Bioimpedance spectroscopy in prediction of type I osteoporosis in menopaused women

Abstract

Bone mineral density (BMD) is a measure of survival for men and women, and it is used to diagnose Osteoporosis that can be diagnosed and treated with an e ective screening. We measured bioimpedance spectroscopy (BIS) parameters of 129 menopaused women and compared them with their DEXA reference measurements. We observed a region speci city for the central BMD assessment using BIS. When sensing electrodes are on the dominant hand and infraclavicular fossa, dominant arm fc correlates with the hip BMD (r = −0.412, P < 0.05), and fcut for Osteoporosis is 49.565 kHz. When sensing electrodes are over the hands, fc correlates with lumbar BMD (r = 0.580, P < 0.05), and fcut is 32.4 kHz. BMI also a ects BIS measure ments, and if BMI < 30 kg/m2 , the correlation of fc with the hip BMD is improved (r = −0.456, P < 0.05). fc may be alternatively calculated using the proposed origi nal 3P-Nyquist method. Both fc and the phase angle of the impedance measured at a single frequency are a function of the same impedance model parameters, and measure ment at a single frequency is less complicated than BIS. Phase angle of the measured impedance at 5 kHz has correlations with both lumbar (r = 0.403, P < 0.05) and hip (r = 0.559, P < 0.05) BMDs. When DEXA devices are not available or inaccessible, with its high mobility, non-invasive and cost-e ective nature, BIS can be a good substi tute in screening for BMD; however, clinical studies should be continued over a larger population to obtain the normative BIS cuto frequency or phase angle values. A prac tical 2D-ROC method for combining two discrete markers in a 2-way classi er is also proposed: both for simulated and clinical data, the AV ERAGE function combining markers has higher correct classi cation rates than the individual markers.|Keywords : Osteoporosis, Bone Mineral Density, Bioimpedance Spectroscopy, 3-Point Nyquist, Single Frequency Phase Angle, Characteristic Frequency, 2D-ROC.