Does Alzheimer's Disease Protect against Cancers? A Nationwide Population-Based Study.

Background: Previous studies suggested a decreased risk of cancer among patients with Alzheimer's disease (AD). There is still a lack of data on the specific types of cancer, the risk factors, and the impact of cholinesterase inhibitors on developing cancer in AD. Methods: We performed a nationwide population-based study of 6,960 patients with AD between 1997 and 2006 using Taiwan's National Health Insurance d tabase. Patterns of cancer incidence in AD patients were compared with those of the general population using standardized incidence ratios (SIRs). Results: Patients with AD had a reduced risk of developing overall cancer [SIR = 0.88 95% confidence interval (CI) = 0.80-0.97]. Specifically, patients with AD were protected from lung cancers (SIR = 0.75, 95% CI = 0.57-0.98), especially men (SIR = 0.61, 95% CI = 0.40-0.88). In subgroup analyses, women, patients aged 60-79 years, and those diagnosed as having AD for more than 1 year were more likely to be protected from cancers. Conclusions: Our study demonstrates a decreased incidence of overall cancers in patients with AD, a finding lower than but consistent with Western countries. Patients with AD had a significantly decreased risk of lung cancer. Further investigation of genetic evidence linking AD to cancer is warranted. [ABSTRACT FROM AUTHOR]