Vasectomy is a popular sterilization procedure for men--after tubal ligation and the pill, it is the most common form of birth control. About 500,000 men undergo a vasectomy every year in the United States alone. Over the past decade or so, however, some people have grown concerned that the surgery can lead to dementia or Alzheimer's later in life. To date, such fears are unfounded and not backed up by the research.
Vasectomy is a minor surgical procedure, in which the vas deferens tubes that transport sperm are cut, blocked, or cauterized to prevent sperm from mixing with semen and being ejaculated.
Anti-sperm antibodies have been found in the blood of about 66 percent of men who have had a vasectomy. These antibodies, which are produced by the body's immune system to attack substances it believes are foreign and can cause harm, contain some of the same proteins found in the brain.
The fear that vasectomy could cause dementia stems from a small study of 104 men, published in the journal Cognitive and Behavioral Neurology in 2006. The researchers found that men who had a very rare form of dementia that impairs speech -- called primary progressive aphasia or PPA -- were more likely to have had a vasectomy than men without the disease. This same study also suggested a possible link between vasectomy and frontotemporal dementia, the second-most common form of dementia.
While the above study suggested that vasectomy could be a risk factor for various types of degenerative brain disease, it was far too small and not rigorous enough to prove any definite link. Additionally, the mechanism for how a sterilization procedure could have an effect on the brain remains unknown. At the time, researchers who led the 2006 study theorized that it might be possible for the anti-sperm antibodies to recognize the same protein in brain cells that they do in sperm and attack them, causing the dementia.
Subsequent research, however, has found no correlation. According to a 2010 paper, published in the Archives of Gerontology and Geriatrics, there was no correlation between those who had anti-sperm antibodies and those with Alzheimer's or other forms of cognitive impairment. (This study did not look at vasectomy rates.)
Physicians and researchers alike point out that precisely because vasectomies are so common, a substantial number of men in any large group are likely to have had the procedure. And yet, despite the frequency with which vasectomy is performed, PPA remains a very rare disease. Until further research can effectively prove otherwise, those in the field agree that vasectomy remains safe and relatively free of long-term risks.