NASA & UCSF: Combating Bone Loss in Space

The following article was written by Thomas Lang, PhD, Professor in Residence, faculty member of the Musculoskeletal Quantitative Imaging Research Group, and leader of the Musculoskeletal CT Imaging Research Group at UCSF.

Did you know that the effects of space travel on the human body are similar to those of aging over decades? It’s true! Recently, we used quantitative imaging methods developed here at UCSF to understand the effect of space flight on the skeletal health of astronauts, specifically at the hip, where the largest loss of bone is found and the most serious fractures occur in people with osteoporosis.

For astronauts, recovery from bone loss from the hip in prolonged spaceflight resulted in irreversible structural changes, even if the total mass of lost bone was recovered. The changes are very similar to those that occur in the decades of aging. The key take home is that it is very important to prevent the loss, if possible through appropriate diet and exercise, but also through drug treatment if necessary. The emphasis on prevention is important both for astronauts and for aging or bedridden populations on Earth.

Astronauts lose bone in spaceflight because they are in a microgravity environment where their bones and muscles are not loaded. When they return to Earth and must suddenly readapt to gravity, it puts all of these systems under stress, creating the risk of short-term injury or long-term bone health issues. It’s possible for some of this injury and bone loss to be irreversible.

Our research group has received a series of grants funded by NASA to study astronauts from the first eight crews to serve on the International Space Station. Previously, we knew about bone mass loss, but we didn't know how it was distributed throughout the hip or how it was recovered. In this study, we’ve taken CT scans of the hip and used my software to study the 3-D characteristics of the bone change. We discovered that the loss of mass was distributed heterogeneously throughout the hip, and that after recovery, the hip structure was more like that of an older person.

The research findings indicate that loss of hip bone strength in a microgravity environment is very common. The amount of bone loss is large on average, and tends to not be fully recovered. It is absolutely critical to prevent early bone loss in these instances.

Learn more about the major occupational health risk of bone mass loss for astronauts and its correlations to bone mass loss in osteoporosis in this NASA interview.

Learn more about my team’s recognition as a past recipient of the Top Discoveries in Microgravity Team Award from the American Astronautical Society and NASA here!