The condition is more common in blacks than in whites. The cause of nodular hyperplasia is unknown.
Prepubertal castration prevents subsequent development of nodular hyperplasia.
In individuals with 5 a -reductase deficiency, the enzyme that converts testosterone to dihydrotestosterone, the growth of the prostate is impaired. Administration of 5 a -reductase inhibitors is associated with reduction in size of the gland in many cases of nodular hyperplasia. There is some experimental evidence in dogs that estrogens may also play a role in nodular hyperplasia. In aging men estradiol levels increase and may possibly be involved in the etiopathogenesis of this disease. Symptoms of nodular hyperplasia are related to its secondary effects.