title: Measurement properties of the Chinese version of the Youth Quality of Life Instrument-Weight Module (YQOL-W).
abstract: BACKGROUND
  Childhood obesity is a growing public health concern in China. It not only compromises physical health, but also has negative impacts on psychosocial well-being. As obesity rates increase, finding out what the perceptions of Chinese youth are regarding their weight is important for intervention planning and evaluation. However, there is a paucity of available obesity-specific instruments for children and adolescents in China and youth weight-specific quality of life (QOL) has been little reported. This study aimed to evaluate the measurement properties of the Chinese version of the Youth Quality of Life Instrument - Weight Module (YQOL-W).
  
  
  METHODS
  The Chinese version of the YQOL-W was administered to 840 youth aged 11-18 from nine schools. Measurement properties including measurement model, reliability, validity and burden were evaluated.
  
  
  RESULTS
  Confirmatory factor analysis showed that a three-factor model had acceptable model fit. The instrument had robust internal consistency reliability with Cronbach's α ranging from 0.84 to 0.96 and acceptable test-retest reliability with the intraclass correlation coefficients (ICCs) all higher than 0.7. The standard error of measurement (SEM) values for the Self, Social and Environment factors and total score were 10.352, 9.526, 12.086 and 8.425, respectively. The small real differences (SRDs) for the Self, Social and Environment factors and total score were 28.675, 26.387, 33.478, and 23.337, respectively. The Pearson's correlation coefficients between the YQOL-W and the PedsQL4.0 General Core Scales were stronger between comparable dimensions than those between less comparable dimensions, demonstrating convergent and discriminant evidence of construct validity. Significant differences were found in subscale and total scores across weight status, age and genders (P<0.01), supporting the known-groups validity of the instrument.
  
  
  CONCLUSIONS
  The Chinese version of the YQOL-W has acceptable measurement properties and can be used to assess the weight-specific QOL of children and adolescents in China.
authors.affiliation: Institute of Social Medicine and Family Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Jiang
authors.affiliation: Institute of Social Medicine and Family Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Hong-Mei
authors.initials: HM
authors.lastname: Wang
authors.affiliation: Department of Health Services, University of Washington, Seattle, Washington, United States of America.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Edwards
authors.affiliation: Institute of Social Medicine and Family Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Ying-Ping
authors.initials: YP
authors.lastname: Chen
authors.affiliation: Institute of Social Medicine and Family Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Yi-Ran
authors.initials: YR
authors.lastname: Lv
authors.affiliation: Department of Health Services, University of Washington, Seattle, Washington, United States of America.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Patrick
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D011594:Psychometrics / Q000706:statistics & numerical data*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012647:Self-Assessment; D011795:Surveys and Questionnaires