Changes in Trabecular Bone Score and Their Determinants in Young and Middle-aged Men: A Longitudinal Observational Study.

OBJECTIVE

To study bone turnover markers (BTM) and sex steroids in relation to trabecular bone score (TBS) in men.

MATERIAL AND

METHODS

Longitudinal, population-based study in 465 healthy men, aged 25 to 45 years at baseline. Lumbar spine TBS was calculated with TBS iNsight® version 4 (v19.4.1, core module, Medimaps, Pessac, France), which adjusts for soft tissue thickness correction via dual-energy X-ray absorptiometry measurements. SHBG, C-terminal telopeptide, and procollagen type 1 N-terminal propeptide were measured using immunoassays. Total testosterone (T) and estradiol (E2) were determined by liquid chromatography-tandem mass spectrometry and free T and free E2 calculated. Statistical analyses were conducted via linear mixed-effects modeling.

RESULTS

At baseline, TBS was positively associated with free T (P = .01), free E2, and total E2 (both P < .001) but not with total T nor with BTM. Over a follow-up of 12.5 years, TBS declined by 1.43% (P < .001). Higher baseline body mass index and trunk fat were predictive of greater decreases in TBS (P = .01 and P = .02). Neither baseline levels of sex steroids and BTM nor changes therein were associated with changes in TBS.

CONCLUSION

TBS already decreases in young and middle-aged healthy men, corroborating earlier studies showing early decrease of trabecular bone volume and changes in trabecular microarchitecture. Although we identified some potentially contributing determinants, the underlying mechanisms of changes in TBS and trabecular bone in young men are yet to be fully elucidated.