Older Adults With Active Social Lives Develop Dementia About 5 Years Later: 1,923 People Followed

Many studies have linked social activity to cognitive health in later life, but statistics such as hazard ratios are hard for the public to grasp. Researchers at the Rush Alzheimer's Disease Center at Rush University Medical Center in the United States turned this into an intuitive figure, 'the age at which dementia begins,' and reported it in Alzheimer's & Dementia.

1,923 older adults without dementia, followed for an average of 6.7 years

In the Rush Memory and Ageing Project, the researchers assessed the level of social activity in 1,923 older adults without dementia and confirmed the occurrence of dementia and mild cognitive impairment (MCI) through yearly clinical examinations. Over an average of 6.7 years, 545 people were diagnosed with dementia and 695 with mild cognitive impairment.

In an accelerated failure time model adjusted for age, sex, education, race and marital status, the predicted average age at dementia onset was 87.7 for the least socially active and 92.2 for the most active, a difference of about 5 years. The age at onset of mild cognitive impairment likewise differed by about 5 years. The researchers interpreted the results to mean that community-level support for social activity could be a way to reduce the burden of dementia.

Limitations

Because this is an observational study, it does not prove that social activity delays dementia. It is also hard to fully rule out the possibility (reverse causation) that subtle cognitive changes in early dementia reduced social activity first.