A limp handshake could mean more than just a bad first impression, but also a marker of poor health, researchers say.
According to a new study, a weak handgrip is linked to a higher risk of dying from both cardiovascular and non-cardiovascular diseases.
The study also finds that grip strength is better at predicting the risk of dying from these diseases than blood pressure.
“One important message is really how vulnerable you are to dying of a range of illnesses if you have lower grip strength,” said lead researcher Darryl Leong, an assistant professor of medicine at McMaster and a cardiologist at the hospital.
Conducted by the Population Health Research Institute of McMaster University and Hamilton Health Sciences, the study was published in The Lancet, a U.K. medical journal, on Wednesday.
The study took place in 17 culturally and economically diverse countries, from Canada and Sweden to Zimbabwe and Pakistan. Researchers followed about 140,000 adults between the ages of 35 to 70 for four years.
They examined the relationship between a range of health conditions and muscle strength, which was measured by grip strength.
Participants were asked to squeeze a hand-grip dynamometer, which gives a reading in kilograms, as hard as they can.
The study showed that for every five kilograms of decline in grip strength, there was:
- 16 per cent increase in risk of death from any cause.
- 17 per cent increase in risk of cardiovascular death.
- 17 per cent increase in risk of non-cardiovascular death.
- Modest increases in risk of heart attack (seven per cent) or stroke (nine per cent).
These associations persisted even after adjusting for factors that can affect mortality or heart disease, such as age, education, employment status, physical activity, and tobacco and alcohol use, according to the study.
The grip test is particularly useful in countries where sophisticated and expensive tests are less accessible, Leong said, because it is simple and affordable.
“It’s not a very sophisticated test, but I think in many ways that’s the beauty of it,” Leong told CBC News.
It can help doctors identify those who are more likely to die from the diseases, so they can receive the appropriate care.
More research, however, still needs to be done to understand muscle strength, Leong said.
For example, it is still unclear whether the association is solely with muscle strength or other factors that are related to muscle strength.
“So increasing the strength just by training alone may not make a large amount of difference,” Leong said. “We just don’t know the answer.”
Grip strength varies by ethnicity, country
The study also finds that grip strength varies by ethnicity and country. Europeans tend to have a stronger grip, whereas South Asians tend to have a weaker grip.
The next step for the researchers, Leong said, is to understand more about muscle strength, such as determining what the normal level of strength is for a certain sex, age group and ethnic community, as well as the genetic and environmental effects on muscle strength.
The researchers hope to repeat the study on the participants to examine how muscle strength changes over time, what factors contribute to the change, and whether that change leads to improvement or decline in health outcomes.
“The numbers by themselves probably don’t mean a whole lot to people,” Leong told CBC News. “What might mean a lot more is when [the tests] are repeated and if their strength has increased because of something they have done, or if it’s decreased a lot.”