The researchers suggest that it could be used as a quick, low-cost screening tool by doctors to identify high-risk patients among people who develop major illnesses such as heart failure and stroke.
Reduced muscular strength, which can be measured by grip strength, has been consistently linked with early death, disability, and illness. But there has been limited research on whether grip strength could be used to indicate heart health.
The new study followed 139,691 adults aged between 35 and 70 living in 17 countries from The Prospective Urban-Rural Epidemiology (PURE) study for an average of four years. Grip strength was assessed using a handgrip dynamometer.
It is measured as the force exerted when a subject squeezes an object as hard as possible with their hands.
The findings show that every five kilos decline in grip strength was associated with a 16 per cent increased risk of death from any cause; a 17 per cent greater risk of cardiovascular death; a 17 per cent higher risk of non-cardiovascular mortality; and more modest increases in the risk of having a heart attack (seven per cent) or a stroke (nine per cent).
Overall, grip strength was a stronger predictor of all-cause deaths, including deaths from heart disease, than systolic blood pressure, which is normally seen as a "robust causal factor" for death, the study showed.
The associations persisted even after taking into account differences in other factors that can affect mortality or heart disease such as age, education level, employment status, physical activity level, and tobacco and alcohol use.
A low grip strength was linked with higher death rates in people who suffer a heart attack or stroke and non-cardiovascular diseases, for example cancer, suggesting muscle strength can predict the risk of death in people who develop a major illness.
Lead author Dr Darryl Leong, of McMaster University in Canada, said: "Grip strength could be an easy and inexpensive test to assess an individual's risk of death and cardiovascular disease.
"Further research is needed to establish whether efforts to improve muscle strength are likely to reduce an individual's risk of death and cardiovascular disease."
Commenting on the findings, Professor Avan Aihie Sayer, of Southampton University, and Professor Thomas Kirkwood, of Newcastle University, discuss whether grip strength could be a new biomarker of ageing.
Prof Sayer said the idea built on previous theories.
He said: "Loss of grip strength is unlikely to lie on a single final common pathway for the adverse effects of ageing, but it might be a particularly good marker of underlying ageing processes, perhaps because of the rarity of muscle-specific diseases contributing to change in muscle function."
The countries involved in the study were Canada, Sweden, United Arab Emirates, Argentina, Brazil, Chile, Malaysia, Poland, South Africa, Turkey, China, Colombia, Iran, Bangladesh, India, Pakistan, and Zimbabwe.
Doireann Maddock, Senior Cardiac Nurse at the British Heart Foundation, said: “The findings of this study are interesting, however it doesn’t explain why grip strength should be related to cardiovascular disease. More research is needed to understand any possible link between the two.
“The good news is we already know there are several established risk factors for cardiovascular disease and an NHS health check can assess your risk. So if you’re over 40 years old speak with your GP or practice nurse about getting this done.
“Whatever your situation, you can help reduce the impact of any risk factors by adopting healthy lifestyle habits such as stopping smoking, keeping active and eating a healthy diet.”
