Independent Associations of Circulating 25-Hydroxyvitamin D and Parathyroid Hormone Concentrations with Blood Pressure Among Koreans: The Korea National Health and Nutrition Examination Survey (KNHANES), 2009–2010

Although lower vitamin D and higher parathyroid hormone (PTH) concentrations have been associated with hypertension, their independent contribution to blood pressure (BP) is unclear. The independent associations of serum 25-hydroxyvitamin D (25[OH]D) and PTH levels with BP were therefore investigated. This is a population-based cross-sectional study from the Korea National Health and Nutrition Examination Surveys, which includes a total of 4,513 participants (2,019 men and 2,494 women) aged ≥50 years. 25(OH)D and PTH were measured by radioimmunoassays, and BP was determined with a sphygmomanometer. Hypertensive subjects had significantly lower 25(OH)D (p = 0.023) and significantly higher PTH (p < 0.001) concentrations than normotensives. In subjects not taking antihypertensive medications, 25(OH)D showed reverse correlations with systolic and diastolic BP, both in men (p = 0.038–0.061 and p = 0.011–0.038, respectively) and in women (p = 0.006–0.018 and p = 0.001–0.011, respectively), while serum PTH concentrations showed positive correlations with systolic and diastolic BP in men (p = 0.001–0.014 and p < 0.001, respectively) and women (p < 0.001–0.008 and p = 0.001–0.040, respectively). When 25(OH)D and PTH were included in the same model, both remained independently associated with BP in men and women. In conclusion, both lower 25(OH)D and higher PTH may be independent factors for the development of hypertension.