Studies show exposure to diesel exhaust may increase lung cancer mortality

March 2, 2012

Heavy diesel exhaust (DE) exposure in humans may increase the risk of dying from lung cancer, according to two papers released March 2nd by the Journal of the National Cancer Institute.

Starting in the 1980s, studies have investigated a possible between exposure to and lung cancer. In 1989, the International Agency for Research on Cancer (IARC) classified diesel exhaust as a probable .

To determine the association between diesel exhaust exposure and the risk of dying from lung cancer, Michael D. Attfield, Ph.D., formerly of the National Institute for Occupational Safety and Health, in Morgantown, West Virginia, Debra T. Silverman, Sc.D., of the National Cancer Institute, and colleagues, conducted a of 12 315 workers in eight underground nonmetal mining facilities, called the Diesel Exhaust in Miners Study. Information was collected on workers starting in the year of introduction of diesel-powered equipment in each facility (between 1947 and 1967) to the end of the follow-up period on Dec. 31, 1997. The authors estimated the exposure of each worker to respirable elemental carbon (REC), a surrogate for diesel exhaust exposure, from a variety of sources including a 1998-2001 survey of diesel exhaust exposure at each facility, data from the US Mine Safety and Health Administration Mine Information Data Analysis System compliance database, data on diesel equipment usage over time at each facility, and historical mine ventilation data.

The researchers found a statistically significantly increased risk of lung cancer with increasing REC exposure among underground workers. Some evidence of increased risk was also shown for longer-term workers above ground who were exposed to elevated levels of REC. Other workplace exposures such as silica, asbestos, non-diesel exhaust-related polycyclic , respirable dust, and radon, had little or no effect on the findings.

Silverman, lead author of the study, and her colleagues conducted another study, a nested case-control study of lung cancer deaths in 198 workers, drawn from the same cohort of workers in the original study. In the nested case-control study, the researchers also found a statistically significantly increased risk of lung cancer mortality with increasing levels of exposure to REC, after adjusting for smoking history, employment in high-risk occupations for lung cancer, and history of nonmalignant respiratory diseases.

Silverman writes, "Our findings are important not only for miners but also for the 1.4 million American workers and the 3 million European workers exposed to diesel exhaust and for urban populations worldwide," adding that in past decades, cities such as Mexico City, Estarreja, Portugal, and nine urban centers in China have reported diesel exposure levels comparable to some underground workers in the lower range of diesel exposure found in this study.

"Because such workers had at least a 50% increased lung cancer risk, our results suggest that the high air concentrations of elemental carbon reported in some urban areas may confer increased risk of lung cancer," Silverman continues. "Thus, if the diesel exhaust/ relation is causal, the public health burden of the carcinogenicity of inhaled diesel exhaust in workers and in populations of urban areas with high levels of diesel exposure may be substantial."

Silverman and colleagues point out certain limitations of their study, namely the uncertainty in retrospective exposure assessment and information on workers' hazardous exposures before and after the study job, and the fact that certain lifestyle factors, such as smoking, were obtained from next of kin.

In an accompanying editorial, Lesley Rushton, Ph.D., of Imperial College in London, writes that this sharp rise in risk at lower levels of diesel exposure necessitates "stringent occupational and particularly environmental standards for DE exposure." Her suggestions include: improving ventilation and regular vehicle maintenance, limiting workers' time in vehicles, and turning off engines when vehicles are not in use. Furthermore, reducing carbon exposure in the general environment poses an imminent challenge. "The necessity for such reduction is becoming increasingly apparent and is essential if the health of large numbers of people is not to be compromised," Rushton writes.

Explore further: Diesel-engine exhaust filter reduces harmful particles by 98 percent

Related Stories

Diesel-engine exhaust filter reduces harmful particles by 98 percent

April 11, 2011
A commercially available particle trap can filter microscopic pollutants in diesel-engine exhaust and prevent about 98 percent of them from reaching the air, according to research reported in Circulation: Journal of the American ...

Recommended for you

Many pelvic tumors in women may have common origin—fallopian tubes

October 17, 2017
Most—and possibly all—ovarian cancers start, not in ovaries, but instead in the fallopian tubes attached to them.

New bowel cancer drug target discovered

October 17, 2017
Researchers at the Francis Crick Institute have discovered a new drug target for bowel cancer that is specific to tumour cells and therefore less toxic than conventional therapies.

Researchers find novel mechanism of resistance to anti-cancer drugs

October 17, 2017
The targeted anti-cancer therapies cetuximab and panitumumab are mainstays of treatment for advanced colorectal cancer, the second leading cause of cancer-related deaths in the United States. However, many patients have tumors ...

Using artificial intelligence to improve early breast cancer detection

October 17, 2017
Every year 40,000 women die from breast cancer in the U.S. alone. When cancers are found early, they can often be cured. Mammograms are the best test available, but they're still imperfect and often result in false positive ...

New assay may boost targeted treatment of non-Hodgkin lymphoma

October 17, 2017
Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer and the most frequently diagnosed non-Hodgkin lymphoma worldwide (nearly 40% of cases). Recent advancements indicate that both the prognosis and choice of treatment ...

Biology of childhood brain tumor subtypes offers clues to precision treatments

October 17, 2017
Researchers investigating pediatric low-grade gliomas (PLGG), the most common type of brain tumor in children, have discovered key biological differences in how mutated genes combine with other genes to drive this childhood ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.