Risk factors for earlier dementia onset in autopsy-confirmed Alzheimer\u27s disease, mixed Alzheimer\u27s with Lewy bodies, and pure Lewy body disease.

Abstract

INTRODUCTION: Clinical Alzheimer\u27s disease (AD) and dementia with Lewy bodies often have mixed AD and Lewy pathology, making it difficult to delineate risk factors. METHODS: Six risk factors for earlier dementia onset due to autopsy-confirmed AD (n = 647), mixed AD and Lewy body disease (AD + LBD; n = 221), and LBD (n = 63) were entered into multiple linear regressions using data from the National Alzheimer\u27s Coordinating Center. RESULTS: In AD and AD + LBD, male sex and apolipoprotein E (APOE) ɛ4 alleles each predicted a 2- to 3-year-earlier onset and depression predicted a 3-year-earlier onset. In LBD, higher education predicted earlier onset and depression predicted a 5.5-year-earlier onset. DISCUSSION: Male sex and APOE ɛ4 alleles increase risk for earlier dementia onset in AD but not LBD. Depression increases risk for earlier dementia onset in AD, LBD, and AD + LBD, but evaluating the course, treatment, and severity is needed in future studies