HEALTH

Safe— but sorry?

Researchers are studying if vasectomies can cause dementia

BYDANYLO HAWALESHKA March 5 2007
HEALTH

Safe— but sorry?

Researchers are studying if vasectomies can cause dementia

BYDANYLO HAWALESHKA March 5 2007

Safe— but sorry?

HEALTH

Researchers are studying if vasectomies can cause dementia

BYDANYLO HAWALESHKA

It began with an uneducated guess by a male patient of Sandra Weintraub, a clinical neuropsychologist at Northwestern University’s Cognitive Neurology and Alzheimer’s Disease Center in Chicago. The man was in the early stages of primary progressive aphasia, a rare neuro-degenerative disease that slowly destroys a person’s ability to remember and understand words. PPA victims eventually lose all capacity to care for themselves. The man was convinced the vasectomy he had had a couple of years earlier was responsible for his deteriorating mental faculties. Understandably, Weintraub dismissed the idea—the man could just as easily have blamed a switch to a different brand of toothpaste. But a short time later, at one of the centre’s orientation meetings for PPA patients and their families, the same man asked who among the two dozen people in the room had PPA. Nine men raised their hands. “And then he asked, ‘Well, how many guys had a vasectomy?’ And eight of the nine put their hands up,” Weintraub recalls. “My reaction was, ‘Wow!’ ”

It could have been a coincidence. Still, Weintraub was intrigued by the possible link between the common procedure for sterilizing men and the unusual form of dementia. She and her colleagues went on to survey 47 men with PPA and 57 men with no cognitive impairment. They were between the ages of 55 and 80. The results, published in December in the journal Cognitive and Behavioral Neurology, showed that 40 per cent of the PPA patients had a vasectomy. Only 16 per cent in the unimpaired group had one. The researchers concluded vasectomy may increase the risk of developing PPA in men.

Weintraub freely admits her study is too small (not to mention the only one of its kind) to be used to dissuade men from seeking the commonly performed procedure. What the findings do suggest is the need for more research. “I would say that this study has absolutely no bearing, at present, on making any kind of prescriptive recommendations about vasectomies,” Weintraub cautions. “People are asking me, ‘Well, should I reverse my vasectomy?’ There’s no proof that the vasectomy actually causes [PPA].”

But her findings do raise questions. Over the next several months, Weintraub will try

to find between 200 and 300 PPA patients to further test the possible link in a new study. She also has a theory. It’s based on the fact the testes are protected by a physical barrier to keep blood-borne infections from damaging sperm. However, a vasectomy breaks that protective wall, and allows semen to enter the blood. In up to 70 per cent of men who have had a vasectomy, the immune system responds to the semen as it would to a foreign infectious agent: it produces antibodies that attack the sperm. Perhaps, Weintraub theorizes, these antibodies also damage certain brain cells to cause the dementia in some men.

The human body attacking itself in a socalled autoimmune response is not unprecedented. Autoimmune reactions are implicated in serious health problems including rheumatoid arthritis, juvenile diabetes, and multiple sclerosis. They can contribute to atherosclerosis-blocked arteries. In the late 1970s, a study of 10 monkeys showed an increased risk of clogged arteries in the animals that had been vasectomized. Alarm bells went off then, too, but more rigorous research laid those con-

cerns to rest. Published in the British Medical Journal in 1992, a study called the Health Status of American Men involved researchers questioning more than 10,000 vasectomized men, and the same number of men who hadn’t

had one, to determine whether they had any of 99 different disorders. The only condition found to be more common in men with a vasectomy was inflammation of the testes.

According to the U.S. National Institute of Child Health & Human Development, a number of studies to assess the safety of vasectomies continue today, including a major

OF THE NINE DEMENTIA PATIENTS IN THE GROUP, EIGHT HAD UNDERGONE THE OPERATION

investigation in several developing countries to determine whether there is a link between the procedure and prostate cancer. “There have been many, many studies on vasectomies,” says Dr. Luc Valiquette, president of the Canadian Urological Association. “And many, many false alarms.” And while work like Weintraub’s merits further investigation, Valiquette has a swift, sarcastic reply to anyone who suggests vasectomies cause dementia. “My answer to that is the cause of breast cancer is wearing nylon stockings because every woman who’s had breast cancer has worn nylon stockings at least once in her lifetime.” For now, Weintraub’s findings remain a scientific curiosity, and fodder perhaps for late-night TV jokes about how men who get vasectomies really might be crazy. M