Dementia cases seem to be stabilizing in some Western European countries despite population aging, according to researchers who caution against shifting away from prevention.

In a policy paper published in Thursday's issue of The Lancet Neurology, researchers discuss the findings of five large studies on dementia occurrence in Sweden, the Netherlands, the U.K. and Spain during the past 20 to 30 years using the same diagnostic methods.

"In the British figures, the suggestion is that the age-specific prevalence has gone down, which means that the numbers estimated to have dementia have stabilized despite population aging," said lead author Carol Brayne, a professor of public health medicine at the University of Cambridge.

The U.K. study found a reduction of about 22 per cent in overall prevalence in people aged 65 in 2011 than had been predicted in the 1990 estimates.

Prof. Carol Brayne

Prof. Carol Brayne called for a "rebalancing" from what could be seen as an overemphasis on diagnostics and drug and toward prevention of dementia. (CBC)

The suggested decrease in dementia occurrence coincides with improvements in protective factors such as education and improved living conditions for those with dementia, and a reduction in risk factors such as high blood pressure cholesterol over recent decades.

Despite the stabilizing picture, dementia care will remain a lasting challenge for many years, in particular since those aged 85 and older are the fastest growing age group in the population.

Brayne called for a "rebalancing" from what could be seen as an overemphasis on diagnostics and drugs, and toward prevention.

Brain health late in life is rooted in physical and mental health early in life so prevention of dementia depends on paying attention to optimizing health at all stages of life, the researchers said.

Too soon to change global projections

"This evidence from the western European studies reinforces the potential of preventive strategies throughout life to reduce dementia risk rather than the overemphasis on pharmaceutical interventions in late life; policy makers need to bear this potential in mind when drafting their present plans for investment," the paper said

Similar contemporary data isn't available from Canada to assess whether there is a similar reduction, Brayne said.

Dr. William Reichman, the president and CEO of Baycrest and a professor of geriatric psychiatry at the University of Toronto, said the findings are welcome.

"The most important lesson to be learned here is that dementia and the prevention of dementia is not hopeless," Reichman said. "There's emerging evidence that — like with our heart, with cancer — [there are] things we can do earlier in life, mid-life, to lower our risk. It doesn't completely eradicate the risk as we get older, but it can lower the risk."

Reichman also cautioned against reading too much into this data.

"Are they informative? Are they helpful? Of course. But I don't think the data is strong enough and replicated enough in other jurisdictions around the globe to dramatically change our projections on the public health impact of dementia as the population ages."

Currently,  700,000-800,000 people in Canada have been diagnosed with dementia, and the numbers are expected to grow as the population ages, he said .

"What we all hope for is that we'll be able to come up with therapies, interventions that reduce the risk," Reichman said. "But few of us in the field believe we will be eradicating this illness within the next decade."