Inverse association between cancer and Alzheimer’s disease: results from the Framingham Heart Study

 

Abstract

Objectives To relate cancer since entry into the Framingham Heart Study with the risk of incident Alzheimer’s disease and to estimate the risk of incident cancer among participants with and without Alzheimer’s disease.
 

Design

Community based prospective cohort study; nested age and sex matched case-control study.
 

Setting

Framingham Heart Study, USA.
 

Participants

1278 participants with and without a history of cancer who were aged 65 or more and free of dementia at baseline (1986-90).
 

Main outcome measures

Hazard ratios and 95% confidence intervals for the risks of Alzheimer’s disease and cancer.
 

Results

Over a mean follow-up of 10 years, 221 cases of probable Alzheimer’s disease were diagnosed. Cancer survivors had a lower risk of probable Alzheimer’s disease (hazard ratio 0.67, 95% confidence interval 0.47 to 0.97), adjusted for age, sex, and smoking. The risk was lower among survivors of smoking related cancers (0.26, 0.08 to 0.82) than among survivors of non-smoking related cancers (0.82, 0.57 to 1.19). In contrast with their decreased risk of Alzheimer’s disease, survivors of smoking related cancer had a substantially increased risk of stroke (2.18, 1.29 to 3.68). In the nested case-control analysis, participants with probable Alzheimer’s disease had a lower risk of subsequent cancer (0.39, 0.26 to 0.58) than reference participants, as did participants with any Alzheimer’s disease (0.38) and any dementia (0.44).
 

Conclusions

Cancer survivors had a lower risk of Alzheimer’s disease than those without cancer, and patients with Alzheimer’s disease had a lower risk of incident cancer. The risk of Alzheimer’s disease was lowest
in survivors of smoking related cancers, and was not primarily explained by survival bias. This pattern for cancer is similar to that seen in Parkinson’s disease and suggests an inverse association between cancer and neurodegeneration.
See More : www.ncbi.nlm.nih.gov/pubmed/23843468
Source : http://www.bmj.com/permissions :Inverse occurrence of cancer and Alzheimer disease: a population-based incidence study.