Introduction: Studies on the association of cancer and risk of dementia are inconclusive due to result heterogeneity and concerns of survivor bias and unmeasured confounding.
Methods: This study uses data from the Memento cohort, a French multicenter cohort following persons with either mild or isolated cognitive complaints for a median of 5 years. Illness-death models (IDMs) were used to estimate transition-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for incident cancer in relation to dementia from time since study entry.
Results: The analytical sample (N = 2258) excluded 65 individuals without follow-up information. At the end of follow-up, 286 individuals were diagnosed with dementia, 166 with incident cancer, and 95 died. Incident cancer was associated with a reduced risk of dementia (HR = 0.58, 95% CI = 0.35-0.97), with a corresponding E-value of 2.84 (lower CI = 1.21).
Discussion: This study supports a protective relationship between incident cancer and dementia, encouraging further investigations to understand potential underlying mechanisms.
Keywords: Alzheimer's disease; cancer; dementia; epidemiology; illness-death model; selection bias.
© 2021 The Authors. Alzheimer's & Dementia published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.