Radiation dose estimation for epidemiologic studies of flight attendants.

BACKGROUND: NIOSH is conducting health studies of female flight attendants. Exposures of interest include cosmic radiation and circadian rhythm disruption, however, the data needed to estimate cumulative radiation dose are not found in work histories. METHODS: We developed an algorithm to generate from work histories the required input data for Federal Aviation Administration radiation estimation software and evaluated whether effects of cumulative radiation dose could be distinguished analytically from effects of circadian rhythm disruption. RESULTS: The algorithm has relatively low bias (< 6%) for longer flights, which contribute most to cumulative radiation dose. In one NIOSH study, 44 crew incurred an estimated average annual occupational dose of 1.5-1.7 mSv. Selection of a study population flying predominantly North-South flights can provide the necessary distinction between radiation and time zone crossing exposures. CONCLUSIONS: Methods developed will be useful for exposure assessment in cabin crew studies with relatively short study periods, (e.g., reproductive health studies) for which limited flight history details are generally available.