US dementia decline reported
medwireNews: The prevalence of dementia in the USA has decreased between 2000 and 2012, and increasing educational attainment appears to be one of the contributing factors.
The full set of social, behavioral, and medical factors contributing to the decline remains to be determined, say the researchers in JAMA Internal Medicine, noting that improvements in treatments for cardiovascular risk factors, such as diabetes, also played a role.
Kenneth Langa (University of Michigan, Ann Arbor, USA) and co-researchers used data for over 21,000 adults (10,546 in 2000 and 10,511 in 2012) aged 65 years or older from the Health and Retirement Study.
Between 2000 and 2012, the prevalence of dementia fell from 11.6% to 8.8%, corresponding to a relative decrease of about 24.0% and an absolute decrease of 2.8 percentage points.
The group from 2012 had, on average, about one more year of education than the earlier cohort and this explained some of the decrease in dementia risk.
This supports the theory of “cognitive reserve,” whereby education enables an individual to better tolerate, or compensate for, the effect that accumulation of brain pathologies has on cognitive performance, explain Ozioma Okonkwo and Sanjay Asthana, both from the University of Wisconsin School of Medicine and Public Health in Madison, USA, in a related commentary. Alternatively, education may “forestall the accumulation of brain pathologies,” they write.
The commentators conclude: “The focus now should be on better understanding the factors that underlie this trend, and translating that knowledge into interventions that can reduce the risk of dementia for both individuals and the society as a whole.”
By Lucy Piper
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