Bone Abstracts

Areal bone mineral density (aBMD) of the PA spine and proximal femur remained the gold standard for WHO classification of osteoporosis, fracture prediction and patient monitoring. Unfortunately, with age it is not infrequent to observe the presence of degenerative disease such as spinal osteoarthritis which would have a positive artifactual impact on aBMD which could lead to an erroneous interpretation. In a previous study it has been demonstrated that apparently such artifact would have limited impact on the trabecular bone score (TBS). The aim of this study was to evaluate the PA spine TBS and site matched BMD (BMDLS) in healthy women of various ages and verify how the ‘normal’ presence of such artifact would impact the outcome.

All women who had prior exposure to corticosteroids, systemic illness or who were taking medications known to affect bone metabolism were not included. Similarly all fractured subjects were excluded from this analysis. We’ve examined 176 healthy women aged 40–79 years (mean age – 53.4±0.6 years; mean height – 1.64±0.005 m; mean weight – 80.4±1.1 kg). The patients were divided into the following age-dependent groups: 40–49 years (n=53), 50–59 years (n=89), 60–69 years (n=17), 70–79 years (n=17). BMD of whole body, PA lumbar spine and proximal femur were measured by DXA method (Prodigy, GEHC Lunar, Madison, WI, USA) and PA spine TBS were assessed by TBS iNsight software package installed on our DXA machine (Med-Imaps, Pessac, France).

We observed a significant decrease of TBS (L1–L4) as a function of age (40–49 years – 1.334±0.016; 50–59 years – 1.289±0.013; 60–69 years – 1.194±0.034; 70–79 years – 1.205±0.050; F=6.56; P=0.0003) whereas PA spine BMD was significantly increasing with age (BMDLS: 40–49 years – 1.126±0.015 g/cm²; 50–59 years – 1.234 0.013 g/cm²; 60–69 years – 1.343±0.053 g/cm²; 70–79 years – 1.348±0.100 g/cm²; F=4.04; P=0.008). In this population, BMD of femoral neck didn’t show any significant variations.

TBS decreased with age significantly. BMD of lumbar spine significantly increased in healthy women depending on their age, as it seems to reflect the impact of aggravating spinal osteoarthritis. This contradiction can be traced to the spinal osteoarthritis and degenerative diseases progressing with age in the elderly patients. Thus, TBS is an independent parameter which has a potential diagnostic value of its own, without taking into account the bone mineral density in case of bone degenerative diseases.