Bone treatment may extend life

A team at Sydney`s Garvan Institute of Medical Research, has based its findings on data from the long running Dubbo Osteoporosis Epidemiology Study.

Out of a total cohort of around 2,000, a sub-group of 121 people were treated with bisphosphonates for an average of 3 years. When compared with other sub-groups taking other forms of treatment, such as Vitamin D or hormone therapy, the longer life linked to bisphosphonate treatment was clear.

"While the results seemed surprisingly good, they are borne out by the data -- within the limitations of any study-- and appear to apply to men as well as women.

"When we first looked at the figures, we thought that there had to be a fallacy, that we were missing something. One of the most obvious things might be that these are people who seek medical attention, so may be healthier and live longer.

So we compared the bisphosphonate group with people taking Vitamin D and calcium or women on hormone therapy.

"The comparison against these other groups of similarly health aware people simply confirmed that our results were not skewed by that factor.

"In a group of women with osteoporotic fractures over the age of 75, you would expect 50 per cent to die over a period of five years. Among women in that age group who took bisphosphonates, the death rate dropped to 10 per cent.

"Similarly, in a group of younger women, where you would expect 20 to 25 per cent to die over 5 years, there were no deaths. The data were consistent with about a five year survival advantage for people on bisphosphonates," lead researcher Prof Jacqueline Center said. The researchers are intrigued by their findings.

"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 and cadmium. So when people get older, they lose bone. When this happens, these toxic materials are released back into the body and may adversely affect health.

"By preventing bone loss, bisphosphonates prevent some of this toxic metal release. While we know that this is the case, we don?t yet have evidence that this produces the survival benefit," and team member Prof John Eisman.

The findings have been published in the `Journal of Clinical Endocrinology and Metabolism`.