Alzheimer Disease and Cancer: A National Inpatient Sample Analysis.

INTRODUCTION

Studies have demonstrated an inverse relationship between Alzheimer dementia (AD) and cancer. This inverse relationship was further explored. In addition, Pin1 expression has been implicated in the cell cycle regulation of both disease processes. The relationship of Pin1 expression in 10 cancer types and secondary diagnosis of AD was examined.

MATERIALS AND METHODS

A cross-sectional analysis was performed using discharge data from the National Inpatient Sample from 1999 to 2008. Cancer was defined as the primary discharge diagnosis and AD was defined as the secondary discharge diagnosis. Cancer types were grouped according to their Pin1 expression to examine its relationship with AD. Analysis was performed by logistic regression.

RESULTS

Of ∼3 million cancer discharge diagnoses, 1.0% had a secondary diagnosis of AD. Discharge data of all 10 cancer types revealed a lower likelihood of secondary AD diagnosis. Prostate [crude odds ratios (OR): 0.26 (0.24 to 0.29), multivariate OR: 0.39 (0.35 to 0.43)], ovarian [crude OR: 0.38 (0.32 to 0.44), multivariate OR: 0.35 (0.30 to 0.41)], and lung cancer [crude OR: 0.39 (0.36 to 0.41), multivariate OR: 0.41 (0.39 to 0.44)] demonstrated the lowest odds of secondary AD diagnosis. When cancer types were grouped per Pin1 expression, cancer types with Pin1 underexpression were more likely to be associated with secondary diagnosis of AD than cancer types with Pin1 overexpression [crude OR: 1.4 (1.3 to 1.4), multivariate OR: 1.08 (1.02 to 1.14)].

DISCUSSION

This secondary data analysis further demonstrated an inverse relationship between AD and 10 cancer types, with prostate, ovarian, and lung cancers displaying the greatest inverse relationship. Pin1 underexpressing cancer types had a significantly higher likelihood of secondary diagnosis of AD than Pin1 overexpressing cancer types.