Vasectomy and atherosclerosis in Macaca fascicularis. New findings in a controversial issue

The influence of vasectomy on diet-induced atherosclerosis was studied in ten Macaca fascicularis monkeys. After a six-month control period the monkeys were divided into two groups and matched for cholesterol levels. Five monkeys were given vasectomies and five sham vasectomies, and all animals were placed on a high-cholesterol, atherogenic diet. The vasectomized monkeys showed a significant increase in sperm antibody formation as compared with the control group. Both groups developed similar high cholesterol levels. After ten months all monkeys were necropsied, and their vascular systems were carefully evaluated to determine the extent of atherosclerosis. There was no difference in the occurrence of atherosclerotic plaques between the study and control groups despite sperm antibody development in the study group. This finding is in contrast to those of previous animal studies in which it was theorized that vasectomy aggravated the development of atherosclerosis. This study, however, confirms the results of several human studies that have failed to find any increase in cardiovascular disease among men who have undergone vasectomy.