Contrary to long-held beliefs that social isolation is a major risk factor for Alzheimer’s disease, a new study suggests that increased social engagement might also be an early warning sign of the condition.
Researchers from the University of California, San Francisco (UCSF) and Boston University studied the social behaviors and genetic data of over 500,000 individuals in the UK, with an average age of 56. The findings, published recently, indicate that people with a higher genetic risk for Alzheimer’s were actually more socially active, at least in the early stages of the disease.
“Their social lives may even expand,” said Dr. Ashwin Kotwal, co-senior author from UCSF.
“We don’t yet know whether individuals are consciously seeking more social engagement, or if their loved ones are responding to subtle behavioral changes with increased interaction.”
Data from the UK Biobank revealed that those at greater genetic risk for Alzheimer’s reported lower levels of social isolation, greater involvement in a variety of social activities, and more positive family relationships. Interestingly, there was no significant difference between high- and low-risk groups in terms of loneliness, friendship quality, or emotional support.
This challenges the traditional view that Alzheimer’s leads to withdrawal from social life in its early phases. Instead, researchers believe early neural changes may subtly alter social behavior before memory loss and cognitive decline become noticeable.
While strong social ties are known to build cognitive reserve—the brain’s ability to adapt and stay functional despite damage—this study introduces a more nuanced view. Being socially active may not always reflect healthy cognitive functioning, especially in genetically at-risk individuals.
The study also reinforces the role of modifiable risk factors for Alzheimer’s, which include:
Physical inactivity
Poorly managed diabetes or high blood pressure
Depression
Sleep disturbances
Smoking
Certain medications
Experts estimate that about 30% of Alzheimer’s cases may be preventable through lifestyle and health management.
In a related development, Japanese researchers from the National Institutes for Quantum Science and Technology (QST) recently found that mood disorders in people over 40, including depression, bipolar disorder, or mania, could also serve as early indicators of neurodegenerative diseases such as dementia.
Their study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, examined the presence of abnormal tau proteins—a hallmark of several neurodegenerative disorders—in individuals with late-life mood disorders (LLMDs). These changes were observed even years before cognitive symptoms emerged, suggesting a crucial window for early intervention.
Together, these studies emphasize the importance of tracking subtle behavioral and emotional changes, not just memory loss, when identifying early signs of Alzheimer’s and related conditions.