A focused evaluation of lumbar spine trabecular bone score in the first year post-menarche.

Abstract

Trabecular bone score (TBS) evaluates lumbar spine (LS) trabecular texture from DXA images. Limited evidence suggests low TBS in pre-pubertal girls. TBS has not been assessed in the context of the key peri-menarcheal bone accrual phase. Thus, we evaluated (1) whether "normal" adult TBS (≥1.35) is reached in the first year post-menarche and (2) the role of maturational timing (menarcheal age) and status (gynecological age) in TBS variation. For 44 healthy girls aged 11 to 13years, whole body and LS DXA scans were obtained within 1year post-menarche. As TBS is optimized for adults and can be affected by body thickness, custom software provided unadjusted "rawTBS" and adjusted for tissue thickness "corrTBS" (TBS iNsight, Medimaps, France). Correlations evaluated menarcheal age and gynecological age as factors in LS bone mineral content (BMC), areal bone mineral density (BMD), and TBS. Lowest observed TBS exceeded 1.35 (rawTBS=1.362; corrTBS=1.352). Menarcheal age correlated negatively with rawTBS (r=-0.34, p=0.02), with a similar trend for corrTBS (r=-0.29, p<0.06). Gynecological age did not correlate with TBS but was positively correlated with LSBMD (r=+0.37, p=0.01). Correlations with body composition variables differed between rawTBS and corrTBS. In this healthy cohort, "normal" adult TBS is present by 1year post-menarche, 2years before projected LS peak bone mass. Thus, TBS may be a useful bone architectural screen during the first post-menarcheal year, enabling intervention to improve structure prior to "peak bone mass". Longitudinal studies are needed to elucidate TBS development and intervention response.