Thesis (M.S.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 40-46.

Background and objectives. Spurred by the longstanding interest in the intimate relationship between anxiety and depression, different conceptual models of negative affectivity have been proposed to account for their common and unique features. The two-factor model (Tellegen, 1985; Watson, Clark & Tellegen, 1988) proposes that Negative Affect (NA) represents a nonspecific factor common to both depression and anxiety, whereas low Positive Affect (PA) is a specific factor to depressed mood. The tripartite model (Clark & Watson, 1991b) divides symptoms into three groups: Negative Affect (general distress) symptoms that are largely non-specific; low Positive Affect (anhedonia) symptoms that are specific to depression; and Physiological Hyperarousal (PH) symptoms that are unique to anxiety. The structural model of negative affectivity (Zinbarg et al., 1994; Zinbarg & Barlow, 1996; Brown et al., 1998) postulates NA and PA as higher order factors under which PH, DSM-IV anxiety and depression are subsumed as lower order factors in a hierarchical arrangement. For the cognitive approach, Beck's cognitive content-specificity hypothesis (Beck, 1976) emphasizes the important role of specific cognitions in differentiating anxiety and depression. The objectives of the present study were: (1) To examine the relationship between anxiety and depression in an adolescent sample of Hong Kong; (2) To examine the phenotypic structure of anxiety and depression in the Hong Kong adolescent sample; and (3) To assess the validity and applicability of the western negative affectivity models and cognitive model for differentiating anxiety and depression in the Hong Kong adolescent sample. / Conclusions. Overall, the present study provides good support for the affective models of negative affectivity and the cognitive model developed in the west which constitutes a good basis for elucidating the relationship between anxiety and depression in the Chinese adolescents of Hong Kong. Although cross-cultural differences in anxiety and depressive symptoms are not directly addressed in this study, the results tend to suggest that Chinese adolescents do not uniformly over or under-report depressive or anxiety symptoms as compare to their Western reference groups. The results generally support the view that there is a large degree of universality or commonality of emotional constructs and affect structures between adolescents in the East and West. (Abstract shortened by UMI.) / Results. Good construct and concurrent validity were established for all the scales applied. Both the two-factor model and the tripartite model showed good fit to our data which also supported the various predictions by the models. Moreover, the results provided good evidence for the hierarchical model in which NA and PA were interpreted as higher orders, whereas Physiological Hyperarousal (PH), DSM-IV anxiety disorders, and depression were specific lower order factors. Consistent with the content-specificity hypothesis, anxious and depressive cognitions were found to specifically predict anxiety and depressive symptoms respectively. / Kwok, Wai Yee Alice. / "April 2007." / Source: Dissertation Abstracts International, Volume: 69-01, Section: B, page: 0221. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 155-179). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional structural spine deformity with lateral curve and vertebral rotation occurring predominantly in adolescent girls during the peri-pubertal period. The prevalence of AIS is nearly 4% in Hong Kong and 2-3% worldwide. AIS without treatment or with improper treatment may deteriorate progressively and lead to significant cosmetic problems and functional disabilities. In severe cases, increased mortality rate can result from the associated early onset of cardiopulmonary failure. Up to now, the treatment of the AIS is basically passive through bracing and corrective spinal surgery. The current protocol of treatment is not totally satisfactory since the curve may continue to progress with brace treatment and corrective surgery is associated with major surgery and permanent fusion of parts of the spine. This