Estrogens and bone health in men

Area of Science:

• Endocrinology
• Bone Biology
• Gerontology

Background:

• Traditionally, estrogen and testosterone were considered primary sex steroids for female and male bone metabolism, respectively.
• Genetic studies in males with mutations affecting estrogen pathways revealed roles for estrogen in male bone health.
• Previous observational studies suggested estrogen's stronger correlation with bone mineral density (BMD) in elderly men compared to testosterone.

Purpose of the Study:

• To elucidate the distinct roles of estrogen and testosterone in regulating bone metabolism in elderly men.
• To determine whether estrogen primarily influences bone mass acquisition or retards bone loss in aging males.
• To establish causality through direct interventional studies on sex steroid withdrawal and replacement.

Main Methods:

• An interventional study was conducted on 59 elderly men (mean age 68 years) with suppressed endogenous testosterone and estrogen production.
• Participants underwent conditions involving withdrawal or continuation of testosterone and estrogen replacement.
• Bone turnover markers were assessed to evaluate the impact of different hormonal conditions on bone metabolism.

Main Results:

• Estrogen was identified as the primary regulator of bone resorption in elderly men.
• Both estrogen and testosterone were found to be important for maintaining bone formation.
• Estrogen demonstrated a dominant role in the regulation of the male skeleton.

Conclusions:

• Estrogen plays a dominant role in regulating bone resorption in elderly men.
• Estrogen and testosterone are both vital for maintaining bone formation.
• These findings challenge traditional views and highlight estrogen's critical importance in male skeletal health.