Frequency of Chromosome Aberrations Clinical Trial
Official title:
Study of Markers of Cosmic Radiation Exposure and Effect Among Flight Crews
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.
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.
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