Background and purpose: The purpose of this study was to assess the association of vitamin D deficiency and indices of mineral metabolism with subclinical carotid markers that predict cardiovascular events.
Methods: Two hundred three community-dwelling adults (Northern Manhattan Study; age, 68 ± 11; age range, 50 to 93 years) had serum measurements (calcium, phosphorus, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroid hormone) and carotid ultrasound (plaque presence, number, maximal carotid plaque thickness, intima-media thickness).
Results: Adjusting for cardiovascular risk factors, plaque number was associated with phosphorus levels (β=0.39 per 1-mg/dL increase; P=0.02) and calcium-phosphorus product (β=0.36 per 10-U increase; P=0.03). In those with plaque (N=116 [57%]), the association of plaque number with phosphorus and calcium-phosphorus product persisted. In addition, 25-hydroxyvitamin D was inversely associated with both intima-media thickness (β=-0.01 per 10-ng/mL increase; P=0.05) and maximal carotid plaque thickness (β=-0.10 per 10-ng/mL increase; P=0.03). In a model containing traditional cardiac risk factors and indices of mineral metabolism, 25-hydroxyvitamin D accounted for 13% of the variance in both intima-media thickness and maximal carotid plaque thickness. Calcium, parathyroid hormone, and 1,25-dihydroxyvitamin D levels were not associated with carotid measures.
Conclusions: After adjusting for cardiovascular risk factors and renal function, serum phosphorus and calcium-phosphorus product were associated with a greater burden of subclinical carotid atherosclerosis. Low 25-hydroxyvitamin D levels were associated with increased intima-media thickness and maximal carotid plaque thickness in those with plaque, and 25-hydroxyvitamin D contributed in a robust manner to the variance in both. These results confirm and extend data on the association of low vitamin D levels with subclinical carotid atherosclerosis. The precise nature of this association and the optimum levels of vitamin D for vascular health remain to be elucidated.