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

Abstract

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.

PIP: Researchers compared data provided by mothers of 37 testicular cancer patients 46 years old (1986) at 9 hospitals on the northern island of Hokkaido in Japan with those from 37 mothers of matched controls (1987) to examine the significance of maternal or prenatal factors associated with testicular cancer in Japan. The univariate analysis did not indicate any statistically significant differences in the variables. Yet when data were controlled for age at indexed birth, duration of breast-feeding the indexed child, birth order, and experience of an induced abortion, the researchers found that mothers of testicular cancer patients were more likely to have fewer live births than the mothers of the controls (relative risk=0.43; p=.025). No other significant differences existed. The researchers suggested several possible explanations and proposed that a common third factor may have played a role. For example, studies in Europe showed that the significant factor may be higher social class, since higher social class mothers have fewer live births, and testicular cancer is more prevalent in higher social class men. This also may be due to a different diet or sedentary life style in these men. The hormonal state of an infertile mother may be related to a higher incidence of testicular cancer in her son. Two possible bias sources in this study included a low incidence of testicular cancer in Japan which yielded a small sample size and a low response rate (60% for case mothers and 70% for control mothers). The researchers concluded that additional research is needed to clarify the association between testicular cancer and maternal subfertility.