The purpose of the study is to assess the effects of sustained aromatase inhibitor therapy to reduce estrogen levels in elderly men with mild hypogonadism (a decreased level of sex hormones).

It has long been accepted that aging in men is associated with a slow, steady decline in gonadal androgen (male sex hormone) production. Several studies have explored androgen replacement, but the safety and efficacy of testosterone administration remains controversial. Aromatase inhibitors may provide a particularly useful way to restore normal androgen production in aging men.

This study will recruit 150 male volunteers, 60 years of age or older, to be randomized to receive either anastrozole or a placebo for 24 months. Six visits are planned over the 96-week treatment period.

Inclusion Criteria:

• Men ages 60 and older
• Serum testosterone between 150-300 ng/dL
• Symptoms suggestive of androgen deficiency