The jury’s still out on the value of the term osteosarcopenia – a combination of low bone mineral density (osteopenia and osteoporosis) and low muscle mass and function (sarcopenia).
While it helps draw attention to the often-neglected condition sarcopenia, there is little evidence that the combined entity has any greater utility in predicting falls and fractures than either of the underlying conditions alone.
A study of 1,575 men from the NSW Concord Health and Ageing in Men Project found the prevalence of sarcopenia alone was 7%, osteopenia/osteoporosis was 34% and the combination of osteosarcopenia affected 8%. More than half the men (51.5%) had normal bone density on DXA scan and acceptable hand grip and gait speed. The men were all 70 years or older and living independently in the community.
Those with osteosarcopenia were more likely than other men to live alone, smoke, do less physical activity and have more comorbidities.
However over a two-year follow-up, men with osteosarcopenia had similar adjusted rates of falls to men with osteopenia/osteoporosis alone or sarcopenia alone (IRR=1.41, 1.16 and 1.61 respectively, compared to men without bone and muscle loss).
Men with osteosarcopenia also had similar adjusted rates of any fracture compared to men with either bone or muscle loss alone (HR=1.87, 1.85, 1.06)
The study concluded that men with osteosarcopenia were not at higher risk of falls and fractures than men with only one of these conditions.
“Sarcopenia, but not osteopenia/osteoporosis, was independently associated with increased likelihood of falls, while osteopenia/osteoporosis, but not sarcopenia, was associated with increased likelihood of fractures,” it said.
Researcher Dr David Scott, from Monash University, told the limbic the combination entity of osteosarcopenia had been gathering interest for close to 10 years.
But it was still more of an academic premise than a clinical one in part because of the difficulties with diagnosing and managing sarcopenia.
“Given its very small prevalence, is it worth paying attention to the combined condition or should we just be thinking about osteopenia, osteoporosis or sarcopenia? Does it really matter if they’ve got both? We should be looking at ways to treat either condition.”
He said there were good medical treatments in place for osteopenia and osteoporosis but not for sarcopenia.
“As researchers, we know that the best thing we can be doing at the present time is exercise training, particularly resistance training involving weights that targets the muscles. But that’s not something probably being done in the clinical setting very consistently.”
He said while there were some promising trials of drugs for improving muscle mass and strength, exercise and nutrition remained the main treatment options for sarcopenia.
Dr Scott said their findings in men were similar to those from other studies including studies in women.
“We are starting to see more evidence that osteosarcopenia is not worse than either condition alone but certainly looking at different populations is warranted.”
In a smaller, subset analysis of people who had osteoporosis combined with sarcopenia, and excluding those with osteopenia, there was signal for an increased risk of fracture beyond that for either condition alone.
Dr Scott said while men generally had lower rates of bone loss than women, they were typically under-investigated.
“We’ve focused the majority of our research on women because they do have the higher rates of osteoporosis but as men continue to live longer we are going to see more and more of them falling into that category and we need a better understanding of their risk factors and outcomes.”
“From the middle-age on, considering people’s muscle health and bone health is likely to make a big contribution to maintaining independence for older men.”