Alzheimer's disease is associated with prostate cancer: a population-based study.

Alzheimer's disease and cancer are increasingly prevalent with advancing age. However, the association between Alzheimer's disease and prostate cancer remains unclear. The aim of this study was to examine the relationship between prior Alzheimer's disease and subsequent prostate cancer using a population-based dataset in Taiwan. Data for this study were sourced from the Taiwan Longitudinal Health Insurance Database 2005. This case-control study included 2101 prostate cancer patients as cases and 6303 matched controls. We used conditional logistic regression analyses to calculate the odds ratio (OR) and corresponding 95% confidence interval (CI) for Alzheimer's disease between prostate cancer patients and controls. We found that of the 8404 sampled patients, 128 (1.5%) had been diagnosed with Alzheimer's disease prior to the index date. A Chi-squared test showed that there was a significant difference in the prevalences of prior Alzheimer's disease between prostate cancer patients and controls (2.1% vs. 1.3%, p < 0.001). The conditional logistic regression analysis showed that the OR of prior Alzheimer's disease for prostate cancer patients was 1.53 (95% CI: 1.06∼2.21) compared to controls. Furthermore, the OR of prior Alzheimer's disease for prostate cancer patients was 1.52 (95% CI: 1.04∼2.22) compared to controls after adjusting for hypertension, diabetes, coronary heart disease, hyperlipidemia, obesity, prostatitis, gonorrhea or chlamydia infection, testitis or epididymitis, and alcohol abuse/alcohol dependency syndrome. This study revealed an association between prior Alzheimer's disease and prostate cancer. We suggest that clinicians be alert to the increased risk of prostate cancer when caring for elderly individuals with Alzheimer's disease.