Relationship between calcitrophic hormones and blood pressure in elderly subjects

The effect of ultraviolet irradiation compared to oral vitamin D supplementation on blood pressure of nursing home residents with dementia

Background

Observational studies have reported an inverse association between ultraviolet (UV) radiation and hypertension. The aim of this study was to assess differences in blood pressure changes between persons with dementia receiving UV light versus vitamin D (VD) supplementation.

Methods

Post-hoc analysis of randomized controlled trial data concerning nursing home residents with dementia (N = 61; 41 women, mean age 84.8 years). The participants received half-body UV irradiation, twice weekly over 6 months, at one standard erythema dose (UV group, n = 22) or 5600 international units of cholecalciferol once a week (VD group, n = 39). Short-term effects were evaluated after 1 month and long-term effects after 3 and 6 months. Differences in blood pressure changes were assessed using linear mixed models.

Results

With the VD group as a reference, the estimated difference in mean change of systolic blood pressure was − 26.0 mmHg [95% confidence interval (CI) -39.9, − 12.1, p = .000] at 1 month, 4.5 mmHg (95% CI -6.8, 15.9, p = 0.432) at 3 months, and 0.1 (95% CI -14.1, 14.3, p = 0.83) at 6 months. The estimated difference in diastolic blood pressure was − 10.0 mmHg (95% CI -19.2, − 0.7, p = 0.035) at 1 month, 3.6 mmHg (95% CI -4.1, 11.2, p = 0.358) at 3 months, and 2.7 (95% CI -6.8, 12.1, p = 0.580) at 6 months.

Conclusions

UV light had only a short-term effect but not a long-term effect on blood pressure reduction compared to VD use in this sample of normotensive to mild hypertensive nursing home residents with dementia. Future studies will be needed to determine the effect of UV light in different samples of the population and especially in a population with hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02538-7.

Effect of cholecalciferol supplementation during winter months in patients with hypertension: a randomized, placebo-controlled trial

BACKGROUND

Low 25-hydroxy-vitamin D (25(OH)D) levels are inversely related to blood pressure (BP) and have been associated with incident hypertension. In people living at northern latitudes diminished cholecalciferol synthesis in the winter increases the risk of vitamin D deficiency. We wanted to test the hypothesis that daily cholecalciferol supplementation in the winter lowers BP in patients with hypertension.

METHODS

We investigated the effect of 75 µg (3,000 IU) cholecalciferol per day in a randomized, placebo-controlled, double-blind study in 130 hypertensive patients residing in Denmark (56º N). Ambulatory BP (24-h BP) and arterial stiffness were measured before and after 20 weeks of treatment, that took place between October and March.

RESULTS

A total of 112 patients (mean age 61 ± 10) with a baseline p-25(OH)D of 23 ± 10 ng/ml completed the study. Compared with placebo, a nonsignificant 3/1 mm Hg (P = 0.26/0.18) reduction was found in 24-h BP. In patients with vitamin D insufficiency (<32 ng/ml) at baseline (n = 92), 24-h BP decreased by 4/3 mm Hg (P = 0.05/0.01). Central BP (CBP) estimated by applanation tonometry and calibrated with a standardized office BP was reduced by 7/2 mm Hg (P = 0.007/0.15) vs. placebo. No differences in carotid-femoral pulse wave velocity (PWV) or central augmentation index (AIx) were found between treatment arms.

CONCLUSIONS

Cholecalciferol supplementation, by a dose that effectively increased vitamin D levels, did not reduce 24-h BP, although central systolic BP decreased significantly. In a post-hoc subgroup analysis of 92 subjects with baseline p-25(OH)D levels <32 ng/ml, significant decreases in 24-h systolic and diastolic BP occurred during cholecalciferol supplementation.

Role of vitamin D in arterial hypertension

Vitamin D deficiency is highly prevalent and may contribute to arterial hypertension. The antihypertensive effects of vitamin D include suppression of renin and parathyroid hormone levels and renoprotective, anti-inflammatory and vasculoprotective properties. Low 25-hydroxyvitamin D levels, which are used to classify the vitamin D status, are an independent risk factor for incident arterial hypertension. Meta-analyses of randomized controlled trials showed that vitamin D supplementation reduces systolic blood pressure by 2-6 mmHg. However, further studies are needed before drawing a final conclusion on the effect of vitamin D therapy on blood pressure and cardiovascular risk. In our current clinical practice we should take into account the high prevalence of vitamin D deficiency, the easy, cheap and safe way by which it can be supplemented and the promising clinical data suggesting that vitamin D might be useful for the treatment of arterial hypertension as well as other chronic diseases. Therefore, we recommend that testing for and treating vitamin D deficiency in patients with arterial hypertension should be seriously considered.

