ANZOS 2013 abstracts e101

183

Bioelectrical impedancemeasurement of body compositionin obese adolescents

Ching S. Wan 1, Leigh C. Ward 2,Jocelyn Halim 3, Megan Gow 3,∗,Mandy Ho 3, Sarah P. Garnett 3

1 Department of Nutrition andDietetics, University of Sydney,Sydney, NSW, Australia2 Chemical and MolecularBiosciences, University ofQueensland, Brisbane, QLD,Australia3 Institute of Endocrinology andDiabetes, The Children’s HospitalWestmead, Westmead, NSW,Australia

Background: A stand-on bioelectrical impedanceanalysis (BIA) system is a safe, non-invasive, rel-atively inexpensive method of measuring bodycomposition. However, little is known about howthe body composition parameters measured by BIArelate to those determined by dual-energy X-rayabsorptiometry (DXA) in an obese, adolescent pop-ulation.

Objectives: To compare body composition meas-ures from the Tanita stand-on BIA (MC-180MA),determined by (a) in-built equations and (b)published and derived equations using raw data(resistance (R) and reactance (Xc)), with body com-position parameters measured by DXA in obeseadolescents.

Methods: 66 obese adolescents (age: 10—18 y,BMI: 22—48 kg/m2) had body composition measuredby both BIA (Tanita MC-180MA) and DXA (LunarProdigy). Raw data obtained from the BIA, R andXc at frequencies of 5, 50, 250 and 500 kHz, wereused in published bioimpedance spectroscopy [1]and BIA equations [2]. Raw data was also used togenerate a new prediction equation for FFM using adouble cross-validation method.

Results: Compared to DXA, the BIA in-built equa-tions overestimated fat-free mass (FFM) by 4.3 kg[95% limits of agreement −13.9 to 5.3] and under-estimated % body fat (%BF) by 10.8% [−11.1 to35.3]. There were no significant differences in theestimates of body composition parameters deter-mined by published/derived equations using rawdata and DXA; the mean differences in FFM and%BF were 0.4—0.9 kg and 0.5—0.8%, respectively.However, similar to the BIA in-built equations, all

estimates had wide limits of agreement of approx-imately ±7 kg for FFM and ±10% for %BF.

Conclusion: The Tanita BIA (MC-180MA) in-builtequations cannot be recommended as a measure ofbody composition in obese adolescents. However,equations using the raw data can be used to mea-sure body composition in groups, but there is thepotential for significant error if used for an individ-ual.

References

[1] Ward. Nutrition 2007;23:657—64.[2] Ramírez. Eur J Clin Nutr 2012, http://dx.doi.

org/10.1038/ejcn. 2012.89.

http://dx.doi.org/10.1016/j.orcp.2013.12.682

184

Arterial elasticity in adolescentswith insulin resistance and type 1diabetes

Mandy Ho 1,2,∗, PaulBenitez-Aguirre 1,2, Kim Donaghue 1,2,Paul Mitchell 3, Louise Baur 1,2, AliciaJenkins 4,5, Maria Craig 1,2,6, ChrisCowell 1,2, Sarah Garnett 1,2

1 University of Sydney, Sydney, NSW,Australia2 The Children’s Hospital atWestmead, Sydney, NSW, Australia3 Centre for Vision Research,Westmead Millennium Institute,Sydney, NSW, Australia4 St Vincents Hospital, Melbourne,VIC, Australia5 Faculty of Medicine, MelbourneUniversity, Melbourne, VIC, Australia6 School of Women and Children’sHealth, University of New SouthWales, Sydney, NSW, Australia

Introduction: Reduced small arterial elasticity(SAE) in adults is associated with increased riskof cardiovascular events. The data relating tothe association between arterial elasticity, obesityand glycaemic status in adolescents is limited andconflicting. This study aimed to determine if SAEdiffered between obese adolescents with clinicalinsulin resistance (IR), adolescents with type 1 dia-betes (T1D) and healthy non-obese controls.

Methods: The IR group (n = 68) were participantsof a RCT, RESIST. The T1D group were recruitedthrough the Diabetes Complications Assessment