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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 Wards 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.