Body fat, regional body fat and bone mineral mass, are linked to health conditions such as obesity and osteoporosis. The ethnic comparison of body composition may help to explain and understand the difference of health outcomes and health status in different ethnic groups. NZ Chinese is the largest Asian group in New Zealand, however, knowledge about health risks and body composition for NZ Chinese is very limited. Therefore, the aims of this thesis were: 1) To compare the relationships between body mass index (BMI) and percentage body fat (%BF) of European (M29, F37), Maori (M23, F23), Pacific people (M15, F23), and Asian Indian (M29, F25) (existing data) with NZ Chinese aged 30-39 years; 2) To compare fat distribution, appendicular skeletal muscle mass (ApSM), bone mineral density (BMD) and limb bone lengths across these five ethnic groups. A convenience sample of healthy NZ Chinese (M20, F23) was selected by BMI to cover a wide range of body fatness. Total and regional body fat, fat free mass (FFM) and bone mineral content were measured by whole-body Dual-energy X-ray absorptiometry (DEXA). The main study findings were: • For a fixed BMI, NZ Chinese had a higher %BF than European and less %BF than Asian Indian. At a %BF equivalent to a BMI of 30 kg.m-2 in Europeans (WHO threshold for obesity), BMI values for Asian Indian and NZ Chinese women were 5.8 and 2.2 BMI units lower than European, respectively, and for Asian Indian and NZ Chinese men, 8.2 and 3.0 BMI units lower. • Abdominal-to-thigh fat ratio of NZ Chinese was significantly higher than that of European (P<0.001) and similar to that of Asian Indian. NZ Chinese had a significantly higher central-to-appendicular fat ratio than both Asian Indian and European (P<0.001). NZ Chinese was centrally fatter than European and Asian Indian. • For the same height and weight, NZ Chinese had significantly less FFM (-2.1 kg, P=0.039) and ApSM (-1.4kg, P=0.007) than European. NZ Chinese had significantly more FFM (+3.2 kg, P=0.001) than Asian Indian and similar ApSM to Asian Indian. • For the same weight, NZ Chinese had a similar BMD as European for female and male. NZ Chinese male had a higher BMD (+0.07 g.cm-2, P= 0.001) than Asian Indian male. • Among the five ethnic groups, NZ Chinese had the shortest leg (-1.5cm, P=0.016) and arm bone lengths (-2.3cm, P=0.001) (measured by DEXA) for the same DEXA height. Therefore, the relationship between percent body fat and BMI for Asian Indian and NZ Chinese differs from Europeans and from each other, which indicates that different BMI thresholds for obesity may be required for these Asian ethnic groups. Given the relatively high percentage body fat, low appendicular skeletal muscle mass and high central fat to appendicular fat ratio of NZ Chinese aged 30-39 years demonstrated in this study, promotion of healthy eating and physical activity is needed to be tailored for NZ Chinese. The NZ Chinese community should be advised to keep fit, prevent limited movements in older age, and to prevent obesity and obesity-related diseases.

