New study reveals a '20% fall in new cases of dementia' in past two decades

Video report by ITV News Science Correspondent Alok Jha.

Over the past two decades, there has been a 20% fall in new cases of dementia, equivalent to a reduction of 40,000 cases per year, according to a study led by scientists at the University of Cambridge.

Though the overall number of people with dementia in the UK is still rising, better lifestyles in the latter half of the 20th century seem to be contributing to better brain health as people get older.

But dementia remains one of the biggest public health challenges for the UK’s future.

As healthcare and medicine has improved in recent decades, more people are living longer than ever before. In our ageing population, doctors would expect to see more cases of dementias such as Alzheimer’s disease.

Previous studies had predicted that we should see around 250,000 cases of dementia every year by now. But the new study - published in Nature Communications - revised that prediction down to 210,000 new cases per year, made up of 74,000 men and 135,000 women. (There are more cases in women simply because many more of them live to the older ages where dementia becomes more prevalent.)

The largest part of the fall in new cases of dementia seems to be an improvement in the brain health of men, who saw a drop in dementia rates of 40% over the study period. Why that has happened is unknown but could be related to a drop in smoking and better heart and vascular health in that population.

In fact, smoking, mid-life obesity, physical inactivity, high blood pressure and diabetes are all risk factors for dementia in later life.

In the new study, Professor Carol Brayne of the University of Cambridge compared generations of people born around the early and middle of the 20th century. The latter generation would have had access to much better health advice and lived generally healthier lives, she told ITV News, a change in risk factors that seems to have also been reflected in their brain health too.

The research re-enforces a point that has been made by multiple research studies in recent years - living a life that is generally healthier, in particular healthier for your heart, will provide protection for your brain too.

Dr James Pickett, head of research at the Alzheimer’s Society said that it was encouraging to see the latest research but warned "however, people are living for longer and with other risk factors such as diabetes and obesity on the rise, there will still be over 200,000 new cases of dementia each year."

"That’s still an enormous number of people who require better information and health and social care support", he added.

And don’t forget that we still don’t have any treatments for the many types of dementia.

The rates of new cases might be levelling off slightly, and we now know a lot more about how to give ourselves some mild protection against developing dementia, but dealing with it once the diseases strike is still at its infancy.