The risk of developing dementia at a later age is diminishing, with better healthcare and life style changes as likely causes, a large-scale international investigation led by Erasmus Medical Centre in Rotterdam has shown.

An analysis of seven population screenings carried out in the United States and Europe, in which some 50,000 people over the age of 65s participated, showed that today’s 70-year-olds have a 13% lower risk of developing the disease in the next five years compared to 10 years ago. The preceding 20 years also showed a downward trend of 13% for every decade.

The study did not look into the causes of the decrease but it is likely that better healthcare and life style choices are the main drivers, head researcher Frank Wolters said.

‘Both Europe and the United States have developed an active policy of tackling heart disease in the last decades, for instance by monitoring people with high blood pressure and bad cholesterol which we know are linked with dementia,’ Wolters said. ‘Smoking has also been discouraged. This has limited damage to the brain occurring at a later age.’

Although the genetic factors which may play a role in developing the disease have not changed, Wolters said the results were great news because it meant that people can do things to lower the risk of getting the disease.  Some 280,000 people in the Netherlands have been diagnosed with some form of dementia.

Life style choices may also help to ward of dementia, Wolter said. “A healthy life style is definitely important, including for the brain. A better diet and more exercise have an effect on blood pressure and cholesterol. But we need more research to pinpoint cause and effect. The mysteries surrounding dementia will not be solved for a long time to come.’

Not disappearing

The findings do not mean the disease is disappearing, Wolters said. ‘Certainly not. The risk for an individual to develop dementia before a certain age is going down but the number of people getting the disease continues to rise. That is because the population is growing and the average age is going up as well.’

The number of people with some form of dementia is expected to double by 2050.

Philip Scheltens director of the Alzheimer Centre in Amsterdam said the trend revealed by the study does not guarantee the risk will continue to fall.

‘The question is whether we can increase the effects of better heart health and promoting healthier life styles any further seeing that we are confronted with with new risks like diabetes and obesity,’ Scheltens told the Volkskrant.