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Interaction effects of temperature and ozone on lung function and markers of systemic inflammation, coagulation, and fibrinolysis: A crossover study of healthy young volunteers
Citation:
Kahle, J., L. Neas, R. Devlin, M. Case, Mike Schmitt, M. Madden, AND D. Diaz-Sanchez. Interaction effects of temperature and ozone on lung function and markers of systemic inflammation, coagulation, and fibrinolysis: A crossover study of healthy young volunteers. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 123(4):310-6, (2015).
Impact/Purpose:
Title was modified from: Elevated Temperature Alters Vascular Responses to Ozone but not Lung Function in Healthy Volunteers" Despite almost 30 years of research into the effects of ozone, until recently there have been very few studies of the interaction between ozone and temperature on human health. We report on the first controlled human exposure study to test vascular and systemic responses to ozone at an elevated temperature. We show that while the effect of ozone on lung function is similar at both moderate and high temperatures, there are significant changes in cardiac and vascular effects, most notably an interaction between heat and ozone that results in changes in key agents of fibrinolysis.
Description:
BACKGROUND: Trends in climate suggest that extreme weather events such as heat waves will become more common. High levels of the gaseous pollutant ozone are associated with elevated temperatures. Ozone has been associated with respiratory diseases as well as cardiovascular morbidity and mortality and can reducs lung function and alter systemic markers of fibrinolysis. The interaction between ozone and terrperature is unclear.METHODS: Sixteen healthy volunteers were exposed in a randomized crossover study to 0.3 ppm ozone and dean air for 2 hr at moderate (22°C) temperature and again at an elevated temperature (32.5°C). In each case lung function was performed and blood taken before and immediately after exposure and the next morning.RESULTS: Ozone exposure at 22°C resulted in a decrease in markers of fibrinolysis the next day. There was a 51.8% net decrease in PAI-1 (plasminogen activator inhibitor-1), a 12.1% net decrease in plasminogen , and a 17.8% net increase in D-dimer. These significantly differed from the response at 32.5°C, where there was a 44.9% (p = 0.002) and a 27.9% p = 0.001) increase in PAI-1 and plasminogen, respectively, and a 12.5% (p = 0.042) decrease in D-dimer. In contrast, decrements in lung function following ozone exposure were comparable at both moderate and elevated temperatures (forced expiratory volume in 1 sec, -12.4% vs. -7.5%, p > 0.05). No changes in systemic markers of inflammation were observed for either temperature.CONCLUSION: Ozone-induced systemic but not respiratory effects varied according to temperature. Our study suggests that at moderate temperature ozone may activate the fibrinolytic pathway, while at elevated temperature ozone may impair it. These findings provide a biological basis for the interaction between temperature and ozone on mortality observed in some epidemiologic studies.
