According to the first nationally representative study of cognitive impairment prevalence in over 20 years, almost 1 in 10 U.S. adults aged 65 and older have been diagnosed with dementia, while another 22 percent were diagnosed with mild cognitive impairment (MCI).
The study findings, which were published in the October 24 copy of JAMA Neurology, also shared that the researchers discovered that those with MCI or dementia were ‘more likely to be older, have lower levels of education, and to be Black or Hispanic.’
Professor of neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University in New York City and lead study author, Jennifer J. Manly, PhD, said in a press release, “Such data are critical for understanding the causes, costs, and consequences of dementia and mild cognitive impairment in the United States and for informing policies aimed at reducing their impact on patients, families, and public programs.”
She added, “With increasing longevity and the aging of the Baby Boom generation, cognitive impairment is projected to increase significantly over the next few decades, affecting individuals, families, and programs that provide care and services for people with dementia.”
The impact of dementia on the economy of the United States, which includes unpaid family caregiving, is said to be around $321 billion in 2022 alone. And according to the Joint Economic Committee, this is in addition to another estimated $271 billion in unpaid caregiving.
The Difference Between Mild Cognitive Impairment (MCI) and Dementia
When it comes to mild cognitive impairment (MCI), it’s considered to be an early stage of memory or cognitive ability loss. As explained by the National Institute on Aging, some of the more common symptoms include forgetting appointments, losing things often, or having trouble finding the right words to say something you want to say. Moreover, it is considered as ‘the stage between the expected cognitive decline that comes with aging and the more serious decline of dementia.’
As for dementia, once again the National Institute on Aging describes it as ‘the loss of cognitive functioning, which includes things like the ability to think, remember and reason, to point where it interferes with a person’s daily life.’
As for different types of dementia, this includes Alzheimer’s disease, Parkinson’s disease, Lewy Body dementia, and vascular dementia.
According to Mayo Clinic, people with MCI are at a highly increased risk of developing dementia, yet others may remain stable for a number of years despite having MCI.
The Rate of Dementia Majorly Rose with Age With 1 in 3 Over 90 Having Dementia
Although dementia and MCI are quite common in the United States, the study authors noted that there is still a need for accurate and up-to-date measures of their national prevalence.
The need for this information is quite critical in order to better understand the causes, costs, and consequences of dementia and mild cognitive impairment in the country. Moreover, Dr. Manly also said that further studies are for “informing policies aimed at reducing their impact on patients, families, and public programs.”
As a result, the researchers too information from 3,496 individuals that were enrolled in what they considered a highly unique and comprehensive study from the University of Michigan, which was the nationally representative Health and Retirement Study.
The participants were people aged 65 or older, who had an average age of 76 years. The group was predominantly female, at 60 percent, while 16 percent were Black in ethnicity, 11 percent Hispanic, and 71 percent white, and 2 percent made up of other races.
During the years of 2016 to 2017, each participants was made to complete a comprehensive set of neuropsychological tests and an in-depth interview. In addition, close personal contacts and relatives close to the participants were also interviewed. The research team put together the information they received in order to create an algorithm for diagnosing dementia or MCI.
What they found was that the rates of dementia and mild cognitive impairment took a sharp rise with age. At least 3 percent of those aged 65 to 69 had dementia, a number that rose by 35 percent in those that were aged 90 and above. Moreover, with every five-year age increase, there was an association with higher risk of dementia and MCI.
As for gender, there were no differences found between men and women in rates of either dementia or mild cognitive impairment.
Compared to White Americans, Black and Hispanic Americans More Likely to Have Dementia
The authors note that this study was considered quite unique, since it was both large and diverse enough to look at some of the differences in the national prevalence of dementia and mild cognitive impairment by age, gender, race and ethnicity and education.
Moreover, they found a ‘disproportionate burden of dementia’ in some of the groups.
According to the authors, this is what they found:
- Fifteen percent of Black participants tested positive for dementia, while 22 percent had mild cognitive decline.
- Ten percent of Hispanic participants had dementia, but the rate of milder issues was higher — 28 percent tested positive for mild cognitive impairment.
- Nine percent of white people had dementia, while 21 percent had mild cognitive impairment.
In addition, the authors also note that their educational attainment, something the experts believe to be protective against cognitive decline, also showed a large and substantial gap:
- Nine percent of people with a college degree tested positive for dementia, compared with 13 percent of those who never received a high school diploma.
- Twenty-one percent of people over 65 with college degrees had mild cognitive decline, compared with 30 percent of those with less than a high school degree.
Dr. Manly also explained that throughout history, dementia research mostly focused on white college-educated people. She explained, “This study is representative of the population of older adults and includes groups that have been historically excluded from dementia research but are at higher risk of developing cognitive impairment because of structural racism and income inequality. If we’re interested in increasing brain health equity in later life, we need to know where we stand now and where to direct our resources.”
The Study Findings Will Help Track Trends in the U.S.
Cyrus Sturgis Professor of Medicine at the University of Michigan Medical School in Ann Arbor and study co-author, Kenneth Langa, MD, PhD, said in a press release, “Because it’s part of the nationally representative and long-running Health and Retirement Study, these data not only show the burden of dementia now, but will be used in the future to track the trends in dementia burden in the decades ahead.”
He added, “Following those trends will be especially important given the likely impact of COVID and other recent population health changes on the risk for dementia in the coming decades.”
Moreover, newer research also suggests that the actual number of people around the world diagnosed with dementia will continue to grow due to people living longer, as well as other risk factors such as obesity, high blood sugar, and smoking.
In fact, a study that was published in the January 2022 copy of The Lancet, believes that the number of adults living in the United States with some type of dementia will probably double by 2050. This is a major rise from just 5.2 million people to 10.5 million in less than 30 years.
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