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Long Space Missions Weaken Astronaut Hips, Increase Fracture Risk: Study Reveals
- •A new study links spaceflights over 90 days to higher rates of hip fractures in astronauts after returning to Earth, highlighting a long-term consequence of spaceflight-induced bone loss.
- •The research, published in Mayo Clinic Proceedings, found hip fractures occurred at a younger age in astronauts after long missions compared to the general population.
- •The human skeleton, adapted to Earth's gravity, experiences significant bone and muscle loss in microgravity, which astronauts may not perceive until returning to Earth.
- •Current bone health monitoring methods like DXA may not fully capture fracture risk; NASA is now using QCT scans for more detailed bone structure analysis.
- •As future missions to the Moon and Mars will be longer, developing countermeasures like specialized exercise, diet, and medications is crucial to preserve astronaut skeletal health.
Key Questions Answered
The study found that astronauts who spent more than 90 days in space had a higher rate of hip fractures after returning to Earth compared with periods following shorter spaceflights and non-flight periods. These hip fractures also occurred at a younger age than normally expected in the general population.
Astronauts live in microgravity in space, which dramatically reduces the mechanical load placed on their bones since the human skeleton is built to work against Earth's gravity. This prolonged disuse causes the body to adapt by losing bone and muscle mass.
Conventional dual-energy X-ray absorptiometry (DXA) alone may not provide a complete picture of fracture risk or detect persistent loss of hip trabecular bone. Therefore, NASA has started using quantitative computed tomography (QCT) scans to examine bone structure in greater detail before and after flights.
