Doubts About Vasectomies

Are they good for love but bad for the heart?

About 35 million men worldwide, 6 million in the U.S. alone, have had vasectomies as a means of permanent birth control. The operation is understandably popular. It leaves sexual performance unimpaired. It is inexpensive and can be done in 15 minutes in a doctor's office under local anesthesia. And it is safe. Or is it? Research suggesting a possible link between vasectomy and atherosclerosis, an underlying cause of heart disease and strokes, was reviewed last week at an American Heart Association seminar in Tucson.

Concern over the operation stems primarily from two experiments with different species of monkeys performed by Nancy Alexander, a physiologist at the Oregon Regional Primate Research Center in Beaverton, and Veterinary Pathologist Thomas Clarkson of the Bowman Gray School of Medicine in Winston-Salem, N.C.

In one study, ten male monkeys were fed a diet very high in cholesterol, containing about twice the levels the average American man would eat. After six months on the diet, five of the animals were surgically sterilized. The other five served as controls; they were operated on, but vasectomies were not performed. Ten months later, the arteries were removed and examined for cholesterol deposits. Though all the animals showed fatty lesions, the vasectomized monkeys showed far more extensive damage. A follow-up experiment compared the arteries often male monkeys that had been sterilized nine to 14 years earlier with those of eight contemporaries that had not been operated on. All had been fed lowfat, no-cholesterol diets. Again, the vasectomized monkeys had more widespread fatty deposits.

Normally sperm are conveyed toward the outside of the body through ducts, the vasa deferentia. In a vasectomy, the ducts are cut, but sperm continue to be manufactured. With the exit passage blocked, the sperm break down and leak into surrounding tissue and possibly into the bloodstream, where they are recognized as "foreign" and attacked by antibodies. Alexander and Clarkson postulate that the resultant sperm-antibody complexes injure the artery walls and accelerate formation of atherosclerotic plaques.

The New York City-based Association for Voluntary Sterilization charges that the primate experiments are not statistically valid. A.V.S. Physiologist Ira Richards also says there is no evidence of excessive heart disease in sterilized men.

Indeed, a study published last month in the Lancet, a British medical journal, found that the incidence of heart attacks in almost 5,000 vasectomized men was about the same as that for 24,000 men who had not had the operation. Responds Alexander: "The survey involved mostly men who had had relatively recent vasectomies, and atherosclerosis may take ten years or more to develop."

Although convinced that her studies are sound, Alexander urges caution in extending the monkey findings to humans. Four large-scale epidemiological studies, which will answer some questions regarding vasectomies and atherosclerosis, are now under way, and some preliminary results may be available within six months. As for men now contemplating sterilization, Alexander advises:

"If a man is already a high risk for atherosclerosis--for example, if he has high blood pressure or his parents have had heart attacks or strokes--he may wish to wait until more information is available." Insists Richards: "There are no studies to date that indicate that having a vasectomy is going to exacerbate or increase atherosclerosis."

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