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

Clear link between heavy vitamin B intake and lung cancer

August 22, 2017
New research suggests long-term, high-dose supplementation with vitamins B6 and B12—long touted by the vitamin industry for increasing energy and improving metabolism—is associated with a two- to four-fold increased lung ...

Study provides insight into link between two rare tumor syndromes

August 22, 2017
UCLA researchers have discovered that timing is everything when it comes to preventing a specific gene mutation in mice from developing rare and fast-growing cancerous tumors, which also affects young children. This mutation ...

Retaining one normal BRCA gene in breast, ovarian cancers influences patient survival

August 22, 2017
Determining which cancer patients are likely to be resistant to initial treatment is a major research effort of oncologists and laboratory scientists. Now, ascertaining who might fall into that category may become a little ...

Study identifies miR122 target sites in liver cancer and links a gene to patient survival

August 22, 2017
A new study of a molecule that regulates liver-cell metabolism and suppresses liver-cancer development shows that the molecule interacts with thousands of genes in liver cells, and that when levels of the molecule go down, ...

Zebrafish larvae could be used as 'avatars' to optimize personalized treatment of cancer

August 21, 2017
Portuguese scientists have for the first time shown that the larvae of a tiny fish could one day become the preferred model for predicting, in advance, the response of human malignant tumors to the various therapeutic drugs ...

Scientists discover vitamin C regulates stem cell function, curbs leukemia development

August 21, 2017
Not much is known about stem cell metabolism, but a new study from the Children's Medical Center Research Institute at UT Southwestern (CRI) has found that stem cells take up unusually high levels of vitamin C, which then ...

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.