Smoky Coal Exposure, Genetic Susceptibility, and Lung Cancer in Non-Smoking Women in China
Condition: Lung Neoplasms
MeSH terms: Lung Neoplasms; Genetic Predisposition to Disease
Study type: Observational

Summary: 
      Background:

        -  Women in Xuan Wei County, China, are almost all non-smokers, yet they have the highest
           lung cancer rate in that country.

        -  Non-smoking women in Xuan Wei who use smoky coal for cooking and heating homes can
           inhale 10 times higher levels of polycyclic aromatic hydrocarbons (PAH, compounds formed
           in many burning organic substances, including smoky coal) than someone who smokes 20
           cigarettes a day.

      Objectives:

        -  Determine the health effects of smoky coal in Xuan Wei and Fu Yuan counties in China's
           Yun Nan Province

        -  Determine how different levels of exposure to smoky coal and other types of fuel affect
           the amount of smoky coal emissions that are absorbed into the body

        -  Determine genetic risk factors for lung cancer in the study population and determine how
           they interact with smoky coal and PAH exposure.

      Eligibility:

        -  Women from Xuan Wei and Fu Yuan counties between 18 and 79 years of age who have lung
           cancer and do or do not use smoky coal

        -  Women from Xuan Wei and Fu Yuan counties between 18 and 79 years of age who do not have
           lung cancer and do or do not use smoky coal

      Design:

      -Exposure assessment study for users of smoky coal - 150 households

      Use of air badges, monitors, and dermal badges to determine subjects' exposure to smoky coal

      Collection of blood, urine, cheek cell and sputum samples to measure the amount of smoky coal
      emissions absorbed into the body and evaluate the types of biologic changes they cause

      Interview subjects about their health and family history, occupational exposures, lifestyle
      factors (e.g., tobacco smoking and diet), and inherited differences in genes

      -Case-control study - 1,000 women

      Collection of blood, urine, cheek cell and sputum samples to measure how amount of smoky coal
      emissions absorbed into the body and evaluate types of biologic changes they cause

      Interview subjects about their health and family history, occupational exposures, lifestyle
      factors (e.g., tobacco smoking and diet), and inherited differences in genes

      Gene analysis to determine if a genetic variation is associated with an increased or
      decreased risk of health effects from smoky coal exposure
    

Detailed description: 
      Females in Xuan Wei County are almost all non-smokers, yet they have the highest lung cancer
      rate in China. Non-smoking women in Xuan Wei who use smoky coal in their home can inhale ten
      times higher levels of PAHs than a 20 cigarette per day active smoker, and air concentrations
      approach levels experienced by workers on the top-side of coke ovens. Several lines of
      research have provided strong support that the excess lung cancer in this region is caused
      primarily by PAHs derived from smoky coal exposure. As such, this region of China provides
      one of the best opportunities in the world to carry out a model study of gene-environment
      interactions in lung cancer. We have designed a hospital-based case-control study of 500 lung
      cancer cases and 500 controls among non-smoking women, with controls to be selected through a
      randomized recruitment design to achieve balance for the main effects of smoky coal exposure
      and ultimately greater power to detect interactions. The study will be carried out over a
      three-year period in Xuan Wei and Fu Yuan Counties in Yun Nan Province, China. In addition,
      we will be carrying out an exposure assessment study (n=150 households) to evaluate air and
      dermal exposure to PAHs from smoky coal use in order to model PAH exposure experienced by
      subjects in the case-control study. We will collect buccal cell, sputum, blood, and urine
      samples from all subjects. The primary goal of the study is to characterize genetic risk
      factors at the DNA level for lung cancer in this population and determine how they interact
      with smoky coal and PAH exposure. In addition, the hospital-based design will enable us to
      collect venous blood samples and cryopreserve lymphocytes, which will allow us to carry out
      state-of-the-art functional susceptibility assays such as testing ability to repair
      PAH-damaged DNA and apoptotic capacity, and to measure integrative markers of genomic
      stability such as telomere length and oxidative damage in mitochondrial DNA. These types of
      assays have never been conducted in this population and hold great promise to provide
      insights into cancer risk that will compliment those obtained by genotyping. This study will
      provide an important complement to and contrast with both DCEG and extramural studies of
      tobacco smoking and lung cancer, where unraveling the genetic component is challenging in
      part because hundreds of tobacco carcinogens in various combinations likely contribute.
    

Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        The study population is the non-smoking women lived in Xuanwei and Fuyuan, Yunnan Province
        of China, a region with high lung cancer incidence.
      
Keywords: Air Pollution; Tumor Markers; Genetic Polymorphisms; Molecular Epidemiology; Environmental Epidemiology