Study of Lung Health Among Workers Exposed to Diesel Exhaust

The Occupational and Environmental Epidemiology Branch has a long history of conducting research on the carcinogenicity of diesel exhaust exposure. Most recently, a 20 year effort in collaboration with NIOSH has resulted in a seminal publication showing a dose-response relationship between air levels of elemental carbon, a surrogate for diesel exhaust, and risk of lung cancer in underground miners (Silverman et al. 2012). This study made a critically important contribution to the recent IARC decision to categorize diesel exhaust as a Group I carcinogen. Despite years of experimental studies, and small and limited workplace biomarker studies, there are still major uncertainties about the mechanism by which diesel exhaust causes lung cancer in humans. To address this gap in knowledge, we have identified a diesel truck engine testing facility in China, where workers are exposed to very high levels of diesel exhaust, which provides what we believe to be the very best opportunity to conduct a study to provide new insights into diesel exhaust carcinogenesis. We propose to carry out a cross-sectional molecular epidemiology study of 50 highly exposed workers in this facility and 50 unexposed comparable controls to study potential mechanisms of action for diesel exhaust exposure. These include upper-airway nitro-PAH-DNA adducts; inflammatory effects determined by alterations in cytokines and related markers that have been linked prospectively to risk of lung cancer; and alterations in gene expression in a wide range of potentially relevant pathways.

• INCLUSION:

Inclusion criteria

for workers exposed to diesel exhaust:

To be current workers in the diesel engine testing facility of a study factory in the selected region of China. All workers in this facility are male.

Inclusion criteria

for workers not exposed to diesel exhaust (controls):

To be a current male worker in a selected control study factory, that does not have exposure to diesel exhaust or other types of particulates, or any known or suspected genotoxic, hematotoxic, or immunotoxic chemicals, who is comparable to workers working in the diesel engine testing facility by age and smoking status .

Exclusion criteria

None.