In Korea, the vasectomy has been adopted by the government as a means of family planning program since early 1960´s and approximately 750,000 vasectomies were performed up to 1982 without being noticed of any significant clinical adverse outcomes.
However, recent studies on vasectomized monkeys by alexandar and Clarkson have indicated an increased risk and accelerated rates of atherogenesis and the researchers hypothesized that the immunologic reaction to sperm antigen might have produced vascular damage.
These findings have aroused considerable concern among the providers of vasectomy services and their past and prospective clients.
The primary unresolved problem is whether the alleged higher risk applies to men.
Considering world wide publicity about the animal findings there are both programmatic and scientific reasons to conduct epidemiologic studies of this issue in our country and compare the the results with those derived from the similar studies made in other countries.
In view of complicated nature of such study, however, it is generally agreed that a pilot study is needed in preparation for the future large-scale survey anticipated in Korea, and the study was conducted according to the following design and methodology.
Basically the hospital based "Case-Control Study" method was used. The cases and the controls were chosen from the ever married male patients aged 40-60 whose sociodemographic and some variables possibly related to the atherosclerotic diseases were investigated through face to face interview.
The cases are the patients treated at Han Yang University Hospital of one of the diseases listed below.
1. Ischemic Heart Diseases (I.C.D Codes: 410, 411, 413, 414)
2. Cerebrovascular Diseases (I.C D Codes: 433, 434, 435, 437)
3. Diseases of Arteries, Arteriols and Capillaries (I.C D Codes: 440, 441, 442, 443.1,443.9, 444)
The controls are consisted of the male patients aged 40-60 with diseases not listed above.
The findings of this pilot stududy are anticipated to give us the answers to the following questions.
1. Sample size needed for the case-control study on the vasectomy-atherosclerotic relationship.
2. Size of case group collectable in a hospital setting.
3. Possibility of utilizing medical record system for a follow-up study.
4. Association between the selected factors and atherosclerotic diseases.
A summary of the study is as follows.
1. The sample sizes required for the analysis of the association between vasectomy and atherosclerotic diseases under specified conditions are given in Table 2 in the main text.
2. The analysis of statistics of a hospital with 800 beds showed that the number of patients falling into the diseases category defined above could be estimated 200-260 per year.
The combination of the findings on the sample size and this patient statistics lead us to predict that at least 3 hospitals of 700-800 beds each are required to participate into the study in order to collect an adequate amount of data for meaningful analysis. It was also revealed that the hospital record system was so efficiently operated that patients´ records for specified disease were easily retrievable to make it feasible for the follow up study.
3. A total of 107 cases and 110 controls were interviewed during the period of November 1, 1981 to May 31, 1982, and the comparative analysis has shown that only one factor, that is, "coffee drinking status" has turned out to be statistically significant and enabling us to interpret the relationship in reasonable terms. The sample size and the number of vasectomized were too small to do any further statistical analysis for testing the association and for measuring the relative risk.
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