Australasian Science: Australia's authority on science since 1938

Osteoporosis Treatment Extends Lives by 5 Years

By Stephen Luntz

Life expectancy increases even for those without osteoporosis.

A comparison of people treated for osteoporosis with bisphosphonates and those given only Vitamin D or hormone therapy has found that the first group lives 5 years longer. Astonishingly, the same life expectancy gains appear when those given bisphosphonates are compared with people of similar ages who are osteoporosis-free.

Bisphosphonates are a class of drugs that slow the normal removal of bone mass. For people who would otherwise lose bone material more rapidly than they can replace it, this can improve the strength of bones and reduce the risk that small falls cause fractures.

Bisphosphonates are recommended for those with osteoporosis, which is usually recognised from prior fragility fractures. However, only about 20% of women with bone fractures in Australia are currently prescribed these drugs, and the figure is much lower among men. Prof John Eisman of the Garvan Institute attributes this to underestimations of the seriousness of osteoporosis, and concerns about side-effects such as indigestion.

In work published in the Journal of Clinical Endocrinology and Metabolism Eisman and A/Prof Jacqueline Center found that 121 people treated with bisphosphonates survived 5 years longer than those treated in other ways. While 5 years is a huge gain, it’s not surprising that a treatment that keeps people on their feet and active could extend lives.

However, it is harder to explain why those treated with bisphosphonates should survive longer than those without osteoporosis. “When we first looked at the figures we thought there had to be a fallacy,” Center says.

However, the data seem clear. “In a group of women with osteoporotic fractures over the age of 75 you would expect 50% to die over a period of 5 years,” Center says. “Among women in that age group who took bisphosphonates the death rate dropped to 10%.”

“We speculate it may have something to do with the fact that bone acts as a repository for toxic metals such as lead and cadmium,” Eisman says. “When people get older they lose bone. When this happens, any stored toxic materials would be released back into the body and could adversely affect health. By preventing bone loss, bisphosphonates prevent some of this toxic metal release.”

The theory, if proved, has profound implications for the seriousness of environmental pollutants. However, even this may be overshadowed by the potential for bisphosphonates to be used as protective agents.

Eisman acknowledges that a larger randomised study is required for confirmation, and is keen to see research on the effect of bisphosphonates on the life expectancy of those without severe osteoporosis and without prior fragility fractures.