is due to the fact that one is still uncertain about the etiology of AIS and therefore cannot directly treat the AIS. Among the different proposed etiology of AIS, the role of abnormal skeletal growth and development during peri-pubertal period has been one of the main focuses in addition to genetic predisposition in the development of AIS. / It has been well established that girls with idiopathic scoliosis have a tendency to be taller and more slender than their peers. Recently, it has been shown that the trabecular bone mineral density at the spine, hip, and peripheral bones of AIS girls was lower than their healthy peers. Studies from our center have also demonstrated growth discrepancy between anterior and posterior vertebral column using magnetic resonance imaging (MRI) technique. The vertebral bodies were shown to be slender in AIS patients than that in normal controls. The observation pointed to a disproportionate growth of the anterior and posterior spinal column resulting from imbalance in endochondral and membranous ossification. The present study hypothesizes that the abnormality of skeletal growth could be a systemic problem affected by both endochondral ossification and membranous ossification. The degree of abnormal growth could vary with different curve severities. The concurrent finding of abnormal skeletal growth and osteopenia could be related to certain underlying abnormal genetic factors affecting the etiopathogenesis of AIS. The hypothesis leads to the following objectives: (1) To study the anthropometric measurements and the related changes in AIS girls with different curve severity; (2) To document the presence of abnormal systemic growth through endochondral ossification; (3) To document the presence of abnormal membranous ossification through studies of the morphology and bone mineral density of the midshaft of the appendicular skeleton and the skull; (4) To study the association of occurrence of AIS and its related phenotypes with the genes associated with growth and osteopenia. (Abstract shortened by UMI.) / by Yeung Hiu-Yan. / "January 2006." / Adviser: Jack C. Y. Cheng. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6301. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 206-227). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Mong, Lok Yee. / Thesis submitted in: December 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 124-145). / Abstracts in English and Chinese; some text in appendix also in Chinese. / Acknowledgements --- p.i / Abstract (English version) --- p.iii / Abstract (Chinese version) --- p.v / Table of Contents --- p.vii / List of Tables --- p.ix / List of Figures --- p.xi / List of Abbreviations --- p.xiii / Chapter Chapter 1 - --- Introduction / Chapter 1.1 --- Childhood obesity: a worldwide epidemic --- p.1 / Chapter 1.2 --- Health consequences of childhood obesity --- p.3 / Chapter 1.3 --- Determinants of childhood obesity --- p.5 / Chapter 1.4 --- Hormonal dysregulation and obesity --- p.9 / Chapter 1.5 --- Project objectives and long term significance --- p.14 / Chapter Chapter 2 - --- Research Plan and Methodology / Chapter 2.1 --- Study cohort / Chapter 2.1.1 --- Subject recruitment --- p.15 / Chapter 2.1.2 --- Ethics --- p.16 / Chapter 2.1.3 --- Measurements and blood sample collections --- p.16 / Chapter 2.1.4 --- Subgroup for dietary assessment --- p.18 / Chapter 2.1.5 --- Cohort re-visits in 2006 --- p.19 / Chapter 2.2 --- Genetic study / Chapter 2.2.1 --- Sample size estimation and research subjects --- p.21 / Chapter 2.2.2 --- DNA samples --- p.22 / Chapter 2.2.3 --- Candidate genes --- p.24 / Chapter 2.2.4 --- SNP tagging and prioritizing --- p.25 / Chapter 2.2.5 --- Genotyping methods & quality control --- p.28 / Chapter 2.2.6 --- Statistical analysis --- p.31 / Chapter 2.3 --- Dietary assessment / Chapter 2.3.1 --- Three-day 24-hour dietary recalls --- p.36 / Chapter 2.3.2 --- Lifestyle questionnaire --- p.37 / Chapter 2.3.3 --- Data management --- p.38 / Chapter 2.3.4 --- Statistical methods --- p.39 / Chapter Chapter 3 - --- Results Page / Chapter 3.1 --- Study cohort --- p.41 / Chapter 3.2 --- Genetic study / Chapter 3.2.1 --- Subjects --- p.41 / Chapter 3.2.2 --- SNPs selection --- p.41 / Chapter 