According to a large study conducted among non-metal miners in the United States, diesel exhaust increases the risk of death from lung cancer. These studies were published in the Journal of the National Cancer Institute.
Lung cancer remains the leading cause of death in theUnited States. Each year, more than 87,000 men and 72,000 women die of the disease.
Diesel exhaust is composed of fine particles that can become lodged in the lung. The National Toxicology Program of the US Department of Health and Human Services has classified diesel exhaust as “reasonably anticipated to be a human carcinogen.”
To collect better information about the relationship between exposure to diesel exhaust and health outcomes, researchers from the National Cancer Institute (NCI) and the National Institute for Occupational Safety and Health (NIOSH) conducted the Diesel Exhaust in Miners Study.
The study involved more than 12,000 workers at eight non-metal mining facilities. Non-metal mining facilities were chosen because these types of mines often involve exposure to diesel exhaust from heavy equipment, but usually do not involve high levels of exposure to other causes of lung cancer such as radon, silica, or asbestos. The non-metal substances that were mined for were limestone, potash, salt, and trona.
Measurements of air taken at the mines allowed researchers to develop estimates of diesel exhaust exposure for each job and each year. Information was available for people who worked underground as well as people who worked on the surface.
Two reports were recently published from the study: the first assessed all causes of death among all subjects, and found a higher rate of lung cancer deaths among workers with the highest level of exposure to diesel exhaust.
The second report involved a closer analysis of the lung cancer deaths, and accounted for other lung cancer risk factors such as smoking, employment in other high-risk jobs, and history of respiratory diseases. Key findings from the second report include the following:
- Compared with the workers with the least exposure to diesel exhaust, those who had the highest exposure were roughly three times more likely to die of lung cancer.
- In the subset of workers who were non-smokers, those who had the highest exposure to diesel exhaust were seven times more likely to die of lung cancer.
The most heavily exposed miners had levels of exposure that were well above that of the generalUSpopulation. Lightly exposed underground miners, however, had a level of exposure that is similar to that experienced by people who spend a lifetime in a heavily polluted urban area. This level of exposure was linked with a 50 percent increased risk of lung cancer. The risk from very low levels of exposure to diesel exhaust is uncertain.
The results from these studies provide further evidence that diesel exhaust may increase the risk of lung cancer in humans. Newer diesel engines with lower emissions may reduce the health risks.
National Cancer Institute Press Release. Heavy exposure to diesel exhaust linked to lung cancer death in miners. March 2, 2012.
National Cancer Institute Questions and Answers. Diesel Exhaust in Miners Study: Questions and Answers. March 2, 2012.
Silverman DT, Samaniac CM, Lubin JH, et al. The diesel exhaust in miners study: a nested case-control study of lung cancer and diesel exhaust. J Natl Cancer Inst. March 2, 2012. doi:10.1093/jnci/djs034.
Attfield MD, Schlieff PL, Lubin JH, et al. The diesel exhaust in miners study: a cohort mortality study with emphasis on lung cancer. J Natl Cancer Inst. March 2, 2012. doi:10.1093/jnci/djs035.