Incidence of disease after vasectomy: a record linkage retrospective cohort study.

OBJECTIVE To determine whether vasectomy is associated with an increased risk of several diseases, and in particular testicular cancer, after operation. DESIGN Retrospective cohort study using linked medical record abstracts. SETTING Six health districts in Oxford region. SUBJECTS 13,246 men aged 25-49 years who had undergone vasectomy between 1970 and 1986, and 22,196 comparison subjects who had been admitted during the same period for one of three specified elective operations, appendicitis, or injuries. MAIN OUTCOME MEASURES Hospital admission and death after vasectomy or comparison event. RESULTS The mean durations of follow up were 6.6 years for men with a vasectomy and 7.5 years for men with a comparison condition. The relative risk of cancer of the testis in the vasectomy cohort (4 cases) compared with that in the other cohorts (17 cases) was 0.46 (95% confidence interval 0.1 to 1.4), that of cancer of the prostate (1 v 5 cases) 0.44 (0.1 to 4.0), and that of myocardial infarction (97 v 226 cases) 1.00 (0.8 to 1.3). There was no evidence of an increase associated with vasectomy in the incidence of a range of other diseases. CONCLUSIONS Vasectomy was not associated with an increased risk of testicular cancer or the other diseases studied. With respect to prostatic cancer, while we found no cause for concern, longer periods of observation on large numbers of men are required.