Influence of age at menarche on forearm bone microstructure in healthy young women.

Background: Shorter estrogen exposure from puberty onset to peak bone mass attainment may explain how late menarche is a risk factor for osteoporosis. The influence of menarcheal age (MENA) on peak bone mass, cortical, and trabecular microstructure was studied in 124 healthy women aged 20.4 ± 0.6 (sd) yr. Methods: At distal radius, areal bone mineral density (aBMD) was measured by dual-energy x-ray absorptiometry, and volumetric bone mineral density (BMD) and microstructure were measured by high-resolution peripheral computerized tomography, including: total, cortical, and trabecular volumetric BMD and fraction; trabecular number, thickness, and spacing; cortical thickness (CTh); and cross-sectional area (CSA). Results: Median MENA was 12.9 yr. Mean aBMD T score of the whole cohort was slightly positive. aBMD was inversely correlated to MENA for total radius (R = −0.21; P = 0.018), diaphysis (R = −0.18; P = 0.043), and metaphysis (R = −0.19; P = 0.031). Subjects with MENA more than the median [LATER: 14.0...