ETIOLOGY OF TESTICULAR CANCER - ASSOCIATION WITH CONGENITAL-ABNORMALITIES, AGE AT PUBERTY, INFERTILITY, AND EXERCISE

Objective-To determine the risk of testicular cancer associated with u ndescended testis, inguinal hernia, age at puberty, marital status, in fertility, vasectomy, and amount of exercise. Design-A population base d case-control study with a questionnaire administered by an interview er and with relevant supplementary data extracted from general practit ioners' notes. Setting-Nine health regions within England and Wales. S ubjects-794 men, aged 15-49 years, with a testicular germ cell tumour diagnosed between 1 January 1984 and 1 January 1987; each had an age m atched (within one year) control selected from the list of their gener al practitioner. Results-There was a significant association of testic ular cancer with undescended testis (odds ratio 3.82; 95% confidence i nterval 2.24 to 6.52) and inguinal hernia (1.91; 1.12 to 3.23). The ex cess risk associated with undescended testis was eliminated in men who had had an orchidopexy before the age of 10 years. There were positiv e associations with early age at voice breaking, early age at starting to shave, and infertility. There was a significant association with a sedentary lifestyle and a moderate protective effect of exercise. The re was no association with vasectomy. Conclusion-This study confirms p revious reports that developmental urogenital abnormalities result in an increased risk of testicular cancer. The trend to perform orchidope xy at younger ages may reduce the risk associated with undescended tes tis. The increased risks associated with early age at puberty and low amounts of exercise may be related to effects of exposure to endogenou s hormones. Changes in both of these factors may partly contribute to the increasing rates of testicular cancer observed in the past few dec ades.