Association Between Changes in Air Pollution Levels During the Beijing Olympics and Biomarkers of Inflammation and Thrombosis in Healthy Young Adults

Study Questions:

What is the effect of reducing air pollutant levels on biomarkers of vascular disease processes?

Methods:

During a period of greatly restricted air pollution emissions (instituted during the 2008 Beijing Olympics), pollutants were measured daily and multiple biomarkers related to vascular disease (C-reactive protein [CRP], fibrinogen, von Willebrand factor, soluble CD40 ligand [sCD40L], soluble P-selectin [sCD62P] concentrations; white blood cell count; heart rate; and blood pressure) were measured in 125 healthy young adults before, during, and after the Olympics.

Results:

Concentrations of particulate and gaseous pollutants markedly decreased (−13% to −60%) from the pre-Olympic period to the during-Olympic period. Improvements were noted in sCD62P levels by −34.0% (p < 0.001) from a pre-Olympic mean of 6.29 ng/ml to a during-Olympic mean of 4.16 ng/ml and von Willebrand factor by −13.1% (p < 0.001). Changes in the other outcomes were not statistically significant. In the post-Olympic period when pollutant concentrations increased, most outcomes approximated pre-Olympic levels, but only sCD62P and systolic blood pressure were significantly worsened from the during-Olympic period. The fraction of above-detection limit values for CRP (percentage ≥0.3 mg/L) was reduced from 55% in the pre-Olympic period to 46% in the during-Olympic period, and reduced further to 36% in the post-Olympic period. Increases in pollutant concentrations were consistently associated with statistically significant increases in fibrinogen, von Willebrand factor, heart rate, sCD62P, and sCD40L concentrations.

Conclusions:

The authors concluded that changes in air pollution levels during the Beijing Olympics were associated with acute changes in biomarkers of inflammation and thrombosis, and measures of cardiovascular physiology in healthy young persons. These findings are of uncertain clinical significance.

Perspective:

As part of an agreement to host the Olympics in Beijing, the Chinese government instituted aggressive pollution control measures, which led to a marked reduction in air pollutants. This created an opportunity to study the effects of a real-world pollution intervention on vascular biomarkers. Results demonstrate that changes in air quality lead to reductions in some biomarkers associated with inflammatory vascular processes. These results support previous epidemiologic and laboratory studies that high levels of air pollution promote vascular disease, and suggest this may occur via increased cellular adhesive/thrombotic mechanisms.

Clinical Topics: Heart Failure and Cardiomyopathies, Heart Failure and Cardiac Biomarkers

Keywords: Inflammation, Leukocyte Count, Vascular Diseases, Blood Pressure, Cardiovascular Physiological Phenomena, Heart Rate, P-Selectin, C-Reactive Protein, Biological Markers, Thrombosis, Fibrinogen, CD40 Ligand


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