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Extended Follow-up of Diesel Exhaust in Miners Study Cohort Reveals New Insights

, by Elise Tookmanian, Ph.D.

Bulldozer that runs on diesel in a mine.

The Diesel Exhaust in Miners Study (DEMS), led by Debra T. Silverman, Sc.D., Sc.M., senior investigator and Director of the Occupational and Environmental Epidemiology Branch, is a landmark study that has provided critical data on the carcinogenicity of diesel exhaust. The initial findings, reported in 2012, provided key information that informed the International Agency for Research on Cancer (IARC) Monograph Program re-classification of diesel exhaust as carcinogenic to humans (Group I carcinogen). While diesel exhaust is known to cause lung cancer, its relationship with risk of other cancers is not well understood. DEMS II extends follow-up of the cohort with an additional 18 years of data, more than doubling the number of deaths. Two papers describing the findings for lung cancer death and death from other causes were published together along with an Invited Perspective in Environmental Health Perspectives in August 2023.   

DEMS II followed 12,315 workers at eight non-metal mining facilities through the end of 2015. The researchers estimated exposure to respirable elemental carbon (REC), an index of diesel exhaust, for everyone in the cohort based on extensive historical exposure assessments, developed in the original DEMS.   

The paper led by Dr. Silverman describes findings from a nested case-control study (376 lung cancer deaths, 718 controls) that characterized the exposure-response relationship between diesel exhaust and death from lung cancer. The researchers found risk of lung cancer death increased with increasing diesel exposure up to a high level of exposure (950 to <1700 μg/m3-y REC) and then plateaued. The effects of diesel exposure on lung cancer risk were most pronounced 10-19 years before death. Lung cancer risk remained elevated 20 or more years after exposure ended. This research has important implications for regulatory agencies. 

The second paper, led by Stella Koutros, Ph.D., M.P.H., OEEB investigator, looked at all causes of death (4887 total deaths). An excess of lung cancer death and a positive exposure-response relationship was evident for the entire cohort with 18 years of extended follow-up. The researchers also observed increased risk of death from non-Hodgkin lymphoma with increasing diesel exhaust exposure, and more deaths than expected due to ischemic heart disease, cerebrovascular disease, and non-malignant respiratory  diseases. These associations were driven by workers who had ever worked underground, where exposure to diesel exhaust is highest. Understanding the full public health impact of diesel exhaust exposure will require further investigation. 


1. Silverman DT et al. The Diesel Exhaust in Miners Study (DEMS) II: Temporal factors related to diesel exhaust exposure and lung cancer mortality in the nested case–control studyEnviron Health Perspect. 2023.

2. Koutros S et al. Diesel exhaust exposure and cause-specific mortality in the Diesel Exhaust in Miners Study II (DEMS II) cohortEnviron Health Perspect. 2023.

3. Wagner GR and Michaels D. Invited perspective: Diesel exhaust and lung cancer—Delayed findings confirmed, but consequences continueEnviron Health Perspect. 2023.