Ties to Rare Form of Dementia Seen in Early Research Must Be Confirmed
WebMD Health News
on Thursday, February 22, 2007
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Researchers at Chicago's Northwestern University found that men with a neurological condition known as primary progressive aphasia, or PPA, were more likely to have had the sterilization surgery than men without the disorder.
PPA is a rare condition characterized by a steady loss of language skills.
It primarily occurs after age 50. Those with the disorder have increasing difficulty expressing themselves and understanding speech.
"We definitely aren't saying that having a vasectomy causes this condition or that men should not have vasectomies," researcher Sandra Weintraub, PhD, tells WebMD. "It is way too early for that. We need to do more research to understand this."
Vasectomy and PPA
Weintraub, a professor of neurology and psychiatry at the Northwestern Feinberg School of Medicine, says she began investigating a possible link between PPA and vasectomies after a 43-year-old patient asked her if his sterilization surgery might be linked to his PPA.
He discussed the issue at a support group meeting of men with dementia, and it turned out that eight of the nine men in the room with PPA had had vasectomies.
"That is when we decided to do a systematic investigation, but it took some time because this is not a common disease," Weintraub says.
Study of 104 Men
The researchers surveyed 47 men with PPA undergoing treatment at Northwestern's Cognitive Neurology and Alzheimer's Disease Center and 57 men without dementia who were volunteers from the community. All the men were aged 55 to 80.
The researchers concluded that more than twice as many men with PPA had undergone vasectomies as men without the dementia -- 40% vs. 16%.
In other preliminary research, Weintraub and colleagues found no difference in vasectomy rates between patients with Alzheimer's disease and men without Alzheimer's.
Weintraub theorized that vasectomy may raise the risk of the rare dementias by breaching the protective barrier between the bloodstream and the testes.
When that barrier is broken, as occurs with vasectomy, sperm become exposed to the bloodstream. In response, many men who have had the surgery produce antisperm antibodies.
These antibodies may affect the brain, causing damage which can lead to dementia.
But this is only speculation, and Weintraub says she hopes to conduct much larger studies to better understand the issue.
American Urological Association spokesman Ira Sharlip, MD, agrees that few conclusions can be drawn without such studies.
He points to earlier concerns about vasectomies, including research in the 1980s suggesting an increased risk of atherosclerosis in men who had undergone the procedure, and research in the 1990s suggesting a link between vasectomy and prostate cancer.
None of those concerns turned out to be valid, Sharlip says.
Sharlip is a clinical professor of urology at the University of California, San Francisco.
"There have been many large, epidemiological studies comparing vasectomized and nonvasectomized men, and none of them have shown any health risks associated with vasectomy," he says.
"Vasectomy is the single most reliable form of birth control that exists. I would hope that men would not be frightened by this study, which is very preliminary," says Sharlip.
SOURCES: Weintraub, S. Cognitive and Behavioral Neurology, December 2006; vol 19: pp 190-193. Sandra Weintraub, PhD, Cognitive Neurology and Alzheimer's Disease Center, Chicago. Ira Sharlip, MD, spokesman, American Urological Association; clinical professor of urology, University of California, San Francisco.
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