"It's really unclear what the mechanism would be that would connect hand grip strength to a stroke, for example," said McLean. "Perhaps the musculoskeletal system, being one of the largest organ system in body, a lot of age-related change takes place within it. It could be a general marker of age-related changes."
Dr. Jack Guralnik, a gerontologist at the University of Maryland School of Medicine, did a similar study more than a decade ago and agrees.
"It's a marker for what is going on in the rest of the body," Guralnik said. "I think if you are physically fit, you will have better grip strength and better strength in all your muscles than someone who is not fit. It's an indirect measure."
Doctors know, for instance, that frailty predicts who's closer to dying. Among seniors, those who start to fall down more frequently are closer to death. But this study included young adults. And grip strength was not associated with the risk of falling.
"If you were to ask me from American Heart Association's perspective, we would say this is not ready for routine clinical use…"
Guralnik believes it would be a suitable test for primary care physicians to do as part of a regular exam. "It's so easy to do," he said.
But Dr. Elliot Antman of Brigham & Women's Hospital, who is current president of the American Heart Association, isn't so sure.
"They did a measurement with a specific device, a dynamometer, which is not used in clinical practice," he said. "This is a very precise measurement of grip strength. It requires using a standardized protocol, and a trained research team using the device. While it's not terribly complicated, it is challenging in terms of training people how to use it."
Antman would like to see clear guidelines before suggesting any physician use such a method.
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"If you were to ask me from American Heart Association's perspective, we would say this is not ready for routine clinical use, and would strongly urge that it be reproduced by an independent group and see if this could be translated into routine clinical practice," he said.