Eds: Embargoed to 0200 AEDT Thursday, February 3
By Danny Rose, AAP Medical Writer
SYDNEY, Feb 3 AAP - Australian scientists may have uncovered one of the secrets to a long life, as they identified the "remarkable" life-extending properties of osteoporosis treatment.
It has been found that frail and elderly people with the degenerative bone condition and who are taking a mainline anti-osteoporosis drug have extended their lives by five years on average.
They are outliving similarly aged people who do not have osteoporosis, a result so positive it was initially met with scepticism by the researchers.
"That was the thing that was really remarkable to us - these people were doing better than, if you like, the average community," said Professor John Eisman from Sydney's Garvan Institute of Medical Research.
"Our initial concern was `we've somehow selected a healthier group ... that's why they are doing better`, but whatever way we looked at it, it didn't seem to explain it.
"Everything about these people imply they would do worse, but they were doing at least as well (as the general population), if not better."
Prof Eisman, along with lead researcher Associate Professor Jacqueline Center, drew on data collected as part of the long-running Dubbo Osteoporosis Epidemiology Study, which started in 1989.
They looked at a group of just over 2000 elderly people, of whom 121 had been taking medication from the bisphosphonates class of drugs for around three years.
The medication prevents the loss of bone mass by slowing the pace at which the bones naturally renew themselves, a process which is too fast in people with osteoporosis.
While those on the treatment were expected to suffer fewer debilitating bone fractures, this could not account for all of the medication's life-extending effect.
Prof Eisman said it may be linked to the "toxic" metals that are known to become stored away in our skeletons over time.
"We speculate that it may have something to do with the fact that bone acts as a repository for toxic heavy metals, such as lead," he said.
"So when people get older, they lose bone (and) when this happens, these toxic metals are released back into the body and may adversely affect health.
"By preventing bone loss, bisphosphonates do prevent some of the toxic metal release.
"While we know this is the case, we don't yet have evidence that this produces the survival benefit."
This warranted further research, Prof Eisman said, as the body's ability to keep toxic compounds in safe storage could be a key factor in overall health and, ultimately, how long a person lives.
The study also underscored the importance of treating osteoporosis, a condition often dismissed as part of the ageing process, he said.
It is thought only about 30 per cent of Australian women and 10 per cent of men who have osteoporosis are receiving treatment.
It should also be noted bisphosphonates, as with any treatment, are not without risk.
There have been rare cases where the medication caused jaw problems among patients taking high doses, such as those under treatment to prevent a cancer from spreading to their bones.
The research is published in the Journal of Endocrinology and Metabolism on Thursday.