To the Editor: Dr Yaffe and colleagues recently reported that lower levels of plasma β-amyloid 42/40 were related to worse rates of cognitive decline.1 A major finding was the observation of an interaction between cognitive reserve (as measured by education, literacy, or apolipoprotein E [APOE] ε4 status) and plasma β-amyloid 42/40. Although this finding is intriguing, and the consistency of the interaction across all 3 measures of cognitive reserve is suggestive, nonetheless caution is warranted. Yaffe et al1 found little association between β-amyloid 42/40 levels and cognitive decline in those with at least a high school education.
Okereke OI, Selkoe DJ, Grodstein F. Plasma β-Amyloid Level, Cognitive Reserve, and Cognitive Decline. JAMA. 2011;305(16):1655-1656. doi:10.1001/jama.2011.524