3.2.3 --- Factor analysis of adiposity in the study population --- p.44 / Chapter 3.2.4 --- Genotyping and association testing in stage1 --- p.50 / Chapter 3.2.5 --- Genotyping and association testing in stage2 --- p.52 / Chapter 3.2.6 --- Association of the CART gene with adiposity --- p.55 / Chapter 3.2.7 --- Association of the GHR gene with adiposity --- p.60 / Chapter 3.2.8 --- Association of the GHRHR gene with adiposity --- p.69 / Chapter 3.2.9 --- Association of the IGFBP3 gene with adiposity --- p.75 / Chapter 3.2.10 --- Association of the POMC gene with adiposity --- p.83 / Chapter 3.2 --- Dietary assessment / Chapter 3.3.1 --- Nutrient intakes of the subgroup in2004 --- p.87 / Chapter 3.3.2 --- Nutrient intakes of the subgroup in2006 --- p.92 / Chapter 3.3.3 --- Lifestyle pattern of the cohort in2006 --- p.97 / Chapter Chapter 4 - --- Discussion / Chapter 4.1 --- The role of GH-related genes with adolescent adiposity --- p.102 / Chapter 4.2 --- Nutrient intakes and lifestyle pattern of the adolescents --- p.120 / Chapter 4.3 --- Conclusion of this study --- p.123 / References --- p.124 / Appendices / Chapter A --- Information of the SNPs selected --- p.146 / Chapter B --- Comparison of SNPs minor allele frequency (MAF) among two genotyping stages and HapMap data --- p.154 / Chapter C --- Hardy-Weinberg Equilibrium (HWE) of SNPs in two genotyping stages --- p.162 / Chapter D --- Factor score coefficient matrix --- p.170 / Chapter E --- Association of SNPs with factors scores --- p.172 / Chapter F1 --- Consent form (English version) --- p.207 / Chapter F2 --- Consent form (Chinese version) --- p.209 / Chapter G1 --- 24-hour dietary recall forms (English version) --- p.211 / Chapter G2 --- 24-hour dietary recall forms (Chinese version) --- p.218 / Chapter H --- Food photo booklet --- p.225 / Chapter I1 --- Lifestyle questionnaire (English version) --- p.236 / Chapter I2 --- Lifestyle questionnaire (Chinese version) --- p.238

Yeung, Daniel Chi Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 69-83). / Abstracts in English and Chinese; appendix B also in Chinese. / ACKNOWLEDGMENTS --- p.i / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.vi / INTRODUCTION --- p.1 / Purpose and Significance --- p.3 / Hypothesis --- p.5 / Delimitation --- p.5 / Limitation --- p.5 / Operational Definitions --- p.6 / REVIEW OF LITERATURE --- p.9 / The Epidemic of Childhood Obesity --- p.9 / Increase in Childhood Obesity Over the World --- p.9 / Factors Contribute to Childhood Obesity --- p.12 / Health Consequence --- p.14 / Childhood Obesity Interventions --- p.15 / Measurement of Body Composition in Children --- p.17 / Body Composition Models --- p.17 / Measurement Methods --- p.20 / Laboratory Methods --- p.20 / Hydrodensitometry --- p.20 / Air displacement plethysmography --- p.22 / Hydrometry --- p.23 / Dual energy X-ray absorptiometry --- p.25 / Pros and cons of body fat criterion measures --- p.26 / Field Methods --- p.27 / Bioelectric impedance analysis --- p.27 / Anthropometry --- p.28 / Skinfold thickness measurement --- p.29 / Summary --- p.33 / METHODOLOGY --- p.36 / Participants --- p.36 / Experimental Protocols and Procedures --- p.36 / Criterion Measurement --- p.36 / Field Measurements --- p.38 / Statistical A nalysis --- p.39 / RESULTS --- p.41 / Comparison of ADP and DXA in Measuring Percent Fat Criterion --- p.41 / Sample Distribution and Descriptive Statistics --- p.41 / Correlations --- p.44 / Reliability --- p.46 / Cross Validation of Slaughter Equations --- p.47 / Exploration of Alternative Equations --- p.51 / DISCUSSION --- p.59 / Limitations --- p.66 / Recommendations for Future Study --- p.67 / Conclusions --- p.68 / REFERENCES --- p.69 / APPENDIX / Chapter A --- Standardized Description of Skinfold Sites --- p.84 / Chapter B --- Informed Consent --- p.85 / Chapter C --- Data Sheet --- p.87

