Study findings published in PLOS Medicine showed that more frequent social contact with friends at age 60 years was linked to lower risk of developing dementia over a 28-year follow-up and higher subsequent cognitive performance over a 15-year follow-up.
Andrew Sommerlad, PhD, MRCPsych, from University College London’s division of psychiatry, and colleagues examined the link between social contact frequency and dementia over a long period in a retrospective analysis of the Whitehall study, a prospective cohort study of English participants aged 35 to 55 years at baseline assessment in 1985 to 1988 and followed to 2017.
“There was evidence from previous studies showing association between limited social contact and dementia, but these studies had only followed people up for a few years, so it was difficult to know whether limited social contact was an early consequence or a cause of dementia,” Sommerlad told Healio Psychiatry. “Using the Whitehall study with nearly 30 years of follow-up meant we could be much more certain about the direction of the association.”
Researchers measured social contact at six time points using a self-report questionnaire on frequency of contact with non-cohabiting relatives and friends, and examined cognition at five time points using tests of verbal memory, verbal fluency and reasoning. They examined the connection between social contact at age 50, 60 and 70 years and later development of incident dementia as well as the connection of midlife social contact between 45 and 55 years and cognitive trajectory over the next 14 years.
Overall, 10,228 participants provided data on social contact. After adjusting for covariates, analysis revealed an association between more frequent social contact at age 60 years and lower dementia risk (HR for each standard-deviation higher social contact frequency = 0.88; 95% CI, 0.79-0.98). Though not as robust, Sommerlad and colleagues also reported that social contact at age 50 years (HR = 0.92; 95% CI, 0.83-1.02) and 70 years (HR = 0.9; 95% CI, 0.78-1.06) was linked to lower dementia risk.
Only social contact with friends, not relatives, was associated with lower risk for incident dementia (HR = 0.9; 95% CI, 0.81-1), the researchers found.
In addition, the results showed a link between more frequent social contact during midlife and with better subsequent cognitive trajectory, with the high social contact tertile demonstrating 0.07 (95% CI, 0.03- 0.11) standard deviations higher global cognitive function score compared to the low social contact tertile. This was also driven by contact with friends but not relatives and was maintained over 14 years follow-up.
“When we see people in clinic who are concerned about dementia, they often seek advice on how to maintain their cognitive health,” Sommerlad told Healio Psychiatry. “We can now add social contact to the list of important approaches, alongside managing cardiovascular health and being physically active.” – by Savannah Demko
Disclosures: Sommerlad reports funding by a fellowship from the Wellcome Trust and support from University College London Hospitals’ National Institute for Health Research Biomedical Research Centre. Please see the study for all other authors’ relevant financial disclosures.