Chronic exposure to outdoor air pollution seems to reduce lung function in otherwise healthy adults, a study suggests.
"We know that very high levels of air pollution (such as those in the smogs of the 1950s) harm health, but until now the evidence that lower levels reduce lung function over the long term has been scanty because it requires such complex analysis," Dr. Lindsay J. L. Forbes, of the University of London, UK, told Reuters Health.
Using survey data on a cross section of more than 40,000 white adults from 1995, 1996, 1997 and 2001, Forbes and colleagues examined ties between exposure to common outdoor air pollutants and various measures of lung function.
They found that greater exposure to air pollution heavy in small particles, nitrogen dioxide, and sulfur dioxide was associated with lower lung function, the authors report.
The effects were strongest in men, older individuals, and former smokers.
"Long-term exposure to these pollutants may be responsible for a large number of cases of chronic obstructive pulmonary disease in susceptible people, although it is not likely to have significant health effects in people with good lung function in the first place," Forbes told Reuters Health.
"The next research step should be to untangle whether air pollution affects lung function over the course of adult life or whether it prevents young people from reaching their maximum lung function," Forbes said.
"This will tell us where we should concentrate our efforts to reduce exposure."
SOURCE: Thorax, August 2009.