Vitamin D, muscle function, and exercise performance

Vitamin D has an important role in skeletal muscles. Previously recognized for its effects on bone, it is now known that vitamin D has a much wider spectrum of usefulness for muscle. Studies indicate that vitamin D deficiency is pandemic. Those affected include the young and otherwise healthy members of the population, including athletes. Controversy exists regarding the amount of supplementation required to reverse deficiency and the relative effect of such a reversal on overall health. This article reviews current data on the role of vitamin D on muscle function, and explores the potential implications of its deficiency and supplementation on physical fitness and athletic performance.

Vitamin D status and arterial hypertension: a systematic review

Vitamin D deficiency is common and is primarily caused by a lack of ultraviolet-B (UVB) radiation from reduced sun exposure, and the consequent limiting of vitamin D production in the skin. The vitamin D endocrine system regulates about 3% of the human genome. Observational data support the concept that vitamin D is involved in the pathogenesis of cardiovascular diseases and arterial hypertension. The antihypertensive properties of vitamin D include renoprotective effects, suppression of the renin-angiotensin-aldosterone system, direct effects on vascular cells, and effects on calcium metabolism, including prevention of secondary hyperparathyroidism. The results of clinical studies largely, but not consistently, favor the hypothesis that vitamin D sufficiency promotes lowering of arterial blood pressure. Randomized, placebo-controlled trials are greatly needed to clarify and definitively prove the effect of vitamin D on blood pressure. In general, the antihypertensive effects of vitamin D seem to be particularly prominent in vitamin-D-deficient patients with elevated blood pressure. Thus, in view of the relatively safe and inexpensive way in which vitamin D can be supplemented, we believe that vitamin D supplementation should be prescribed to patients with hypertension and 25-hydroxyvitamin D levels below target values.

Parathyroid hormone and the risk of incident hypertension

OBJECTIVE

The presence of parathyroid hormone receptor mRNA in a wide variety of tissues, including the endothelium, suggests that parathyroid hormone has potentially important effects in addition to the maintenance of calcium and phosphate homeostasis. We conducted a prospective study to examine the association between plasma intact parathyroid hormone levels and the subsequent risk of developing hypertension.

METHODS

We measured intact parathyroid hormone in 481 men without hypertension from the Health Professionals Follow-up Study. During 10 years of follow-up, we observed 142 cases of incident hypertension. Cox proportional hazards regression was used to adjust for age, race, body mass index, alcohol use, smoking, physical activity, predicted plasma 25-hydroxyvitamin D level, and other factors.

RESULTS

Median baseline levels of intact parathyroid hormone were 40.1 pg/ml in individuals who developed hypertension and 36.3 pg/ml in those who did not (P = 0.01). After multivariate adjustment, the relative risk for incident hypertension in men in the highest quartile of parathyroid hormone (median 56.0 pg/ml) compared with the lowest quartile of parathyroid hormone (median 26.3 pg/ml) was 1.83 (95% confidence interval 1.10-3.03; P for trend = 0.01). Analyses restricted to men in the lowest 90th percentage of the parathyroid hormone distribution (< or =58 pg/ml) yielded similar results. Further adjustment for the intake of calcium and sodium, as well as for season and fasting status at time of blood draw, did not materially change the results.

CONCLUSION

Plasma levels of intact parathyroid hormone, even within ranges considered normal, are positively and independently associated with a higher risk of incident hypertension.

Plasma 25-hydroxyvitamin D levels and risk of incident hypertension among young women

Numerous cross-sectional studies demonstrate an inverse association between plasma 25-hydroxyvitamin D [25(OH)D] and blood pressure or hypertension. Prospective data, however, are limited. Among 1484 women aged 32 to 52 years who did not have hypertension at baseline, we prospectively analyzed the association between plasma levels of 25(OH)D and the odds of incident hypertension using a nested case-control study design. We matched cases and controls on age, race, and month of blood collection and further adjusted for body mass index, physical activity, family history of hypertension, oral contraceptive use, and plasma levels of parathyroid hormone, calcium, phosphorous, creatinine, and uric acid. Median plasma 25(OH)D levels were lower in the cases (25.6 ng/mL) than in the controls (27.3 ng/mL; P<0.001). Women in the lowest compared with highest quartile of plasma 25(OH)D had an adjusted odds ratio for incident hypertension of 1.66 (95% CI: 1.11 to 2.48; P for trend=0.01). Compared with women with sufficient levels, those with vitamin D deficiency (<30 ng/mL; 65.7% of the study population) had a multivariable odds ratio of 1.47 (95% CI: 1.10 to 1.97). Plasma 25(OH)D levels are inversely and independently associated with the risk of developing hypertension.

