Progressive impairment of testicular endocrine function in ageing men: Testosterone and dihydrotestosterone decrease, and luteinizing hormone increases, in men transitioning from the 8th to 9th decades of life.

Annualized increases in LH are associated with declines in T and DHT, and predict poorer subsequent physical performance in oldest old men. Men transitioning from 8th to 9th decades exhibit biochemical evidence of progressively impaired testicular endocrine function, warranting further evaluation.