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pubmed:otherAbstract |
PIP: In response to enquiries received by the World Health Organization (WHO) from several countries, the WHO Special Program of Research, Development and Research Training in Human Reproduction convened a meeting of experts in Geneva during August 1981 to review the available animal, clinical, and epidemiological data on vasectomy, with particular emphasis on clinical implications of longterm sequelae of vasectomy in cardiovascular disease. The occurrence of circulating antibodies to sperm antigens has been demonstrated after vasectomy in all animal species studied thus far by various techniques. Prospective clinical studies of vasectomized and nonvasectomized men have been conducted at 4 centers in the U.S. involving clinical and laboratory evaluation of subjects before surgery and at intervals thereafter. A total of 412 vasectomized men were enrolled in these studies; most were followed for 2, 3, or 4 years. The only significant finding was the development of antibody to sperm antigens. Alexander and Clarkson first reported that vasectomy increases the extent and severity of diet-induced atherosclerosis in cynomolgus monkeys. In a 2nd study, Clarkson and Alexander extended their previous findings to evaluate the effects of vasectomy on naturally occurring atherosclerosis in rhesus monkeys. The mechanism by which vasectomy exacerbates atherosclerosis in monkeys has not been defined. At present epidemiological data which have been published come from observations in the U.S. and United Kingdom and in particular from 2 studies involving 4830 and 1764 vasectomized men studied at about 5-6 years after surgery. No health risks of vasectomy were detected in these early years. Other epidemiological projects are in progress in the U.S. Various options were discussed for further epidemiological studies which might be conducted in developing countries where large numbers of men have been vasectomized. The cohort approach and the case control method, the 2 main study options, are briefly reviewed.
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