Trial Information

A Cross-Sectional Molecular Epidemiology Study of Occupational Exposure to Diesel Exhaust and Biomarkers in China

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.