本研究的目的在於以電阻抗法測定的脂肪比例作為標準，評價各種兒童肥胖定義診斷脂肪過量時的診斷準確性。爲了達到這項研究目的，本研究分為三個部份。首先，研究的第一部份評價了生物電阻抗法（Bio-electrical impedance analysis, BIA）在測量中國兒童青少年身體成份時的效度。隨後，幾種被廣泛應用的電子脂肪磅測量身體脂肪比例時的測量準確度被進行了評價。最後，在大規模人群測試中，利用精確的電子脂肪磅及幾種人體測量學指標決定的脂肪水平，不同兒童肥胖定義的診診斷脂肪過量的斷準確性被進行了評價。共有255名9至19歲的中國兒童青少年參與了第一和第二部份的測試，利用雙能X光骨密度儀（Dual-energy X-ray absorptiometry, DEXA）測量的體成份作為標準，比較了通過標準電阻抗法以及幾種被廣泛電子脂肪磅測量而來的體成份。研究結果顯示，生物電阻抗法是測量中國兒童青少年體成份有效的方法，然而，所有以前研究發展的BIA預測方程均未能準確估計受試者的去脂體重（Fat-free mass, FFM）。四種商業電子脂肪磅在測量受試者的體脂有類似的診斷準確度。隨後，另外的2,134名兒童青少年參與了本研究第三部份的測試，利用經過第二部份經過調整的脂肪磅測量受試者的體脂比例，同時測量人體測量學指標。研究結果發現，現有關於兒童肥胖的定義在診斷香港兒童、青少年脂肪過量的診斷準確性不夠。此外，受試者工作特徵曲綫分析（Receiver operating characteristics, ROC）發現利用基於身高和體重的指數來定義兒童肥胖在診斷肥胖兒童時較基於腰圍的指數有更好的敏感度和特異性。因此，研究者可以通過調整這些身高和體重的指數的劃分點來獲得對兒童肥胖更好的診斷準確性。 / 研究一（第3章）的目的在於評價生物電阻抗（Bio-electrical impendence analysis, BIA）方法在預測中國兒童青少年的去脂體重（Fat-free mass, FFM）中的效度，同時，也驗證已有的利用BIA方法發展的方程預測中國兒童、青少年FFM的效度。共有255名9-19歲健康的中國兒童、青少年（127名男生、128名女生）自願參與此次測試。利用傳統的單頻（50 kHz）的手腳電阻抗儀測試人體的電阻與電抗。利用雙能X光骨密度儀（Dual-energy X-ray absorptiometry, DEXA）作為測量FFM的標準。以DEXA測試的FFM為標準，對24個已有的BIA預測FFM的方程進行交互驗證。研究結果顯示，在本研究的人群中，利用24個已有的BIA預測方程所預測FFM與DEXA測量而來FFM高度相關。然而，這24個方程都未能準確預測本研究測試人群中由DEXA測量而來的FFM。利用多元線性回歸及交互驗證的方法，本研究發展了一個預測中國兒童、青少年FFM的預測方程：FFM (kg) = 1.613 + 0.742 × 身高(cm)²/電抗 (Ω) + 0.151 × 體重 (kg); R² = 0.95; SEE = 2.45kg; CV = 6.5%。本研究的研究結果表明，已有的BIA預測FFM的方程均不能通過交互驗證，從而準確的預測本研究人群的FFM。利用本研究人群發展而來的BIA預測FFM的方程，對預測中國兒童、青少年的FFM有良好的效度。本研究證明利用BIA方法可以準確的預測中國兒童、青少年的體成份。 / 研究二（第4章）旨在驗證4種利用BIA原理發展而來的商業電子脂肪磅在測量中國兒童、青少年體脂比例時的效度，以及判斷這些脂肪磅診斷身體脂肪過量時的診斷表現。參與研究一的255名中國兒童、青少年也參與本研究。利用DEXA作為測量體成份的標準測量。同時，4種電子脂肪磅（Model A, Biodynamics-310; Model B, Tanita TBF-543; Model C, Tanita BC-545 和 Model D, InBody 520）利用製造商內置的BIA方程測量受試者的體成份。研究結果表明，採用製造商內置的BIA方程測量體脂比例時，在男性中，Model B和Model C測量的體脂比例與DEXA測量的體脂比例有明顯差異 （p < 0.05）；Model C低估了脂肪過量兒童、青少年在在受試人群中的百分比（X²=10.714, p=0.001）。在女性中，Model B、Model C和Model D測量的體脂比例與DEXA測量的體脂比例有明顯差別，脂肪過量兒童在占受試人群中的比例被這三種脂肪磅所低估。由於在這四種脂肪磅和DEXA測量的%BF有著較高的相關性，回歸分析被用於調整這四種脂肪磅所測量的體脂比例。在調整后，在男性和女性中，所有調整的脂肪磅測試的體脂比例與DEXA測量的體脂比例之間沒有分別。在男性和女性受試者中，卡方檢驗結果顯示，所有校正的脂肪磅診斷的脂肪過量兒童、青少年占受試人群中的比例與DEXA的診斷比例之間沒有發現明顯區別。 此外，在女性中，與未校正的脂肪磅的對脂肪過量兒童、青少年診斷的敏感度比較，調整后的Model B 和 ModelC 脂肪磅對脂肪過量的兒童診斷的敏感度得到明顯改善 (Model B, X²=9.818,p=0.002; Model C, X²=4.615, p=0.032)。本研究的研究結果建議在利用電子脂肪磅內置方程測量中國青少年、兒童的體脂比例時，其效度需要進行驗證。因為在脂肪磅和DEXA測量之間有較高的相關性和較小的偏差，經調整的脂肪磅可以用於在進行大規模人群測試時，測量中國青少年、兒童的體脂比例，以及作為對脂肪過量兒童、青少年的診斷工具。 / 研究三（第5章）的目的在於調查基於身高體重的指數和基於腰圍的指數在診斷香港兒童、青少年脂肪過量時的總體診斷表現；以及判斷現有兒童肥胖定義診斷香港兒童、青少年脂肪過量時的診斷表現。共有來自香港多所中小學的2134名9-19歲的受試者，包括1135名男性、999名女性參與本研究。利用研究二調整的便攜式足對足電子脂肪磅測量受試者的體脂比例。基於體脂比例的兒童肥胖，即脂肪過量，被定義為體脂比例在男性高於25%，女性高於30%。四種基於BMI的兒童肥胖定義、兩種基於香港數據利用腰圍對兒童肥胖的定義、以及香港現有的兒童肥胖定義用於此研究。受試者工作特徵曲綫分析（Receiver operating characteristics, ROC）被用於分析身高體重指數（BMI）、標準身高體重（PWH）、腰圍（WC）和腰圍身高比（WHtR）在診斷香港兒童、青少年脂肪過量時的總體診斷表現。診斷試驗的指標被用來判斷現有兒童肥胖的定義診斷香港兒童、青少年脂肪過量時的診斷表現。本研究發現，在男性中，BMI、PWH、WC和WHtR在診斷香港兒童、青少年脂肪過量時有相同的良好的診斷表現[受試者工作特徵曲綫下面積(area under the curve of ROC, AUC) = 0.909-0.923]。然而，在女性中，WC（AUC=0.840）和WHtR（AUC=0.850）診斷香港兒童、青少年脂肪過量時的診斷表現差於BMI（AUC=0.900）和 PWH （AUC=0.903）。此外，現有兒童肥胖定義在診斷香港兒童、青少年脂肪過量時診斷敏感度較低，敏感度在男性中為0.325-0.761；女性中為0.128-0.588。利用最好診斷準確度的方法來確定的BMI、PWH、WC和WHtR的劃分點在診斷脂肪過量時，在男性中有相似的診斷表現，診斷敏感度在0.816-0.868之間，診斷特異度在0.803-0.869之間；對於女性，BMI和PWH 較WC和WHtR有較高的敏感度和特異度。本研究的發現表明，在診斷脂肪過量時，基於身高和體重的指數總體診斷表現好於基於腰圍的指數；現有兒童肥胖定義在診斷香港兒童、青少年脂肪過量時的診斷表現不佳。進一步，通過調整以身高和體重為基礎指數的劃分點可以使其在診斷脂肪過量時有更好的診斷表現。 / The purpose of this study was to evaluate the diagnostic accuracy of various childhood obesity definitions using bioelectrical impedance analysis (BIA) as a criterion measure of body fat. To achieve such an objective, the study involved three phases. First, the validity of BIA in measuring body composition in Chinese children and adolescents was evaluated. Then, examination on measuring accuracy of several popular BIA scales was performed. Finally, mass testing of body fat levels using an accurate BIA scale, as well as other anthropometric measures, was conducted to evaluate the diagnostic accuracy of childhood obesity definitions. A total of 255 healthy Chinese children and adolescents aged 9 years to 19 years participated in the first and second phases of the study. Body composition was measured from BIA using a criterion device (Biodynamics 310) and four popular commercial BIA scales and compared with measurements from dual-energy X-ray absorptiometry (DEXA). BIA provided excellent predictions of body composition among Chinese children and adolescents. However, all of the previously developed BIA equations yielded biased estimation. The four commercial BIA scales had similar diagnostic accuracy in measuring body fat. Subsequently, another 2,134 boys and girls were recruited