Even one fracture can reduce your bone density

Breaking a bone can cause bone density losses throughout the body, not just close to the site of the fracture and primarily around the time of the fracture, results from two studies have showed.

The studies focus on identifying changes in musculoskeletal tissue due to injury, ageing or disease.

"We know one fracture seems to lead to others, but we haven't known why," said Blaine Christiansen, associate professor at the University of California-Davis.

"Our work is the first step on the path to identifying the cellular mechanisms of systemic bone loss," Christiansen added.

The first study, published in Osteoporosis International, showed that older women who had fractured a bone, even if the fracture was not near the hip, had decreased bone mineral density (BMD).

Out of 4,000 participants, BMD reductions averaged between 0.89 and 0.77 per cent per year for those with fractures, and 0.66 per cent per year for those with no fractures. Those losses were greatest within the first two years of a break.

In the second study, published in the Journal of Bone and Mineral Research, bone loss occurred throughout the body, most notably in the spine, and was greatest within the first two weeks of fracture in mice with femur (thighbone) fractures.

It also was accompanied by higher levels of inflammatory markers in the blood.

Importantly, the team found that younger mice eventually recovered their pre-fracture BMD levels, while older mice did not.

Christiansen next hopes to further characterise the post-fracture inflammatory factors that may contribute to bone loss following fracture.

"It's possible that these factors are key to initiating BMD loss once a bone is broken," Christiansen said.

"Ultimately, we hope to develop therapeutic strategies that interrupt those processes and prevent bone loss."

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