NEW YORK, Jul 19 (Reuters Health) - People whose jobs expose them to high
levels of exhaust from diesel fuel face an increased risk of lung cancer,
Swedish researchers have found.
In a study of more than 3,400 men with and without lung cancer,
investigators found that those with the highest on-the-job exposure to diesel
fumes were 63% more likely than men not exposed to the exhaust to develop lung
cancer. This increased risk was comparable to the 68% higher risk found for
on-the-job asbestos exposure, a well-established risk factor for lung cancer.
Occupations associated with a high exposure to diesel exhaust were machinery
and motor repairer, miner/rock blaster, truck driver, bus driver, construction
machine operator and forklift truck driver, report Dr. Per Gustavsson of the
Karolinska Hospital in Stockholm, Sweden, and colleagues in the American Journal
of Epidemiology.
While asbestos has been definitively linked to lung cancer, studies have
yielded conflicting results on whether prolonged exposure to diesel fumes poses
a similar threat. In the current study, Gustavsson and his colleagues measured
workers' exposure to asbestos and diesel exhaust, as well as metal dust, welding
fumes, oil "mist," and chemicals released by the burning of organic materials,
such as wood and coal. During combustion, organic products give off polycyclic
aromatic hydrocarbons, a number of which are cancer-causing.
The researchers found that men with the heaviest exposure to asbestos,
diesel fumes, and the burning of organic products all had an increase in lung
cancer risk of 60% or more compared with those with little or no exposure.
According to Gustavsson's team, nearly 10% of lung cancer cases in this study
could have been prevented had the men not been exposed to such pollutants.
Smoking is by far the major cause of lung cancer, followed by exposure to
radon, a naturally-occurring radioactive gas. The researchers determined that
2.7% of lung cancer cases could be attributed to diesel exhaust, 4% to asbestos
and 2.2% for other combustion products. The other types of work exposures showed
no link to lung cancer, according to the report.
Although the relationship between diesel exhaust and lung cancer has been
unclear, the authors write, a number of studies have suggested that prolonged
exposure to high levels of the fumes may boost a worker's odds of developing the
disease. These findings give further evidence of a link and indicate that 4% of
all men in Stockholm County have been exposed to enough diesel exhaust to raise
their risk for lung cancer, Gustavsson and colleagues add.
