Vitamin D deficiency and high parathyroid hormone (PTH) levels have been linked with hypertension. Nondipper hypertension is associated with increased morbidity and mortality. We aimed to investigate the relationship of vitamin D and PTH levels with nondipper hypertension and nocturnal decline in untreated hypertensive patients.
This cross-sectional study included a total of 73 hypertensive and 34 normotensive participants. Each patient underwent 24-hour ambulatory blood pressure monitoring, routine biochemical tests, vitamin D, and PTH analysis.
The study population was divided into three groups according to ambulatory blood pressure monitoring records: 40 nondippers (mean age; 59.8±10.8 years, 24 women and 16 men), 33 dipper hypertensives (mean age; 58±11.8 years, 13 women and 20 men), and 34 normotensives (mean age; 56.9±11.7 years, 19 women and 15 men). Nondipper hypertensives showed lower levels of vitamin D than dippers and normotensives (9.7±6.1 vs. 14.9±10.1 vs. 16.4±9.5 ng/ml, P=0.001, for both) and higher levels of PTH than dippers (74.8±34.7 vs. 53.3±19.9 ng/ml, P=0.001). A significant positive correlation was observed between vitamin D and nocturnal decline (r=0.34, P=0.001), whereas a significant negative correlation was present between PTH and nocturnal decline(r=−0.26, P=0.006). In multivariate analysis, PTH level was correlated independently with nocturnal decline (β=−0.07, 95% confidence interval: −0.114–0.025, P=0.003).
In this study, vitamin D levels were significantly lower and PTH levels were significantly higher in nondippers. The vitamin D level was correlated positively and the PTH level was correlated negatively with nocturnal decline. In addition, PTH level was associated independently with nocturnal decline in hypertension.
Cardiology Clinic, Elazig Education and Research Hospital, University of Health Sciences, Elazig, Turkey
Correspondence to Makbule K. Karadag, MD, Cardiology Clinic, Elazig Education and Research Hospital, University of Health Sciences, Inonu Street, 23100 Elazig, Turkey Tel: +90 532 764 4795; fax: +90 424 212 1461; e-mail:email@example.com
Received December 9, 2016
Received in revised form July 21, 2017
Accepted August 8, 2017