Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Jun 20;12(6):e0179857.
doi: 10.1371/journal.pone.0179857. eCollection 2017.

Risk of Alzheimer's disease or dementia following a cancer diagnosis

Erin J Aiello Bowles  1 , Rod L Walker  1 , Melissa L Anderson  1 , Sascha Dublin  1   2 , Paul K Crane  3 , Eric B Larson  1   3
Affiliations

Risk of Alzheimer's disease or dementia following a cancer diagnosis

Erin J Aiello Bowles et al. PLoS One. .

Abstract

Objective: We evaluated dementia and Alzheimer's disease (AD) risks after a cancer diagnosis in a population-based prospective cohort, the Adult Changes in Thought (ACT) study.

Methods: We followed community-dwelling people aged ≥65 years without dementia at study entry for incident dementia and AD from 1994-2015. We linked study data with cancer registry data and categorized cancer diagnoses as prevalent (diagnosed before ACT study enrollment) or incident (diagnosed during follow-up). We used Cox regression to estimate cause-specific hazard ratios (HRs) with 95% confidence intervals (CIs) for dementia or AD risk comparing people with a cancer diagnosis to people without cancer. We conducted sensitivity analyses restricted to people surviving beyond age 80, and stratified by cancer stage, type, and whether the cancer was smoking-related.

Results: Among 4,357 people, 756 (17.4%) had prevalent cancer; 583 (13.4%) developed incident cancer, 1,091 (25.0%) developed dementia, and 877 (20.1%) developed AD over a median 6.4 years (34,482 total person-years) of follow-up. Among complete cases (no missing covariates) with at least one follow-up assessment, adjusted HRs for dementia following prevalent and incident cancer diagnoses were 0.92 (95%CI: 0.76, 1.11) and 0.87 (95%CI: 0.64, 1.04), compared to no cancer history. HRs for AD were 0.95 (95%CI: 0.77, 1.17) for prevalent cancer and 0.73 (95%CI: 0.55, 0.96) for incident cancer. In sensitivity analyses, prevalent late-stage cancers were associated with reduced risks of dementia (HR = 0.51, 95%CI: 0.30, 0.89) and AD (HR = 0.50, 95%CI: 0.27, 0.94). When limited to people who survived beyond age 80, incident cancers were still associated with reduced AD risk (HR = 0.69, 95%CI: 0.51, 0.92).

Conclusions: Our results do not support an inverse association between prevalent cancer diagnoses, which were primarily early-stage, less aggressive cancers, and risk of dementia or AD. A reduced risk of AD following an incident cancer diagnosis is biologically plausible but may reflect selective mortality.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: Rod Walker has received funding as a biostatistician from a research grant awarded to Kaiser Permanente Washington Health Research Institute from Pfizer. Sascha Dublin received a Merck/American Geriatrics Society New Investigator Award. Eric Larson receives royalties from UpToDate. All other authors have no competing interests. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

References

    1. Demetrius LA, Simon DK. The inverse association of cancer and Alzheimer's: a bioenergetic mechanism. Journal of the Royal Society, Interface / the Royal Society. 2013;10(82):20130006 doi: 10.1098/rsif.2013.0006 ; - DOI - PMC - PubMed
    1. Driver JA, Beiser A, Au R, Kreger BE, Splansky GL, Kurth T, et al. Inverse association between cancer and Alzheimer's disease: results from the Framingham Heart Study. BMJ (Clinical research ed). 2012;344:e1442 doi: 10.1136/bmj.e1442 ; - DOI - PMC - PubMed
    1. Roe CM, Behrens MI, Xiong C, Miller JP, Morris JC. Alzheimer disease and cancer. Neurology. 2005;64(5):895–8. doi: 10.1212/01.WNL.0000152889.94785.51 . - DOI - PubMed
    1. Musicco M, Adorni F, Di Santo S, Prinelli F, Pettenati C, Caltagirone C, et al. Inverse occurrence of cancer and Alzheimer disease: a population-based incidence study. Neurology. 2013;81(4):322–8. doi: 10.1212/WNL.0b013e31829c5ec1 . - DOI - PubMed
    1. Realmuto S, Cinturino A, Arnao V, Mazzola MA, Cupidi C, Aridon P, et al. Tumor diagnosis preceding Alzheimer's disease onset: is there a link between cancer and Alzheimer's disease? Journal of Alzheimer's disease: JAD. 2012;31(1):177–82. doi: 10.3233/JAD-2012-120184 . - DOI - PubMed

Substances