Relationship of ultrasonographic endometrial thickness and uterine size to bone mineral density in postmenopausal women

Abstract

Objectives: The aim of the present study was to investigate the relations of ultrasonographic endometrial thickness and uterine size to bone mineral density (BMD).

Methods: Subjects were 200 postmenopausal women (mean age +/- S.D., 57.4 +/- 7.7 years; range, 46-75 years). Age, age at menopause, years since menopause (YSM), height, weight, and body mass index (BMI, weight/height2) were recorded. Endometrial thickness and uterine size (i.e. uterine volume and cross-sectional area) were measured by transvaginal ultrasonography. BMD of the nondominant forearm (one-tenth of the distance from the distal end of the radius) was measured by dual-energy X-ray absorptiometry. Relations of these variables to BMD were investigated.

Results: BMD was inversely correlated with age and YSM (r = -0.69, P < 0.0001; r = -0.56, P < 0.001, respectively), while was positively correlated with uterine volume, uterine cross-sectional area, and endometrial thickness (r = 0.52, P < 0.001; r = 0.45, P < 0.01; r = 0.32, P < 0.05, respectively). After adjusting for age, YSM, and BMI, BMD was still correlated with uterine volume and uterine cross-section (P < 0.01 and 0.05, respectively), while correlation of endometrial thickness with BMD disappeared.

Conclusion: Ultrasonographic uterine size shows higher correlation with BMD than endometrial thickness in postmenopausal women. This may be attributable to the fact that uterine size rather than endometrial thickness reflects the duration of estrogen deficiency after menopause.