title: Changes in body mass index and health related quality of life from childhood to adolescence.
abstract: OBJECTIVE
  To determine longitudinal relationships between body mass index (BMI) and health-related quality of life (HRQoL) in an adolescent population sample. Design. Data collected in 2000 and 2005 within the Health of Young Victorians longitudinal cohort study.
  
  
  METHODS
  Originally a community sample of elementary school students in Victoria, Australia. Follow-up occurred in either secondary schools or individuals homes.
  
  
  METHODS
  Cohort recruited in 1997 via a random sampling design from Victorian elementary schools. Originally comprising 1 943 children, 1 569 (80.8%) participated in 2000 (wave 2, 8-13 years) and 851 (54%) in 2005 (wave 3, 13-19 years). Main outcome measures. In both waves participants and their parents completed the PedsQL, a 23-item child HRQoL measure, and BMI z-scores and status (non-overweight, overweight or obese) were calculated from measured height and weight. Associations were tested cross-sectionally and longitudinally (linear regression, adjusted for baseline values)
  
  
  RESULTS
  A total of 81.6% remained in the same BMI category, while 11.4% and 7.0% moved to higher and lower categories, respectively. Cross-sectional inverse associations between lower PedsQL and higher BMI categories were similar to those for elementary school children. Wave 2 BMI strongly predicted wave 3 BMI and wave 2 PedsQL strongly predicted wave 3 PedsQL. Only parent-reported Total PedsQL score predicted higher subsequent BMI, though this effect was small. Wave 2 BMI did not predict wave 3 PedsQL.
  
  
  CONCLUSIONS
  This novel study confirmed previous cross-sectional associations, but did not provide convincing evidence that BMI is causally associated with falling HRQoL or vice versa across the transition from childhood to adolescence.
authors.affiliation: Murdoch Childrens Research Institute, Parkville, Australia. jo.williams@mcri.edu.au
authors.forename: Joanne W
authors.initials: JW
authors.lastname: Williams
authors.forename: Louise
authors.initials: L
authors.lastname: Canterford
authors.forename: Kylie D
authors.initials: KD
authors.lastname: Hesketh
authors.forename: Pollyanna
authors.initials: P
authors.lastname: Hardy
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Waters
authors.forename: George C
authors.initials: GC
authors.lastname: Patton
authors.forename: Melissa
authors.initials: M
authors.lastname: Wake
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D000367:Age Factors; D000375:Aging; D015992:Body Mass Index; D016009:Chi-Square Distribution; D002648:Child; D002652:Child Behavior; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D050177:Overweight / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D011788:Quality of Life; D012044:Regression Analysis; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014739:Victoria