title: Cardiorespiratory fitness status and body mass index change over time: a 2-year longitudinal study in elementary school children.
abstract: OBJECTIVE
  This study aimed to examine the prospective relationship of baseline body mass index (BMI) and performance in a cardiorespiratory fitness (CRF) field test with a change in BMI (DeltaBMI) over a 2-year period in a sample of rural children from elementary school in Fundão, Portugal.
  
  
  METHODS
  Obesity status was obtained by the age- and sex-specific BMI cut-off points and CRF by a 9-minute run test.
  
  
  RESULTS
  BMI stratification at baseline showed that overweight/obese children were over 11 times (OR=11.31; p=0.007) more likely to be DeltaBMI gainers than their normal weight peers. Those who were classified as unfit were 3.9 times more likely to be DeltaBMI gainers than those classified as fit at baseline. Both BMI at time 1 and CRF change (DeltaCRF) were not significantly associated with DeltaBMI over time.
  
  
  CONCLUSIONS
  The findings of this study suggest that children who have higher BMI and lower CRF are likely to have greater BMI gain over time.
authors.affiliation: Research Centre in Physical Activity Health and Leisure, Faculty of Sports, Porto University, Portugal. jmota@fade.up.pt
authors.forename: Jorge
authors.initials: J
authors.lastname: Mota
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Ribeiro
authors.forename: Joana
authors.initials: J
authors.lastname: Carvalho
authors.forename: Maria Paula
authors.initials: MP
authors.lastname: Santos
authors.forename: Júlio
authors.initials: J
authors.lastname: Martins
mesh_terms: D015992:Body Mass Index; D002648:Child; D005080:Exercise Test; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D016017:Odds Ratio; D010101:Oxygen Consumption; D010809:Physical Fitness; D011174:Portugal / Q000453:epidemiology; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012423:Rural Health; D013334:Students; D013997:Time Factors