Carotid artery plaque thickness is associated with increased serum calcium levels: The Northern Manhattan study

Background: Elevated serum calcium concentrations are associated with vascular calcification and cardiovascular disease. It is unknown whether there is a relationship between high-normal serum calcium levels and sub-clinical vascular effects. We investigated the association between serum calcium and carotid plaque thickness, a powerful early predictor of clinical coronary and cerebrovascular events. Methods: Epidemiological study of 1194 subjects from the Northern Manhattan Study cohort, a prospective community-based study designed to investigate risk factors for vascular disease in different race-ethnic groups. Results: Subjects with carotid plaque had higher corrected serum calcium levels within the normal range than those without carotid plaque (2.21 ± 0.09 mmol/L versus 2.19 ± 0.09 mmol/L, p < 0.002). The relationship between carotid plaque and serum calcium persisted after adjustment for traditional cardiovascular risk factors. Subjects in the top quintile of maximal carotid plaque thickness (≥1.7 mm) were more likely to be in the highest quintile of serum calcium level (OR = 1.64, 95% CI = 1.17-2.29, p < 0.004). The interaction of age and corrected serum calcium was the most significant predictor of carotid plaque thickness when traditional vascular risk factors were considered (p < 0.001). Conclusions: Serum calcium levels in a multi-ethnic population of older men and women were positively associated with carotid plaque thickness, a powerful early predictor of clinical coronary and cerebrovascular events.