Investigating the Association of Cardiovascular Effects with Personal Exposure to Particle Components and Sources

Background: Few studies included information on components and sources when exploring the cardiovascular health effects from personal exposure to particulate matters (PM). We previously reported that exposure to PM between 1.0 and 2.5 μm (PM(2.5-1)) was associated with increased cardio-ankle vascular index (CAVI, an arterial stiffness index), while exposure to PM smaller than 0.25 μm (PM(0.25)) decreased the heart rate variability (HRV) indices. The purpose of this study was to investigate the association between PM elements and cardiovascular health effects and identify responsible sources.

Methods: In a panel study of seventeen mail carriers, the subjects were followed for 5-6 days while delivering mail outdoors. Personal filter samples of PM(2.5-1) and PM(0.25) were analyzed for their elemental concentrations. The source-specific exposures were further estimated by using absolute principal factor analysis. We analyzed the component- and source-specific health effects on HRV indices and CAVI using mixed models.

Results: Several elements in PM(2.5-1) (e.g., cadmium and strontium) were associated with the CAVI. Subsequent analyses showed that an interquartile range increase in exposure to PM from regional sources was significantly associated with a 3.28% increase in CAVI (95% confidence interval (CI), 1.47%-5.13%). This significant effect remained (3.35%, CI: 1.62%-5.11%) after controlling for the ozone exposures. For exposures to PM(0.25), manganese, calcium, nickel, and chromium were associated with the CAVI and/or the HRV indices.

Conclusions: Our study suggests that PM(2.5-1) and PM(0.25) components may be associated with different cardiovascular effects. Health risks from exposure to PM from sources other than vehicle exhaust should not be underappreciated.