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Has dementia plateaued in the US? Mysterious CDC data cast doubt on predictions of spiralling diagnoses
Rates of dementia in the US appear to have hit a plateau — casting doubt on previous predictions of spiralling diagnoses in the years to come.
The CDC’s latest National Health Interview Survey reported that four percent of American seniors over 65 have dementia, a figure that is largely unchanged since the last poll in 2019.
The figure is lower than the rates of seniors who have other chronic conditions, such as heart disease, which is suffered by 14 percent of those aged 65-74, and cancer, which is prevalent in the lifetimes of 17 percent of the age group.
The data suggests prior dire predictions that diagnoses will be up to 14 million by 2060 — driven partly by the US' increasingly aging popular — may be an overestimate.
The above pie chart was created from data from Rajan et al. The percentages do not total 100 due to rounding
The survey covered more than 9,200 people 65 and older, asking them either over the phone or in person whether they had ever been given a diagnosis of dementia, including the most common type, Alzheimer's disease.
The CDC researchers interviewed people from all walks of life, taking into account race, education level, family income as a percentage of the federal poverty level, where they lived, and whether they were veterans.
Overall, the researchers found no statistically significant difference in dementia rates between 2019 and 2022.
Diagnoses have increased steadily over the past decade and a half, from 4.7 million seniors with the disease in 2010 to 5.8 million in 2020, according to one 2020 report by the Alzhiemer's Association.
However, a number of other studies seem to suggest different.
A study published in the journal Neurology included data from nearly 50,000 participants who were followed for 27 years between 1994 and 2000.
They found a the overall risk of dementia has decreased by 13 percent, on average, since 1998.
Meanwhile, the Population Research Bureau reported that out of the total population of older individuals, a smaller percentage is being diagnosed with dementia each year.
Improvements in healthcare, better management of lifestyle-related risk factors, and increased awareness may contribute to this decline.
A growing number of people embracing healthy lifestyles, particularly heart-healthy behaviors, could be helping drive down the rates.
Dr Keith Vossel, the Alzheimer's Disease Program Director in the department of neurology at the University of California Los Angeles told DailyMail.com: 'Dementia rates are plateauing in the US likely due to better attention to modifiable risk factors like high blood pressure and overall fitness.
'Rates of dementia continue to climb in developing countries.'
However, other researchers told DailyMail.com that some of the data showing an plateau — for instance, the new CDC figures — are based on unreliable studies.
Dr Elizabeth Landsverk, a geriatrician based in New York, told DailyMail.com that the survey omitted some crucial questions, possibly excluding a large share of people.
She said: 'They're talking about non-institutionalized older adults with a dementia diagnosis. Many people with the condition are in full time care and would be missed from the survey.'
Other experts have highlighted that the pandemic, which took place in between the two surveys, may have meant fewer people could access screening and obtain a diagnosis.
Dr Landsverk said: 'There's several hurdles to get through to say that someone's got the diagnosis.'
The CDC's data collection could also have been unreliable because it relied on answers from patients — and those with dementia may struggle to answer questions accurately.
An estimated seven million Americans have dementia, of which Alzheimer’s Disease is the most common form.
The degenerative condition is associated with aging and causes parts of the brain involved in memory consolidation and formation to atrophy.
Concerns about the rise in dementia cases have centered around the rise of the older population in the US, with the number of Americans aged over 65 rising more than 10-fold over the last century, reaching 55.8 million.
The figure is expected to reach 82 million by 2050, with the demographic's share of the total population growing from 17 percent to 23 percent.
Experts have predicted that the aging population, along with unhealthy lifestyle habits, are likely to cause rising dementia rates over the coming decades.
It is also likely that Covid itself, which has been shown to cause damage to blood vessels causing lifelong vascular issues, will produce more instances of dementia.
There is currently no cure for Alzheimer’s and few treatments available. But there is hope of more.
The FDA’s committee of independent advisors voted unanimously this week to recommend the approval of Eli Lilly’s drug donanemab.
The monoclonal antibody slowed cognitive decline in patients contending with the early stages of the disease. It came with the risk of brain swelling and bleeding, but the committee ruled that the consequences of Alzheimer’s are so dire that any benefit is worthwhile.
The drug draws on a long-held belief that Alzheimer’s is rooted in dysfunctional cell activity in the brain that causes the build-up of a protein called amyloid beta. When those proteins build up, they form clumps that set off a domino effect that results in the death of brain cells.
Another amyloid-fighting drug was approved recently. Leqembi was approved last year and, while also showing a modest benefit, was deemed to have benefits that outweigh the risk of brain bleeds.