A new study has found that physical frailty may do more than just make everyday tasks harder—it could also raise the risk of developing dementia.
The research was published on September 17, 2025, in the journal Neurology®, the medical journal of the American Academy of Neurology.
Frailty is a condition where the body becomes weaker and less able to cope with stress. It’s defined by having at least three of these five symptoms: often feeling tired, doing very little physical activity, walking slowly, having a weak grip, and losing weight without trying.
While past studies have shown a link between frailty and dementia, this new study suggests that frailty might actually cause dementia.
The study was led by Dr. Yacong Bo from Zhengzhou University in China and involved nearly half a million people. Researchers followed 489,573 participants, with an average age of 57, for about 14 years. At the beginning of the study, 4.6% of people were considered frail, 43.9% were pre-frail (having one or two symptoms), and 51.5% were not frail at all.
During the follow-up period, 8,900 people developed dementia. Among those who were frail, 4.6% developed dementia. That’s compared to 2.2% of pre-frail people and only 1.3% of people who were not frail.
After accounting for factors like age, education, and physical activity, the researchers found that frail people were almost three times more likely to develop dementia than those who had no signs of frailty. Even people in the pre-frail group were 50% more likely to get dementia.
The risk was even higher for frail people who also had genes known to increase dementia risk. These individuals were nearly four times more likely to develop the disease compared to people without frailty or genetic risk.
Researchers also studied brain scans and biological markers and found that frail individuals were more likely to have changes in their brain linked to dementia. This suggests that frailty may play a direct role in how dementia develops.
Interestingly, when looking at the data from the opposite direction, the researchers found that having dementia does not seem to increase the risk of becoming frail. This supports the idea that frailty might come first and play a role in triggering dementia, not the other way around.
Dr. Bo said that these findings highlight the importance of spotting and managing frailty early in life. If doctors and patients work to reduce frailty through better diet, exercise, and other healthy habits, it might help prevent dementia later on.
One limitation of the study is that four out of the five symptoms of frailty were self-reported by participants, which means the information might not be entirely accurate. Still, the size of the study and the strong results offer valuable insights into how physical health affects brain health.
The study was supported by several organizations in China, including the National Health Commission and the Henan Medical Science and Technology Research Program.
If you care about dementia, please read studies about a simple solution to fight dementia and big causes of memory loss, dementia you need to know.
For more health information, please read studies that people who take high blood pressure medications have lower dementia risk and early indicators of dementia: 5 behaviour changes to look for after age 50.
The study is published in Neurology.
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