Trial Information

The Incidence of Breast and Other Cancers Among Female Flight Attendants

Flight attendants may be at an increased risk of breast and other cancers due to work-place
exposures including cosmic radiation and circadian rhythm disruption from traveling across
multiple time zones. This cancer incidence study will determine whether female flight
attendants are at increased risk of breast and other cancers and whether the risk is
dose-related. The study will include a cohort of approximately 9,631 women who were
employed as flight attendants for one or more years.

Breast cancer cases will be identified from telephone interviews of living subjects and
next-of-kin of deceased subjects, as well as from death certificates. The interview will
also provide information about non-occupational risk factors for breast cancer such as
parity. Both internal and external comparisons will be made. The primary analysis will
evaluate the risk associated with occupational exposure within the cohort, controlling for
non-occupational risk factors by stratification or modeling. The secondary analysis will
compare the incidence of breast cancer in the cohort to that in the general population, with
adjustment for factors such as lower parity which might increase breast cancer risk in the
cohort independent of occupational exposure to cosmic radiation and circadian rhythm
disruption. The risk of other ionizing radiation-related cancers, such as leukemia, lung
cancer, and thyroid cancer, among flight attendants will also be evaluated. The results of
the study will apply to female flight crew and frequent fliers.