to take part in body fat measurements using the best BIA scale identified in the second phase with adjusted equations, as well as other anthropometric measurements. The diagnostic accuracy of all existing definitions of childhood obesity was poor in both genders. Moreover, Receiver Operating Characteristics (ROC) analysis found that childhood obesity definitions using weight-and-height based indices [Body mass index (BMI) and weight-for-height) had superior sensitivity and specificity in identifying obese children compared with waist circumference-based indices. Therefore, with adjusted cut-off criteria for weight-and-height indices, the diagnostic accuracy of childhood obesity would be improved. / Study I : Validity of BIA method in predicting FFM / The first study (Chapter 3) aimed to examine the validity of the BIA method in predicting fat-free mass (FFM) in Chinese children and adolescents and of various published BIA equations in estimating FFM in this particular group. A total of 255 healthy Chinese children and adolescents (127 boys and 128 girls) aged 9 years to 19 years participated in this study. BIA variables (e.g., resistance and impedance) were measured at 50 kHz between the hand and foot using a traditional BIA device. The criterion of FFM measurement was also assessed using DEXA. FFM estimated from 24 published BIA equations were cross-validated against the criterion measure from DEXA. FFM estimated from the 24 published BIA equations yielded high correlations with the directly measured FFM from DEXA. However, none of the 24 equations was statistically equivalent with the DEXA-measured FFM. Using multiple linear regression and cross-validation against the DEXA measurement, an alternative prediction equation was developed as follows: FFM (kg) = 1.613 + 0.742 × height (cm)²/impedance (Ω) + 0.151 × body weight (kg); R² = 0.95; SEE = 2.45 kg; CV = 6.5%. None of the previously developed BIA equations was able to cross-validate the FFM estimates of the present sample. An alternative BIA equation, with evidence of validation and cross-validation, was thus proposed. The method based on the BIA principle provides a valid estimation of body composition among Chinese children and adolescents. / Study II: Validity of popular BIA consumer scales in measuring body fat / The second study (Chapter 4) examined the validity in measuring body fat and the diagnostic performance of four different consumer BIA scales. The 255 Chinese children and adolescents from the first study also participated in this study. DEXA was used as the criterion measurement for %BF, which was also assessed using four BIA scales [Model A (Biodynamics 310), Model B (Tanita TBF-543), Model C (Tanita BC-545), and Model D (InBody 520)]. The validity in measuring body fat and the diagnostic performance in screening excess body fat of these BIA scales was first examined. In boys, differences in %BF between Models B, C, and DEXA were significant (p < 0.05). In girls, significant differences in %BF were observed between Models B, C, D, and DEXA (p < 0.05). The prevalence of overfat in boys was underestimated by Model C (X² = 10.714, p = 0.001). For girls, the prevalence of overfat was underestimated in Models B, C, and D. Because of the high correlation between the BIA scales and DEXA (r = 0.770.94), regression analysis was used to adjust the BIA scales in measuring %BF in this sample. After adjustment, the paired t-tests did not show differences in %BF between the adjusted BIA scales and the DEXA measurement in both genders. All adjusted BIA scales except Model A in girls showed substantial agreement with the DEXA measurement. In addition, compared with overfat classification using DEXA measurement, X² test showed that the prevalence of overfat in the present samples was classified correctly by all adjusted BIA scales in both genders. Compared with the original BIA measurements, the use of the adjusted Models B and D offered significant improvements in sensitivity for girls. These findings suggest that the embedded equations in BIA scales should be validated in assessing body compositions among Chinese children and adolescents. The adjusted BIA scales can be used in large population surveys due to the high