THE EFFECT OF ADIPOSE TISSUE INCLUSION OVER PORK LOINS ON DUAL-ENERGY X-RAY ABSORPTIOMETRY (DXA) MEASUREMENTS

Abstract Text: Dual-energy X-ray absorptiometry (DXA) measurements can be affected by the special distribution of sample tissues. The objective of this study was to evaluate the impact of adding adipose tissues (AT) over pork loins on DXA measurements. Four commercial pork loins and 3 square pieces of AT were scanned with a GE Lunar Prodigy Advance DXA device equipped with total body GE Lunar Encore software in thin and standard configurations. All images were analyzed using a custom region of interest. The loins were individually positioned on the DXA table and kept in the same position until the end of tests. The AT pieces were positioned over the loins one by one without (NoOvPos) or with (OvPos) overlapping to measure bone mineral density (BMD, g cm^-2), bone mineral content (BMC, g), bone area (BA, cm²), and fat and lean masses (g). Loin DXA measurements without AT inclusion were subtracted from loins after AT inclusion and the analysis of covariance performed to study the effects of DXA configuration, AT positioning, AT inclusion, and all interactions. Linear regressions were generated afterwards. The AT pieces had 69 and 57% fat in NoOvPos and OvPos AT positioning, respectively. DXA measurements were not affected by device configurations but the interaction between AT inclusion and AT positioning was significant (P < 0.05) for BMC, BA, and fat and lean masses. BMD was not affected (P > 0.05) by any factor. The regression slopes between AT inclusion in NoOvPos positioning and BMC, BA, and fat and lean masses were respectively of -0.013, -0.016, 0.698, and 0.315. The equivalent slopes in OvPos positioning were of -0.016, -0.019, 0.591, and 0.438. All intercepts were not different (P > 0.05) from zero. The inclusion of AT over the loins reduced the values of BMC and BA but not BMD values. The difference between slopes was in general small and therefore, the special distribution of sample tissues is not expected to have an important effect on DXA measurements. DXA can therefore be used to measure pork loin composition.

Keywords: adipose tissue, DXA, pork loin