Risk factors for cryptorchism among populations at differing risks of testicular cancer

Cryptorchism is strongly associated with the development of testicular germ cell tumours (TGCTs), possibly owing to a common aetiology. However, while TGCT incidence varies greatly between white and black men, little variability has been reported between the two groups in cryptorchism prevalence. This may suggest that cryptorchism risk factors differ by ethnicity.

To examine this hypothesis, a prospective analysis was conducted among black and white participants in the US Collaborative Perinatal Project. White participants included 238 cryptorchid sons and 12,296 non-cryptorchid sons, while black participants included 188 cryptorchid sons and 11,942 non-cryptorchid sons.

While cryptorchism was significantly more common among white sons (1.90% vs 1.55%; P = 0.04), the difference was incompatible with the 5-fold difference in TGCT rates. The principal maternal risk factors among white sons were age (P = 0.03), hypertension/proteinuria (P = 0.006), and length of time to become pregnant (P = 0.055), while major maternal risk factors among black sons were age (P = 0.06), height (P = 0.007), weight (P = 0.06), and radiation exposure (P = 0.02). Only maternal height, however, had a different relationship with risk among black and white sons. Neonatal associations with risk (shorter gestational age, lower birthweight, shorter length) were similar in the two groups.

These results do not support the hypothesis that the risk factors for cryptorchism vary dramatically by ethnicity but may suggest that cryptorchism is not as closely linked to TGCT among black men as among white men.