Relationship of sex steroid hormones with bone mineral density (BMD) in a nationally representative sample of men

Objective Sex steroid hormones influence bone mineral density (BMD) in women, but are less well‐studied in men. We evaluated the association of serum total and free sex steroid hormones and SHBG with osteopaenia in a nationally representative sample of men aged 20–90 years. Design BMD and sex steroid hormones were measured among participants in NHANES III, a cross‐sectional study of the US population. Population A total of 1185 adult men in morning examination session of Phase I of NHANES III (1988–91). Measurements Relation of oestradiol (E₂), testosterone, and SHBG concentrations with BMD. Osteopaenia was defined as 1–2·5   SD below the mean for white men aged 20–29 years. Results Men in the lowest quartile of free E₂ had 70% increased odds (OR = 1·69, 95% CI 0·95–2·98) of osteopaenia compared with men in the highest quartile. Men in the lowest quartile of free testosterone had nearly four times the odds of osteopaenia than those in the highest quartile (OR = 3·82, 95% CI 1·87–7·78). Lower concentrations of SHBG appeared protective against osteopaenia (P‐trend = 0·01). Neither total testosterone nor total E₂ was associated with BMD, although men with clinically low E₂ (< 20 ng/l) had lower BMD (0·930 g/cm², 95% CI 0·88–0·98) than men with normal‐range E₂ (1·024 g/cm², 95% CI 1·01–1·04; P = 0·004). Findings for free E₂ were most pronounced among elderly men, while the findings for free testosterone were most pronounced among younger men. Conclusions In this nationally representative study, men with lower free E₂, lower free testosterone, and higher SHBG concentrations in circulation were more likely to have low BMD.