Poor hand grip strength ID'd as Parkinson's risk factor: UK study

Low socioeconomic status, poor health found to partially explain this link

by Lindsey Shapiro, PhD | November 1, 2024

Among adults in the U.K., poor hand grip strength is associated with an increased risk of developing Parkinson’s disease, especially among those who also have genetic risk factors for the neurodegenerative condition, according to a new report.

Indeed, “compared with those with high [grip strength], low-[grip strength] individuals had a 58.5% increased risk of [Parkinson’s disease],” the researchers wrote.

In the study, low socioeconomic status and poor physical or psychological health were found to partially explain the link between hand grip strength and Parkinson’s disease. Thus, such factors could represent modifiable factors for reducing Parkinson’s risk, the team noted.

“In addition to enhancing [grip strength], interventions targeting risk factors (e.g., unhealthy lifestyles) might also reduce the excess risk,” the researchers wrote.

The study, “Grip strength, genetic predisposition, and Incident Parkinson’s disease: a prospective cohort study in the UK Biobank,” was published in the journal npj Parkinson’s Disease.

A growing body of research indicates that measuring a person’s grip strength, essentially an indicator of how strong the muscles in the hands are, may be able to predict the development of neurodegenerative diseases.

It’s a promising screening tool, given that it’s both inexpensive and easily measured relative to other assessments.

A few previous studies have linked low grip strength to an increased risk of Parkinson’s. But the scientists noted that there’s still a need for more analyses to examine the relationship and the possible mechanisms that underlie it.

Factors such as socioeconomic status, physical health, and psychological well-being have been linked to both grip strength and Parkinson’s, and thus, could help explain the relationship between them.

Genetic factors also contribute to Parkinson’s risk, but studies haven’t looked at whether they play a role in the link between poor grip strength and Parkinson’s development.

“Quantifying the contribution of these risk factors in the association could facilitate the development of targeted interventions to lower the risk of PD [Parkinson’s] in individuals with low GS [grip strength],” the researchers wrote.

To learn more, the scientists examined clinical data from 411,648 people contained in the UK Biobank, an ongoing study collecting long-term clinical data from middle-aged adults in the U.K.

Over a median follow-up of slightly longer than 12 years, 2,409 of these people developed Parkinson’s disease.

Grip strength was measured by having individuals squeeze a handheld dynamometer — a device that measures force — as hard as they could. Nearly one-third of the participants (29.7%) were considered to have low hand grip strength while more than a third (38.5%) were found to have intermediate grip strength. The remaining one-third (31.8%) were categorized as having high grip strength.

In general, higher grip strength was associated with factors such as being younger, male, and white individuals, and having a higher socioeconomic status.

The high grip strength group also skewed toward having healthier lifestyle habits, such as being nonsmokers, getting better sleep, and being more physically active. The low grip strength group, meanwhile, was associated with worse physical health, including cardiovascular problems, and mental health issues such as loneliness and depression.

A similar distribution was observed when comparing people who did and did not develop Parkinson’s disease with those who later developed the neurodegenerative condition and had lower socioeconomic status and worse health.

Overall, people with the lowest grip strength were found to be at the highest risk of developing Parkinson’s disease, with nearly 60% higher odds relative to individuals with high grip strength.

The strength of the association between grip strength and Parkinson’s risk was reduced by 16.3% when adjusting for other clinical factors — which essentially means that those factors partially explained why people with low grip strength were at an increased risk of the disease.

Physical factors explained the largest proportion of the relationship, at 7.7%, followed by lifestyle factors at 6.2%, and psychological factors at 4.7%. In particular, employment status, physical activity levels, depression, and diabetes were the most significant explainers, the study found.

According to the researchers, tailored interventions to target these mediating factors could be useful for preventing the onset of Parkinson’s disease. Still, these factors only accounted for about one-fifth of the relationship between grip strength and Parkinson’s, the team noted. Thus, “further studies are warranted to explore more mediating factors linking the association,” the team wrote.

Our findings [emphasize] the imperative to prioritize monitoring the [grip strength] of populations with high genetic predisposition. … Implementing targeted preventive measures to enhance their [grip strength] becomes crucial for reducing the risk of [Parkinson’s].

In another analysis, the researchers found that participants with low grip strength who were also considered to be highly genetically predisposed to Parkinson’s were at the highest risk of developing the neurodegenerative disease.

“Our findings [emphasize] the imperative to prioritize monitoring the [grip strength] of populations with high genetic predisposition,” the researchers wrote. “Implementing targeted preventive measures to enhance their [grip strength] becomes crucial for reducing the risk of [Parkinson’s].”