Want to avoid dementia? You need this ‘very powerful’ relationship in your life

Being married or in a relationship does not necessarily reduce the risk of dementia in Western countries, but having someone we can confide in does, according to a new study by researchers from the University of New South Wales.

For a longer life, being engaged in our community is what matters most, the study also found.

It’s already known that our relationships matter, not just for our emotional health, but the health of our brain. In fact, in 2020 a paper in The Lancet attributed 4 per cent of dementia cases worldwide to social isolation.

Having someone we can confide in may help to protect our brains as we age.Credit: Getty

What was unclear was whether the type of relationship made a difference and how much interaction we need for those relationships to benefit us.

So, for the study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, the researchers conducted a meta-analysis of 13 longitudinal studies from around the world, including Australia, looking at more than 39,000 people aged 65 or over.

Specifically, they looked at the type of relationship, whether it provided general social support or someone they could confide in and how often the participants connected within those relationships.

They found that seeing friends or family at least once a month or once a week could reduce the risk of dementia by up to half. The type of relationship mattered too.

“Having a confidante was a very powerful factor for reducing the risk of dementia,” said lead author, Dr Suraj Samtani, who is a clinical psychologist and researcher at the Centre for Healthy Brain Ageing at UNSW. “It wasn’t just how often you are meeting, but whether you had someone to open your heart to.”

Interestingly, only in Asian countries did being married or in a relationship seem to reduce the risk of dementia.

Samtani says this may be related to greater stigma and ostracism related to being unmarried in Asian culture.

In contrast, being married was not an important predictor in Western cohorts, but regular community engagement and feeling supported socially was, points out associate professor Fiona Kumfor, an expert in social cognition and dementia at the University of Sydney.

“There is increasing recognition that we cannot take a one size fits all approach, and people from different cultural backgrounds may benefit from different types of support,” says Kumfor, who was not involved with the study. “This is particularly relevant for people living in Australia, where we know that one-third of people were born overseas and one-fifth speak a language other than English at home.”

Why is it that our relationships are so protective of our brains?

“Good social connections are linked to reducing the negative impact of stress by down-regulating our body’s response to stress,” says co-author, Saly Mahalingam.

“Stress can negatively impact our memory and contribute to faster cognitive decline. Good social connections are also involved in increasing and maintaining cognitive reserve, which is our ability to perform our usual brain functions in the face of damage to our brain.”

Being chronically stressed leads to inflammation and chronic production of adrenaline, which can cause multiple health conditions including dementia.

There is also the social contagion effect where we pick up the health habits of those we’re closest to. If they are walking or cycling or going to the gym, we’re more likely to do those activities too. By providing cognitive stimulation and promoting cognitive reserve, our relationships also make a difference.

For longevity, what mattered most was community engagement and living with other people, which is significant when about a quarter of older Australians live alone.

Samtani suggests this is because when we are living with others, they are more likely to spot changes in our health and encourage us to see a doctor. Being involved with others also keeps us cognitively stimulated:

“So doing activities, whether it’s volunteering or playing card games or being involved in Rotary or whatever community cultural activities keeps your brain active, and your body active as well.”

Dementia affects approximately 44 million people worldwide and by 2050, as the population ages, the prevalence of dementia is set to triple.

Yet, social engagement is among the 12 modifiable risk factors that account for about 40 per cent of worldwide dementias: exercise, diet (i.e. midlife obesity), diabetes, high blood pressure, head injury, smoking, air pollution, depression, excessive alcohol, hearing impairment, education and social isolation.

And although some risk is genetic, cognitive decline is not inevitable, Samtani promises:

“Our message for everyone is to try to meet with friends or family at least monthly and try to open your heart to someone so that you know you are not carrying all the stress inside you, and you can feel lighter, more connected, and happier, and live a longer life.”

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