Trabecular bone score (TBS) extracts a texture parameter from pixel grey-level variations in DXA lumbar spine images. The TBS is claimed to be a measure of trabecular structure and was validated in an in-vitro study of vertebral bodies with micro-CT1. TBS has shown the potential for fracture pre-diction in adults2. However, data are sparse regarding the reliability and usefulness of TBS3 and the method has not previously been applied in children.
Methods: The Manchester Childrens DXA BMD reference database (Hologic QDR Discovery) was published and is widely applied in UK4. The LS-DXA (n=463; males; age mean (S.D.) range; n=252, 15.0 (5.6), 5.225 years; females n=211; 12.6 (3.9), 5.420.7 years) have been retrospectively analyzed and TBS L1L4 extracted. The relationships between TBS and age, BMD (g/cm2), bone mineral apparent density (BMAD), height, weight and BMI were examined. Linear regression analysis explored predictors of TBS; model 1 included LSBMD, age, BMI, model 2 LSBMAD, age, BMI. Significant predictors are reported.
Results: There was a significant correlation between TBS and age in females (r=0.63, P<0.001) and males (r=0.67, P<0.001), and between TBS and BMI (females r=0.41, P<0.001; males r=0.41, P<0.001). For both males and females mean TBS was lower in the younger (<13 years) relative to the older (>13 years) age groups (P<0.001), but not significantly different between children in annually adjacent year groups. TBS was lower (P<0.001) in children with a lower (<20 kg/m2) vs a higher BMI (>20 kg/m2). Correlation between BMAD and TBS was r=0.61, P<0.01 in females and r=0.62, P<0.01 in males. Predictors of TBS were: females: i) L1L4 aBMD (P<0.001), and BMI (P=0.002); ii) L1L4 BMAD (P<0.001), age (P<0.001), BMI (P=0.086); males: i) L1L4 BMD (P<0.001), BMI (P<0.001); ii) L1L4 BMAD (P<0.001), age (P<0.001), BMI (P=0.004).
Conclusions: TBS is related to age, aBMD and BMAD in growing children. The dichotomy of the relationship with age and BMI may be due to technical limitations in the method. Our findings require further investigation in this and other populations. A critical evaluation of the tool and whether it improves our understanding of childrens bone health is required.
K Ward is funded by Medical Research Council Grant Code U10596037.
Acknowledgement for access to specialist TBS analysis software: http://www.medimaps.fr/.
References: 1. J Clin Densitom 2011 14 302312.
2. J Bone Miner Res 2011 26 27622769.
3. Osteoporos Int 2012 23 14891501.
4. Arch Dis Child 2007 92 5359.
22 - 25 Jun 2013