Can social interaction predict cognitive decline?

A recent study concludes that social interaction might be more than just a pleasant pastime; it might help doctors predict an individual's risk of cognitive decline and, perhaps, dementia.

Cognitive decline refers to a general reduction in mental abilities over time.

It affects many people as they age and, in some cases, can lead to dementia.

As the average age of the population rises, an increasing number of people are likely to experience cognitive decline.

A group of researchers from Brigham and Women's Hospital in Boston, MA, are interested in the potential role that social interaction might play.

Specifically, their most recent study looked at whether there is an interaction between levels of social activity, cognitive performance, and the amount of beta-amyloid in the brain, which is a neurological hallmark of Alzheimer's disease.

To investigate, the scientists followed 217 older adults involved in the Harvard Aging Brain Study. At the beginning of the study, participants were aged 63–89 and showed no cognitive deficits. The authors followed the group for 3 years.

Each participant completed a questionnaire that ascertained their levels of social interaction; this included meeting family and friends, religious activities, and volunteer work.

The researchers also measured levels of beta-amyloid in each participant's brain. As expected, there was significant variability, with some people having much higher levels, putting them at increased risk of developing Alzheimer's.

The authors published their findings in The American Journal of Geriatric Psychiatry.

Although earlier studies have shown a relationship between social engagement and cognitive decline, scientists have not fleshed out the relationship between these two factors and levels of beta-amyloid in the brain.

Overall, the authors found no relationship between social interaction and cognitive decline. However, when they delved into the beta-amyloid data, a pattern formed.

The researchers found that the influence of social activity was significant in individuals who had the highest levels of beta-amyloid in their brains. In this group, those with the lowest levels of social interaction showed higher levels of cognitive decline than individuals with similar levels of beta-amyloid but greater levels of social activity.

They also found that individuals who had lower cognitive abilities at the start of the study were more likely to become less socially engaged over the 3 years.

 

This effect remained significant even after the researchers accounted for a range of variables, including education, sex, level of social interaction at baseline, and age.

Interestingly, this relationship was not related to levels of beta-amyloid in the brain, which was counter to the authors' expectations.

These findings and those from earlier studies point to a relationship between social engagement and cognitive decline. However, it is still not clear whether individuals who socialize less are more at risk, or whether cognitive decline increases the likelihood of social withdrawal. Similarly, the relationship could run both ways and probably varies between individuals.