Fagan and colleagues1 reported on the use of the CSF tau/Aβ42 ratio in predicting cognitive decline in nondemented older adults. Although they stated that participants in the study had no systemic medical illness that could contribute importantly to dementia, they made no mention of the participants' medication profiles.
Statins have been thought to play a role in preventing cognitive decline2 and possibly in altering CSF biomarkers3 among patients with Alzheimer disease (AD). In the preliminary results of a randomized controlled trial, the use of atorvastatin in patients with mild to moderate AD was shown to be beneficial in improving their cognitive scores on the Alzheimer's Disease Assessment Scale at 6 and 12 months.2 In addition, CSF levels of ptau were reduced among patients treated with simvastatin.3 These effects of statins could have been confounding factors in the results of the study by Fagan and colleagues.
Wong V. Medication Use as a Confounding Factor in the Use of the Cerebrospinal Fluid tau/β-Amyloid42 Ratio. Arch Neurol. 2007;64(9):1357. doi:10.1001/archneur.64.9.1357-a