title: The prevalence of rapid weight gain in infancy differs by the growth reference and age interval used for evaluation.
abstract: BACKGROUND
  Infant rapid weight gain (RWG) may predict subsequent obesity, but there are inconsistencies in the growth references and age intervals used for assessment.
  
  
  METHODS
  This study evaluated whether the prevalence of RWG (an increase of >0.67 in weight-for-age z-score) differed by growth reference (2006 WHO standards vs 2000 CDC references) and age interval of assessment (0-3, 0-6, 6-12 and 0-12 months). Pooled data from singleton term infants from two observational studies on maternal mood disorders during pregnancy were used (n = 161). Differences in RWG prevalence by growth reference and age interval were tested using Cochran's Q and McNemar's tests.
  
  
  RESULTS
  The CDC reference produced a higher RWG prevalence (14% of infants additionally categorized as RWG, p < 0.0001) within the 0-3 month age interval compared to the WHO standards; this pattern was reversed for the 6-12 and 0-12 month intervals. RWG prevalence did not differ across age interval within the WHO standards, but did differ with the CDC references (range: 22% for 0-3 months to 4.2% for 6-12 months, p < 0.0001).
  
  
  CONCLUSIONS
  Caution is advised when comparing studies with different criteria for RWG. Future studies should use the 2006 WHO standards and a consistent age interval of evaluation.
authors.affiliation: a School of Community Health, Portland State University , Portland , OR 97201 , USA .
authors.forename: Cara L
authors.initials: CL
authors.lastname: Eckhardt
authors.affiliation: b Department of Epidemiology , Graduate School of Public Health, University of Pittsburgh , Pittsburgh , PA 15261 , USA , and.
authors.forename: Heather
authors.initials: H
authors.lastname: Eng
authors.affiliation: b Department of Epidemiology , Graduate School of Public Health, University of Pittsburgh , Pittsburgh , PA 15261 , USA , and.
authors.forename: John L
authors.initials: JL
authors.lastname: Dills
authors.affiliation: c Departments of Psychiatry and Behavioral Sciences, and Obstetrics and Gynecology , Asher Center for the Study and Treatment of Depressive Disorder, Northwestern University , Chicago , IL 60611 , USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Wisner
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000886:Anthropometry; D001835:Body Weight; D002487:Centers for Disease Control and Prevention, U.S.; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009765:Obesity / Q000517:prevention & control*; D064887:Observational Studies as Topic; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D015995:Prevalence; D012015:Reference Standards; D012016:Reference Values; D014481:United States; D015430:Weight Gain; D014944:World Health Organization; D055815:Young Adult
keywords: Growth references; infant growth; rapid weight gain