Researchers from UNSW Sydney's Centre for Healthy Brain Ageing (CHeBA) have shown that having more relationships with friends and family outside of the home helps preserve cognition.
The study, led by Dr Anne-Nicole Casey, Research Associate at CHeBA, asked whether a person's ability in specific mental tasks would predict the number of people they contacted regularly. The study also asked whether the number of people that a person contacted would predict their future ability in the tasks.
Social relationships impact brain health throughout life. Understanding how social relationships affect brain health in late life can lead to better dementia risk reduction strategies.
This research, published in the Journal of Gerontology, used data collected across six years in CHeBA's Sydney Memory and Ageing Study. The Sydney Memory and Ageing Study is a study of older Australians that began in 2005. It looks at the effects of ageing on cognition over time. The research used data from adults aged 70 to 90 years who did not have dementia when they entered the study.
"We found that people who performed better than expected in language tasks lost fewer social ties in the future. And this was after accounting for the effects of age, sex, education, medical conditions, and depressive symptoms," said Dr Anne-Nicole Casey.
Interestingly, when people had more social ties outside of the home than expected they also had less decline in higher-level ability. This indicates the importance of maintaining relationships outside of the home for better cognitive ability in late life.
Dr Anne-Nicole Casey, CHeBA Research Associate
According to Dr Casey, different mechanisms may be behind these outcomes.
"It may be that less decline in language performance predicted preserved ability to maintain social relationships outside of the home," she says.
At the same time, social relationships outside of the home may have represented diverse social networks.
"Diverse social networks include close ties with family and friends and less close social ties in the community. Older adults who have more diverse social networks are more physically active, less sedentary, and have more positive daily mood," says Dr Casey.
Senior author and Co-Director of CHeBA Professor Henry Brodaty, who is also Co-Leader of the Sydney Memory and Ageing Study, says that cognitive impairment and dementia are debilitating disorders.
"Risk reduction of dementia has become a global research priority," says Professor Brodaty.
This research considered data from 1037 study participants. Researchers looked at two-way influence between social network size and scores in each of seven cognitive domains.
Previous analysis from our group found that poor social engagement, including small network size and less frequent contact, was a risk factor for dementia. Good social engagement was protective. However, the specific impact of network size on cognition, and vice versa, remained unclear.
Professor Henry Brodaty, CHeBA Co-Director
Findings from this research showed that preserved language ability amongst participants, most of whom were aged 80 or more, may have enabled more diverse social ties. Greater network diversity may have then supported a more active lifestyle and positive emotional benefits over time.
Less decrease in social network size may have meant more opportunity to experience the physical and emotional benefits of diverse networks. This may in turn have helped preserve executive functional performance in older late life.
"Identifying the effects of specific network characteristics on cognition is important for informing dementia risk reduction strategies," says Dr Casey.
"Each person's approach to social relationships develops across their life. Identifying a precise role for social networks in healthy brain ageing will require additional investigation."
Longer follow up times than those used in this study and greater focus on the diversity, quality, and meaningfulness of relationships are needed to provide more precise information. This will enable specific, targeted social network interventions that promote healthy brain ageing for at-risk members of the community.
Dr Anne-Nicole Casey, CHeBA Research Associate
