Fine particulate matter results in hemodynamic changes in subjects with blunted nocturnal blood pressure dipping

Abstract

Particulate matter with aerodynamic diameter of <2.5μm (PM2.5) is associated with blood pressure and hemodynamic changes. Blunted nocturnal blood pressure dipping is a major risk factor for cardiovascular events; limited information is available on whether PM2.5 exposure-related hemodynamic changes vary with day–night blood pressure circadian rhythms. In this study, we enrolled 161 subjects and monitored the changes in ambulatory blood pressure and hemodynamics for 24h. The day–night blood pressure and cardiovascular metrics were calculated according to the sleep–wake cycles logged in the subject׳s diary. The effects of PM2.5 exposure on blood pressure and hemodynamic changes were analyzed using generalized linear mixed-effect model. After adjusting for potential confounders, a 10-μg/m3 increase in PM2.5 was associated with 1.0mmHg [95% confidence interval (CI): 0.2–1.8mmHg] narrowing in the pulse pressure, 3.1% (95% CI: 1.4–4.8%) decrease in the maximum rate of left ventricular pressure rise, and 3.6% (95% CI: 1.6–5.7%) increase in systemic vascular resistance among 79 subjects with nocturnal blood pressure dip of <10%. In contrast, PM2.5 was not associated with any changes in cardiovascular metrics among 82 subjects with nocturnal blood pressure dip of ≥10%. Our findings demonstrate that short-term exposure to PM2.5 contributes to pulse pressure narrowing along with cardiac and vasomotor dysfunctions in subjects with nocturnal blood pressure dip of <10%.