MedWire News: Greater early- and middle-life cognitive activity is associated with lower β-amyloid deposition, according to research published in the Archives of Neurology.
"The recent development of the radiopharmaceutical carbon 11-labeled Pittsburgh Compound B ([11C]PiB) has made it possible to image fibrillar forms of the β-amyloid (A β) protein, which is the major constituent of the amyloid plaque in Alzheimer disease (AD)," explain Susan Landau (University of California, Berkley, USA) and colleagues.
Recent studies have shown that significant [11C] PiB uptake also occurs in 20-30% of healthy older adults, a better understanding of which, the researchers say, could be important for disease prevention.
Landau and co-workers studied 65 healthy older adult participants (mean age 76.1 years), 10 patients with AD (mean age 74.8 years), and 11 young adults (mean age 24.5 years). [11C]PiB imaging was conducted on the participants after magnetic resonance imaging (MRI) was used to identify four large areas of interest: prefrontal cortex, lateral temporal cortex, parietal cortex, and anterior and posterior cingulated gyrus.
Participant cognitive and physical activity was assessed at interview. They were asked how often they engaged in cognitively demanding activities, such as reading books or newspapers, writing letters or emails, going to the library, and playing games, at five points in their lifetime - at 6, 12, 18, and 40 years of age, and their current cognitive activity. The participants were also asked to report on the physical activities they were involved in over a 2-week period.
The researchers found that greater participation in cognitively stimulating activities throughout their lifetime, but especially in early and middle life, was significantly associated with reduced [11C]PiB uptake, after adjusting for age, gender, and number of years spent in education. The older participants who fell within the highest cognitive activity score tertile (based on participant-reported past cognitive activity) had [11C]PiB uptake similar to that of seen in the younger group.
Physical activity was not significantly associated with [11C]PiB, but it was linked to cognitive activity.
The researchers conclude that although "it is unlikely that our results reflect a single unitary cause of AD," they say "the present findings extend previous findings that link cognitive stimulation and AD risk (an indirect downstream effect of Aβ) by providing evidence that is consistent with a model in which cognitive stimulation is linked directly to the AD-related pathology itself."
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