Comparative study of the density of L(2), L(3), and L(4) vertebrae in menopausal women aged over 50 years with osteoporosis

BACKGROUND: The Index used for osteoporosis detection was BMD measured in L(2), L(3), and L(4) vertebrae. We compared the density of the vertebrae to select the one with maximum change in the density for decreasing the cost and the time. METHODS AND MATERIALS: Ninety seven osteoporotic post-menopausal women with a mean age of 61.78 ± 8.48 (50 - 86) years and a mean body mass index (BMI) of 24.75 ± 2.66 (kg/m(2)) (18 - 30) without any known diseases and on any medication affecting bone mineral density (BMD) were examined at osteoporosis section of a teaching hospital. The vertebral bodies (L(2 -) L(4)) of participants were measured by using a dual energy X-ray absorptiometry system (DEXA). To investigate if the BMD measurement of a single vertebra could replace the total L(2 -) L(4) measurement, the mean BMDs and the correlations of the L(2 -) L(4) were compared. RESULTS: Among the 97 studied women, the mean BMI was 24.75 ± 2.66. The mean BMD of L(2), L(3), and L(4) vertebrae were 0.7199, 0.7258, and 0.7402, respectively. There was no significant difference between the mean BMD of L(2) and L(3) vertebrae (P > 0.05), suggesting a strong relationship between L(2) and L(3). The mean BMD in the L(4) vertebra was significantly higher than the other two vertebrae (P < 0.05), Statistical analysis showed that the BMD in all three L(2), L(3), and L(4) vertebrae were associated with BMI (r > 0 and P < 0.05), but there was no significant relationship between BMD and age in the three L(2), L(3), and L(4) vertebrae (r ≅ 0 and P > 0.05). CONCLUSION: Since the mean BMDs of L(2) and L(3) were not significantly different, and due to a very high correlation between L(2) and L(3), we recommend the measurement of L(2) rather than L(2 -) L(4) in order to save patient scanning time, cost, and the patient X-ray exposure.