Testicular torsion and low relative humidity in a tropical country.

One hundred and thirty one patients with testicular torsion were reviewed retrospectively to investigate the association of testicular torsion with air temperature and low relative humidity in Zaria, Nigeria. The incidence of testicular torsion was significantly increased during the harmattan season (November to February), when relative humidity is low and temperature decreased. Relative humidity was more closely correlated with the incidence of testicular torsion than was air temperature. Testicular torsion is a major contributor to male infertility in Zaria, and further study of its causes is required.