Vitamin D, parathyroid hormone levels, and the prevalence of metabolic syndrome in community-dwelling older adults

OBJECTIVE

Accumulating research suggests low-circulating vitamin D concentrations, i.e., 25-hydroxyvitamin-D [25(OH)D], may be associated with an increased prevalence of metabolic syndrome; however, previous studies have not accounted for parathyroid hormone (PTH) levels. We examined the association of 25(OH)D and PTH with the prevalence of metabolic syndrome in a community-based cohort of older adults.

RESEARCH DESIGN AND METHODS

Participants included 410 men and 660 women, 44-96 years old, who completed a follow-up clinic visit in 1997-1999 as part of the Rancho Bernardo Study. Sex-specific logistic regression models were fit to estimate the odds of ATP III (Adult Treatment Panel III)-defined metabolic syndrome across quintiles of 25(OH)D and PTH, adjusting for age, season, and major lifestyle factors.

RESULTS

In men, there was a significant trend (P = 0.03) of increasing adjusted odds for metabolic syndrome with increasing PTH concentrations, primarily due to an odds ratio of 2.02 (95% CI 0.96-4.24) in men in the top quintile (> or =63 ng/l) of PTH concentration. This association remained unchanged after taking into account 25(OH)D levels and excluding men with diabetes or impaired renal function; it was attenuated after adjustment for the homeostasis model assessment of insulin resistance. Neither PTH in women nor 25(OH)D levels in either sex was related to the metabolic syndrome.

CONCLUSIONS

These findings suggest an increased risk of metabolic syndrome with elevated PTH levels in older men and no effect of 25(OH)D concentrations in either sex. The reason for the sex difference in the PTH-metabolic syndrome association is unknown. Prospective studies are necessary to better determine the roles of 25(OH)D and PTH in the etiology of metabolic syndrome.

Vitamin D status and parathyroid hormone levels in relation to blood pressure: a population-based study in older men and women

BACKGROUND

Evidence is accumulating that the vitamin D endocrine system has physiological functions beyond bone health including a role in the regulation of blood pressure. Effects of poor vitamin D status on blood pressure may be mediated by elevated parathyroid hormone (PTH) levels.

AIM

To evaluate whether serum 25-hydroxyvitamin D [25(OH)D] and PTH levels are independently associated with blood pressure in a population-based study of older men and women.

METHODS

Subjects were participants of the Longitudinal Aging Study Amsterdam, aged 65 years and older. In 1205 participants, serum 25(OH)D and PTH levels were determined and diastolic and systolic blood pressure were measured. Linear and logistic regression analyses were performed with adjustments for age, sex, region, season, lifestyle factors (physical activity, smoking, alcohol intake), and waist circumference.

RESULTS

Serum 25(OH)D was not significantly associated with diastolic (beta 0.00, P = 0.98) or systolic (beta 0.06, P = 0.11) blood pressure. In contrast, higher ln-PTH levels were significantly associated with higher diastolic (beta 1.93, P = 0.03) and systolic (beta 4.67, P = 0.01) blood pressure. Higher PTH levels were associated with a substantially higher prevalence of hypertension (OR 2.00, 95% CI 1.31-3.06 for the highest versus the lowest quartile), whereas 25(OH)D showed no significant association (OR 0.89, 95% CI 0.47-1.69 for the lowest versus the highest 25(OH)D category).

CONCLUSION

These results indicate that PTH is a potentially modifiable determinant of blood pressure in the general elderly population. Serum 25(OH)D, however, was not associated with blood pressure, possibly due to the relatively high levels in our population.

HYPERPARATIROSIS AND CARDIOVASCULAR SYSTEM PATHOLOGY

For many years, hyperparathyroidism, including primary, primarily associated with severe pathology of the osseous system and kidneys, was considered a rare disease. The widespread introduction into the clinical practice of the determination in the blood of calcium, and then parathyroid hormone, and osteodensitometry made it possible to recognize this disease more often and at earlier stages and to treat it more successfully. By now, the specific gravity of mild and asymptomatic forms of hyperparathyroidism has increased from 10-15% in the 1980s to 80%. Conservative management of these forms of hyperparathyroidism requires more thorough research on the prognosis of survival, duration and quality of life, and the risk of developing associated diseases in these patients.

