3D bone-imaging study stresses structure

New research shows that while everyone loses bone strength as they get older, structural changes at work appear to differ between men and women.

'Micro-architecture' could explain why women more prone to fractures than men

A rare bone-imaging machine at the University of Calgary was used in recently published studies showing the importance of not just bone density, but bone structure. ((CBC))

New research shows that while everyone loses bone strength as they get older, structural changes at work appear to differ between men and women.

Using high-resolution, three-dimensional imaging equipment to measure the wrist and lower leg bones of more than 600 Calgarians, researchers at the University of Calgary found that knowing a bone's structure is crucially important.

Bone health and strength is usually determined by a measurement called bone mineral density.

"Our regular bone density technique is just like looking at a house," said Dr. David Hanley, a professor in the departments of medicine, community health sciences and oncology at the University of Calgary. "We can say how many bricks are in the house. This [new] technique can tell us how those bricks are put together.

"And of course, the number of bricks in a house isn't really the best indicator of how strong that structure is. It's how the bricks are joined to each other [that matters]."

Hanley and Steven Boyd recently published studies in the journal Bone and the Journal of Bone and Mineral Research.

Imaging machine 1 of 4 in Canada

Boyd said the imaging showed that the way the bone structure — what he calls micro-architecture — deteriorates with age is different for men and women.

Osteoporosis, a bone disease that involves the deterioration of bone tissue leading to bone fragility and risk of fracture, affects one in four Canadian women over age 50.

That's twice the rate for men.

Biomedical engineer Steven Boyd said the study of bone structure with rare 3D bone-imaging machines might help explain why women are more prone to fractures. ((CBC))

"Women tend to lose bone more by losing these inter-connections in their micro-architecture, whereas men have a general thinning of the micro-architecture," said Boyd, biomedical engineer with the university's Schulich School of Engineering and researcher with the McCaig Institute for Bone and Joint Health.

"So if you take in combination the smaller size bones of women, plus a difference in the way they lose micro-architecture, it may help explain why there is a much higher incidence of fracture in women compared to men."

The university has one of only four 3D bone-imaging machines in Canada.

Boyd said the added detail would help develop better drug and physical treatments, and that studying the micro-architecture of bone offers valuable clues when it comes to predicting the onset of osteoporosis.

According to Osteoporosis Canada, the condition affects two million Canadians and often causes disfigurement and reduction or loss of mobility.