title: Physical activity and 3-year BMI change in overweight and obese children.
abstract: OBJECTIVE
  Targeting physical activity (PA) is a mainstay in obesity treatment, but its BMI benefits are poorly quantified. We studied long-term predictive PA-BMI relationships in overweight/obese children presenting to primary care.
  
  
  METHODS
  Three-year follow-up of 182 overweight/obese 5- to 10-year-olds recruited from 45 Melbourne general practices.
  
  
  METHODS
  7-day accelerometry (counts per minute, cpm).
  
  
  RESULTS
  change in BMI z score, BMI category, and clinically significant BMI improvement (z score change ≥0.5).
  
  
  METHODS
  Linear and logistic regression.
  
  
  RESULTS
  Mean (SD) baseline and 3-year BMI z scores were 1.8 (0.6) and 1.8 (0.7), and mean (SD) activity scores 334 (111) and 284 (104) cpm, respectively. Baseline activity did not predict BMI change. However, for every 100 cpm increase in change in activity over 3 years, BMI z score fell by 0.11 (95% confidence interval [CI] 0.03-0.20; P = .006). There were also trends toward greater odds of staying in the same, versus moving to a higher, BMI category (odds ratio 1.85, 95% CI 0.99-3.46) and clinically significant BMI improvement (odds ratio 1.96, 95% CI 0.90-4.27; P = .09). Change in percentage time spent in moderate-vigorous (P = .01), but not sedentary (P = .39) or light (P = .59), activity predicted reduced BMI z score.
  
  
  CONCLUSIONS
  Sustained increase in moderate-vigorous PA predicts reducing BMI z score over 3 years in overweight/obese children presenting to primary care. However, the small BMI change associated with even the largest activity changes may explain disappointing BMI outcomes of brief primary care interventions targeting PA.
authors: Centre for Community Child Health, Royal Children's Hospital, Flemington Rd, Parkville 3052 Australia. melissa.wake@rch.org.au
authors: Andrew
authors: A
authors: Trinh
authors: Michele
authors: M
authors: Campbell
authors: Obioha C
authors: OC
authors: Ukoumunne
authors: Bibi
authors: B
authors: Gerner
authors: Melissa
authors: M
authors: Wake
mesh_terms: D061725:Accelerometry; D001521:Behavior Therapy; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D004038:Diet, Reducing; D004493:Education; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009765:Obesity / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D016017:Odds Ratio; D050177:Overweight / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D011320:Primary Health Care