Monday, November 21, 2016

Dementia Prevalence in United States Falls From 2000 to 2012, Report Finds


Between 2000 and 2012, the proportion of U.S. adults 65 and older with dementia decreased significantly, from 11.6% to 8.8%, reported a study published today in JAMA Internal Medicine. Dementia rates fell even as obesity, diabetes, and hypertension—cardiovascular risk factors believed to increase dementia risk—went up.

In addition to helping experts to better estimate the future societal impact of dementia, continuing to monitor dementia trends could one day lead to a better understanding of potential protective and risk factors for cognitive decline.

While recent studies have suggested that the age-specific risk of dementia may be declining in several high-income countries, this is the first study to provide this evidence in a nationally representative population. 

Kenneth M. Langa, M.D., Ph.D., and colleagues at the University of Michigan Medical School, analyzed data from the Health and Retirement Study—a nationally representative longitudinal survey of U.S. adults (65 years or older) that collects data on health, cognition, family, employment, and wealth. The sample included about 10,500 people from the 2000 and 2012 waves of the survey, and about 4,000 participants were featured in both the 2000 and 2012 datasets.

The study revealed that as dementia rates fell from 11.6% in 2000 to 8.8% in 2012, educational attainment increased significantly, with those 65 years or older in 2012 having nearly one additional year of education compared with the 2000 cohort. More years of formal education were associated with a lower risk for dementia. 

“Our study, along with prior studies, supports the notion that ‘cognitive reserve’ resulting from early-life and lifelong education and cognitive stimulation may be a potent strategy for the primary prevention of dementia in both high- and low-income countries around the world,” wrote the study authors. “However, it should be noted that the relationships among education, brain biology, and cognitive function are complex and likely multidirectional.”

The authors also noted that while rates of cardiovascular risk factors have gone up since 2000, treatments for cardiovascular disease have improved, which may contribute to the reduced dementia incidence.

For more information, see the Psychiatric News article “Framingham Study Suggests Dementia Rates May Be Falling” and the AJP article “Computerized Cognitive Training in Older Adults With Mild Cognitive Impairment or Dementia: A Systematic Review and Meta-Analysis.”

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