Low cancer rates among patients with dementia in a population-based register study in Sweden.
BACKGROUND
Some studies have suggested a lower incidence of cancer in patients with dementia. We studied this further for 18 cancer types in population-based registers.


METHODS
In 19,756 cases and in 147,324 age- and sex-matched controls a diagnosis of dementia was studied 9-45 months prior to the diagnosis of cancer.


RESULTS
Overall a diagnosis of dementia was significantly less common among the cancer cases (risk ratio, RR = 0.60; 95% CI = 0.52-0.69).


CONCLUSIONS
The study confirms previous findings that patients with dementia have a lower risk of cancer. Because the effect was seen for all tumour types and especially for patients older than 70 years and since the deficit was more pronounced for patients with tumours situated within the body, the data suggest that malignancies are underdiagnosed for persons with dementia.
Attner
Bo
B
Department of Cancer Epidemiology, Clinical Sciences, Lund University, Lund, Sweden.
Lithman
Thor
T
Noreen
Dennis
D
Olsson
Håkan
H
D000367:Age Factors; D000368:Aged; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D011153:Population; D012042:Registries; D012306:Risk; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology