25-hydroxyvitamin D and parathyroid hormone levels do not predict changes in carotid arterial stiffness: the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE To evaluate the impact of vitamin D and parathyroid hormone (PTH) on longitudinal changes in arterial stiffness. APPROACH AND RESULTS Distensibility coefficient and Young's elastic modulus of the right common carotid artery were evaluated at baseline and after a mean (SD) of 9.4 (0.5) years in 2580 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Cross-sectional and longitudinal associations were evaluated using multivariable linear regression and analysis of covariance. At baseline, participants were 60.1 (9.4) years old (54% female; 26% black, 20% Hispanic, 14% Chinese). Mean annualized 25(OH)D was <20 ng/dL in 816 participants, and PTH was >65 pg/dL in 285 participants. In cross-sectional analyses, low 25(OH)D (<20 ng/mL) was not associated with stiffer arteries after adjustment for cardiovascular disease risk factors (P>0.4). PTH >65 pg/mL was associated with stiffer arteries after adjustment for cardiovascular disease risk factors, other than systolic blood pressure (distensibility coefficient: β=-2.4×10(-4) mm Hg(-1), P=0.003; Young's elastic modulus: β=166 mm Hg, P=0.01); however, after adjustment for systolic blood pressure, these associations no longer were statistically significant. Longitudinal arterial stiffening was associated with older age (P<0.0001), higher systolic blood pressure (P<0.008), and use of antihypertensive medications (P<0.006), but not with 25(OH)D or PTH (both P>0.1). CONCLUSIONS Carotid arterial stiffness is not associated with low 25(OH)D concentrations. Cross-sectional associations between arterial stiffness and high PTH were attenuated by systolic blood pressure. After nearly a decade of follow-up, neither baseline PTH nor 25(OH)D concentrations were associated with progression of carotid arterial stiffness.