Predictive equations for abdominal fat depot volumes with MRI as reference in a multi-ethnic cohort of 4.5 year old Asian children
Suresh Anand Sadananthan1, Navin Michael1, Mya Thway Tint2, Kuan Jin Lee3, Jay Jay Thaung Zaw2, Khin Thu Zar Hlaing2, Pang Wei Wei2, Lynette Pei-Chi Shek4, Yap Kok Peng Fabian5,6, Peter D. Gluckman1,7, Keith M. Godfrey8, Yap Seng Chong1,2, Melvin Khee-Shing Leow9,10, Yung Seng Lee1,4, Christiani Jeyakumar Henry9, Marielle Valerie Fortier11, and S. Sendhil Velan1,3

1Singapore Institute for Clinical Sciences, A*STAR, Singapore, 2Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 3Singapore BioImaging Consortium, A*STAR, Singapore, 4Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 5Department of Paediatric Endocrinology, KK Women’s and Children’s Hospital, Singapore, 6Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 7Liggins Institute, University of Auckland, Auckland, New Zealand, 8MRC Lifecourse Epidemiology Unit & NIHR Southampton Biomedical Research Centre, University of Southampton & University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom, 9Clinical Nutrition Research Centre, Singapore Institute for Clinical Sciences, A*STAR, Singapore, 10Department of Endocrinology, Tan Tock Seng Hospital, Singapore, 11Department of Diagnostic and Interventional Imaging, KK Women’s and Children’s Hospital, Singapore

Synopsis

Longitudinal assessment of abdominal fat compartments in children can help delineate some of the early risk factors that can predispose an individual to high abdominal adiposity and insulin resistance. While accurate determination of abdominal fat can be achieved using CT or MRI, it is often not performed in large cohort studies involving young children due to radiation exposure, high costs or poor compliance with scan procedures. The goal of this work is to develop and validate predictive equations for abdominal fat compartments from anthropometric values with MRI-based abdominal fat volumes as reference in multi-ethnic cohort of 4.5 year-old Asian children.

Introduction

Longitudinal assessment of abdominal fat compartments in children may help delineate some of the early risk factors that can predispose an individual to high abdominal adiposity and insulin resistance. While accurate determination of abdominal fat can be achieved using computed tomography (CT) or magnetic resonance imaging (MRI), it is often not performed in large cohort studies involving young children due to radiation exposure, high costs or poor compliance with scan procedures. The goal of this work is to develop and validate predictive equations for abdominal fat compartments (subcutaneous (SAT) and internal (IAT) adipose tissue) from anthropometric values with MRI-based abdominal fat volumes as reference in multi-ethnic cohort of 4.5 year-old Asian children.

Methods

Our data for the study included observations from 54 children (31 Chinese, 14 Malays and 9 Indians) aged 4.5 years from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study [1]. Anthropometric measures including height, weight, abdominal and upper mid-arm circumference and skinfold thickness (subscapular, triceps, biceps and suprailiac) were measured. Axial abdominal images with 5 mm slice thickness and in-plane resolution of 0.94 × 0.94 mm were acquired using water suppressed HASTE sequence (TR=1000 ms, TE=95 ms) on the 3T MR scanner (Siemens Skyra). The SAT and IAT volumes between the diaphragm and S1 sacral level were segmented with an automated algorithm [2] and edited manually for correction of any mis-segmented regions. The total sample (n=54) was randomly divided into training (n=30) and testing (n=24) groups. Statistical analyses were performed using SPSS 23.0 software. Linear predictive models were created for the SAT and IAT depots with anthropometric measures, ethnicity, weight, height and gender as potential predictors. Forward stepwise selection was performed using the Akaike information criterion (AIC) to select/remove predictors from the model in an automated fashion. The predictive equation derived from the training set was validated against the MRI-based fat volumes of the test set.

Results

The optimal predictive equations yielded by the linear modeling for SAT and IAT are shown in Table 1. Within the training dataset (Fig. 1 & 2), the equations had a strong predictive power for SAT (R2 = 0.97) and a moderate predictive power for IAT (R2 = 0.73). When the equations were cross-validated on the test dataset (Fig. 3 & 4), the R2 for prediction of SAT was 0.88, while R2 for IAT was 0.32. Body weight was the strongest predictor of IAT.

Conclusion

We have developed equations to predict abdominal fat depot volumes using anthropometric measures in 4.5 year-old Asian children. We found that SAT can be predicted with high accuracy from anthropometric measures while equation for IAT had poor predictive power. These equations will benefit large cohort studies in Asian preschoolers for the interpretation of anthropometric data with regard to abdominal fat partitioning.

Acknowledgements

This research is supported by the Singapore National Research Foundation under its Translational and Clinical Research (TCR) Flagship Programme and administered by the Singapore Ministry of Health’s National Medical Research Council (NMRC), Singapore- NMRC/TCR/004-NUS/2008; NMRC/TCR/012-NUHS/2014. Additional funding is provided by the Singapore Institute for Clinical Sciences, Agency for Science Technology and Research (A*STAR), Singapore.

References

[1] Shu-E et al., Cohort Profile: Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort study. International Journal of Epidemiology 2014, 43(5):1401-1409.

[2] Suresh Anand Sadananthan et al., Automated Segmentation of Visceral and Subcutaneous (Deep and Superficial) Adipose Tissues in Normal and Overweight Men. Journal of Magnetic Resonance in Imaging 2015, 41(4):924-934.

Figures

Table 1. Predictive equations for abdominal fat volumes.

Fig. 1. Predicted vs. measured values of SAT in the training dataset.

Fig. 2. Predicted vs. measured values of IAT in the training dataset.

Fig. 3. Predicted vs. measured values of SAT in the test dataset.

Fig. 4. Predicted vs. measured values of IAT in the test dataset.



Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)
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