Effects of aromatase inhibition in hypogonadal older men: a randomized, double-blind, placebo-controlled trial

To assess the effects of sustained aromatase inhibition in older hypogonadal men. In a 1-year randomized, double-blind, placebo-controlled trial, 88 men, aged 60 years and older with testosterone levels between 5.2 and 10.4 nmol/l on a single measure or between 10.4 and 12.1 nmol/l on two consecutive measures, and with symptoms of hypogonadism were recruited. Subjects received either anastrozole 1 mg daily or placebo. Changes in gonadal steroid hormone levels, body composition [by computerized tomography (CT) and dual X-ray absorptiometry (DXA)], strength, prostate specific antigen (PSA), symptoms of benign prostatic hypertrophy (BPH), haematocrit and lipid levels were assessed. Testosterone levels increased from 11.2 +/- 3.3 nmol/l at baseline to 18.2 +/- 4.8 nmol/l at month 3 (P < 0.0001 vs. placebo) while bioavailable testosterone levels increased from 2.7 +/- 0.8 nmol/l at baseline to 5.4 +/- 1.7 nmol/l at month 3 (P < 0.0001 vs. placebo). Testosterone and biotestosterone levels peaked at month 3 and then declined by month 12 (though they remained significantly higher than baseline and greater than placebo). E-2 levels decreased from 55.8 +/- 15.4 pmol/l at baseline to 42.2 +/- 13.6 pmol/l at month 3 and then remained stable (P < 0.0001). Body composition and strength did not change, nor did PSA, BPH symptoms, haematocrit or lipid levels. Anastrozole administration normalized androgen production in older hypogonadal men and decreased E-2 production modestly. These alterations did not improve body composition or strength.