Healthy lifestyle lowers dementia risk irrespective of genetics

A healthy lifestyle can reduce the risk of getting dementia, even in people who have a genetic predisposition, according to a new study.

Scientists at the University of Exeter found that people who take regular exercise, eat a balanced diet as well as avoid smoking and heavy drinking are 30 percent less likely to suffer from dementia, irrespective of genetic predisposition.

'We think there is a similar reduction in your risk of dementia associated with lifestyle, regardless of your genetic risk,' said lead author Professor David Llewellyn of Exeter University.

The study followed nearly 200,000 people for about eight years from age 64. A polygenic score was used to assess genetic risk and a weighted score was used to categorise lifestyles into favourable, intermediate and unfavourable based on exercise, diet, smoking and alcohol consumption.

During the study, fewer than one percent of participants developed dementia (it is uncommon in people aged 60-70) – around 1.2 percent of those with highest genetic risk and 0.6 percent of those with the lowest. Similarly, around 0.8 percent of those who reported the healthiest lifestyles developed dementia, compared to 1.2 percent of the people with the least healthy lifestyles.

The researchers were able to show that the two effects were completely independent of each other and that even taking into account other factors such as age, sex and socioeconomic status, having a healthy lifestyle conferred a 30 percent reduction in risk of getting dementia.

Previous research had indicated that risk could be cut by up to one third in people without a genetic predisposition, but it was not known if this reduction would also apply to those with increased genetic risk.

Dr Carol Routledge, Director of Research, Alzheimer's Research UK, who was not involved in the study welcomed the findings:

'This is yet more evidence that there are things we can all do to reduce our risk of developing dementia, yet research suggests that only 34 percent of adults think that this is possible.

'Sadly, as genetics still plays an important role in influencing the risk of Alzheimer's, there will always be people who address many or all of these lifestyle factors and still develop the disease. While we can't change the genes we inherit, this research shows that changing our lifestyle can still help to stack the odds in our favour.'

Dr Jessica Teeling, Professor in Experimental Neuroimmunology, University of Southampton who was not involved in the study pointed out that 'this study does not tell us if healthy lifestyle early or later in life determines reduced risk.

'A critical point to make is that this is a retrospective study in people of European ancestry only and lifestyle score is based on self-reporting', she added.