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Low 17-beta-estradiol levels linked to poor cortical bone status in older men
Low levels of 17-beta-estradiol in men aged at least 65 years are linked to poor cortical bone condition and may compromise trabecular bone density, according to findings from the STRAMBO cohort.
“In men, 17-beta-estradiol is a major determinant of cortical bone, mainly in those with low testosterone level,” the researchers wrote. “Although the impact of sex steroid deficits on bone microarchitecture decay in men is modest, men with low sex-steroid levels would benefit from the assessment of bone microarchitecture.”
The cross-sectional study recruited 1,169 male participants aged 20 to 87 years, with no exclusion criteria applied. The participants responded to interviewer questionnaires regarding lifestyle and health status, and underwent blood testing for sex hormone concentrations. Study participants also underwent high-resolution peripheral quantitative CT to assess bone density at the distal radius and distal tibia. The researchers hypothesized that low sex-steroid levels would result in poor bone microarchitecture.
The researchers found that men with bioavailable 17-beta-estradiol levels ≤14.4 pmol/L who were younger than 65 years had higher cross-sectional and trabecular areas compared with men with bioavailable 17-beta-estradiol levels >14.4 pmol/L. Among the men aged at least 65 years, there was a correlation between higher free-testosterone concentration and higher distal tibia cortical density (P <.05). Higher bioavailable 17-beta-estradiol levels also were linked to increases in cortical density and thickness, as well as overall and trabecular bone density.
Adjustment for limb length and body height revealed similar results. The researchers observed lower cortical density and thickness at both skeletal sites in men with low apparent free-testosterone concentration and low 17-beta-estradiol levels compared with the reference group. Of the men with apparent free-testosterone concentrations <272 pmol/L, those with low 17-beta-estradiol levels <25 pmol/L had lower cortical density and thickness at both sites compared with men with higher bioavailable concentrations of 17-beta-estradiol.
The researchers said deficiencies in sex steroids were not found to have a major effect on bone microarchitecture, but these relationships should nevertheless be studied further.
Disclosure: The researchers report no relevant financial disclosures.