A team of scientists have found that people with a high genetic risk for dementia could lower their risk if they were to follow a healthy lifestyle. The scientists were based at the University of Exeter and the results were both published in JAMA, a peer-reviewed science journal and presented at the Alzheimer’s Association International Conference in Los Angeles in July 2019. The scientists worked alongside researchers from the University of Michigan, the University of Oxford and the University of South Australia. The abstract can be read online.
This retrospective cohort study included around 196,000 people, from European descent, who were aged at least 60. They had not been diagnosed with dementia or cognitive impairment at the beginning of the study. The scientists used information from the UK-based Biobank study, choosing participants who were registered there from 2006 - 2010. The participants were followed up until 2016/7 and were put into groups of people with high, intermediate or low genetic risk for developing dementia. The scientists used previously published research to establish all known genetic risk factors for Alzheimer’s disease, weighting each genetic risk factor against the strength of its association with dementia. 20% were at high risk, 60% were at intermediate risk and 20% had low risk scores.
The participants were also grouped into favourable, intermediate and unfavourable categories of lifestyle, basing the groups on diet self-reporting, physical activity, smoking and alcohol consumption. Healthy behaviours included people who currently didn’t smoke, who took regular exercise, followed a healthy diet and moderated their alcohol consumption. Around 68% of the participants followed a favourable lifestyle, approximately 24% followed an intermediate lifestyle and about 8% followed an unfavourable lifestyle.
The scientists found that those patients who had a high genetic risk and followed an unfavourable lifestyle were almost 3 times more likely to develop dementia when compared to those people who had a low genetic risk and followed a favourable lifestyle. This suggests that it is possible to alter your lifestyle in order to help offset a genetic predisposition to dementia. All the groups benefitted from a healthier lifestyle and were less likely to develop dementia.
Dementia is a term used to describe a group of diseases which result decline in mental ability. It can begin as mild cognitive impairment, but as damage to the brain increases, so does the severity of the impairment. Memory loss, confusion, difficulty communicating or finding the right word, difficulty with visual and spatial ability, reasoning or problem-solving, carrying out complex tasks, coordination and motor skills can all be symptoms of dementia. Some people undergo personality changes, suffer from depression or anxiety, may exhibit inappropriate behaviour, agitation, hallucinations or paranoia. Scientists are still working to understand the disease, but damage to the connections of the brain is part of the cause, and the area of the brain affected will affect what the person with the disease will suffer from. Alzheimer’s disease is one of the best known forms of dementia.
Kuzma, E., Llewellyn, D.J., Association of Lifestyle and Genetic Risk With Incidence of Dementia, JAMA, 2019; 322(5): 430-437