Maternal factors of testicular cancer: a case-control study in Japan.

A case-control study was undertaken in Japan to clarify maternal or prenatal factors associated with testicular cancer. Information was obtained from 37 mothers of testicular cancer patients, recruited from the discharge records of nine hospitals in Hokkaido, the northern island of Japan. Thirty-seven mothers forming a control group were then surveyed at five public health centers. Each control was selected by individually matching the sex and birth year to a testicular cancer case. Univariate analysis revealed that there were no statistically significant differences in the variables surveyed. Multivariate logistic regression analysis, however, showed that case mothers had significantly fewer live-births than control mothers when the following four variables were adjusted (adjusted relative risk per live-birth = 0.43, P = 0.025): age at indexed birth, duration of breast-feeding for indexed child, birth order, experience of induced abortion.