Discordant effect of body mass index on bone mineral density and speed of sound

BACKGROUND: Increased BMI may affect the determination of bone mineral density (BMD) by dual X-ray absorptiometry (DXA) and speed of sound (SOS) measured across bones. Preliminary data suggest that axial SOS is less affected by soft tissue. The purpose of this study is to evaluate the effect of body mass index (BMI) on BMD and SOS measured along bones. METHODS: We compared axial BMD determined by DXA with SOS along the phalanx, radius and tibia in 22 overweight (BMI > 27 kg/m(2)), and 11 lean (BMI = 21 kg/m(2)) postmenopausal women. Serum bone specific alkaline phosphatase and urinary deoxypyridinoline excretion determined bone turnover. RESULTS: Mean femoral neck – but not lumbar spine BMD was higher in the overweight – as compared with the lean group (0.70 ± 0.82, -0.99 ± 0.52, P < 0.00001). Femoral neck BMD in the overweight – but not in the lean group highly correlated with BMI (R = 0.68. P < 0.0001). Mean SOS at all measurement sites was similar in both groups and did not correlate with BMI. Bone turnover was similar in the two study groups. CONCLUSIONS: The high BMI of postmenopausal women may result in spuriously high BMD. SOS measured along bones may be a more appropriate means for evaluating bones of overweight women

Quantitative ultrasound bone measurements: normal values and comparison with bone mineral density by dual X-ray absorptiometry.

Normative data for qualitative ultrasound (QUS) measurements: speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness were established in 118 healthy women aged 20-86 years and in 42 healthy men aged 22-76 years. The relations between age, weight, height, and QUS were studied. QUS measurements were negatively correlated with age in both sexes. In women, age was accepted as first factor (R2 = 0.39 for SOS, 0.35 for BUA, and 0.45 for stiffness, P < 0.001); weight was accepted as second factor for BUA (R2 = 0.44, P < 0.001). In men, age was the only significant parameter (R2 = 0.41 for SOS, 0.39 for BUA, 0.43 for stiffness, P < 0.001). QUS measurements of the right and left feet were highly correlated unless unilateral foot pathology such as algodystrophy was present. Significant correlations were found between QUS of the calcaneus and dual X-ray absorptiometry (DXA) of the lumbar spine (R = 0.67, P < 0.01 for SOS; R = 0.57, P < 0.02 for BUA; R = 0.65, P < 0.01 for stiffness).Comparative StudyJournal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Quantitative ultrasound of bone in institutionalized elderly women: a cross-sectional and longitudinal study.

Quantitative ultrasound of bone is a promising method for bone assessment: radiation-free, portable and predictive of hip fracture. Its portability allowed us to study the relationships between ultrasonic parameters of bone with age and with non-vertebral fractures in elderly women living in 19 nursing homes. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the calcaneus were measured (and the stiffness index calculated) in a sample of 270 institutionalized women, aged 85 +/- 7 years, using an Achilles bone densitometer (Lunar). The effects of age, history of non-vertebral and non-traumatic fractures, body mass index, triceps skinfold and arm circumference were assessed on BUA, SOS and stiffness index. Furthermore, to evaluate longitudinally the influence of aging on the ultrasound parameters of bone, 60 subjects from the same group had a second ultrasound measurement after 1 year. The cross-sectional analysis of the data on all 270 women showed a significant decrease (p &lt; 0.001) with age in BUA, SOS and stiffness index (-0.47%, -0.06%, and -1.01% respectively per year). In the 94 women, (35%) with a history of previous non-vertebral fractures, ultrasound parameters were significantly lower (p &lt; 0.0001) than in the 176 women with no history of fracture (-8.3% for BUA, -1.3% for SOS, -18.9% for stiffness index). In contrast, there was no significant difference in anthropometric measurements between the groups with and without previous non-vertebral fractures, although the measurements decreased significantly with age. In the longitudinal study, repeated quantitative ultrasound after 11.4 +/- 0.8 months showed no significant decrease in BUA (-1%) but a significant decrease in SOS (-0.3%, p &lt; 0.0001) and in stiffness index (-3.6%, p &lt; 0.0002). In conclusion, quantitative ultrasound of the calcaneus measures properties of bone which continue to decline in institutionalized elderly women, and is able to discriminate women with previous non-vertebral fractures