This research evaluated photonic imaging devices for assessment of body size and shape. In aim one, laser imaging measurements of circumference, volume, and % fat were examined in 70 women. Bland-Altman analysis indicated minimal error in girth of the waist and hip by laser imaging as compared to tape measure (95% limits of agreement for waist, -2.02-2.29 cm; hip, -3.39-2.90 cm). Volume by laser imaging was related to hydrodensitometry (r = 0.99, p < 0.01), and % fat estimates were not significantly different from hydrodensitometry or dual energy X-ray absorptiometry (DXA) (3.95 ± 1.74, 32.54 ± 1.28, and 35.86 ± 1.06, respectively, p > 0.05). In aim two, 120 adults were evaluated via stereovision imaging. Stereovision was significantly related to volume by air displacement plethysmography (ADP) and hydrodensitometry (R² > 0.99, p < 0.01). However, Bland-Altman analysis indicated variations in body fat between stereovision and ADP (95% limits of agreement, -16.77-16.05 kg). Therefore, aim three was development of a prediction equation to estimate fat from 13 stereovision measurements of body size and shape. These parameters combined to form upper and lower body factor scores, which, with gender, predicted 88.6% of variation in fat mass by ADP (p < 0.01). The equation improved 95% limits of agreement from -16.77-16.05 kg via direct volume measurement to -11.47-8.45 kg compared to ADP. Finally, in aim four, a subset of 56 women from aim two was evaluated for visceral fat by magnetic resonance imaging (MRI). Visceral fat was compared to a new indicator of abdominal adiposity via stereovision imaging: central obesity depth. Central obesity depth was correlated with visceral fat, following adjustment for age and ethnicity (r = 0.75, p < 0.01). Additionally, each 1 cm rise in central obesity depth raised the odds of being in the high versus low visceral fat tertile (Odds Ratio 8.59, 95% Confidence Interval 1.33-55.63, p < 0.05). Thus, both laser and stereovision body imaging appear to be valid techniques for evaluation of body size and shape. Furthermore, central obesity depth is a promising new measurement for assessment of visceral adiposity. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/ETD-UT-2010-05-1059 |
| Date | 01 August 2011 |
| Creators | Pepper, Margery Reese |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | thesis |
| Format | application/pdf |
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