Serum Phosphorus Concentrations and Arterial Stiffness among Individuals with Normal Kidney Function to Moderate Kidney Disease in MESA

Background and objectives: Higher phosphorus levels are associated with cardiovascular disease (CVD) events and mortality. Whether vascular stiffness may be responsible is unknown. Design, setting, participants, & measurements: This study examined the cross-sectional associations of serum phosphorus with ankle brachial index (ABI), pulse pressure, and large and small artery elasticity by radial artery waveform analysis among 1370 individuals (440 with moderate chronic kidney disease) who did not have clinical CVD and participated in the Multi-Ethnic Study of Atherosclerosis. Results: Fifty-nine (4%) individuals had high ABI (> 1.30), a marker of peripheral arterial stiffness. Participants with phosphorus levels > 4 mg/dl had greater than four-fold risk for high ABI compared with participants with phosphate levels < 3 mg/dl (relative risk 4.6; 95% confidence interval 1.6 to 13.2; P = 0.01) after adjustment for demographics, traditional CVD risk factors, and kidney function. Higher phosphorus levels were also associated with greater pulse pressure and lesser large and small artery elasticity in unadjusted models, but these associations were attenuated after adjustment. Conclusions: Higher phosphorus levels are strongly associated with high ABI but not pulse pressure or large or small artery elasticity. If confirmed in future studies, then the association of higher phosphorus concentrations with CVD events may be partially mediated through peripheral arterial stiffness.