Dementia rates in America have fallen by a third in the past two decades — although more people are living with the condition than ever before.
Researchers say lower smoking rates and better education about nutrition and other risk factors led to the relatively rapid decline.
About 8.5 percent of Americans over age 65 are estimated to have had the memory-depriving disorder in 2016 — the latest year — compared with 12.2 percent in 2000.
But a rapidly growing and aging population in the US means the raw number of patients with dementia has grown by more than 200,000 to 4.2 million.
The latest figures for 2021 suggested that about 7 million Americans have dementia – although there is mounting evidence that rates are declining in developed countries.
The number of adults with dementia is expected to double in the next three decades, the Alzheimer’s Association says, to nearly 13 million.
Experts from California-based research organization RAND, which conducted the latest study, said trends were “uncertain” after the Covid pandemic.
This was because Covid survivors are more likely to have conditions such as heart disease – a possible risk factor for dementia – but also because of higher death rates from the virus among those who had the condition.
The above shows the prevalence of dementia – the percentage of people with dementia – per year from 2000 to 2016. It shows a gradual decline in rates
In this graph, the estimated number of people with dementia is broken down by gender. It is more common in women, in part because they live longer, with age being a major risk factor
The newspaper was published today in the Proceedings of the National Academy of Sciences, or PNAS.
Scientists used survey data from 21,000 Americans over the age of 65 from the nationwide Health and Retirement Study (HRS).
In that study, participants were interviewed and through tests of their cognition. Researchers also used their medical records.
Participants are generally followed until their death, but in this study they were followed until 2016.
New participants are recruited every six years, with the final recruitment years being 2004, 2010, 2016 and 2022 respectively.
RAND researchers used a model to predict the prevalence of dementia among the entire U.S. population of over-65s.
This was better than others, they said, as it estimated dementia by age, gender, education, ethnicity and lifetime earnings to get an overall figure.
The results showed that dementia levels dropped significantly by 3.7 percentage points over the 16 years of the study – equivalent to a drop of one-third.
Broken down by gender, the decline was faster in women – by 3.9 percentage points – than in men – by 3.2 percentage points.
But overall, women had a higher prevalence of dementia, with 9.7 percent suffering from the disease in 2016 compared to seven percent of men.
The graph above shows the prevalence of dementia broken down by age and then by gender. The categories considered are 65 to 74 years old, 75 to 84 years old and older than 85 years
Women are more likely to have dementia than men because they tend to live longer, with a higher age.
But scientists also suggest it could be because they have stronger immune systems, which could lead to more amyloid plaques in the brain — potentially increasing the risk of dementia — compared to men.
But as the number of old people in America continues to grow, so does the total number of diagnoses for the disease.
In 2000, an estimated 4.04 million Americans had dementia.
Current estimates have risen to 6.5 million.
The research was funded by the government’s National Institute on Aging.
Peter Hudomiet, the economist who conducted the study, said: ‘The reasons for the decline in dementia prevalence are uncertain, but this trend is good news for older Americans and the systems that support them.
“This drop could help reduce expected pressures on families, nursing homes and other support systems as the U.S. population ages.”
In the paper, he and other researchers suggested the delay may be due to better education, fewer smokers and better blood pressure care.
They also said a longer-term job could be protective because of the “demands to look for and stay in work.”
They suggested that this “could build the cognitive reserve more powerfully than just a few extra years of education.”
When asked by DailyMail.com whether dementia rates will continue to fall, Mr Hudomiet said it was “uncertain” due to the Covid pandemic.
He suggested it may have risen because Covid patients are more likely to have cardiac, psychiatric and neurological complications — which may increase their risk of dementia.
But on the other hand, many dementia patients died from the virus during the pandemic, which can also cause a displacement.
Dementia is an umbrella term for conditions that affect the brain, including Alzheimer’s disease and vascular dementia.
It is caused by damage or loss of nerve cells and their connections in the brain.
This may be due to the build-up of proteins in one part of the brain, which limits communication between the cells.
The Alzheimer’s Association suggests that the number of people with Alzheimer’s disease alone will double by 2050.
It says that while there are currently 6 million patients, there will be nearly 13 million by the time the US is in the middle of the century.
About 260,000 adults die of dementia in the US each year.
WHAT IS DEMENTIA? THE KILLER DISEASE THAT DEPRIVES SUFFERING OF THEIR MEMORIES
Dementia is an umbrella term used to describe a range of neurological disorders
A GLOBAL CARE
Dementia is an umbrella term used to describe a range of progressive neurological disorders (affecting the brain) that affect memory, thinking, and behavior.
There are many different forms of dementia, with Alzheimer’s disease being the most common.
Some people may have a combination of dementias.
Regardless of which type is diagnosed, each person will experience their dementia in their own unique way.
Dementia is a global problem, but it is most often seen in wealthier countries, where people are likely to live very old.
HOW MANY PEOPLE ARE INVOLVED?
The Alzheimer’s Society reports that there are more than 900,000 people living with dementia in the UK today. This is expected to rise to 1.6 million by 2040.
Alzheimer’s disease is the most common form of dementia, affecting between 50 and 75 percent of diagnosed individuals.
There are an estimated 5.5 million Alzheimer’s patients in the US. A similar percentage increase is expected in the coming years.
As a person gets older, so does the risk of developing dementia.
Diagnoses are improving, but it is believed that many people with dementia still remain undiagnosed.
IS THERE A CURE?
Currently, there is no cure for dementia.
But new drugs can slow progression, and the sooner it’s noticed, the more effective treatments are.
Source: Alzheimer’s Society