Men who consider a vasectomy often ask questions about the risks involved. This blog will discuss the risks and the consequences of vasectomy and what every man needs to know before proceeding with the procedure.
There are three main concerns regarding the long-term consequences or general health hazards of vasectomy. These concerns have arisen mainly from isolated studies over the past 50 years. Remember that it is important to show that several things be true when trying to link two medical conditions: a) that the link makes physiological sense and that this is shown in either animal models or in humans, and b) there should be excellent evidence of this link in populations of humans.
Heart Disease Risk
In 1979 a study was published that suggested that atherosclerosis or coronary artery disease might occur prematurely after vasectomy in monkeys. In this small study, monkeys fed high cholesterol diets were found to have what appeared to be increased amounts of atherosclerosis following vasectomy. Subsequent animal studies did not agree with these initial findings, and large epidemiological studies, including an extensive study of U.S physicians followed for 259,000 person-years have concluded that neither early atherosclerosis nor heart attacks or strokes occur more frequently in men who have had vasectomies compared to men who have not.
It is true is that after vasectomy, approximately 60-70% of men develop a form of allergy to their sperm in the form of antisperm antibodies. The body, either during the vasectomy or after, is exposed to sperm proteins that it commonly does not see and antibodies against these proteins can be observed in some patients. However, it has not been shown conclusively that the presence of these antibodies has any significant effect on other organs.
Prostate Cancer Risk
There has been much discussion over the past 15 years about whether vasectomy is associated with the development of prostate cancer later in life. The Journal of the American Medical Association published 2 reports suggesting that men who have had a vasectomy may be at risk for developing prostate cancer. Both studies were coauthored by Dr. Edward Giovannucci. One study evaluated men married to female nurses: men with vasectomies were compared to men without. The second study evaluated men in the health professions (veterinarians, pharmacists etc) who had had a vasectomy, and, again compared them with other male health professionals who had not had vasectomies. In both studies, there appeared to be an increased risk of developing prostate cancer in men who had a vasectomy more than 20-22 years before. On the contrary, several other studies, including several in the U.S showed no statistically significant increase in the risk of prostate cancer following vasectomy. Indeed, it was suggested in the same JAMA issues that a true cause-and-effect relationship could occur by chance alone, or because of biases (selectivity) or other unaccounted variables in these two studies.
Concerns raised from these studies include the fact that the men in the study might not represent the larger population of all men who get vasectomies. This means that the study cannot be used with certainty to predict a similar occurrence in the general population. It is also possible that the men who had had vasectomies in these studies would be more likely to see a urologist rather than an internist or family practice physician for later evaluation of a urologic problem than the men who had not had vasectomies. Urologists are better at finding prostate abnormalities than other kinds of physicians and therefore cancer might have been detected earlier than it would have otherwise. This is called “detection bias.” It has also been suggested this study design makes it impossible to identify all of the factors that might contribute to this end result with two events (vasectomy and cancer) occurring several decades apart. A prospective study is really necessary here to answer the question. A prospective study evaluates groups of patients at the time they have the vasectomy and follows them regularly for years to see, if indeed, cancers do occur. This is the most powerful way to study this relationship, but was not used in the Giovannucci papers. In addition, no study has ever established that there is an increased risk of death after prostate cancer following vasectomy.
Because the question of a relationship between vasectomy and prostate cancer was raised, the American Urological Association first recommended that men who had a vasectomy more than 20 years ago or who were > 40 years of age at the time of vasectomy have an annual examination of their prostates as well as a blood test for prostate cancer (serum Prostate Specific Antigen or PSA). However, given the recent lack of support for this relationship between vasectomy and prostate cancer, this recommendation has been revoked. Finally, no mechanism is known, nor is there any animal model proof of the plausibility of the link between these conditions.
There is a recent, single, small paper that has linked vasectomy to the later development of a rare form of Alzheimer’s disease. The issue is that a researcher found that, among a group of patients suffering a form of dementia called primary progressive aphasia (PPA) that is often confused for Alzheimer’s disease, the men had a higher percentage of vasectomy than was thought normal. The study found that 40% of 47 men with PPA had had a vasectomy, while among another 57 men from the community without PPA there was a vasectomy rate of 16%. What this means is simply that the rate of vasectomy among PPA patients is a little over 2 fold higher than in otherwise healthy patients. This study did not find an increased rate of vasectomy in patients with Alzheimer’s.
The most common form of dementia caused by brain deterioration in individuals over age 65 is Alzheimer’s disease. A very unusual form of Alzheimer’s disease is called primary progressive aphasia. This condition robs people of their ability to speak and understand language, but they are still able to maintain their hobbies and perform other complicated tasks for a long time. By contrast, Alzheimer’s patients lose their memory, interest in hobbies, family life and become idle.
A “mechanism” for the association between PPA and vasectomy was also proposed in the study. It involves the fact that men can have antibodies form to sperm after having a vasectomy (see above risks) and these antibodies may somehow cross-react with the brain and cause PPA. There is no animal model data to support this theory, however.
Problems with this study are similar to that described for prostate cancer risk and vasectomy. How unique were these patients that they gathered from all over the US twice annually to participate in a support group with such rare disease? We really need a prospective study to show this relationship as retrospective studies have too much “bias” or too many uncontrolled issues that could produce the same result. In addition, the study groups were very small: fewer than 20 PPA patients had a vasectomy and fewer than 10 healthy patients had a vasectomy. It is hard to generalize at all from so few patients in a study. Also, the study methods were faulty in that the vasectomy condition should have been confirmed by reviewing the medical charts on the PPA patients, since their disease alters their ability to understand, hear and remember what has happened to them! Indeed, like the issue of prostate cancer and vasectomy, this issue will take at least a decade or two to confirm or disprove.
Bottom Line: Vasectomy remains an effective method of sterilization. Certainly there are risks with any procedure and the risks of prostate cancer, dementia, and heart disease need to be considered by every man who wishes to proceed with the vasectomy.