To the Editor: Dr Yaffe and colleagues reported that a lower β-amyloid 42/40 level in plasma was associated with greater cognitive decline during a 9-year period in nondemented elderly persons.1 Use of certain psychotropic medications, especially benzodiazepines2,3 and other medications with central anticholinergic effects,4,5 is quite common in elderly individuals and can result in significant cognitive deficits, particularly in APOE ε4 carriers. These deficits could be comparable with those related to the lower β-amyloid 42/40 level, especially in association with the ε4 allele, which appears to be more frequent in the group with the lowest β-amyloid 42/40 level. Yaffe et al did not explicitly comment on the use of these classes of medications in their study population; it would be important to ensure that group differences in the use of these medications did not contribute to their results.
Pomara N, Bruno D, Sidtis JJ. Plasma β-Amyloid Level, Cognitive Reserve, and Cognitive Decline. JAMA. 2011;305(16):1655-1656. doi:10.1001/jama.2011.525