MAPT and Alzheimer disease: The third finding that a history of cigarette smoking was not associated with change in CSF Aβ42, t-tau or p-tau levels over time at the prodromal stage of AD is consistent with a previously published postmortem study showing that no significant difference in levels of plaques or tangles between non-smokers and smokers was found in the midfrontal cortex of patients with AD dementia [16].