Well-Being Longevity

Prevalence of dementia in elderly people dropped in multiyear study

“The reasons for the decline in the prevalence of dementia are not certain, but this trend is good news for older Americans and the systems that support them."
Old man.

Story at a glance

  • Between 2000 and 2016, the age-adjusted prevalence of dementia among the nation’s elderly fell by 30 percent. 

  • Disparities based on race and sex also decreased throughout this time.

  • However, researchers stress more needs to be done to close these gaps for good.

The prevalence of dementia decreased from 12.2 percent in 2000 to 8.5 percent in 2016 among those aged 65 and older, potentially due to increased rates of educational attainment and lower smoking rates.

The research, which is based on the nationally representative Health and Retirement Study, included data from more than 21,000 older adults. 

In addition to the overall decline, results also detailed reductions in race- and sex-based disparities. While the prevalence of dementia fell by 2.7 percentage points among white men over the 16-year window, prevalence dropped by 7.3 percentage points among Black men.   

More women than men suffered from dementia over the course of the study period, but that disparity also narrowed. In 2000, 10.2 percent of men had dementia compared with 13.6 percent of women. Those totals fell to 7 percent and 9.7 percent by 2016, respectively. 

Results were published in the journal Proceedings of the National Academy of Sciences, and the study was carried out by the RAND Corporation, a nonprofit research organization. RAND economists determined the totals via a model that increased the precision of dementia classification based on data from the Health and Retirement Study.

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“The reasons for the decline in the prevalence of dementia are not certain, but this trend is good news for older Americans and the systems that support them,” said Péter Hudomiet, an economist and the study’s lead author. 

“This decline may help reduce the expected strain on families, nursing homes and other support systems as the American population ages.”

Dementia is not a specific disease but is an umbrella term that encompasses symptoms like a decline in memory, changes in thinking skills and poor judgment and reasoning skills. Alzheimer’s disease is the most common form of dementia. 

“In 2021, about 6.2 million US adults aged 65 or older lived with dementia,” researchers explained. “Because age is the strongest risk factor for dementia, it has been predicted that increasing life expectancies will substantially increase the prevalence of Alzheimer’s disease and related dementias from about 50 million to 150 million worldwide by 2050.” 

There is currently no cure for Alzheimer’s disease. 

Several factors likely contributed to the overall decline in dementia seen throughout the United States. These include rising levels of education, falling smoking rate, and improved treatment of cardiovascular risk factors like high blood pressure, authors say.

Statistically, education was responsible for around 40 percent of the reduction in dementia prevalence among men, and explained 20 percent of the reduction in women. In 2000, 21.5 percent of men reported having a college education, while that total grew to 33.7 percent in 2016. Similar increases in education attainment were seen among women (12.3 percent v. 23 percent, respectively). 

However, because different demographic groups have different levels of education, this factor could influence rates down the line. 

“Closing the education gap across racial and ethnic groups may be a powerful tool to reduce health inequalities in general and dementia inequalities in particular, an important public health policy goal,” Hudomiet noted.

“Despite these favorable trends, we still find substantial dementia inequalities across subpopulations; women, racial and ethnic minority groups, and those with lower education face substantially higher chances of living with dementia,” authors concluded.