Association of cancer with neuropathological markers of Alzheimer's disease and related dementias.

INTRODUCTION

We assessed associations of cancer diagnoses with neuropathology of Alzheimer's disease (AD) and related dementias.

METHODS

We retrieved 2288 cases from the National Alzheimer Coordinating Center (NACC) cohort with available information on cancer diagnoses and neuropathological scoring of Braak stages, Thal amyloid phases, neuritic plaques, TDP-43 pathology, and Lewy body pathology. We used Bayesian ordinal regression to assess associations of prevalent or incident cancer diagnoses with global cognition and postmortem neuropathological scores.

RESULTS

We found extreme evidence (Bayes factor [BF] > 2000) that both prevalent and incident cancer diagnoses were associated with better global cognition, strong evidence (BF = 26) for an association of a prevalent cancer diagnosis with lower TDP-43 pathology, and weak evidence (BF = 3.2) for an association with lower Lewy body pathology.

DISCUSSION: Our data suggest that selective survival and biological effects may contribute to the lower risk of dementia in people with a cancer diagnosis.

HIGHLIGHTS: A prevalent diagnosis of cancer was associated with a lower risk of cognitive decline in older individuals.A prevalent diagnosis of cancer was associated with a lower risk of TDP-43 pathology and Lewy body pathology in older individuals.Effects of cancer on TDP-43 pathology were maintained when controlling for degree of cognitive decline.