Vasectomy and non-fatal acute myocardial infarction: a hospital-based case-control study in Seoul, Korea

One hundred and sixty-three Korean men aged 35-64 who were admitted to a university-affiliated hospital diagnosed for the first time with acute myocardial infarction (AMI) were compared with 326 matched non-AMI patients hospitalized with a diagnosis considered unrelated to vasectomy. When other potentially confounding variables were controlled for, vasectomized men were found to be 2.6 times (adjusted odds ratio) more likely to have had an AMI as compared to the non-vasectomized men (95% CL: 1.1, 6.1). The adjusted odds ratio of AMI for subjects having had a vasectomy less than or equal to 9 years ago was the same as those who had a vasectomy greater than or equal to 15 years (OR = 2.5), although those who had had a vasectomy 10-14 years ago were associated with a higher odds ratio of 4.2. Among those subjects with vasectomies who were also cigarette-smokers and/or hypertensive, the risk of development of AMI increased multiplicatively compared with those with none of these conditions. We suspect that our finding of this positive association may be spurious due to possible bias introduced during selection of controls and during the process of data collection. Cancer patients may have been less likely to undergo an elective surgical procedure such as vasectomy prior to the admission. When multivariate analysis included only controls who were non-cancer patients (N = 241 controls), the adjusted odds ratio between vasectomy and hospitalization for AMI was reduced to 2.1, (95% CL: 0.8, 5.7), which is no longer statistically significant. When the analysis was further limited to only those control subjects admitted with a diagnosis of digestive system problems, the adjusted odds ratio was reduced to close to unity (1.1). Recognizing the importance of the study topic and the fact that all previous epidemiological studies showed no association between vasectomy and cardiovascular diseases, we urge further studies. A historical cohort study in the Korean setting is considered feasible and is recommended.