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Estimation of visceral adipose tissue and body fat in middle aged men

University of British Columbia

BACKGROUND: Human obesity is associated with a large number or diseases and metabolic complications such as heart disease, diabetes mellitus, hypertentension, gallbladder disease and some types of cancer (Bjorntorp,1990; Depres et al., 1991). Though a causative relationship has not been established between adipose tissue (AT) distribution and these metabolic disturbances, both prospective and epidemiological studies have demonstrated that measures of visceral adipose tissue (VAT) stores are strong predictors of coronary heart disease, diabetes and stroke. Thus the ability to measure abdominal AT, especially VAT, may be important in epidemiological and clinical research. Advanced imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) offer new promise for the visualization and quantification of abdominal A T masses. However, these imaging techniques are expensive, not generally available, and in the case of CT, expose the subjects to ionizing radiation. OBJECTIVE: The aim of this study was to offer a less expensive, quick, safe and accurate method to predict VAT and body fat (BF) using measurements from dual-energy X-ray absorptiometry (DXA) and anthropometry. Eleven men over 50 (50r69 y) participated in this study with a wide range of Body Mass Index's. VAT, subcutaneous abdominal adipose tissue (SAAT) and total abdominal adipose tissue (TAAT) was measured from the 1st to the 5th.lumbar vertebrae using MRI as the criterion measure. BF and trunk fat (TF) were also measured using DXA . RESULTS: Measurements of TF by DXA explained about 70% of the variation in the VAT[sub L1-L5] measured by MRI. TF measured by DXA ( x₁) in combination with the subscapular (x₂) and sum of seven skinfolds (X3) could accurately predict the VAT[sub L1-L5] mass measured by MRI (r² = 0.95, SEE = 8.00 %): VAT (kg) = 0.304(x₁) - 0.0526(x₂) - 0.00707(x₃) + 0.414. A single MRI scan at the L2-L3 intervertebral disk region was found to be the best predictor of VAT[sub L1-L5] mass (r = 0.95). The waist-to-hip ratio was highly correlated with VAT[sub L1-L5] (r = 0.83). This study also found that BF and TF measured by DXA could be accurately predicted with the suprailiac skinfold (x₄) and waist girth (x₅): BF (kg) = 0.341(x₄) + 0.274(x₅) - 15.5 (r² =. 0.96, SEE = 7.18 %). TF (kg) = 0.150(x₄) + 0.199(x₅) - 9.01 (r² = 0.95, SEE = 8.80 %). CONCLUSION: D X A combined with anthropometry can accurately predict V A T mass from the L1-L5 vertebrae, and anthropometry alone can accurately predict BF.and TF in men over 50 y.

Thesis/Dissertation

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2009-06-16

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http://hdl.handle.net/2429/9321

Human Kinetics

University of British Columbia

UBCV

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