Cosmic radiation and circadian disruption are potential reproductive hazards for flight attendants.
Flight attendants from 3 US airlines in 3 cities were interviewed for pregnancy histories and lifestyle, medical, and occupational covariates. We assessed cosmic radiation and circadian disruption from company records of 2 million individual flights. Using Cox regression models, we compared respondents (1) by levels of flight exposures and (2) to teachers from the same cities, to evaluate whether these exposures were associated with miscarriage.
Of 2654 women interviewed (2273 flight attendants and 381 teachers), 958 pregnancies among 764 women met study criteria. A hypothetical pregnant flight attendant with median first-trimester exposures flew 130 hours in 53 flight segments, crossed 34 time zones, and flew 15 hours during her home-base sleep hours (10 pm–8 am), incurring 0.13 mGy absorbed dose (0.36 mSv effective dose) of cosmic radiation. About 2% of flight attendant pregnancies were likely exposed to a solar particle event, but doses varied widely. Analyses suggested that cosmic radiation exposure of 0.1 mGy or more may be associated with increased risk of miscarriage in weeks 9–13 (odds ratio = 1.7 [95% confidence interval = 0.95–3.2]). Risk of a first-trimester miscarriage with 15 hours or more of flying during home-base sleep hours was increased (1.5 [1.1–2.2]), as was risk with high physical job demands (2.5 [1.5–4.2]). Miscarriage risk was not increased among flight attendants compared with teachers.
Miscarriage was associated with flight attendant work during sleep hours and high physical job demands and may be associated with cosmic radiation exposure.
Supplemental Digital Content is available in the text.
From the aNational Institute for Occupational Safety and Health, Cincinnati, OH; and bNational Aeronautics and Space Administration, Hampton, VA.
Submitted 25 February 2014; accepted 5 September 2014; posted 7 January 2015.
Supported, in part, by interagency agreements with the Federal Aviation Administration and the Department of Defense Women’s Health Research Program.
This work was part of the Intramural Research Program of the National Institute for Occupational Safety and Health (NIOSH).
The authors report no conflicts of interest. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention (CDC). Mention of any company or product does not constitute endorsement by the CDC.
Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com). This content is not peer-reviewed or copy-edited; it is the sole responsibility of the author.
Correspondence: Barbara Grajewski, National Institute for Occupational Safety and Health (R-15), Centers for Disease Control and Prevention, 1090 Tusculum Avenue, Cincinnati, OH 45226. E-mail: email@example.com.