Bad dementia genes can be overcome through healthy living, study finds

People with the worst genetic risk of dementia can reduce their chances of developing the disease by a third through exercise and healthy eating, new research finds.

The first study to analyse the combined effect of genetic and lifestyle factors established that the impact of living healthily was enough to substantially lessen the danger from bad genes.

Regular moderate exercise, quitting smoking, drinking sensibly, plus eating lots of fish and vegetables, was linked to roughly the same reduction in the chance of dementia, regardless of genetic risk, the research found.

This means the benefit of adopting a healthy lifestyle is likely to be highest for those with the worst genes.

Dr David Llewellyn, who co-led the study at the University of Exeter, 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."

The study, published in the Journal of the American Medical Association, 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.

Participants were grouped into those with high, intermediate and low genetic risk for dementia.

Researchers looked at previously published data and identified all known genetic risk factors for Alzheimer's disease.

Each 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.

A hypothetical example of someone considered to be living a healthy lifestyle would be someone who does not currently smoke, and cycles at a normal pace for two-and-a-half hours a week.

Food-wise, they eat a balanced diet that includes more than three portions of fruit and vegetables a day, eat fish twice a week, rarely eat processed meats, and drinks up to one pint of beer a day or equivalent.

Someone living an unfavourable lifestyle would currently smoke regularly, not exercise regularly, and their diet would include less than three servings of fruit and of vegetables a week.

It would also include two or more servings of processed meats and of red meat a week, and they would drink three pints of beer a day.

Dr Llewlyn said that knowing one’s genetic risk of dementia might help motivate people improve their lifestyle, but he stopped short of recommending universal screening.

Previous studies suggest that only 34 per cent of people believe it is possible to alter the risk of dementia through living more healthily.

Dr Jessica Teeling, Professor in Experimental Neuroimmunology, University of Southampton:

“These [lifestyle]  findings may be partly explained by anti-inflammatory effects, supporting previous studies which have identified inflammation as a key driver for dementia.”