Leading a healthy lifestyle may help offset a person’s genetic risk of dementia, new research shows.
The research* from the University of Exeter, published this week in JAMA and presented at the Alzheimer’s Association International Conference 2019 in Los Angeles, found that the risk of dementia was 32% lower in people with a high genetic risk if they had followed a healthy lifestyle, compared to those who had 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.
Joint lead author Dr Elżbieta Kuźma, at the University of Exeter Medical School, said: “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 that we can take action to try to offset our genetic risk for dementia. Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk.”
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.
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.
Joint lead author Dr David Llewellyn, from the University of Exeter Medical School and the Alan Turing Institute, said: “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.”
Commenting on the findings, Fiona Carragher, chief policy and research officer at Alzheimer’s Society, said: “From research we supported, we know that a third of dementia cases could be prevented through lifestyle changes. This study takes our understanding a step further, showing that healthy behaviours can help even in people who have a higher risk due to their genes.
“This is a well-powered and thoughtfully designed study that starts to tease apart the complex interplay between our genes and lifestyle choices when it comes to dementia risk. Its strengths include using a combination of known Alzheimer’s risk genes to get a more accurate indication of genetic risk and its large sample size made possible through UK Biobank.
“Dementia is the most feared condition in the over 50s. Unsurprisingly, one of the most frequent questions we get asked is whether someone who has watched their parent develop dementia, will go on to develop it too.
“Reassuringly, this study suggests that, even if you have a high genetic risk of developing dementia, adopting risk reducing techniques like eating well, not smoking, drinking less alcohol and keeping active can significantly reduce your risk of developing dementia.”
The study was led by the University of Exeter in collaboration with researchers from the University of Michigan, the University of Oxford, and the University of South Australia.
*Lourida I, Hannon E, Littlejohns TJ, et al. Association of Lifestyle and Genetic Risk With Incidence of Dementia. JAMA. Published online July 14, 2019. doi:10.1001/jama.2019.9879