Study: Alzheimer's Patients Get Less Cancer

Dec. 23, 2009 -- Having Alzheimer’s disease just may convey some protection
against cancer, and vice versa, early research suggests.
Compared to elderly study participants without Alzheimer’s disease, those
with Alzheimer’s were less likely to be diagnosed with cancer over eight years
of follow-up.
Elderly whites with cancer at the beginning of the study were less likely to
develop Alzheimer’s disease over five years of follow-up, but the lower risk
was not seen in other groups.
Several previous studies have shown a lower incidence of cancer in patients
with Parkinson’s disease, which, like Alzheimer’s, is a degenerative disorder
affecting the brain.
The newly published research suggests a similar link between cancer and
Alzheimer’s disease.
“This study adds to the literature suggesting that cancer and
neurodegenerative diseases may be related,�? lead researcher Catherine M. Roe,
PhD, of Washington University School of Medicine in St. Louis, tells
WebMD.
Alzheimer’s Patients Get Cancer Later
In an earlier study, Roe and colleagues reported that elderly patients with
Alzheimer’s developed cancer later than patients without dementia. Patients
with a history of cancer also tended to be diagnosed with dementia later in
life.
But it was not clear if the association was because of confounding factors,
such as the fact that cancer patients often die before they reach the high-risk
age for Alzheimer’s disease and Alzheimer’s patients tend to be screened less
aggressively for cancer.
In their newly published study, Roe and colleagues attempted to control for
many of these potential confounders.
The study included patients with Alzheimer’s disease, caused by loss of
nerve cells within the brain, and vascular dementia, caused by impaired blood
flow to the brain as a result of stroke and other cardiovascular causes.
Alzheimer’s disease is the most common type of dementia and vascular dementia
is the second most common type.
About 3,000 people aged 65 and older enrolled in a large heart health study
were included in the analysis.
Alzheimer's Patients Had 69% Lower Cancer Risk
Having vascular dementia at the start of the study appeared to have no
impact on hospitalization for cancer over eight years of follow-up.
But compared to people without Alzheimer’s, patients with Alzheimer’s
disease at study entry were 69% less likely to be hospitalized with cancer
during the same time period.
The risk of developing Alzheimer’s disease was reduced by 43% in white
patients with a history of cancer, compared to participants without cancer, but
the finding did not hold for other racial and ethnic groups.
The study appears online and in the Jan. 12 issue of the journal
Neurology.
Roe says more research is needed to determine if cancer and degenerative
brain diseases like Alzheimer’s and Parkinson’s really are related.
http://www .webmd.com/alzheimers/news/20091223/study-alzheimers-patients-get-less-cancer?src=RSS_PUBLIC