Text Box: MEASUREMENT OF BODY FAT USING LEG TO LEG BIO-IMPEDANCE METHOD IN CHILDREN Sung YT Rita1, Yu CW1, Lau Patrick2, Lam KW Peggo3, Nelson EAS1 1 Department of Paediatrics, 2 Department of Sports Science and Physical Education, 3 Centre for Clinical Trials and Epidemiological Research, The Chinese University of Hong Kong, Shatin, Hong Kong Objective: To validate a leg-to-leg bioimpedance analysis (BIA) device in the measurement of body composition in children by assessment of its agreement with dual-energy X-ray absorptiometry (DXA) and its repeatability, and 2) to establish a reference range of percentage body fat in Hong Kong Chinese children. Methods: Sequential BIA and DXA methods were used to determine body composition in 49 children aged 7-18 years and the agreement between the two methods was calculated. Repeatability for the BIA method was established from duplicate measurements. Body composition was then determined by BIA method in 1139 girls and 1243 boys aged 7 to 16 years who were randomly sampled in 8 local primary and secondary schools to establish reference ranges. Results: The 95% limits of agreement between BIA and DXA methods were considered acceptable (-3.3 kg to -0.5 kg fat mass and -3.9 to 0.6 % body fat). The percentage body fat increased with increasing age. Compared to the 1993 Hong Kong growth survey, these children had higher BMIs. The mean (SD) percentage body fat at 7 years old was 17.2% (4.4%) and 14.0% (3.4%) respectively for boys and girls, which increased to 19.3% (4.8%) and 27.8% (6.3%) at age 16. Using BMI standard to define overweight and obesity, corresponding cut-off points for percentage body fat were tabulated by sex and age. Conclusion: Leg-to-leg BIA is a valid alternative method to DXA for the measurement of body fat. Provisional reference ranges for percentage body fat for Hong Kong Chinese children 7 to 16 years old are provided. 2375