Leo Sher, M.D.

Dementia, a deterioration in memory and other cognitive functions that leads to a loss of independent function is a major medical and social problem. Alzheimer’s disease is the most frequent cause of dementia. Dementia can also be caused by a head injury, a stroke, a brain tumor, and other causes.

JAMA Internal Medicine has published an article entitled, “A comparison of the prevalence of dementia in the United States in 2000 and 2012” (1). The authors used data from the Health and Retirement Study (HRS), a nationally representative, population-based longitudinal survey of individuals in the United States 65 years or older.A study sample of 21,057 included all HRS participants aged 65 or older, living in the community or in nursing homes in 2000 and 2012. The research group found that, among those 65 years or older, the prevalence of dementia decreased from 11.6% to 8.8% between 2000 and 2012, representing an absolute decrease of 2.8 percentage points, and a relative decrease of about 24%.
 
The authors believe that the results of the study confirm the notion that “cognitive reserve” resulting from early-life and lifelong education and cognitive stimulation may be a potent strategy for the prevention of dementia.  The results of this study are consistent with observations that the age-specific risk of dementia may have declined in some high-income countries over the past 25 years. This is probably related to increasing levels of education and better control of key cardiovascular risk factors, such as hypertension, diabetes, and hypercholesterolemia.

Reference
1.    Langa KM, Larson EB, Eileen M. Crimmins EM, Faul JD, Levine DA, Kabeto MU, Weir DR. A comparison of the prevalence of dementia in the United States in 2000 and 2012. JAMA Internal Medicine. In press. Published online November 21, 2016.