correlation and small mean bias between the BIA scales and the DEXA measurements. In conclusion, the adjusted BIA scales can serve as diagnostic tools to classify overfat Chinese children into relevant subgroups. / Study III: Diagnostic accuracy of definitions of childhood obesity / The third study (Chapter 5) aimed to investigate the diagnostic performance of weight-and-height-based indices and waist circumference (WC-based indices as diagnostic tests to screen excess body fat in Hong Kong children and adolescents and to investigate the diagnostic accuracy of existing definitions of childhood obesity in Hong Kong. A total of 2,134 participants (1,135 boys and 999 girls) were recruited from local schools. The adjusted foot-to-foot BIA scale (Model B) in the second study was applied to assess %BF. The criterion of childhood obesity (i.e., overfat) was defined as over 25%BF for boys and over 30%BF for girls. Childhood obesity was also determined from four BMI-based references, two WC-based references, and the 1993 HK reference. The diagnostic accuracy of the existing definition for childhood obesity in screening excess body fat was evaluated using diagnostic indices. The Receiver Operating Characteristics (ROC) analysis was used to evaluate the general performance of BMI, PWH, WC, and WHtR in detecting overfat. In boys, ROC analysis showed no significant difference among the four indices in screening overfat [(area under the curve of ROC, AUC) = 0.909-0.923]. In girls, BMI and PWH performed better in detecting overfat than WC and WHtR (AUC of BMI = 0.900; AUC of PWH = 0.903; AUC of WC = 0.840 and AUC of WHtR = 0.850). All definitions for obesity showed low sensitivity (boys, 0.325-0.761; girls, 0.128-0.588) in detecting overfat. Cut-offs derived for best accuracy showed similar diagnostic performance in each index in boys but not in girls. In boys, the cut-offs of BMI, WC, WHtR, and PWH can provide similar sensitivity (0.816-0.868) and specificity (0.803-0.869) in screening overfat. In girls, BMI and PWH can provide higher sensitivity and specificity than WC and WHtR. This study’s findings demonstrate that the diagnostic performance of all existing definitions for obesity is poorer than expected in both genders. BMI and PWH are superior to use as proxy measures in screening overfat among Hong Kong Chinese children and adolescents for both genders. Moreover, the diagnostic performance of these indices can be improved by adjusting the existing cut-offs. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wang, Lin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 166-197). / Abstract and appendixes also in Chinese. / ABSTRACT --- p.i / 摘要 --- p.v / ACKNOWLEDGEMENT --- p.ix / PUBLICATIONS --- p.xi / LIST OF TABLES --- p.xv / LIST OF FIGURES --- p.xvii / ABBREVIATIONS --- p.xviii / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- Background --- p.1 / Chapter 1.2. --- Purposes and significance --- p.4 / Chapter 1.3. --- Operational definitions --- p.5 / Chapter 1.3.1. --- Childhood overweight and obesity --- p.5 / Chapter 1.3.2. --- Body composition --- p.6 / Chapter 1.3.3. --- Bioelectric impedance analysis (BIA) --- p.6 / Chapter 1.3.4. --- Validity --- p.6 / Chapter 1.3.5. --- Diagnostic performance --- p.6 / Chapter 1.4. --- Hypothesis --- p.6 / Chapter 1.5. --- Limitations --- p.7 / Chapter 1.6. --- Delimitations --- p.7 / Chapter CHAPTER 2. --- LITERATURE REVIEW --- p.9 / Chapter 2.1. --- The epidemic and health consequence of childhood obesity --- p.10 / Chapter 2.1.1. --- Prevalence of childhood obesity --- p.10 / Chapter 2.1.2. --- Health consequence of childhood obesity --- p.15 / Chapter 2.2. --- Contributors of Childhood obesity --- p.16 / Chapter 2.2.1. --- Genetics --- p.17 / Chapter 2.2.2. --- Dietary intake --- p.17 / Chapter 2.2.3. --- Physical activity --- p.18 / Chapter 2.2.4. --- Sedentary behaviors --- p.18 / Chapter 2.3. --- Definitions of overweight and obesity in children and adolescents --- p.19 / Chapter 2.3.1. --- General definition of obesity --- p.19 / Chapter 2.3.2. --- Definitions and prevalence of childhood obesity in different countries --- p.21 / Chapter 2.3.3. --- Methods and current practices for identifying childhood obesity --- p.21 / Chapter 