The investigations described in this thesis were conducted in order to increase the understanding of the relationships between physical activity, aerobic fitness, body composition, asthma, and asthma severity in children and adolescents. This was largely achieved by examining the aforementioned factors in a sizeable population of Melbourne school children and adolescents. However, during the course of the school-based testing, it became apparent that the severe asthmatic category was under-represented, typical of the current literature. Thus, effort was also directed at addressing this knowledge gap by examining a severely asthmatic cohort in a laboratory-based setting. The outcomes generated by these investigations can be summarised as follows: 1) In ‘school-tested’ youth aged 10 to 14 years, prevalence rates of overweight and obesity were 19.1% and 4.0%, respectively. Approximately 16% of participants also suffered from asthma. These rates appear to be representative of similarly aged children and adolescents within Australia. The latter observation also adds weight to the view that asthma prevalence has attenuated in recent years. In addition, overweight and obesity were more prevalent in asthmatics than non-asthmatics, supporting the proposed notion of an asthma-obesity association. 2) Asthmatic and non-asthmatic young people had comparable aerobic fitness and daily physical activity levels and the severity of disease did not influence aerobic fitness nor involvement in physical activity. Males possessed greater aerobic fitness and physical activity levels and had a lower percentage body fat compared to age-matched females, independent of asthma status (i.e. asthmatic or non-asthmatic). 3) There was a significant inverse relationship between aerobic fitness and markers of increased body fat among non-asthmatic children and adolescents, even after corrections to aerobic fitness were made for fat free mass. Differences in daily physical activity could only partially explain this association. In fact, the current findings suggest that decreased levels of daily physical activity are not the cause of the increased overweight/obesity prevalence among this sample, and that physical activity lacks a strong link to paediatric overweight/obesity in this population. These findings were also present in asthmatic youth. 4) Severely asthmatic youth, premedicated with bronchodilator, had aerobic fitness levels comparable to their non-asthmatic and less severe asthmatic peers. This finding indicates that severely asthmatic youngsters should be able to train at work intensities sufficient to bring about improvements in cardio-respiratory fitness without any added functional limitation due to their condition. In addition, a state of well-controlled asthma (as were the severe asthmatics in this study) afforded the participants the ability to engage in similar levels of physical activity as their non-asthmatic or less severe asthmatic peers. In agreement with data from the ‘school-tested’ asthmatics, a significantly greater proportion of severely asthmatic participants were overweight or obese in comparison to their non-asthmatic peers. These findings (i) highlight the association between aerobic fitness and overweight/obesity; (ii) suggested that decreased levels of daily physical activity were not associated with the increased overweight/obesity prevalence in a youth sample within Australia; (iii) emphasize that well-controlled asthmatic young people can undertake levels of physical activity and achieve cardio-respiratory fitness similar to that of their non-asthmatic peers, independent of asthma severity, and; (iv) indicated that asthma is either a risk factor for overweight and obesity or that overweight and obesity may precede asthma.

Dietary energy is the largest single cost in pork production. Accurate and current understanding of energy metabolism is crucial to production efficiency. The overall objective of this thesis was to evaluate the effects of dietary energy concentration and energy intake on growth, nutrient deposition rates and energy utilization in weaned pigs. In experiment 1, the optimum total lysine:DE ratio for weaned pigs was estimated at 4.27 and 4.46 g/Mcal for pigs growing from 7.5 to 12.8 kg and 7.5 to 22.5 kg BW, respectively. Experiment 2 determined if a more predictable growth, nutrient deposition and energy utilization in the weaned pig is achieved with NE or with DE. ADG either remained similar or was depressed with increased NE compared to the control (P < 0.05). Empty body protein content and deposition (PD) declined relative to the control (P < 0.05) and lipid content and deposition (LD) tended to increase (P < 0.10). Body composition and nutrient deposition rates were more correlated with determined NE concentration and intake compared with DE. The results of Experiment 3 indicated that amino acid intake impaired the growth of pigs when an energy intake restriction greater than 30% occurred. Experiment 4 investigated the interaction of dietary NE concentration and feeding levels (FL) on body weight gain, tissue (protein, lipid, ash, water) accretion rates and ratios. Growth performance was not affected by NE (P > 0.05) but increased with feeding level (P < 0.001). Energy intake increased with NE and FL (P < 0.001), but the efficiency of energy utilization for growth declined (P < 0.05). Empty body protein content declined (P < 0.05) while lipid content increased with NE (interaction, P < 0.05). Empty body PD was not affected by NE (P > 0.05) but both LD and LD:PD ratio increased (interaction, P < 0.001). These data suggest that when amino acid:energy ratio is optimal, increasing dietary energy concentration increased energy intake but does not improve PD and overall body weight gain of weaned pigs. However, body lipid content and LD were increased. Finally, NE offers an advantage over the DE in predicting the body composition and nutrient deposition rates rather than in overall BW gain.

