Trial Information

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.

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.