Ultrasound findings from a cross-sectional study of 162 postmenopausal women might help explain the paradox that women with type 2 diabetes can have higher bone mineral density than nondiabetic women and yet have a greater risk of fractures.
The study confirmed previous reports that bone mineral density (BMD) as measured by dual x-ray absorptiometry (DXA) is higher in women with type 2 diabetes than in women without diabetes. Yet a new diagnostic tool, quantitative ultrasound, revealed that the speed of sound through bone was lower in diabetic women.
This may indicate that their denser bone is in some way of lesser quality, compared with the bone of women without type 2 diabetes.
The findings suggest that quantitative ultrasound is a useful tool in detecting impaired bone quality in postmenopausal women with type 2 diabetes, and that it might have greater promise than DXA in detecting bone defects in diabetic patients, the authors wrote.
Dr. Bei Tao of Shanghai (China) Jiao-tong University School of Medicine and colleagues enrolled 76 postmenopausal women with type 2 diabetes and 86 nondiabetic postmenopausal women. In the diabetic women, mean BMD as measured by DXA was 1.06 g/m
Quantitative ultrasound was used to assess the axial speed of sound along the distal third of the radius, the proximal phalanx of the third finger, and the midshaft of the tibia. The speed of sound was higher at all three locations in the nondiabetic women, compared with the diabetic women (see bar chart), the investigators reported online in the Journal of Clinical Endocrine Metabolism (2008 Mar. 4 [doi:10.1210/jc.2007–1760]).
Among the nondiabetic women, BMD at each site correlated significantly with the speed-of-sound measurements. But among the diabetic women, only the speed of sound at the phalangeal site correlated significantly with all three BMD values; the speed of sound in the tibia correlated with none of the BMD values, and the speed of sound in the radius correlated with only the BMD of the femoral neck.
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