Background: Studies have not examined the relationships between serum vitamin D (SVitD), serum cortisol (SCort), bone mineral density (BMD), and body fat percent (BF%) in elite figure skaters. However, studies of non-athletes have found that BMD is inversely related to SCort and directly related to SVitD, and BF% is inversely related to SVitD and directly related to SCort. It was, therefore, the purpose of this study to assess the relationships between SCort, SVitD, BMD, and BF% in elite figure skaters. Methods: U.S. national team figure skaters were assessed at a national training camp during the summer, 2012. BMD and body composition were measured by dual energy x-ray absorptiometry (DEXA). Blood chemistry values for SVitD and SCort were obtained via venous puncture after an overnight fast, the same morning as the DEXA measurement. Georgia State University Institutional Review Board approval was obtained for the assessment of data collected at this training camp. Results: 24 out of 39 training camp attendees (61.5%) volunteered to be assessed as part of this study. Subjects ranged from 17 to 34 years and included males (n=11) and females (n=12). In all skaters statistically significant negative correlations (2-tailed Spearman) were found between SCort and BMD of the spine (r=-0.458, p=0.032), pelvis (r=-0.532, p=0.011), ribs (r=-0.517, p=0.014), and trunk (r=-0.538, p=0.010). In females, SCort was negatively correlated with BMD of the pelvis (r=-0.664, p=0.026) and trunk (r=-0.609, p=0.047), and was positively correlated with total BF% (r=0.657, p=0.020) and trunk fat % (r=0.708, p=0.010). In males, SCort was significantly correlated with BMD of the ribs (r=-0.627, p=0.039). The 3 skaters (all female) with SCort > 28 mcg/dL had significantly lower mean BMD of the total body, left femoral neck, legs, trunk, and pelvis, and significantly greater BF% of the total body and trunk when compared to the 20 skaters with SCort 7-28 mcg/dL. No significant correlations between SVitD and BMD or BF% were found. A Mann-Whitney U test found no significant differences in BMD and BF% between the 8 skaters with SVitD ≥ 30 ng/mL compared to the 15 skaters with SVitD < 30 ng/mL (p>0.05). Females with SVitD ≥ 30 ng/mL had significantly higher BMD (p=0.041) of the right femoral neck when compared to those with lower SVitD. Conclusions: Correlations consistently found negative associations between SCort cortisol and BMD in multiple assessment areas, particularly those composed of trabecular bone. Higher SCort was also associated with higher BF% in female skaters. Despite spending a great deal of time in indoor facilities, limiting vitamin D creation through sunlight exposure, no significant correlation between SVitD and BMD was found. Female athletes in ‘appearance’ sports, may be predisposed to restrained eating behaviors, which may be associated with elevated SCort. These findings suggest a need for further study of the interaction between SCort, BMD, and BF% in these athletes. The lack of a statistically significant relationship between SVitD and BMD suggests the need to investigate additional factors associated with bone injury risk in athletes.

