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After 90 days in space, hip fractures became more likely back on Earth

Qurexa Editorial Team1 October 20266 min read 0 0
After 90 days in space, hip fractures became more likely back on Earth

What happened

A study published on 1 October 2026 in Mayo Clinic Proceedings found that astronauts had a higher rate of hip fractures after spaceflights lasting more than 90 days. The paper is titled 'Increased Rates of Hip Fractures Associated With Longer Spaceflight Durations'. The lead investigator is Dr Jean D. Sibonga of NASA's Johnson Space Center, working with Dr Matthew T. Drake and Dr Moshe Gertzulin of the Hospital for Special Surgery in New York. The researchers used records of all fractures reported by a group of US-based astronauts at their annual clinical examinations. They then analysed those records using a statistical approach called Bayesian probabilistic modelling. Two findings stand out. The rate of hip fractures was higher in the period after a spaceflight of more than 90 days than after shorter flights, and higher than in people who had not flown. But the rate of fractures overall was not raised. It was specifically hips. The hip fractures also happened at younger ages than would be usual outside the astronaut group. Dr Sibonga made a point about how bone loss feels, which is to say it does not. Her team's concern is that after returning to Earth and feeling stable or recovered, astronauts may go back to physically demanding activity while their skeleton is still carrying the effects of long periods of disuse. The timing matters for NASA. The agency is planning several missions lasting more than six months, including Artemis IV's first crewed mission to the lunar south pole in 2028.

Why this matters

Bone is not a fixed structure. It is living tissue that is constantly being broken down and rebuilt, and it responds to load. Push on it and it strengthens. Take the load away and it thins. In orbit, almost all the load goes. There is no body weight pressing down through the hips with every step. Astronauts exercise hard to compensate, but weightlessness is a powerful signal to the skeleton that less bone is needed. The hip is where that matters most. It carries the body, and it is the site where a fracture does the most damage to someone's life. On Earth, hip fracture in older people is one of the clearest examples of an injury that can change everything that follows it. There is a wider reason this study is interesting beyond spaceflight. Astronauts are an unusually well-measured group of healthy adults who undergo a sudden, severe period of skeletal unloading and then return to normal life. That is not so different in principle from what happens to a person who spends months on bed rest, in hospital, or largely immobile after an illness or operation. The lesson that transfers is the one Dr Sibonga highlighted: you cannot feel bone loss. Feeling recovered is not the same as being structurally recovered.

What the evidence actually says

This is careful work on a small group, and the researchers say so. The quotation from the team is direct about it: 'While data to date on bone loss associated with spaceflight are consistent, a major limitation is accuracy, as astronaut cohort sample sizes are small and spaceflights are rare.' That is the central constraint. There have only ever been a few hundred astronauts, and far fewer who have flown long missions. With numbers that small, ordinary statistics struggle. Bayesian probabilistic modelling is a legitimate way to get useful estimates from sparse data, but it is a way of handling a limitation, not of removing it. The finding is also narrower than headlines might suggest. Overall fracture rates were not raised. Only hip fractures were. That specificity is scientifically interesting, because it points to load-bearing bone rather than to bones in general, but it also means this is a signal in one site rather than a general picture of fragile astronauts. Because this is observational, it cannot prove that the spaceflight caused the fractures. Astronauts are highly active people who take part in demanding physical pursuits, and that is a plausible alternative contributor. What the study does do is add to a consistent body of earlier evidence that long-duration spaceflight reduces bone mineral density and that recovery on return is incomplete. Set against that background, a raised hip fracture rate is what you would expect to find, which strengthens the case.

Practical advice

Almost none of us will go to space. The bone-health principles still apply, especially after any long period of being off your feet. Load your bones regularly. Walking, stair climbing, dancing and any activity where your feet take your weight all send the signal to maintain bone. Swimming and cycling are excellent for the heart but do far less for bone. Add some resistance work if you can. Carrying shopping, gardening, bodyweight exercises or light weights two or three times a week all count. Get enough calcium and vitamin D. In the UK, adults are advised to consider a daily vitamin D supplement of 10 micrograms in autumn and winter, because there is not enough sunlight to make what we need. After illness, surgery or a long spell in bed, build back gradually. Feeling fine is not evidence that your bones and muscles have caught up. Ask a physiotherapist or your GP what a sensible return looks like. If you are over 50 and break a bone after a minor fall, ask about a bone density scan and a fracture risk assessment. That fracture is information, not just bad luck. If you have had a steroid course, an eating disorder, early menopause, or a long period of immobility, mention it when bone health comes up. These are all recognised risk factors. Do not start or stop any prescribed bone medicine on the basis of a news article. Ask your pharmacist or GP.

What to know

A NASA-led study published on 1 October 2026 in Mayo Clinic Proceedings reports that hip fracture rates were higher after spaceflights of more than 90 days than after shorter flights or in people who had not flown, and that these fractures occurred at younger ages than usual. Overall fracture rates were not raised. The astronaut group is small and spaceflights are rare, so the researchers used Bayesian modelling and are open about the limits on accuracy. The finding fits a long-standing body of evidence that unloading the skeleton costs bone and that recovery is incomplete. The transferable message for the rest of us concerns any long period off our feet: bone loss cannot be felt, so build back gradually and load your bones on purpose. Sources: Phys.org, '90-plus-day spaceflights linked to higher rates of hip fractures in astronauts', 1 October 2026, https://phys.org/news/2026-09-day-spaceflights-linked-higher-hip.html; Mirage News, 'Long Spaceflights Linked to Higher Hip Fracture Rates in Astronauts', 1 October 2026, https://www.miragenews.com/long-spaceflights-linked-to-higher-hip-fracture-1753322/; Mayo Clinic Proceedings, 'Increased Rates of Hip Fractures Associated With Longer Spaceflight Durations', 1 October 2026, https://www.mayoclinicproceedings.org/. This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.

#bone health#space medicine#NASA#osteoporosis#hip fracture#research

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