title: Age-based reference ranges for annual height velocity in US children.
abstract: OBJECTIVE
  Clinicians caring for children rely on measures of linear growth as a biomarker of development and overall health. Current reference ranges for height velocity (HV) for US children are unable to provide HV percentiles or Z-scores for early maturing and late maturing children at ages other than age at peak velocity. We present empirically acquired, age-specific reference ranges for HV from a contemporary sample of US youth.
  
  
  METHODS
  Subjects were enrolled in the Bone Mineral Density in Childhood Study, a large, multicenter, multiethnic, contemporary cohort of children (aged 5-19 y at enrollment) from the United States followed for up to 7 years. More than 4000 annual (12 ± 1 mo) HV measurements from approximately 1500 children were available. Pubertal status was determined by breast stage or testicular volume assessed by experienced health providers. Age-specific reference ranges were determined using the LMS method.
  
  
  RESULTS
  Reference ranges (third to 97th percentiles) were generated for the entire cohort and for subgroups whose pubertal timing was defined as "earlier," "average," or "later." African American girls experienced earlier pubertal onset and had greater HV at younger ages and lower HV at older ages, compared to non-African American girls; differences did not persist after adjustment for pubertal timing. These differences were not observed for males.
  
  
  CONCLUSIONS
  These reference ranges for annual HV can be used to assess growth relative to peers of the same age and sex, with consideration of pubertal timing. Z-scores and exact percentiles for HV can also be determined for population studies.
authors.affiliation: Department of Pediatrics (A.K., B.S.Z.), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Eunice Kennedy Shriver National Institute of Child Health and Human Development (K.K.W.), Bethesda, Maryland 20892; Department of Pediatrics (H.K.), Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229; Department of Pediatrics (S.E.O.), Columbia University Medical Center, New York, New York 10032; Department of Medicine (J.L.), Creighton University, Omaha, Nebraska 68102; and Departments of Orthopaedic Surgery and Radiology (V.G.), Children's Hospital Los Angeles, Los Angeles, California 90027.
authors.forename: Andrea
authors.initials: A
authors.lastname: Kelly
authors.forename: Karen K
authors.initials: KK
authors.lastname: Winer
authors.forename: Heidi
authors.initials: H
authors.lastname: Kalkwarf
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Oberfield
authors.forename: Joan
authors.initials: J
authors.lastname: Lappe
authors.forename: Vicente
authors.initials: V
authors.lastname: Gilsanz
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
mesh_terms: D000293:Adolescent; D001741:Black or African American / Q000706:statistics & numerical data; D017677:Age Distribution; D000367:Age Factors; D001827:Body Height / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D057238:Growth Charts; D006801:Humans; D008297:Male; D012016:Reference Values; D012737:Sex Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult