Prolonged spaceflight can damage bone structure permanently and age parts of the skeleton prematurely by as much as 10 years, according to a new report.
In space, the decrease in mechanical load in microgravity can lead to substantial loss of bone mineral density and strength, as well as deterioration of trabecular microarchitecture. Bone recovery after returning to Earth's gravity can take time, the study authors wrote, and many astronauts' bones never recover completely.
The research team also assessed biomarkers of bone turnover to gauge whether some people may face greater risks for incomplete bone recovery, which could help determine the feasibility of missions beyond low-Earth orbit in the future. Similar disparities were noted for total, trabecular, and cortical bone mineral density. The astronauts with incomplete recovery had higher biomarkers of bone turnover as well.Overall, nine of the 17 astronauts didn't fully recover tibia total bone mineral density after 12 months. The incomplete recovery of the weight-bearing tibia was comparable to a decade or more of age-related bone loss on Earth.
"A major challenge of space research is that it takes a long time to get enough astronauts measured, since we typically don't fly too many per year," Boyd said."That will change as commercial flights become more common."