Background:

- Diesel fuel is the most commonly used fuel to power cars and trucks worldwide. However, diesel exhaust fumes can have harmful effects on the body. Researchers are interested in studying how diesel exhaust exposure can affect lung health. To study these effects, researchers will look at employees of a diesel truck engine testing facility in China. Some workers at this facility are exposed to high levels of diesel exhaust. This study will compare tests and monitoring information from a group of highly exposed workers and a similar group of unexposed comparable controls.

Objectives:

• To study the effects of diesel exhaust on lung health.

Eligibility:

• Participants will be drawn from a diesel truck engine testing facility and other workplaces in China.
• Individuals at least 18 years of age who work in workshops with diesel fuel.
• Individuals at least 18 years of age who work in workshops that do not use diesel fuel.

Design:

• Depending on what type of factory study subjects work in, participants will wear personal air pumps and small badges on their clothing on one or more days. This equipment will measure particles, chemicals, and other compounds in the air. This information plus other information collected in the study including workplace practices will be used to estimate exposure to diesel exhaust among study subjects.
• Participants will provide a number of study samples. These samples include blood, urine, and sputum. To collect other samples, participants will also have a mouth rinse, cheek cell scrapes, and nasal cell scrapes. They will also have a physical exam.
• Treatment will not be provided as part of this study. Participants will receive financial compensation for participation in the study.

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.

This is a cross-sectional molecular epidemiologic study of workers exposed to diesel exhaust in an enginetesting facility. These workers, all of whom are male, spend most of their shift in direct proximity to the engine being tested and as a consequence have potential for exposure to substantial levels of diesel exhaust. Fifty male workers will be selected who are non-smokers or light smokers (< 10 cigarettes per day) and who have worked in the testing facility for the longest amount of time. Fifty male controls, frequency-matched to the exposed workers by age and smoking status (i.e., never, former, current light smoking) will be identified in factories that work in the same local region of China with work processes that do not involve exposure to diesel exhaust, other types of particulates, or any known or suspected@@@genotoxic, hematotoxic, or immunotoxic chemicals.