Washington, USA: According to a recent study, the incidence of dementia among Americans over the age of 65 has decreased by 3.7 percentage points between 2000 and 2016.
From 12.2% of those over 65 in 2000 to 8.5% of those over 65 in 2016, the age-adjusted prevalence of dementia has decreased by almost a third since 2000. Throughout the period , the prevalence of dementia decreased, although between 2000 and 2004 the rate of reduction was faster.
Differences in dementia prevalence between black men and white men narrowed, with dementia prevalence falling by 7.3 percentage points among black men compared to 2.7 percentage points among white men .
The findings are published in the latest issue of the journal Proceedings of the National Academy of Sciences.
“The reasons for the decline in dementia prevalence aren’t certain, but this trend is good news for older Americans and the systems that support them,” said Peter Hudomiet, lead author of the study and an economist at RAND, an organization non-profit research. . “This decline may help reduce the expected pressure on families, nursing homes and other support systems as the American population ages.”
Michael D. Hurd and Susann Rohwedder of RAND are co-authors of the study.
The prevalence of dementia was higher among women than men throughout the period, but the difference narrowed between 2000 and 2016. Among men, the prevalence of dementia decreased by 3.2 percentage points, from 10.2 % to 7.0%. The decline was greatest among women, 3.9 percentage points, from 13.6 to 9.7 percent.
In 2021, about 6.2 million American adults age 65 and older were living with dementia. Because age is the strongest risk factor for dementia, increasing life expectancy has been predicted to substantially increase the prevalence of Alzheimer’s disease and related dementias from around 50 million to 150 million worldwide. the world by 2050.
However, there is growing evidence that the age-adjusted prevalence of dementia has decreased in developed countries, possibly due to increased levels of education, a reduction in smoking, and better treatment of key cardiovascular risk factors. such as high blood pressure.
Any change in these age-specific rates has important implications for projected prevalence and associated costs, such as nursing care payments by households, insurance companies, and the government.
The new RAND study uses a novel model to assess cognitive status based on a broad set of cognitive measures obtained from more than 21,000 people participating in the National Health and Retirement Study, a large representative population survey that has been conducted for more than two decades.
The model increases the accuracy of dementia classification by using the longitudinal dimension of the data. Most importantly for the study of inequality, the model is built to ensure that dementia classification is calibrated within population subgroups and is therefore equipped to produce accurate estimates of dementia prevalence. by age, sex, education, race and ethnicity, and by a measure of lifetime earnings.
The RAND study found that education was a major contributing factor, in a statistical sense, to the reduction in dementia, explaining about 40 percent of the reduction in dementia prevalence among men and 20 percent of reduction among women.
The fraction of college-educated men in the study increased from 21.5% in 2000 to 33.7% in 2016, and the fraction of college-educated women increased from 12.3% to 23% during this period.
Trends in education level differ between demographic groups, which may affect inequalities in dementia in the future. For example, while women traditionally had lower levels of education than men, among younger generations, women are more educated. Although racial and ethnic minority groups still have lower levels of education than non-Hispanic white individuals, the gaps between racial and ethnic groups have narrowed.
“Closing the educational gap between racial and ethnic groups can be a powerful tool in reducing health disparities in general and dementia disparities in particular, an important public health policy goal,” Hudomiet said.
The age-adjusted prevalence of dementia tended to be higher among individuals from racial and ethnic minorities, both among men and women. However, among men, the difference in prevalence between black and non-Hispanic white people narrowed, while it remained stable among women. Among non-Hispanic white men, the prevalence of dementia fell from 9.3% to 6.6%. Among non-Hispanic black men, the rate fell from 17.2 percent to 9.9 percent.