Data on the association between bone microarchitecture assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) and sex steroids in men are scarce.

Our aim was to determine the association between serum sex steroids and bone microarchitecture assessed by HR-pQCT in men.

This is a cross-sectional analysis in the Structure of the Aging Men's Bones cohort.

The cohort was recruited from the general population.

We examined 1169 male volunteers aged 20–87 years. No specific exclusion criteria were used.

We collected blood samples and performed HR-pQCT at the distal radius and distal tibia.

We tested the hypothesis that low sex steroid levels are associated with poor bone microarchitecture in men.

Men aged younger than 65 years with bioavailable 17β-estradiol (bio-17β-E2) levels of14.4 pmol/L or less had higher cross-sectional and trabecular areas vs men with bio-17β-E2 greater than 14.4 pmol/L. In men aged 65 years or older, the higher the apparent free T concentration (AFTC), the higher was the distal tibia cortical density (P < .05). Cortical density and thickness as well as total and trabecular density increased with higher bio-17β-E2 levels. Similar results were found after adjustment for limb length and body height. Men with low AFTC and low bio-17β-E2 levels had lower cortical density and thickness at both skeletal sites compared with the reference group. In men with AFTC less than 272 pmol/L, those with low bio-17β-E2 less than 25 pmol/L had lower cortical density and thickness at both skeletal sites vs men having higher bio-17β-E2 levels.

In men aged 65 years and older, low bio-17β-E2 levels were associated with poor cortical bone status and, to smaller extent, lower trabecular density.