), cardiac index (c), and systemic vascular resistance index (d) in tertiles of plasma total calcium concentration adjusted for sex; mean (circle) with 95% confidence intervals of the mean (whiskers), one-way ANOVA with the Bonferroni correction in post-hoc analyses.

Table 2. Significant explanatory variables for radial systolic and diastolic blood pressure in linear regression analysis.

Systolic blood pressure (mmHg)	B	Beta	p	Diastolic blood pressure (mmHg)	B	Beta	p
Model (R^2 = 0.320)				Model (R^2 = 0.310)
(constant)	−66.325			(constant)	9.582
Calcium	27.414	0.138	0.001	Cystatin C	16.029	0.181	<0.001
Cystatin C	18.017	0.137	0.002	LDL cholesterol	1.898	0.140	0.001
Age	0.222	0.135	0.002	PTH	12.181	0.139	<0.001
Body mass index	0.566	0.128	0.004	Age	0.147	0.133	0.003
LDL cholesterol	2.408	0.119	0.006	QUICKI	−37.719	−0.124	0.001
Sex (male)	4.319	0.112	0.005	Calcium	16.023	0.119	0.003
QUICKI	−48.678	−0.108	0.008	Phosphate	−7.887	−0.101	0.014
PTH	12.566	0.096	0.013	Sex (male)	2.312	0.089	0.025
Smoking (current)	−4.917	−0.085	0.022	Alcohol consumption (high)	6.619	0.078	0.034
Calcium supplement use	8.808	0.080	0.030	1,25(OH)2D3	7.212	0.076	0.047

LDL: low-density lipoprotein; QUICKI: quantitative insulin sensitivity check index; PTH: parathyroid hormone; 1,25(OH)₂D₃: 1,25-dihydroxyvitamin D₃. Variables in Model: Age, sex, body mass index, alcohol consumption (moderate, high), smoking status (current, previous), calcium, phosphate, Lg₁₀ of PTH, Lg₁₀ of 25(OH)D₃, Lg₁₀ of 1,25(OH)₂D₃, QUICKI, Lg₁₀ of triglycerides, HDL cholesterol, LDL cholesterol, uric acid, alkaline phosphatase, alanine aminotransferase, sodium, Lg₁₀ of renin, Lg₁₀ of C-reactive protein, cystatin C, calcium supplement use, vitamin D supplement use, and dairy products use (standard doses/day).

Table 3. Significant explanatory variables for cardiac output and systemic vascular resistance in linear regression analysis.

Cardiac output (ml/min)	B	Beta	p	Systemic vascular resistance (dynes × s/cm^5)	B	Beta	p
Model (R^2 = 0.234)				Model (R^2 = 0.146)
(constant)	5.231			(constant)	390
Sex (male)	0.946	0.403	<0.001	Sex (male)	−152	−0.253	<0.001
Body mass index	0.033	0.124	0.003	Age	5	0.195	<0.001
QUICKI	−2.695	−0.098	0.019	Vitamin D supplement use	91	0.111	0.010
Smoking (current)	0.332	0.094	0.014	LDL cholesterol	32	0.100	0.041
				Calcium	306	0.098	0.029
				Smoking (current)	−80	−0.088	0.042

QUICKI: quantitative insulin sensitivity check index; LDL: low-density lipoprotein. Variables in Model as in Table 2.

Data availability

Analyses and datasets of the current study are not available publicly as the clinical database contains several indirect identifiers and the informed consent obtained does not allow publication of individual patient data. The datasets are available from the corresponding author on reasonable request.