Effects of aromatase inhibition on bone mineral density and bone turnover in older men with low testosterone levels.
BACKGROUND
Aging is associated with declining gonadal steroid production, low bone mineral density (BMD), and fragility fractures. The efficacy and safety of testosterone replacement in older men remains uncertain.


OBJECTIVE
The objective of the study was to assess the effects of aromatase inhibition on BMD in older men with low testosterone levels.


METHODS
This was a 1-yr, double-blind, randomized, placebo-controlled trial that was conducted at a tertiary care academic center in Boston, MA.


METHODS
Participants included 69 men aged 60+ yr with borderline or low testosterone levels and hypogonadal symptoms.


METHODS
Intervention included 1 mg anastrozole daily or placebo.


METHODS
Changes in gonadal steroid hormone levels, BMD, and bone turnover markers were measured.


RESULTS
Mean serum testosterone increased from 319 +/- 93 ng/dl at baseline to 524+/-139 ng/dl at month 3 (P < 0.0001) and declined slightly to 474 +/- 145 ng/dl by 1 yr. Estradiol levels decreased from 15 +/- 4 pg/ml at baseline to 12 +/- 4 pg/ml at month 3 and then remained stable (P < 0.0001). Posterior-anterior (PA) spine BMD decreased in the anastrozole group as compared with placebo (P = 0.0014). In the anastrozole group, PA spine BMD decreased from 1.121 +/- 0.141 g/cm(2) to 1.102 +/- 0.138 g/cm(2), whereas in the placebo group, PA spine BMD increased from 1.180 +/- 0.145 g/cm(2) to 1.189 +/- 0.146 g/cm(2). Qualitatively similar, but not statistically significant, changes occurred at the other sites. Bone turnover markers were not affected by anastrozole therapy.


CONCLUSIONS
In older men, aromatase inhibition increases testosterone levels, decreases estradiol levels, and appears to decrease BMD. Aromatase inhibition does not improve skeletal health in aging men with low or low normal testosterone levels.
Burnett-Bowie
Sherri-Ann M
SA
Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114, USA. sburnett-bowie@partners.org
McKay
Elizabeth A
EA
Lee
Hang
H
Leder
Benjamin Z
BZ
D000368:Aged; D000375:Aging / Q000502:physiology; D000077384:Anastrozole; D047072:Aromatase Inhibitors / Q000494:pharmacology*; D015415:Biomarkers / Q000032:analysis; D015519:Bone Density / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D004311:Double-Blind Method; D023381:Endpoint Determination; D004797:Enzyme-Linked Immunosorbent Assay; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009570:Nitriles / Q000494:pharmacology*; D010349:Patient Compliance; D013256:Steroids / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D013739:Testosterone / Q000097:blood*; D014230:Triazoles / Q000494:pharmacology*
D047072:Aromatase Inhibitors; D015415:Biomarkers; D006728:Hormones; D009570:Nitriles; D013256:Steroids; D014230:Triazoles; D000077384:Anastrozole; D013739:Testosterone