Title: AB1324 Studying the relationship between body mass index, bmi, and bone mineral density, bmd, of lumbar vertebrae and femoral neck
Abstract:<h3>Background</h3> There is a well known association between BMI and BMD in as much that patients with higher BMI have higher BMD, secondary to factors including muscle mass and fat mass<sup>1</sup>....<h3>Background</h3> There is a well known association between BMI and BMD in as much that patients with higher BMI have higher BMD, secondary to factors including muscle mass and fat mass<sup>1</sup>. However it is not clear whether this relationship is equal in all areas of the body assessed for bone mineral density (BMD) estimation, which tradtionally are the lumbar vertebrae, and different areas of the femur. Our study sets out to establish if this association exists in the lumbar vertebrae and femoral neck, since Dual Energy X-ray Absorptiometry (DEXA) scans measure BMD of both. <h3>Objectives</h3> To explore the relationship between BMI and BMD in a cohort of patients referred for DEXA scan. <h3>Methods</h3> Data was used from patients referred for DEXA scan to Royal Lancaster Infirmary between (2006 and 2010). The following were recorded: age, sex, height, weight, BMI, BMD at L1-L4, BMD at femoral neck (left and right) and BMD at hip (left and right). Male and female patients were analysed separately. A Linear regression model was fitted using BMI with BMD at L1, L2, L3, L4, total right hip, total left hip, right neck of femur and left neck of femur as explanatory variables. Adjusted r-squared (r2) values were used to compare the fit of the models, both with and without age-adjustment. <h3>Results</h3> 35759 patients were used in the study, of which 84% were female. Mean age was 62.2 years (SD 12.8), mean height was 161.9 cm (SD 8.3), mean weight was 70.4 kg (SD 15.3), mean BMI was 26.8 kg/cm2 (SD 5.2). <h3>Conclusions</h3> Our study identifies that there is a positive correlation between increasing BMI and BMD at lumbar vertebrae and at the hips, in both male and female patients. We also identified age as a contributing factor. The relationship between BMI and BMD appears to be more significant in the hip and neck of femur than the lumbar spine. When studying the lumbar spine we found that the association is greater the higher up the lumbar spine, with most positive correlation being in L1 of female patients. This would indicate that using the lower lumbar spine might not be appropriate to assess bone health. <h3>Reference</h3> [1] Reid IR. Relationships among body mass, its components, and bone. Bone. 2002;5:547–55 <h3>Disclosure of Interest</h3> None declaredRead More