[Air pollution and heart rhythm disturbance: A retrospective study]

INTRODUCTION

According to many studies, exposure to air pollution increases cardiovascular morbidity and mortality. It has also been shown that the frequency of heart rhythm disorders in Region wallonne is very high.

OBJECTIVES

The objective of this study is to test the hypothesis of a link between rhythm disorders measured by cardiac holters and data from devices measuring the concentration of air pollutants present in ambient air.

METHODOLOGY

The health data were obtained via the Erasme hospital's cardiology center. This is a retrospective data collection over the last 2 to 5 years. The environmental data are: PM2.5, PM10, NO2, O3 and temperature. The statistical models were based on "cross-case" analyses.

RESULTS

An association between PM10 and the number of ESAs was observed. An increase of 10μg/m³ of PM10 increases the number of ESAs by 20% (P=0.040). The number of ESAs increases with age (63% more ESAs when age increases by 10 years). A history of intervention also decreases the number of ESAs (-35%), the same phenomenon is observed for pacemaker wearers (-66%). The strongest association observed between NO2 and ESA with an OR of 1.37 (P=0.027) in the final model. No significant association was observed between the effects of air pollution and VPCs.

CONCLUSION

Our analyses resume the effects of the different pollutants on rhythm disorders, the effects adjusted for treatment and co-morbidities. They open the door to other more refined studies based on individual measurements.

Cardiovascular effects of air pollution

Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM₁₀), fine particles (PM_2.5) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10μg/m³ increase in long-term exposure to PM_2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution and road traffic was associated with an increased risk of arteriosclerosis, as shown by premature aortic and coronary calcification. Short-term increases in air pollution were associated with an increased risk of myocardial infarction, stroke and acute heart failure. The risk was increased even when pollutant concentrations were below European standards. Reinforcing the evidence from epidemiological studies, numerous experimental studies demonstrated that air pollution promotes a systemic vascular oxidative stress reaction. Radical oxygen species induce endothelial dysfunction, monocyte activation and some proatherogenic changes in lipoproteins, which initiate plaque formation. Furthermore, air pollution favours thrombus formation, because of an increase in coagulation factors and platelet activation. Experimental studies also indicate that some pollutants have more harmful cardiovascular effects, such as combustion-derived PM_2.5 and ultrafine particles. Air pollution is a major contributor to cardiovascular diseases. Promotion of safer air quality appears to be a new challenge in cardiovascular disease prevention.

[Effects of fine particulate matter from on bronchial epithelial cells]

INTRODUCTION

Ambient air contains a variety of pollutants including solid particles. Human bronchial epithelial cells (HBEC) play a key role following inhalation of these toxic particles. In a cell culture system of HBEC, we investigated the effects of several fractions of Lyons air-derived particles on cell viability/proliferation and production of the inflammatory mediators IL-8 and TGF-β.

METHODS

Air particles were collected in Lyon (France) by filtration of the air and impaction on filters located on a tapered element oscillating microbalance. Several diameter-based fractions of particles were prepared. HBEC were then exposed to different concentrations of these fractions.

RESULTS

HBEC survival was not altered after 48hours of culture in the presence of particles regardless of their diameter and concentration. A dose-dependent inhibitory effect on cell growth was observed for all fractions. The particles caused an increase of both TGF-ß and Il-8 protein levels as a function of their diameters and/or concentrations.

CONCLUSION

Air-derived particle fractions exhibit both an inhibitory effect on cell proliferation and a pro-inflammatory activity on HBEC.