The long-term effect of specific type II 5alpha-reductase inhibition with finasteride on bone mineral density in men: results of a 4-year placebo controlled trial.

Purpose: We determine the effect of long-term suppression of dihydrotestosterone with finasteride, a specific type II 5alpha-reductase inhibitor, on bone mineral density.

Materials And Methods: As part of a large (3,040 cases) 4-year, double-blind, placebo controlled trial designed to assess the long-term effects of finasteride in men with benign prostatic hyperplasia, 157 men 46 to 76 years old who were randomized to receive either 5 mg. finasteride or placebo underwent dual energy x-ray absorptiometry of the lumbar spine at baseline and at years 2, 3 and 4.