The relationship between blood pressure and serum parathyroid hormone with special reference to urinary calcium excretion: the Tromsø study

The aim of the present cross-sectional epidemiological study from Tromsø, Northern Norway, was to evaluate the relation between blood pressure and serum PTH, and to examine whether this relation can be explained by a blood pressure-induced increase in urinary calcium. Ten thousand-four hundred and nineteen subjects were invited to participate and 8,128 attended. Those with serum calcium outside the reference range (2.20-2.60 mmol/l), with increased serum creatinine (upper limit 120 micromol/l for men and 100 micromol/l for women) and those using antihypertensive medication were excluded. Three thousand- six hundred and twenty subjects had complete data on outcome measures. Height, weight, blood pressure, serum calcium, PTH, and creatinine were measured and smoking status recorded. A morning urine sample was collected and urinary calcium, sodium and creatinine measured. The urinary calcium/urinary creatinine ratio (Uca/Ucr) and urinary sodium/urinary creatinine ratio (Una/Ucr) were calculated. There was a significant association between both systolic and diastolic blood pressure and serum PTH. The Uca/Ucr increased with increasing blood pressure. However, the Uca/Ucr did not affect the association between blood pressure and serum PTH in a multiple linear regression model. The relationship between blood pressure and serum PTH was also seen in subjects with similar Uca/Ucr, and a negative association between serum PTH and the Uca/Ucr was found. In conclusion, blood pressure and serum PTH are associated. This association cannot be explained by the urinary calcium excretion alone.

Serum parathyroid hormone as a predictor of increase in systolic blood pressure in men

BACKGROUND

In cross-sectional studies there appears to be a link between calcium metabolism and blood pressure, and most studies have found a positive association between serum parathyroid hormone (PTH) and hypertension.

OBJECTIVE

To determine the prognostic value of serum PTH regarding a future increase in blood pressure.

DESIGN

A prospective cohort study.

SUBJECTS

A total of 1784 individuals who had measurements of PTH in serum samples from both the fourth (1994) and fifth (2001) Tromsø studies, who did not use blood pressure medication during the observation period, and had serum calcium less than 2.61 mmol/l, were included.

MAIN OUTCOME MEASURE

Delta blood pressure (blood pressure from 2001 minus blood pressure from 1994).

RESULTS

The mean delta systolic blood pressure in the men and women during these 7 years was 5.8 and 8.1 mmHg, respectively. In a sex-specific linear regression model correcting for age, body mass index (BMI), and smoking status, serum PTH from 1994 was a significant predictor of delta systolic blood pressure in men (P < 0.01), but not in women. The difference in delta systolic blood pressure between those in the highest and those in the lowest PTH quartile was 3.5 mmHg. Similarly, delta serum PTH (serum PTH from 2001 minus serum PTH from 1994) was a significant predictor of delta systolic blood pressure in men (P < 0.05).

CONCLUSIONS

Although these findings do not prove a causal relationship between PTH and blood pressure, it adds to the growing number of indications that PTH is involved in the development of hypertension.

Effects of a short-term vitamin D(3) and calcium supplementation on blood pressure and parathyroid hormone levels in elderly women

Calcium supplementation is effective in reducing blood pressure in various states of hypertension, including pregnancy-induced hypertension and preeclampsia. In addition, calcitropic hormones are associated with blood pressure. The hypothesis is that short-term therapy with calcium and vitamin D(3) may improve blood pressure as well as secondary hyperparathyroidism more effectively than calcium monotherapy. The effects of 8 weeks of supplementation with vitamin D(3) (cholecalciferol) and calcium on blood pressure and biochemical measures of bone metabolism were studied. The sample consisted of 148 women (mean +/- SD age, 74 +/- 1 yr) with a 25-hydroxycholecalciferol (25OHD(3)) level below 50 nmol/L. They received either 1200 mg calcium plus 800 IU vitamin D(3) or 1200 mg calcium/day. We measured intact PTH, 25OHD(3), 1,25-dihydroxyvitamin D(3), blood pressure, and heart rate before and after treatment. Compared with calcium, supplementation with vitamin D(3) and calcium resulted in an increase in serum 25OHD(3) of 72% (P < 0.01), a decrease in serum PTH of 17% (P = 0.04), a decrease in systolic blood pressure (SBP) of 9.3% (P = 0.02), and a decrease in heart rate of 5.4% (P = 0.02). Sixty subjects (81%) in the vitamin D(3) and calcium group compared with 35 (47%) subjects in the calcium group showed a decrease in SBP of 5 mm Hg or more (P = 0.04). No statistically significant difference was observed in the diastolic blood pressures of the calcium-treated and calcium- plus vitamin D(3)-treated groups (P = 0.10). Pearson coefficients of correlation between the change in PTH and the change in SBP were 0.49 (P < 0.01) for the vitamin D(3) plus calcium group and 0.23 (P < 0.01) for the calcium group. A short-term supplementation with vitamin D(3) and calcium is more effective in reducing SBP than calcium alone. Inadequate vitamin D(3) and calcium intake could play a contributory role in the pathogenesis and progression of hypertension and cardiovascular disease in elderly women.

