Study of Lung Health Among Workers Exposed to Diesel Exhaust
Condition: Inflammation Biomarkers; mRNA Expression; nitroPAH Adducts
MeSH terms: Inflammation
Study type: Observational

Summary: 
      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.
    

Detailed description: 
      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.
    

Observational model: Other
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        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.
      
Keywords: Biomarkers; Deisel Exhaust; Occupational Exposure; Cross-Sectional Study