Cancer as a risk factor for long-term cognitive deficits and dementia.
Previous studies have shown that cancer survivors frequently experience short-term cognitive deficits, but it is unknown how long these deficits last or whether they worsen over time. Using a co-twin control design, the cognitive function of 702 cancer survivors aged 65 years and older was compared with that of their cancer-free twins. Dementia rates were also compared in 486 of the twin pairs discordant for cancer. Cancer survivors overall, as well as individuals who had survived cancer for 5 or more years before cognitive testing, were more likely than their co-twins to have cognitive dysfunction (odds ratio [OR] = 2.10, 95% confidence interval [CI] = 1.36 to 3.24; P<.001; and OR = 2.71, 95% CI = 1.47 to 5.01; P<.001, respectively). Cancer survivors were also twice as likely to be diagnosed with dementia as their co-twins, but this odds ratio did not reach statistical significance (OR = 2.0, 95% CI = 0.86 to 4.67; P = .10). These results suggest that cancer patients are at increased risk for long-term cognitive dysfunction compared with individuals who have never had cancer, even after controlling for the influence of genetic factors and rearing environment.
Heflin
Lara H
LH
Department of Psychology, University of Southern California, Los Angeles, CA 90089-1061, USA.
Meyerowitz
Beth E
BE
Hall
Per
P
Lichtenstein
Paul
P
Johansson
Boo
B
Pedersen
Nancy L
NL
Gatz
Margaret
M
D000368:Aged; D003071:Cognition / Q000187:drug effects / Q000528:radiation effects; D003072:Cognition Disorders / Q000139:chemically induced / Q000453:epidemiology* / Q000209:etiology*; D003704:Dementia / Q000139:chemically induced / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D008498:Medical Record Linkage; D009369:Neoplasms / Q000150:complications*; D016017:Odds Ratio; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology