Study of Markers of Cosmic Radiation Exposure and Effect Among Flight Crews
Condition: Frequency of Chromosome Aberrations
MeSH terms: Chromosome Aberrations
Study type: Observational

Summary: 
      Ionizing radiation efficiently induces chromosomal aberrations (CA) and several studies of CA
      have now been conducted among small groups of flight crews. However, most of the studies only
      evaluated the unstable aberrations that reflect recent exposures, but not long-term
      cumulative cosmic radiation exposure. Chromosome painting by fluorescence in situ
      hybridization (FISH) is a widely used and established cytogenetic method for detecting stable
      aberrations such as translocations. Thus, FISH can be used for estimating chromosomal damage
      from cumulative radiation exposure. No large studies of flight crews utilizing FISH have been
      conducted to date.

      We propose a study to measure CA using FISH in a group of pilots estimated to have high comic
      radiation exposure based on flight histories, i.e., those with long duration flying
      international routes, and a comparison group of university faculty with minimal flying
      history. These measurements will be used to determine if pilots have elevated frequencies of
      CA (specifically stable translocations) as compared with the university faculty. In addition,
      the frequencies of CA will be examined in relation to the cumulative cosmic radiation dose to
      determine if there is a dose-response relationship. Individual cumulative doses will be
      calculated from pilot flight histories using a computer program developed by the FAA which
      estimates cosmic radiation does by accounting for changes in altitude and latitude, and the
      11-year solar cycle at the time of the flight. We will collect information on age, lifestyle
      factors, diet, health history, family cancer history, and medical radiation exposures from
      personal interview and self-administered dietary questionaire. These factors may affect the
      CA frequency and so we plan to adjust for them in the statistical analyses.

      Pilots will be identified based on the Allied Pilots Association roster and faculty from a
      commercial company that maintains a database of university faculty, including those in the
      Chicago area. Potential participants will be notified of the study by mail and
      recruited/screened for eligibility over the telephone. We will compensate participants $100
      for their time. A field station will be set up at a medical or health clinic convenient to
      the participants, where interviews Will be conducted and a peripheral blood sample collected.
      Participants will be notified of the overall study results and may request their personal CA
      results at the end of the study. Participants may also choose to have additional blood drawn,
      however this blood sample will be anonymized so that it cannot be linked back to the
      participant. Genotypic variants in DNA repair (and possibly other) genes will be evaluated
      for an effect on CA frequency.
    

Detailed description: 
      Ionizing radiation efficiently induces chromosomal aberrations (CA) and several studies of CA
      have now been conducted among small groups of flight crews. However, most of the studies only
      evaluated the unstable aberrations that reflect recent exposures, but not long-term
      cumulative cosmic radiation exposure. Chromosome painting by fluorescence in situ
      hybridization (FISH) is a widely used and established cytogenetic method for detecting stable
      aberrations such as translocations. Thus, FISH can be used for estimating chromosomal damage
      from cumulative radiation exposure. No large studies of flight crews utilizing FISH have been
      conducted to date.

      In collaboration with the National Institute for Occupational Safety and Health (NIOSH), we
      proposed a study to measure CA using FISH in a group of pilots estimated to have high comic
      radiation exposure based on flight histories, i.e., those with long duration flying
      international routes, and a comparison group of university faculty with minimal flying
      history. These measurements will be used to determine if pilots have elevated frequencies of
      CA (specifically stable translocations) as compared with the university faculty. In addition,
      the frequencies of CA will be examined in relation to the cumulative cosmic radiation dose to
      determine if there is a dose-response relationship. Individual cumulative doses will be
      calculated from pilot flight histories using a computer program developed by the FAA which
      estimates cosmic radiation does by accounting for changes in altitude and latitude, and the
      11-year solar cycle at the time of the flight. We will collect information on age, lifestyle
      factors, diet, health history, family cancer history, and medical radiation exposures from a
      self-administered study and dietary questionnaire. These factors may affect the CA frequency
      and so we plan to adjust for them in the statistical analyses.

      Pilots were identified based on the Allied Pilots Association roster and faculty from a
      commercial company that maintains a database of university faculty, including those in the
      Chicago area. Potential participants will be notified of the study by mail and
      recruited/screened for eligibility over the telephone. We compensated participants $100 for
      their time and inconvenience. Two field stations were arranged at the O'Hare UIC medical
      clinic for pilots and at the UIC Health Services clinic (on campus) for the faculty, where
      interviews were conducted and a peripheral blood sample collected. Participants will be
      notified of the overall study results and may request their personal CA results at the end of
      the study. Participants may also choose to have additional blood drawn, however this blood
      sample will be anonymized so that it cannot be linked back to the participant. Genotypic
      variants in DNA repair (and possibly other) genes will be evaluated for an effect on CA
      frequency.
    

Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Pilots estimated to have high comic radiation exposure based on flight histories.
      
Keywords: Chromosome Translocations; Cosmic Radiation; Airline Flight Crew; Airlines; Flight Crew; Occupational Exposure