The dementia is Primary Progressive Aphasia (PPA), a neurological disease in which people have trouble recalling and understanding words. In PPA, people lose the ability to express themselves and understand speech. It differs from typical Alzheimer's disease in which a person's memory becomes impaired.
Sandra Weintraub, principal investigator and professor of psychiatry and behavioral sciences and of neurology at Northwestern's Feinberg School of Medicine, began investigating a possible link between the surgery and PPA when one of her male patients connected the onset of his language problem at age 43 to the period after his vasectomy.
At a twice-yearly Chicago support group for PPA patients Weintraub sees from around the country, the male patient rushed into the room and asked the men sitting there, "OK, guys, how many of you have PPA?" Nine hands went up.
"How many of you had a vasectomy?" he demanded next. Eight hands shot up.
Weintraub and her team of researchers surveyed 47 men with PPA who were being treated at Northwestern's Cognitive Neurology and Alzheimer's Disease Center and 57 men with no cognitive impairment who were community volunteers. They ranged from 55 to 80 years old.
Of the non-impaired men, 16 percent had undergone a vasectomy. In contrast, 40 percent of the men with PPA had had the surgery.
"That's a huge difference," said Weintraub, director of neuropsychology in the Cognitive Neurology and Alzheimer's Disease Center. "It doesn't mean having a vasectomy will give you this disease, but it may be a risk factor to increase your chance of getting it."
In addition, the men who had undergone a vasectomy developed PPA at a younger age (58 years) than men with PPA who hadn't had one (62 years.)
While PPA robs people of their ability to speak and understand language, an unusual twist of the disease is patients are still able to maintain their hobbies and perform other complicated tasks for a number of years before other symptoms develop. Some people garden, build cabinets and even navigate a city subway system. By contrast, Alzheimer's patients lose interest in their hobbies, family life and may become idle. As PPA progresses over a number of years, however, patients eventually lose their ability to function independently.
Preliminary evidence from the study also seemed to connect another form of dementia to a vasectomy. In a smaller group of 30 men with a dementia called frontotemporal dementia (FTD,) 37 percent had undergone a vasectomy. The earliest symptoms of FTD are personality changes, lack of judgment and bizarre behavior. As in PPA, FTD usually starts at an earlier age, in the 40s and 50s.
One of Weintraub's patients with FTD was eating lunch in a restaurant with his family and excused himself to go to the bathroom. When he hadn't returned after 10 minutes, his sons went to investigate. They found him doing pushups on the bathroom floor. Other FTD patients begin shoplifting, compulsively gambling, misspending large amounts of money or become sexually demanding.
The most common form of dementia caused by brain deterioration in individuals over age 65 is Alzheimer's disease. Weintraub did not find an increased rate of vasectomy in patients with Alzheimer's.
Many patients with FTD and PPA share a common brain disease that is completely different from Alzheimer's. Whether a patient will get the behavioral or language problems depends on where the disease causes the most destruction in the brain. In FTD, most of the damage is in the frontal lobes; in PPA, it's in the language centers of the left hemisphere of the brain.
Weintraub theorizes a vasectomy may raise the risk of PPA (and possibly FTD) because the surgery breeches the protective barrier between the blood and the testes, called the blood-testis barrier.
Certain organs – including the testes and the brain – exist in what is the equivalent of a gated community in the body. Tiny tubes within the testes (in which sperm are produced) are protected by a physical barrier of Sertoli cells. The tight connections between these cells prevent blood-borne infections and poisonous molecules from entering the semen.
After a vasectomy, however, the protective barrier is broken and semen mixes into the blood. The immune system recognizes the sperm as invading foreign agents and produces anti-sperm antibodies in 60 to 70 percent of men.
Weintraub said these antibodies might cross the blood-brain-barrier and cause damage resulting in dementia. "There are other neurological models of disease which you can use as a parallel," Weintraub said. Certain malignant tumors produce antibodies that reach the brain and cause an illness similar to encephalitis, she noted.
The next step in Weintraub's research will be to launch a national study to see if her results will be confirmed in a larger population.
"I don't want to scare anyone away from getting a vasectomy," Weintraub stressed. "It's obviously a major birth control alternative. This is just a correlational observation," she said of the dementia connection. "We need to do more research to find out."
northwestern.edu | EurekAlert!
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences