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Healthy lifestyle may counteract genetic risk of dementia

By Dan Lander and Michèle Nardelli

New research suggests that people with a genetic risk of dementia can substantially reduce their dementia risk by living a healthy lifestyle. New research suggests that people with a genetic risk of dementia can substantially reduce their dementia risk by living a healthy lifestyle.
> Creating “best days” to help stave off dementia

Living a healthy lifestyle may help counteract a person’s genetic risk of dementia, according to new international research.

The study was led by the University of Exeter in collaboration with researchers from UniSA, the University of Michigan, the University of Oxford, published in JAMA and presented at the Alzheimer’s Association International Conference 2019 in Los Angeles.

The research found the risk of dementia was 32 per cent lower in people with a high genetic risk if they had followed a healthy lifestyle, compared to those with an unhealthy lifestyle.

Participants with high genetic risk and an unfavourable lifestyle were almost three times more likely to develop dementia compared to those with a low genetic risk and favourable lifestyle.

Professor Elina Hyppönen, Director of UniSA’s Australian Centre for Precision Health, was a senior collaborator advising on genetic and statistical aspects of the study.

“Our results clearly show that in the context of dementia risk, it is possible to notably reduce the inherited risk by our own actions,” Prof Hyppönen says.

“Indeed, I was delighted to see the lifestyle choices which appear to work against dementia are those which we know to also be beneficial for reducing the risks of other chronic diseases, including cardiovascular disease and cancer.”

The study analysed data from 196,383 adults of European ancestry aged 60 and older from UK Biobank. The researchers identified 1769 cases of dementia over a follow-up period of eight years. The team grouped the participants into those with high, intermediate and low genetic risk for dementia.

To assess genetic risk, the researchers looked at previously published data and identified all known genetic risk factors for Alzheimer’s disease. Each genetic risk factor was weighted according to the strength of its association with Alzheimer’s disease.

Dr Elżbieta Kuźma, from the University of Exeter Medical School, says it was the first study to analyse the extent to which you may offset your genetic risk of dementia by living a healthy lifestyle.

“Our findings are exciting as they show we can take action to try to counteract our genetic risk for dementia. Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk,” she says. 

To assess lifestyle, researchers grouped participants into favourable, intermediate and unfavourable categories based on their self-reported diet, physical activity, smoking and alcohol consumption. The researchers considered no current smoking, regular physical activity, healthy diet and moderate alcohol consumption as healthy behaviours. The team found that living a healthy lifestyle was associated with a reduced dementia risk across all genetic risk groups.

Dr David Llewellyn, from the University of Exeter Medical School and the Alan Turing Institute, says the research delivers a really important message that undermines a fatalistic view of dementia.

“Some people believe it’s inevitable they’ll develop dementia because of their genetics,” Dr Llewellyn says. “However, it appears that you may be able to substantially reduce your dementia risk by living a healthy lifestyle.”

The study was partly funded by Australia’s National Health and Medical Research Council (NHMRC), and Prof Hyppönen anticipates further UniSA and NHMRC involvement in future related research.

“This study suggests that much of dementia is preventable,” Prof Hyppönen says. “There is a saying, that ‘what is good for your heart, is good for your brain’, and these results very much support that notion.

“We will be working further to establish pathways and drivers of dementia risk. What I find particularly exciting with these new studies is that we will be using hypothesis-free, large-scale data driven approaches, which are not limited by the current scientific understanding, and which therefore will have the potential to suggest new solutions and help to identify new ways to prevent dementia.”

Creating “best days” to help stave off dementia

UniSA researchers have won more than $1.2 million from the National Health and Medical Research Council (NHMRC) to uncover the aspects of diet and activity that make up a kind of “best practice day” for people who want to reduce their risk of dementia. 

Lead researcher for the project, Dr Ashleigh Smith, says while there is a plethora of research looking at how individual lifestyle factors can mitigate the chances of getting dementia, knowing how factors work together to optimise dementia prevention is increasingly important. 

The research project being undertaken with local and international colleagues, will focus on diet and activity and will examine longitudinal data from a cohort of 450 people aged between 60 to 70 years over three years. 

“We are starting with two basic variables – diet and activity – and in adjusting those, we hope to learn more about which factors and combinations of factors will support the best outcomes for cognition,” Dr Smith says. 

“The ultimate goal of the study is to develop an evidence-based tool that people can use to target improvements in diet and activity, designed to underpin better brain health.” 

Dr Smith says we suspect how people use their time can be very important in maintaining a healthy brain throughout life and keeping dementia at bay. 

“There are just 24 hours in a day, but how you carve up that time can either increase or decrease your future dementia risk,” she says. 

“We are aiming to develop an easy to use app that will help people adjust their activities – give them the opportunity to choose to sleep a little longer, walk a little more often, spend less time on passive activities, or switch out less nutritious foods for options from a healthy Mediterranean diet.” 

She hopes the research will help to mitigate the burgeoning dementia rates that the United Nations Population Division predicts will double by 2050, to 2.1 billion people over 60 years. 

“Interventions to stem the tide of dementia globally need to be affordable, practical and above all evidence-based and the goal of this work is to contribute directly to the knowledge we have about the impact of combinations of behaviours that may help to improve brain function and delay age-related cognitive decline,” Dr Smith says.

The research will be undertaken across four universities: UniSA, Newcastle, Flinders and Adelaide and includes specific and unique experts in the use of time epidemiology, cognitive assessment, diet, cerebrovascular assessment, neuroimaging and non-invasive brain stimulation from Australia and the University of Illinois-Urban Champaign.