Study finds sharp decrease (nearly one-third) in the prevalence of dementia among those 65+ in the United States

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Demen­tia plum­mets by near­ly one-third among U.S. seniors, RAND says (UPI):

The preva­lence of demen­tia in the Unit­ed States is declin­ing among peo­ple over age 65, falling dra­mat­i­cal­ly from 2000 to 2016, a RAND Corp. study says.

Nation­wide, the age-adjust­ed preva­lence of demen­tia fell to 8.5% of peo­ple over age 65 in 2016, down by near­ly one-third from 12.2% of peo­ple over age 65 in 2000, accord­ing to the researchers.

Females are more like­ly to live with demen­tia, but the sex dif­fer­ence has nar­rowed, the study found.

Among men, the preva­lence of demen­tia fell by 3.2 per­cent­age points, from 10.2% to 7.0% over the 16-year span. The decrease was larg­er among women, down 3.9 per­cent­age points, from 13.6% to 9.7% … the researchers cit­ed “grow­ing evi­dence” that age-adjust­ed demen­tia preva­lence has been declin­ing in devel­oped coun­tries, pos­si­bly due to ris­ing lev­els of edu­ca­tion, a reduc­tion in smok­ing and bet­ter treat­ment of key car­dio­vas­cu­lar risk fac­tors such as high blood pressure…

(Péter Hudomi­et, the study’s lead author) said it’s also pos­si­ble that, giv­en numer­ous stud­ies being released on steps to take to avoid demen­tia, some of the decline may be attrib­uted to peo­ple heed­ing such advice.

“It is also plau­si­ble that oth­er behav­ior fac­tors, such as smok­ing [ces­sa­tion], cog­ni­tive activ­i­ties, social activ­i­ties, etc., played a role,” he said.

The Study:

Trends in inequal­i­ties in the preva­lence of demen­tia in the Unit­ed States (PNAS). From the Abstract:

  • This paper presents esti­mates of the preva­lence of demen­tia in the Unit­ed States from 2000 to 2016 by age, sex, race and eth­nic­i­ty, edu­ca­tion, and a mea­sure of life­time earn­ings, using data on 21,442 indi­vid­u­als aged 65 and old­er … We devel­oped a lon­gi­tu­di­nal, latent-vari­able mod­el of cog­ni­tive sta­tus, which we esti­mat­ed using the Markov Chain Monte Car­lo method … The age-adjust­ed preva­lence of demen­tia decreased from 12.2% in 2000 (95% CI, 11.7 to 12.7%) to 8.5% in 2016 (7.9 to 9.1%) in the 65+ pop­u­la­tion, a sta­tis­ti­cal­ly sig­nif­i­cant decline of 3.7 per­cent­age points or 30.1%. Females are more like­ly to live with demen­tia, but the sex dif­fer­ence has nar­rowed. In the male sub­sam­ple, we found a reduc­tion in inequal­i­ties across edu­ca­tion, earn­ings, and racial and eth­nic groups; among females, those inequal­i­ties also declined, but less strong­ly. We observed a sub­stan­tial increase in the lev­el of edu­ca­tion between 2000 and 2016 in the sam­ple. This com­po­si­tion­al change can explain, in a sta­tis­ti­cal sense, about 40% of the reduc­tion in demen­tia preva­lence among men and 20% among women, where­as com­po­si­tion­al changes in the old­er pop­u­la­tion by age, race and eth­nic­i­ty, and car­dio­vas­cu­lar risk fac­tors mat­tered less.

The Study in Context: