Single prediction equation for bioelectrical impedance analysis in adults aged 22–59 years

Abstract

The purpose of this study was to validate a single bioelectrical impedance analysis (BIA) equation in healthy Indian subjects aged 22–59 years with a body mass index (BMI) between 16.8 and 47.3 kg m⁻². Healthy subjects (34 men and 30 women) were measured by two methods: bone mineral content (BMC) was measured by a commercial body composition analyser and bioelectrical impedance at various frequencies was measured by a newly developed bioelectrical impedance measurement system. As correlations were high and prediction error was low, a single equation was developed using all subjects as follows: BMC = −3.5268 + (0.0279 × h) + (0.0145 × w) + (184 × (h²/Z_body50)) – (1.08 × (w × h²/Z_body6.25)) – (0.0032 × (age)) – (0.103 × (sex); men = 1, women = 0). BMC measured from commercial instrument InBody720 was 2.552 ± 0.457 kg. BMC predicted by equation was 2.554 ± 0.447 kg (R = 0.976, adjusted R² = 0.948, standard error of estimate = 0.104 kg, total error = 0.09987 kg). The results of this study show that the newly developed multi-frequency bioelectrical impedance measurement system with the single prediction BIA equation can be used in screening the subjects suspected with osteoporosis and for follow-up study of the patient under the therapy for osteoporosis. For validation of commercial instrument InBody720, BMC of 22 healthy subjects was measured by InBody720 and dual-energy X-ray absorptiometry. High correlation (R = 0.9531) and low error (total error = 0.0913 kg) was found between these two methods.

Keywords:

• Body parameters
• Bioelectrical impedance analysis
• Bone mineral content
• Osteoporosis

Acknowledgements

This study was supported by the Electronics Division, Bhabha Atomic Research Centre (BARC), Mumbai and Dr Balabhai Nanavati Hospital, Mumbai. We are thankful to Aarti Karkera for helping in data collection and S. K. Athawale for proof-reading. We are also grateful to G. P. Srivastava, Director, E & I Group, R. K. Patil, Associate Director, E & I Group (C) and C. K. Pithawa, Head, Electronics Division of BARC for their support and encouragement.

Declaration of interest: The authors declare that they have no conflict of interest.