T-SCORE OF TRABECULAR AND CORTICAL BONE IN NORMAL POSTMENOPAUSAL WOMEN

Objective: The T score of the cortical and trabecular bone compartment s (T score of BMDTrab and T score of BMDCorti) was calculated in healt hy postmenopausal women to determine which bone compartment loses more bone mass. Material and methods: A total 134 healthy postmenopausal w omen (mean age 55.1 +/- 6.3 years) and 67 healthy premenopausal women (mean age 36.0 +/- 8.6 years) were studied. Determinations were made u sing peripheral quantitative computed tomography (pQCT) of the nondomi nant forearm. The postmenopausal women were divided into groups by yea rs since menopause (YSM): two early postmenopausal groups: < 5 YSM and 6-10 YSM; and two late postmenopausal groups: 11-20 YSM and > 20 YSM. Results: There was a significant correlation between the T score of B MDTrab and the T score of BMDCorti (P < 0.0001). Both correlated negat ively and significantly with age (P < 0.001 and P < 0.0001, respective ly) and neither correlated with weight. The Wilcoxon test showed no si gnificant differences between the trabecular and cortical T scores in the overall group of women. By YSM, only the > 20 YSM group showed sig nificant differences (P < 0.005). The ANOVA post hoc Bonferroni/Dunn t est showed a gigficant difference in the T score of BMDTrab by YSM onl y in the < 5 YSM versus 11-20 YSM groups (P = 0.007) and in the < 5 YS M versus > 20 YSM groups (P < 0.0001). The T score of BMDCorti by YSM differed significantly only between the < 5 YSM versus 11-20 YSM group s (P < 0.0001) and between the 11-20 YSM and > 20 YSM groups (P < 0.00 5). Conclusion: In contrast with what has been postulated in recent st udies, our results showed that postmenopausal bone loss was similar in the cortical and trabecular bone compartments in the first 20 years a fter menopause. Trabecular bone loss was greater than cortical bone lo ss in late menopause (> 20 years). (C) 1998 Elsevier Science Ireland L td. All rights reserved.