Lead author Susan Landau of the University of California, at Berkeley's Helen Wills Neuroscience Institute, and colleagues assessed the association between lifestyle practices -- cognitive and physical activity -- and beta-amyloid deposition -- proteins thought to cause Alzheimer's disease.
The researchers used positron emission tomography using carbon 11–labeled Pittsburgh Compound B in healthy older individuals age 65, with a median age of 76.1.
The study involved patients with Alzheimer disease and 11 young controls -- mean age 24.5 -- studied from Oct. 31, 2005, to Feb. 22, 2011.
Landau explained scientists said dementia and memory loss in older adults is believed to be caused by increasing levels of amyloid protein in the brain.
The study, published in the Archives of Neurology, found people with greater early- and middle life cognitive activity -- reading, writing and playing games such as crossword puzzles -- had lower beta-amyloid levels.
"The tendency to participate in cognitively stimulating activities is likely related to engagement in a variety of lifestyle practices that have been implicated in other studies showing reduced risk of Alzheimer's disease-related pathology," the researchers said in a statement. "We report a direct association between cognitive activity and beta-amyloid uptake, suggesting that lifestyle factors found in individuals with high cognitive engagement may prevent or slow deposition of beta-amyloid, perhaps influencing the onset and progression of Alzheimer's disease."