Association of Noise Annoyance with Measured Renal Hemodynamic Changes.

BACKGROUND Chronic mental stress is recognized as a modifiable risk factor for cardiovascular disease. The aim of this study was to demonstrate that noise annoyance-induced stress is associated with changes in renal hemodynamics. METHODS Renal hemodynamic parameters were measured using steady-state input clearance with infusion of para-aminohippuric acid and inulin in individuals with normal, high normal, and elevated blood pressure. All individuals ranked subjective annoyance due to noise in everyday life on a 7-grade Likert scale. The median of all rankings was used as a cutoff point to divide the group into noise-annoyed and non-noise-annoyed individuals. Different renal hemodynamic parameters were calculated based on the Gomez equation. RESULTS Noise-annoyed individuals (n = 58) showed lower renal plasma flow (599 ± 106 vs. 663 ± 124 mL/min, p = 0.009), lower renal blood flow (1,068 ± 203 vs. 1,172 ± 225 mL/min, p = 0.047), higher filtration fraction (22.7 ± 3.3 vs. 21.3 ± 3.0, p = 0.012), higher renal vascular resistance (88.9 ± 25.6 vs. 75.8 ± 22.9 mm Hg/[mL/min], p = 0.002), and higher resistance of afferent arteriole (2,439.5 ± 1,253.4 vs. 1,849.9 ± 1,242.0 dyn s-1 cm-5, p = 0.001) compared to non-noise-annoyed individuals (n = 55). There was no difference in measured glomerular filtration rate (133 ± 11.8 vs. 138 ± 15 mL/min, p = 0.181), resistance of efferent arteriole (2,419.4 ± 472.2 vs. 2,245.8 ± 370.3 dyn s-1 cm-5, p = 0.060), and intraglomerular pressure (64.0 ± 3.1 vs. 64.6 ± 3.5 mm Hg, p = 0.298) between the groups. After adjusting for age, renal plasma flow, renal blood flow, and renal vascular resistance remained significantly different between the groups, with a trend in increased afferent arteriolar resistance and filtration fraction. CONCLUSION In this study, noise annoyance was associated with reduced renal perfusion attributed to increased renal vascular resistance predominantly at the afferent site. Long-term consequences of this renal hemodynamic pattern due to noise annoyance need to be investigated.