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Vehicle density associated with reduced lung function in COPD patients

In people with chronic obstructive pulmonary disease, motor vehicle traffic density related to significant reductions in lung function, according to recent study findings.

“Considering that people with chronic obstructive pulmonary disease (COPD) have to preserve remaining lung function, it is important to find out the relevance of where people live, their exposure to traffic and the potential effects on their lung function,” Monika Nitschke, PhD, from the department for health and ageing at the University of Adelaide, and colleagues wrote. “COPD is a progressing inflammatory disease and the additional effect of exposure to particulate matter and gases may add to the already ongoing inflammatory action and airflow obstruction which may have been originally caused by cigarette smoking or occupational exposures.”

In this study, the researchers aimed to examine effects of vehicular traffic density, measured around the homes of adults with COPD, on lung function using data from a cross-sectional study conducted in South Australia. They assessed pre- and postbronchodilator spirometry of identified COPD patients between May 2004 and February 2006 and presented the data as postbronchodilator percentage of predicted forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). The investigators expressed traffic density as the daily numbers of vehicles travelling within a 200-meter diameter zone around participants’ geocoded residences.

Nitschke and colleagues found connections between increasing daily vehicle volume and decreases in lung function parameters after adjustment for smoking and socioeconomic variables in subjects with COPD (FEV1/FVC < 0.7; n = 221; 7.1%). In the low vehicle exposure group (7,179 or less per day), researchers found 81% (76-87) post-bronchodilator percent predicted FEV1 compared to 71% (67-75) in the high exposure group (15,270 or greater per day; P < .05). Analysis in all participants with COPD showed reductions in postbronchodilator FEV1/FVC ratio of 0.03 and percent predicted FEV1 of 0.05% per daily increase in 1,000 vehicles.

“This study demonstrated for the first time, clinically important lung function reductions in relation to traffic density in people with spirometrically determined COPD,” Nitschke and associates concluded. “Community-based interventions that improve air quality would assist in prevention of disease progression of COPD and would benefit the entire community considering that [particulate matter derived from combustion processes] and other air pollutants are linked to other respiratory and to cardiovascular disease.” –by Savannah Demko

Disclosure: The researchers report no relevant financial disclosures.