Serum Phosphate and Microvascular Function in a Population-Based Cohort

Background and objectivesHigher serum phosphate is associated with cardiovascular events and all-cause mortality. Explanations of this association have focused on large vessel calcification and stiffness. Studies suggest that a higher serum phosphate induces microvascular dysfunction, but relationships in humans with direct measures of microvascular function are lacking.Design, setting, participants, & measurementsWe performed a cross-sectional analysis of 3189 community-living participants that underwent skin capillaroscopy, laser-Doppler flowmetry, and flicker light?induced retinal vessel responses. We used linear regression to assess the association between serum phosphate and each microvascular outcome. The primary outcome was skin capillary recruitment during postocclusive peak reactive hyperemia by capillaroscopy. Secondary outcomes included capillary recruitment during venous congestion, heat-induced skin hyperemic response, flicker light?induced retinal arteriolar, and venular dilation.ResultsThe mean age of the cohort was 59?8 years, 48% were women, 7% had an eGFR