MedicalResearch.com Interview with: Barbara Grajewski, Ph.D., M.S., Epidemiologist Elizabeth Whelan, Ph.D., Branch Chief Christina Lawson, Ph.D., Epidemiologist Division of Surveillance, Hazard Evaluations and Field Studies National Institute for Occupational Safety and Health Centers for Disease Control and Prevention Medical Research: What is the background for this study? Response: The study, published January 5 online ahead of print in the journal Epidemiology, looked at potential workplace reproductive hazards for flight attendants. While in flight, flight attendants are exposed to cosmic radiation from space and, periodically, can be exposed to radiation from solar particle events. Flight attendants can also experience circadian disruption (disruption to the body’s internal time clock) from traveling across time zones and from working during hours when they would normally be asleep. For this study, we analyzed 840 pregnancies among 673 female flight attendants and examined company records of 2 million single flights flown by these women. From these data, we estimated a marker of circadian disruption—working during normal sleeping hours—and exposure to cosmic and solar particle event radiation for each flight. This gives us a much more specific estimate of the exposures these workers face on the job every day. We also assessed the physical demands of the job, such as standing and walking for more than 8 hours a day and bending at the waist more than 25 times a day. Cosmic radiation and circadian disruption among flight attendants are linked very closely on many flights and are very difficult to look at separately when trying to understand what causes miscarriage. This is the first study that has attempted to separate these two exposures to determine which is potentially linked to miscarriage. This study is also an improvement over other studies in its assessment of cosmic radiation for each individual flight flown and from documentation of solar particle events. Earlier studies have looked at how many years a flight attendant has worked or other ways to estimate exposures that are not as specific. (more…)