Evidence suggests low
vitamin D and elevated
parathyroid hormone (PTH) concentrations may increase risk for
cardiovascular disease. However, little is known about the association between
vitamin D or PTH and subclinical
atherosclerosis. This cross-sectional study included 654 community-dwelling older adults aged 55-96 years (mean age, 75.5 years) without a history of
coronary heart disease, revascularization, or
stroke enrolled in the Rancho Bernardo Study who completed a clinic examination in 1997-1999 and provided a blood sample for determination of serum
25-hydroxyvitamin D [25(
OH)D],
1,25-dihydroxyvitamin D [
1,25(OH)(2)D], and PTH concentrations. Carotid artery intima-media wall thickness (IMT) was measured as an
indicator of
atherosclerosis at two sites with B-mode ultrasound. After adjusting for age, sex, smoking, alcohol intake, waist-to-hip ratio, exercise, season of blood draw, diabetes, and
hypertension, geometric mean internal carotid IMT (p(trend) 0.022), but not common carotid IMT (p(trend) 0.834) decreased in a dose-dependent fashion with increasing concentration of 25(
OH)D. There was no association of
1,25(OH)(2)D or PTH with either measure of carotid IMT. In subgroup analyses,
1,25(OH)(2)D was inversely associated with internal carotid IMT among those with
hypertension (p for interaction 0.036). These findings from a population-based cohort of older adults suggest a potential role for
vitamin D in the development of subclinical
atherosclerosis. Additional research is needed to determine whether
vitamin D may influence the progression of
atherosclerosis, including the effects of supplementation on the atherosclerotic process.