Poor grip strength is associated with an increased risk of dying prematurely and, to a lesser extent, with a increased risk of having a heart attack or stroke, according to a new, large international study.
In fact, the study found that grip-strength test results were a stronger predictor of death from any cause (but not of heart attack or stroke) than systolic blood pressure readings.
The study, which was led by researchers at McMaster University in Ontario, Canada, was published this week in the journal The Lancet.
For the study, researchers tested the grip strength of about 140,000 people aged 35 to 70 across 17 low-, medium- and high-income countries, and then followed them for an average of four years. After adjusting for a variety of factors (such as age, education level, physical activity level, and tobacco use), the researchers found that every 5-kg decrease in grip strength was associated with a 16 percent increase in death from all causes, a 17 percent increase in death from heart disease, a 17 percent increase in death from an illness not related to heart disease (such as cancer), a 7 percent increase in the risk of a heart attack and a 9 percent increase in the risk of stroke.
Grip strength was not associated with diabetes, bone fractures, fall-related injuries or admission to a hospital for pneumonia or chronic obstructive pulmonary diseases (COPD).
As a result of these findings — and previous research linking weakened muscle strength with early death — the study’s authors suggest that grip strength might prove to be an easy and inexpensive screening tool for physicians to use to identify people at high risk of death after developing a major illness.
Caveats and limitations
But don’t expect your physician to be asking you to squeeze a handgrip dynamometer at your next office visit. As the study’s authors point out, “The observational nature of this study does not allow us to make strong conclusions on the causal role of muscular strength in death or cardiovascular disease.”
In other words, the findings may be interesting, but they are not conclusive. Here’s how the experts who reviewed the study for the “Behind the Headlines” website of the United Kingdom’s National Health Service (NHS) put it:
What we don’t know from the study is why and how muscle strength is linked to the chances of death. It might seem obvious that people who are weak and frail are more at risk of death than other people, but we don’t know whether this is because they are already ill, or whether their weak muscle strength makes them more vulnerable to getting ill, or less able to survive illness if they do get sick.
Importantly, the study doesn’t tell us what can be done for people with low muscle strength. Should we all be doing weight training to increase our strength, or would that make no difference? Low muscle strength may reflect lots of things, such as the amount of exercise people do, what type of diet they eat, their age and occupation. We know that muscle strength declines as we age, but we don’t know the effect of trying to halt this decline.
Should doctors routinely measure people’s grip strength to test their health? The researchers say it is a better predictor of cardiovascular death than blood pressure, and could be easily used in lower-income countries. But raised blood pressure and cholesterol both increase the risk of cardiovascular disease, and there are treatments available to get them under control. Simply measuring a person’s grip strength would miss this opportunity and not lead to any preventive strategies.
“It is unlikely that a ‘grip test’ would replace standard protocols for diagnosing cardiovascular diseases, which rely on a combination of risk assessment methods and tests, such as electrocardiogram (ECG) and a coronary angiography,” the NHS reviewers conclude. “However, such a test could be useful in areas of the world where access to medical resources is limited.”
You’ll find an abstract of the study at The Lancet’s website. You can read the NHS review of the study at that organization’s “Behind the Headlines” website.