Abstract
Subclinical carotid artery disease anticipates major cardiovascular events, and previous studies show that low vitamin D levels are associated with arterial stiffening in hypertension. The aim of the study was to examine the relationship of 25-hydroxyvitamin D [25(OH)D] levels with subclinical carotid disease in hypertensive patients. In 223 middle-aged, nondiabetic, primary hypertensive patients free of major cardiovascular and renal complications, we measured 25(OH)D and parathyroid hormone (PTH) and assessed subclinical carotid arteries changes by B-mode ultrasonography. The carotid intima-media thickness (IMT) and presence of plaques were assessed together with measurements of indexes of carotid artery distensibility (coefficient of distensibility) or stiffening (Young's elastic modulus; β-stiffness). Lower 25(OH)D levels were associated with older age (p < 0.001), longer duration of hypertension (p = 0.019), higher fasting plasma glucose (p = 0.037), and insulin (p = 0.044), Homeostatic Model Assessment (HOMA) index (p = 0.044), and PTH (p < 0.001). Insufficient and deficient 25(OH)D were associated with progressively greater carotid IMT (p < 0.001), frequency of carotid plaques (p = 0.026), Young's elastic modulus (p = 0.002), and β-stiffness (p < 0.001), and progressively lower carotid coefficient of distensibility (p < 0.001). Serum levels of 25(OH)D were negatively correlated with age (p < 0.001), duration of hypertension (p = 0.006), fasting glucose (p < 0.001), HOMA index (p = 0.032), PTH (p < 0.001), carotid IMT (p < 0.001), Young's elastic modulus (p = 0.025), and β-stiffness (p < 0.001), and positively related with carotid coefficient of distensibility (p < 0.001). Multivariate regression analysis showed that both higher carotid IMT (p = 0.004) and lower coefficient of distensibility (p = 0.002) were related to lower 25(OH)D independent of age, severity, and duration of hypertension and metabolic variables. In conclusion, deficiency/insufficiency of 25(OH)D independently predicts subclinical carotid disease in uncomplicated, middle-aged, hypertensive patients and might predispose these patients to major cardiovascular complications.