ASSOCIATION OF CALCITRIOL AND BLOOD-PRESSURE IN NORMOTENSIVE MEN

The purpose of this study was to clarify the possi ble associations be tween the serum 1,25-dihydroxyvitamin D (calcitriol) level and blood p ressure. Cross-sectional analysis of data was performed. Data collecte d included levels of serum calcitriol, parathyroid hormone, serum calc ium, and blood lead; blood pressure; dietary history; and demographic and anthropometric variables. One hundred normotensive male industrial employees made up the study population. Systolic blood pressure and d iastolic blood pressure were main outcome measures. After possible con founders were controlled for, multivariate analyses yielded an inverse , independent, and statistically significant association between calci triol level and systolic blood pressure (standardized beta=-0.2704, P= .0051). A similar trend of borderline significance was found for the a ssociation between calcitriol and diastolic blood pressure (standardiz ed beta=-0.1814, P=.0611). Parathyroid hormone, serum calcium, and blo od lead levels were not associated with blood pressure. When subjects were divided into four groups by calcitriol level, those in the lowest quartile showed significantly higher systolic and diastolic blood pre ssures than those in the upper quartile (difference=11 mm Hg, P=.007, and difference=4 mm Hg, P=.071, respectively). There is an inverse ass ociation between serum calcitriol level and blood pressure. This sugge sts that in addition to its role in calcium homeostasis, the active me tabolite of vitamin D may play a role in determining blood pressure. T he differences in both systolic and diastolic blood pressures between the upper and lower quartiles of serum calcitriol were substantial and may be of clinical significance.