Healthy lifestyle may counteract genetic risk of 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 the University of South Australia, the University of Michigan, the University of Oxford, published this week in JAMA andpresented 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, and says, “Our results clearly show that in the context of dementia risk, it is possible to notably reduce the inherited risk by our own actions. 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 1,769 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, “This is 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.”

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, “This 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. 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.”

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