New guide helps doctors determine normal height loss

Feb 19 2006

As we age we can expect to shrink an average of three to four centimeters. Such loss is normal due to shrinkage of the disks within the spine.

However, researchers at the University of Alberta have developed a guide to help doctors determine when height loss is a normal part of aging, and when it is likely due to something else--usually osteoporosis. And the guide could not be simpler to follow.

Dr. Kerry Siminoski, an endocrinologist with the U of A and the Capital Health Authority, said doctors can ask patients what's the tallest height they've ever been, and then measure them to check how much height, if any, has been lost.

When patients are six centimeters shorter than their tallest recalled height then there is a 60 per cent chance the patient's height loss is due to vertebral fractures, Siminoski said, adding that he suggests doctors prescribe X-rays to check for vertebral fractures in all patients who have shrunk six centimeters or more.

Vertebral fractures, which can be painless and hard to detect, are most often a symptom of osteoporosis, a disease that weakens the bones.

"We call osteoporosis the silent thief--you don't know you have it until you break a bone--usually a big bone like a wrist or a hip," Siminoski said. "But vertebral fractures are indicators of osteoporosis, and because there are a number of drugs that can effectively prevent or mitigate the onset of this diesease, early detection is critical."

"I would like everyone over 50 to know that height loss can relate to vertebral fractures, and if you've lost six centimeters or more you should go to your doctor and check it out," he added.

Siminoski and his research team published the results of their study this month in the journal Osteoporosis International. They arrived at their conclusions after analyzing more than 300 post-menopausal women--the group most susceptible to osteoporosis.

They found the likelihood of vertebral fractures predictably rises as the height loss of the patient increases, and they determined--after considering many factors, including the costs involved--that six centimeters is the optimal measure to trigger a call for an X-ray.

They also found that if a patient loses two centimeters or more over a period of one to three years then there is a greater than 40 per cent chance that a vertebral fracture is the cause of the height loss, and an X-ray to check should be prescribed.

"Of course these numbers may be modified for specific patients--they aren't set in stone. All that we've done here is create a guideline," Siminoski said.

Siminoski also noted there are other, simple ways to check to see if a patient likely has osteoporosis. One way is try to place two fingers between a patient's bottom rib and her pelvis. If it can't be done there is a 60 per cent chance the patient has vertebral fractures.

Another way is to have the patient stand naturally with her heels against a wall (the correct way to measure height), and then measure the distance between her head and the wall. If the distance exceeds six centimeters the patient likely has one or more vertebral fractures.