There's good news for aging adults: Prevalence of dementia declined in the United States from 2000 to 2016, a new study reveals.
In people ages 65 and up, prevalence of dementia dropped by 3.7 percentage points. Disparities also decreased between white and Black men and between men and women.
"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 lead author Péter Hudomiet, an economist at RAND, a nonprofit research organization.
"This decline may help reduce the expected strain on families, nursing homes and other support systems as the American population ages," Hudomiet added in a RAND news release.
In 2000, the age-adjusted prevalence of dementia was 12.2% for people over 65. By 2016 it was 8.5%, a nearly one-third drop. The rate of decline was especially rapid between 2000 and 2004, the study found.
Gaps in dementia rates between Black and white men narrowed over the years, with prevalence dropping 7.3 percentage points among Black men during those years, compared to dropping 2.7 percentage points among white men.
Women continued to have a higher rate of dementia, but it dropped from 13.6% to 9.7% in those years. For men, the rate fell from 10.2% to 7%.
To study the issue, RAND used data on more than 21,000 people in the national Health and Retirement Study.
Researchers credit rising levels of education, a reduction in smoking and better treatment of key heart risk factors such as high blood pressure as potential reasons for the improvements.
Education appears key, according to the study.
About 22% of men in the study in 2000 were college-educated, compared to almost 34% in 2016. And the fraction of college-educated women nearly doubled -- from just over 12% to 23% -- during that time.
However, researchers noted that trends in the level of education differed across demographic groups. This could affect inequality in the future.
"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 said.
In 2021, about 6.2 million U.S. adults ages 65 or older were living with dementia.
The findings were published in Proceedings of the National Academy of Sciences.
The U.S. Centers for Disease Control and Prevention has more on dementia.
SOURCE: RAND Corporation, news release, Nov. 7, 2022