Vasoactive and proliferative effects of parathyroid hormone and parathyroid hormone-related peptide on human vascular smooth muscle

BACKGROUND

Hyperparathyroidism is associated with an increased incidence of hypertension and cardiovascular disease. Experiments in rats suggest that this results from desensitization of the normally inhibitory effects of parathyroid hormone-related peptide (PTHrP) on vascular smooth muscle cells (VSMCs) by previous exposure to parathyroid hormone (PTH).

METHODS

Isometric tension in vitro was measured in segments of vessels obtained at neck surgery from six normotensive patients with hyperparathyroidism and 12 eucalcaemic controls undergoing thyroid surgery. Vessels were precontracted with noradrenaline to allow the vasodilatory effects of PTH and PTHrP to be observed. Human VSMCs were cultured in 0.5, 5 and 15 per cent serum with or without PTH (10(-11) to 10(-7) nmol l-(1)) and proliferation was assessed by cell counts after 14 days.

RESULTS

Vasodilatation of arterial segments produced by both PTH 20 nmol l(-1) and PTHrP 100 nmol l(-1) did not differ significantly between control and hyperparathyroidism groups (P > 0.08, Mann-Whitney U test). Vasodilatation by PTHrP was not reduced by preincubation of vessels in vitro with PTH 50 nmol l(-1) for 1 h (P > 0.36, Wilcoxon test). No effects of PTH on serum-induced proliferation of human VSMCs were observed.

CONCLUSION

These data imply that homologous desensitization to PTHrP is not implicated in the pathogenesis of vascular disease in patients with hyperparathyroidism.

Relationship between serum parathyroid hormone levels in the elderly and 24 h ambulatory blood pressures

BACKGROUND

An association between serum parathyroid hormone (PTH) levels in normotensive elderly subjects and blood pressure values had been reported.

OBJECTIVE

To examine the relationship between PTH levels and other biochemical markers of calcium metabolism in elderly subjects and 24 h ambulatory blood pressures.

METHODS

We performed 24 h ambulatory blood pressure recordings for 123 independent elderly subjects aged 63-88 years using a SpaceLabs 90207 recorder. Mean night-time blood pressures were calculated from the average of readings during sleep; mean daytime blood pressures were calculated from the remaining recordings. Demographic data and details concerning the alcohol consumption and medication usage of the subjects were recorded. Serum PTH, 25-hydroxy-vitamin D, albumin, renin, aldosterone, noradrenaline, creatinine and calcium levels were measured.

RESULTS

Fifty-five patients were being administered antihypertensive therapy. Serum PTH levels correlated to the nocturnal systolic blood pressure (SBP; beta = 0.29, P = 0.002), nocturnal diastolic blood pressure (DBP), daytime SBP and mean 24 h SBP on univariate and multivariate analysis. Aldosterone levels were related to nocturnal SBP in univariate analysis (beta = 0.21, P = 0.02) but the relationship was weakened when PTH levels were included in the analysis (beta = 0.16, P = 0.09). Nocturnal, daytime and mean 24 h blood pressures were not significantly related to serum calcium, 25-hydroxy-vitamin D, age, body mass index and alcohol consumption. Sex was a significant predictor of the DBP, men having higher levels than did women (daytime DBP beta = 0.29, P = 0.001).

CONCLUSIONS

Serum PTH levels are related strongly to the blood pressure, particularly the nocturnal blood pressure in the elderly. It is not known whether PTH levels are a consequence or a cause of the elevation in blood pressure.