Most of us think of astronauts as being among the fittest of the fit, but space travel can have an impact on the bones that’s similar to advanced old age, based on a recent study of the bone mineral density of astronauts measured 6 and 18 months after returning from a space flight.
Scientists know that the weightlessness of space causes astronauts to lose BMD, but the impact on long-term bone health has not been well studied, Dr. Shreyasee Amin of the Mayo Clinic in Rochester, Minn., said at the annual scientific meeting of the American College of Rheumatology. Dr. Amin and her colleagues reviewed data from 28 U.S. astronauts immediately after a space flight and approximately 12 months later. Dr. Amin presented the results at a press conference at the meeting.
The immediate post-flight BMD values for the total body, total hip, spine, ultradistal radius, and midshaft radius were significantly lower than predicted, but were in keeping with what scientists know about the effects of weightlessness on the body. But BMD measurements for the total hip, spine, ultradistal radius, and midshaft radius remained significantly lower than predicted at 12 months after the space flight. Predicted BMD values were based on models created from community-based controls. In addition, the recovery of BMD varied among crew members, which points to the need to identify other risk factors for bone loss, so space travelers who are at greater risk can take extra steps to keep their bones strong, Dr. Amin said in an interview.
The implications? More research needs to be done to prevent bone loss during extended space missions, Dr. Amin said. So, by the time space travel becomes as routine as a bus ride, we will likely see new strategies to maintain bone health during the voyage. Check out comments from Dr. Amin here.
-Heidi Splete (on twitter @hsplete)