Study: Alzheimer's Patients Get Less Cancer
Cancer History Linked to Less Alzheimer’s
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.