2.4. --- Methods for assessing body composition --- p.42 / Chapter 2.4.1. --- Body composition models --- p.42 / Chapter 2.4.2. --- Measurements methods to estimate body composition --- p.44 / Chapter 2.4.3. --- Specific issues of body fat in childhood --- p.60 / Chapter 2.5. --- Diagnostic accuracy of different definitions of childhood obesity --- p.61 / Chapter CHAPTER 3. --- STUDY I: VALIDITY OF BIOELECTRICAL IMPEDANCE MEASUREMENT IN PREDICTING FAT-FREE MASS OF CHINESE CHILDREN AND ADOLESCENTS --- p.67 / Chapter 3.1. --- Introduction --- p.67 / Chapter 3.2.1. --- Participants --- p.69 / Chapter 3.2.2. --- Measurements --- p.70 / Chapter 3.2.3. --- Data reduction and statistic analysis --- p.72 / Chapter 3.3. --- Results --- p.78 / Chapter 3.3.1. --- Descriptive statistics --- p.78 / Chapter 3.3.2. --- Cross-validation of published BIA equations --- p.79 / Chapter 3.3.3. --- Development of alternative BIA equations --- p.84 / Chapter 3.4. --- Discussion --- p.86 / Chapter 3.5. --- Conclusion --- p.92 / Chapter CHAPTER 4. --- STUDY II: VALIDITY OF FOUR COMMERCIAL BIA SCALES IN MEASURING BODY FAT AMONG CHINESE CHILDREN AND ADOLESCENTS --- p.93 / Chapter 4.1. --- Introduction --- p.93 / Chapter 4.2. --- Methods --- p.97 / Chapter 4.2.1. --- Participants --- p.97 / Chapter 4.2.2. --- Anthropometrics measurement --- p.97 / Chapter 4.2.3. --- Measurement of body composition --- p.97 / Chapter 4.2.4. --- Statistical analysis --- p.99 / Chapter 4.3. --- Results --- p.102 / Chapter 4.3.1. --- Characteristics of participants --- p.102 / Chapter 4.3.2. --- Reliability of BIA analysis --- p.103 / Chapter 4.3.3. --- Comparison of measuring body composition between BIA commercial devices (manufacturers’ equations) and DEXA measurement-Step 1 --- p.103 / Chapter 4.3.4. --- Comparison of measuring body composition between BIA commercial devices (adjusted equations) and DEXA measurement-Step 2 --- p.110 / Chapter 4.4. --- Discussion --- p.116 / Chapter 4.5. --- Conclusion --- p.123 / Chapter CHAPTER 5. --- STUDY III: DIAGNOSTIC ACCURACY OF DIFFERENT DEFINITIONS OF CHILDHOOD OBESITY IN IDENTIFYING OVERFAT AMONG CHINESE CHILDREN AND ADOLESCENTS --- p.124 / Chapter 5.1. --- Introduction --- p.124 / Chapter 5.2. --- Methods --- p.126 / Chapter 5.2.1. --- Participants --- p.126 / Chapter 5.2.2. --- Anthropometrics measurement --- p.127 / Chapter 5.2.3. --- Body fat measurement --- p.127 / Chapter 5.2.4. --- Definition of excess fatness --- p.128 / Chapter 5.2.5. --- Classification of participants --- p.128 / Chapter 5.2.6. --- Data reduction and statistic analysis --- p.129 / Chapter 5.3. --- Results --- p.131 / Chapter 5.3.1. --- Characteristics of participants --- p.131 / Chapter 5.3.2. --- Age-adjusted correlation among the different indices of obesity --- p.133 / Chapter 5.3.3. --- Prevalence rates of overweight/obesity --- p.134 / Chapter 5.3.4. --- Diagnostic agreement in assessing excess fat between %BF and anthropometric-based definitions --- p.137 / Chapter 5.3.5. --- Sensitivity and specificity --- p.138 / Chapter 5.3.6. --- Diagnostic performance of anthropometric indices in assessing excess fat --- p.141 / Chapter 5.3.7. --- Cut-offs of the anthropometric indices for screening excess fat --- p.143 / Chapter 5.4. --- Discussion --- p.148 / Chapter 5.5. --- Conclusion --- p.157 / Chapter CHAPTER 6. --- GENERAL DISCUSSION AND CONCLUSION --- p.158 / REFERENCE --- p.166 / APPENDIX A --- p.198 / APPENDIX B --- p.202 / APPENDIX C --- p.204 / APPENDIX D --- p.206 / APPENDIX E --- p.210

You, Jianing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (p. 72-79). / Abstract also in Chinese. / List of Tables --- p.vi / List of Figures --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Method --- p.24 / Chapter Chapter 3 --- Results --- p.30 / Chapter Chapter 4 --- Discussion --- p.56 / References --- p.65

