Majallah-i Dānishgāh-i ’Ulūm-i Pizishkī-i Shahīd Ṣadūqī Yazd (Oct 2004)
Relationship between Body Mass Index and Bone Mineral Density in 45-55 Aged Women Referred to Imam Khomeini Hospital from 2000 to 2004
Abstract
Introduction: Fat body mass and body mass index (BMI) are important determinants of bone mineral density (BMD). Although the mechanism involved in this relation is uncertain, it seems that aromatization of androgens to esteradiol in adipose tissue is the most important explanatory mechanism. Materials & Methods: The purpose of this study is to evaluate the correlation between BMI and BMD among 63 women aged 45 to 55; 36(57.1%) postmenopausal and 27(42.9%) premenopausal; referred to Imam Khomeini hospital. We measured BMD at the lumbar spine (L1-L4), hip (femoral neck, trochanter, and intertrochanter), and Ward's triangle by dual energy X-ray absorptiometry (DEXA). Additionally, body composition was measured in this group. Results: Using WHO BMD T-score criteria, 28.8% of these women had osteoporosis in the lumbar spine and/or the femoral neck. As expected, relative positive linear correlations were found between BMI and BMD at L1-L4 (r=0.315; p = 0.026) and femoral neck (r=0.297; p=0.036), but these correlations were not significant in premenstrual women. Between the age, postmenopausal duration and BMI in relation with BMD, using multiple regression analyses, only BMI remained significant predictor for BMD. The correlation between BMI and BMD was improved after adjustment for age and postmenopausal period (R=0.402, p=0.034 for L1-L4; R=0.376, p=0.049 for femoral neck). Conclusion: The present results, confirming the results of other studies, have revealed a significant correlation between BMD and BMI in perimenopausal women. Our findings suggest that maintenance of adequate body mass (prevention for leanness) is important for prevention of postmenopausal bone loss.