Dietary energy is the largest single cost in pork production. Accurate and current understanding of energy metabolism is crucial to production efficiency. The overall objective of this thesis was to evaluate the effects of dietary energy concentration and energy intake on growth, nutrient deposition rates and energy utilization in weaned pigs. In experiment 1, the optimum total lysine:DE ratio for weaned pigs was estimated at 4.27 and 4.46 g/Mcal for pigs growing from 7.5 to 12.8 kg and 7.5 to 22.5 kg BW, respectively. Experiment 2 determined if a more predictable growth, nutrient deposition and energy utilization in the weaned pig is achieved with NE or with DE. ADG either remained similar or was depressed with increased NE compared to the control (P < 0.05). Empty body protein content and deposition (PD) declined relative to the control (P < 0.05) and lipid content and deposition (LD) tended to increase (P < 0.10). Body composition and nutrient deposition rates were more correlated with determined NE concentration and intake compared with DE. The results of Experiment 3 indicated that amino acid intake impaired the growth of pigs when an energy intake restriction greater than 30% occurred. Experiment 4 investigated the interaction of dietary NE concentration and feeding levels (FL) on body weight gain, tissue (protein, lipid, ash, water) accretion rates and ratios. Growth performance was not affected by NE (P > 0.05) but increased with feeding level (P < 0.001). Energy intake increased with NE and FL (P < 0.001), but the efficiency of energy utilization for growth declined (P < 0.05). Empty body protein content declined (P < 0.05) while lipid content increased with NE (interaction, P < 0.05). Empty body PD was not affected by NE (P > 0.05) but both LD and LD:PD ratio increased (interaction, P < 0.001). These data suggest that when amino acid:energy ratio is optimal, increasing dietary energy concentration increased energy intake but does not improve PD and overall body weight gain of weaned pigs. However, body lipid content and LD were increased. Finally, NE offers an advantage over the DE in predicting the body composition and nutrient deposition rates rather than in overall BW gain.

The effects of feeding with two high energy diets ( high carbohydrate and high lipid) and the feeding regime of the two diets on growth, feeding conversion rate, and body composition of the cobia were studied. Based on the observation of lipid redistribution under dietary regime change in rats, this study was aimed to understand how regime change affects the tissue lipid content in the cobia. The study had three parts: preliminary experiment, experiment I, and experiment II. The preliminary experiment was designed to find the proper time to switch the high energy diets and to see the adaptation of cobia to the highe energy dietary treatments. The experiment I was conducted to monitor the growth and body composition of cobia fed for thirty-two days with different experimental diets, including control diets, high carbohydrate diets (HC), high lipid diets (HL), and different feeding regimes (HC¡÷HL: feeding the HC diet for the first sixteen days and the HL diet for the subsequent sixteen days; HL¡÷HC: feeding the HL diet for the first sixteen days and the HC diet for the subsequent sixteen days. The experiment II was studied serum concentration of glucose, triacylglycerol, and free fatty acids and tissues triacylglycerol concentration in liver and white muscle. The fish fed with the HC diet had higher body weight and lower feeding conversion rate than the HL group in first sixteen days; however, the growth of the two groups was not significantly different during the thirty-two day period. The lipid content of dorsal muscle was significantly higher in HC¡÷HL than that in HL¡÷HC; wherease, the lipid content of ventral muscle and viscera was not signficantly affected. The concentrations of serum triacylglycerol, free fatty acid, and relative mean ratio of triacylglycerol in muscle to triacylglycerol in liver were significantly affected. The results of relative mean ratio of serum TG to serum FFA and relative mean ratio of muscle TG to liver TG, suggest that high carbohydrate diet drives de nova lipid production in liver, which circulates to the peripheral tissues for storage as triacylglycerol. High lipid diet preferentially offers energy for lipolysis to produce energy. These results are consistant with the results in rats. Our results show that high energy diets provided a higher growth rate than the control diet, but there were no growth difference in cobia fed high carbohydrate diets, or high lipid diets, or between different feeding regimes. The cobia fed the high carbohydrate diet and the high lipid diet might use different ways for lipid accumulation. These fed the high carbohydrate diet had formed more triacylglycerol than that these fed high lipid diets. The feeding regime shift between the high carbohydrate diet and the high lipid diet significantly affect the the lipid content of the dorsal muscle in the cobia.

