Summary: Being socially active in early old age can help to prevent against dementia later on. Researchers found those engaged in social activities almost daily at 60 were 12% less likely to develop dementia than those who were socially active only once or twice a month.
Being more socially active in your 50s and 60s predicts a lower risk of developing dementia later on, finds a new UCL-led study.
The longitudinal study, published in PLOS Medicine, reports the most robust evidence to date that social contact earlier in life could play an important role in staving off dementia.
“Dementia is a major global health challenge, with one million people expected to have dementia in the UK by 2021, but we also know that one in three cases are potentially preventable,” said the study’s lead author, Dr. Andrew Sommerlad (UCL Psychiatry).
“Here we’ve found that social contact, in middle age and late-life, appears to lower the risk of dementia. This finding could feed into strategies to reduce everyone’s risk of developing dementia, adding yet another reason to promote connected communities and find ways to reduce isolation and loneliness.”
The research team used data from the Whitehall II study, tracking 10,228 participants who had been asked on six occasions between 1985 and 2013 about their frequency of social contact with friends and relatives. The same participants also completed cognitive testing from 1997 onwards, and researchers referred to the study subjects’ electronic health records up until 2017 to see if they were ever diagnosed with dementia.
For the analysis, the research team focused on the relationships between social contact at age 50, 60 and 70, and subsequent incidence of dementia, and whether social contact was linked to cognitive decline, after accounting for other factors such as education, employment, marital status and socioeconomic status.
The researchers found that increased social contact at age 60 is associated with a significantly lower risk of developing dementia later in life. The analysis showed that someone who saw friends almost daily at age 60 was 12% less likely to develop dementia than someone who only saw one or two friends every few months.
They found similarly strong associations between social contact at ages 50 and 70 and subsequent dementia; while those associations did not reach statistical significance, the researchers say that social contact at any age may well have a similar impact on reducing dementia risk.
Social contact in mid to late life was similarly correlated with general cognitive measures.
Previous studies have found a link between social contact and dementia risk, but they did not have such long follow-up times, so they could not rule out the possibility that the beginnings of cognitive decline may have been causing people to see fewer people, rather than the other way around. The long follow-up in the present study strengthens the evidence that social engagement could protect people from dementia in the long run.
The researchers say there are a few explanations for how social contact could reduce dementia risk.
“People who are socially engaged are exercising cognitive skills such as memory and language, which may help them to develop cognitive reserve – while it may not stop their brains from changing, cognitive reserve could help people cope better with the effects of age and delay any symptoms of dementia,” said senior author Professor Gill Livingston (UCL Psychiatry).
“Spending more time with friends could also be good for mental wellbeing, and may correlate with being physically active, both of which can also reduce the risk of developing dementia,” added Professor Livingston, who previously led a major international study outlining the life-course factors that affect dementia risk.*
The researchers were supported by Wellcome and the National Institute for Health Research UCLH Biomedical Research Centre, while the Whitehall II study is supported by the US National Institutes of Health, UK Medical Research Council and the British Heart Foundation.
The study was conducted by researchers in UCL Psychiatry, UCL Epidemiology & Public Health, Camden & Islington NHS Foundation Trust and Inserm.
Dr. Kalpa Kharicha, Head of Innovation, Policy and Research at the Campaign to End Loneliness, said: “We welcome these findings that show the benefits of frequent social contact in late/middle age on dementia risk. As we found in our Be More Us Campaign, almost half of UK adults say that their busy lives stop them from connecting with other people. It’s important we make changes to our daily lives to ensure we take the time to connect with others. We need more awareness of the benefits that social wellbeing and connectedness can have to tackle social isolation, loneliness and reduce dementia risk.”
Fiona Carragher, Chief Policy and Research Officer at Alzheimer’s Society, said: “There are many factors to consider before we can confirm for definite whether social isolation is a risk factor or an early sign of the condition – but this study is a step in the right direction. We are proud of supporting work which helps us understand the condition better – it is only through research that we can understand true causes of dementia and how best to prevent it.
“As the number of people in the UK with dementia is set to rise to one million by 2021, we must do what we can to reduce our risk – so along with reducing your alcohol intake and stopping smoking, we encourage people across the country to get out into the sunshine, and do something active with family and friends.
“The Government’s recent emphasis on health prevention is a welcome opportunity to reduce the risk of dementia across society. We now need to see Ministers prioritize better support initiatives to help people reduce the risk of dementia, and look forward to seeing this when the results of the Green Paper on Prevention are published later in the year.”
About this neuroscience research article
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Association of social contact with dementia and cognition: 28-year follow-up of the Whitehall II cohort study
Background There is a need to identify targets for preventing or delaying dementia. Social contact is a potential target for clinical and public health studies, but previous observational studies had short follow-up, making findings susceptible to reverse causation bias. We, therefore, examined the association of social contact with subsequent incident dementia and cognition with 28 years’ follow-up.
Methods and findings We conducted a retrospective analysis of the Whitehall II longitudinal prospective cohort study of employees of London civil service departments, aged 35–55 at baseline assessment in 1985–1988 and followed to 2017. Social contact was measured six times through a self-report questionnaire about frequency of contact with non-cohabiting relatives and friends. Dementia status was ascertained from three linked clinical and mortality databases, and cognition was assessed five times using tests of verbal memory, verbal fluency, and reasoning. Cox regression models with inverse probability weighting to account for attrition and missingness examined the association between social contact at age 50, 60, and 70 years and subsequent incident dementia. Mixed linear models examined the association of midlife social contact between 45 and 55 years and cognitive trajectory during the subsequent 14 years. Analyses were adjusted for age, sex, ethnicity, socioeconomic status, education, health behaviours, employment status, and marital status. Of 10,308 Whitehall II study participants, 10,228 provided social contact data (mean age 44.9 years [standard deviation (SD) 6.1 years] at baseline; 33.1% female; 89.1% white ethnicity). More frequent social contact at age 60 years was associated with lower dementia risk (hazard ratio [HR] for each SD higher social contact frequency = 0.88 [95% CI 0.79, 0.98], p = 0.02); effect size of the association of social contact at 50 or 70 years with dementia was similar (0.92 [95% CI 0.83, 1.02], p = 0.13 and 0.91 [95% CI 0.78, 1.06], p = 0.23, respectively) but not statistically significant. The association between social contact and incident dementia was driven by contact with friends (HR = 0.90 [95% CI 0.81, 1.00], p = 0.05), but no association was found for contact with relatives. More frequent social contact during midlife was associated with better subsequent cognitive trajectory: global cognitive function was 0.07 (95% CI 0.03, 0.11), p = 0.002 SDs higher for those with the highest versus lowest tertile of social contact frequency, and this difference was maintained over 14 years follow-up. Results were consistent in a series of post hoc analyses, designed to assess potential biases. A limitation of our study is ascertainment of dementia status from electronic health records rather than in-person assessment of diagnostic status, with the possibility that milder dementia cases were more likely to be missed. Conclusions Findings from this study suggest a protective effect of social contact against dementia and that more frequent contact confers higher cognitive reserve, although it is possible that the ability to maintain more social contact may be a marker of cognitive reserve. Future intervention studies should seek to examine whether improving social contact frequency is feasible, acceptable, and efficacious in changing cognitive outcomes.