Leung, Fung Lin Elean. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 128-157). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Acne is prevalent amongst youth in Hong Kong and has considerable psychological effects. The application of a TCM approach led to the detection of significant associations between diet and the occurence of acne. TCM-syndrome-tailored dietary manipulation was effective in reducing the clinical severity of acne for patients with imbalance of chong-ren subtype. (Abstract shortened by UMI.) / In (1), 1068 Chinese subjects were sampled from the general health evaluation and eight governmental secondary schools in Hong Kong were assessed for their clinical severity of acne. Over 93% of the subjects had a certain degree of acne and the prevalence of clinical acne was of 40.4% and coexisted with a high frequency of acne disability. Assessment of the clinical severity of acne did not correlate strongly with the effect on QOL (gammas= 0.445, P &lt; 0.001). Multivariate logistic regression showed that female gender (P = 0.002), higher GAGS score (P &lt; 0.001), higher perceived stress (P = 0.01) and willingness to pay Hong Kong $15,000 for a hypothetical permanent cure (P = 0.03) were positive predictors for acne disability. / In (2), 322 university entrants completed a dietary questionnaire capturing 11 categories of food intake and were examined for body constitutions of yin-predominance or yang-predominance with a published TCM diagnostic assessment procedure/method. There were 155 (48.1%) participants in the yin-predominant group and 167 (51.9%) in the yang-predominant group. No association of diet and acne was found when the participants were considered as a whole group. In yin-predominant group, intake of foods from street stalls (P = 0.04) was significantly associated with a lower likelihood of acne occurence. In yang-PG, the intake of desserts (P = 0.04) and fresh fruit juices (P = 0.02) was significantly associated with a higher likelihood of acne occurence, whereas the intake of dairy and soy products (P = 0.04) was significantly associated with a lower likelihood of acne occurence. / In (3), 233 students with clinical acne as assessed by GAGS were diagnosed for his or her TCM syndrome subtype, namely wind-heat subtype, damp-heat subtype, stagnant blood or phlegm subtype, and imbalance of chong-ren subtype. They were then randomly assigned to either intervention group (IG) or control group (CG). There were respectively 60 students belonged to each of the wind-heat, damp-heat, and stagnant blood or phelgm subtypes, and 53 students belonged to imbalanced of chong-ren subtype. With the use of a computer generated randomisation list using blocks of six, 30 (50%) students were assigned to either IG or CG for wind-heat, damp-heat, and stagnant blood or phelgm subtypes accordingly, whilst 26 (49%) and 27 (51%) students were assigned to either IG or CG for imbalance of chongren subtype. TCM-syndrome-tailored diet advice plus standard medical advice were given to IG whilst standard medical advice alone was given to CG over 12-week study period. The primary analysis was to compare the percentage change of GAGS from baseline to 12 weeks between the groups using univariate analysis for each TCM syndrome, controlling for the variation in the dependent variables due to gender, age, BMI, schools, physical exercise, and female contraceptive use. Within the imbalance of chong-ren subtype, there was a significant reduction of acne severity in IG compared with that in CG (-11.8% vs 2.1%; p=0.046), after adjusting for gender, age, body mass index, schools, physical exercise, and female contraceptive use. In the other three subtypes, there were no significant differences of acne severity between IG and CG / This research was composed of three major parts: (1) a cross-sectional study investigating the prevalence of acne and the acne disability amongst adolescents and young adults from August 2006 to March 2008 in Hong Kong; (2) a cross sectional study investigate the diet-acne connection from a traditional Chinese medicine (TCM) perspective performed amongst young adults in August 2006; and (3) a randomised controlled trial on the effectivenss of TCM-syndrome-tailored dietary advice for adolescents implemented between November 2007 and March 2008 in Hong Kong. / Law, Pui Man. / Adviser: Albert Lee. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 140-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese; appendix 2-3 in Chinese.

Tang Wai-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 51-61). / Abstracts in English and Chinese.