Association between history of cancer and dementia types: a case-control study in the United Kingdom

Abstract

Abstract Background Cancer and dementia are important diseases of ageing. Cancer affects 1 in 3 people in their lifetime, and dementia will affect 1 in 3 people who reach 90 years of age. Evidence suggests that people who have survived cancer may have a lower risk of subsequently developing Alzheimer's Disease (AD); however, there is no evidence on the association between cancer and incident Vascular Dementia (VD), which is the second most common form of dementia. We evaluated the prevalence of cancer history in cases and dementia-free controls using electronic health records for primary care in the United Kingdom. Methods The association between dementia (AD or VD) and history of cancer was investigated using a retrospective case-control study. N = 45,000 cases of dementia over the age of 65 were matched (age, sex, practice) 1:1 to dementia-free cases within the Clinical Research Practice Datalink. Odds Ratios (OR) for history of cancer among dementia cases and controls were computed using logistic regression models adjusting for potential confounding variables (socio-demographic and lifestyle factors, diabetes, depression, hypertension). Results Preliminary results indicate that history of cancer was less prevalent among dementia cases than among controls. Cases reporting a history of cancer had significantly lower odds of AD than controls; this association remained significant after adjustment. No significant association was found between cancer history and VD. Conclusions This study supports prior research suggesting that cancer survivors may be less likely to experience AD in their lifetime; however, this inverse association requires further research that accounts for potential survivorship bias. Moreover, the absence of an association between cancer and VD suggests a link between neurodegeneration and oncogenesis. Key messages History of cancer may have differential associations with different types of dementia, which may inform research on the aetiology of Alzheimer’s disease. Given the limitations of case-control studies, cohort studies are needed to further assess the relationship between cancer and different forms of dementia.