Objectives of this study were to determine if variation in energy expenditures contributed to differences in feed efficiency between low and high RFI steers. Nine steers with the lowest and highest residual feed intakes (RFI) were selected from 169 Braunvieh-sired crossbred steers that were individually fed a pelleted roughage-based diet for 77 d. Following the RFI measurement period, heat production (HP) measurements were obtained using indirect calorimetry while steers were fed the same roughage diet (RD) and on a high-concentrate diet (CD). Linear regression analyses of log HP or retained energy on ME intake were used to determine energy partitioning. Motion and lying activity were measured concurrently with HP on the RD and CD. During the RFI measurement period, low RFI steers had lower (P < 0.01) RFI (-1.7 vs. 1.6 ± 0.17 kg/d), DMI (7.7 vs. 10.2 ± 0.42 kg/d) and feed:gain ratio (F:G; 7.2 vs. 10.6 ± 0.60), but similar final BW and ADG compared to high RFI steers. However, there were smaller differences in DMI (8.4 vs. 9.7 ± 0.38 kg/d; P < 0.05; 7.56 vs. 8.16 ± 0.31; P = 0.19) and F:G (10.0 vs. 10.9 ± 0.40; P = 0.36; 6.5 vs. 7.5 ± 0.30; P < 0.05) between low and high RFI steers, on the RD and CD, respectively. ME for maintenance (MEm; kg .75 d–1) and the partial efficiencies of ME used for maintenance and gain were similar for low and high RFI steers. Likewise, no differences were found in fasting HP or fed HP. Motion activity was lower (P < 0.05) for low RFI steers compared to high RFI steers during fasting HP. Covariate analysis of HP at the same activity level yielded similar results. At slaughter, weights of lung and trachea (P < 0.05), spleen (P < 0.05) and adrenal gland (P = 0.07) were higher for low RFI cattle. The lack of differences in energy partitioning between divergent RFI steers may have been the result of alterations in feeding behavior or stress imposed by adapting steers to calorimetry chambers.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Laurie Grubbs, Florida State University, School of Nursing. Title and description from dissertation home page (viewed Feb. 25, 2004). Includes bibliographical references.

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

Both obesity and type 2 diabetes are significant health burdens in our society. The prevention of these conditions is vital to individual health and to the health care system, which is inordinately stressed by these chronic diseases. Due to variations in individual response to interventions, prevention strategies may require some tailoring based on heritable traits.The objective of this study was to determine whether insulin sensitivity could be altered by resistance training, and further if body composition or insulin sensitivity response to resistance training in postmenopausal women may be influenced by adrenergic receptor genetic variants and gene-gene interactions.Completers of a 12-month randomized controlled trial of resistance training in sedentary post-menopausal (PM) women, using or not using hormone therapy, were measured for fasting plasma glucose, insulin, and non-esterified fatty acids (NEFA) at baseline and one year. These biomarkers were used to compute models of insulin sensitivity. Body composition was measured by dual x-ray absorptiometry. Subjects were also re-consented for genotyping of adrenergic receptor (ADR) gene variants, ADRA2B Glu9/12, ADRB3 Trp64Arg, ADRB2 Gln27Glu.The resistance training intervention did not have an overall effect on insulin sensitivity in the largest sample and change in insulin sensitivity was largely dependent body composition. There were small favorable effects of genotype on initial measures of both body composition and insulin sensitivity in the ADRA2B Glu9+ carriers versus non-carriers. The effects of ADRA2B alone were no longer present following intervention, but ADRB3 Arg64+ and ADRB2 Glu27+ contribute to improved insulin sensitivity with exercise, when accounting for body composition. ADRB2 Glu27+ was the key to improved biomarkers of insulin sensitivity when in combination with ADRA2B Glu9+ or ADRB3 Arg64+ and a model of insulin sensitivity was most improved by the combination ADRB3 Arg64+ by ADRB2 Glu27+, compared to other ADRB3 by ADRB2 combinations.This is the first trial of ADRA2B, ADRB3, and ADRB2 genetic variation combinations and resistance training in postmenopausal women relative to body composition and insulin sensitivity. Some specific genotypes were identified as responders and non-responders to exercise. These data support independent associations between body composition and insulin sensitivity and the ADR gene variants.