title: Body mass index (BMI) trajectories in infancy differ by population ancestry and may presage disparities in early childhood obesity.
abstract: BACKGROUND
  No consensus definition exists for excess adiposity during infancy. After age 2 years, high body mass index (BMI) is related to adverse cardiometabolic outcomes. Before age 2 years, the utility of BMI as a metric of excess adiposity is unknown.
  
  
  OBJECTIVE
  The objective of the study was to characterize infant BMI trajectories in a diverse, longitudinal cohort and investigate the relationship between the infancy BMI trajectory and childhood obesity.
  
  
  METHODS
  Healthy, nonpreterm infants (n = 2114) in the Genetic Causes for Complex Pediatric Disorders study (The Children's Hospital of Philadelphia) with six or more BMI measurements in the first 13.5 months participated in the study.
  
  
  METHODS
  For each infant, the BMI trajectory was modeled using polynomial regression. Independent effects of clinical factors on magnitude and timing of peak BMI were assessed. The relationship between infancy BMI and early childhood BMI (age 4 y) was examined (n = 1075).
  
  
  RESULTS
  The cohort was 53% male and 61% African-American. Peak BMI was 18.6 ± 1.7 kg/m(2) and occurred at 8.6 ± 1.4 months. In multivariate analysis, boys had a higher (0.50 kg/m(2), P < .001) peak BMI than girls. The peak was higher (0.53 kg/m(2), P ≤ .001) and occurred earlier (by 12 d, P < .001) in African-American vs white children. The odds of obesity at age 4 years increased among children with higher (odds ratio 2.02; P < .001) and later (odds ratio 1.26; P = .02) infancy peak BMI.
  
  
  CONCLUSIONS
  We demonstrate sex- and ancestry-specific differences in infancy BMI and an association of infancy peak BMI with childhood BMI. These findings support the potential utility of infancy BMI to identify children younger than age 2 years with increased risk for later obesity.
authors: Division of Endocrinology and Diabetes (S.M.R., A.K., S.F.A.G, S.E.M.), Division of Human Genetics (A.C., H.H., S.F.A.G.), Center for Applied Genomics (F.M., R.C., H.H., S.F.A.G.), Division of Gastroenterology, Hepatology, and Nutrition (B.S.Z.), The Children's Hospital of Philadelphia, and Departments of Biostatistics and Epidemiology (R.X., J.A.M.) and Pediatrics (A.K., H.H., S.F.A.G., B.S.Z, S.E.M.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104.
authors: Sani M
authors: SM
authors: Roy
authors: Alessandra
authors: A
authors: Chesi
authors: Frank
authors: F
authors: Mentch
authors: Rui
authors: R
authors: Xiao
authors: Rosetta
authors: R
authors: Chiavacci
authors: Jonathan A
authors: JA
authors: Mitchell
authors: Andrea
authors: A
authors: Kelly
authors: Hakon
authors: H
authors: Hakonarson
authors: Struan F A
authors: SF
authors: Grant
authors: Babette S
authors: BS
authors: Zemel
authors: Shana E
authors: SE
authors: McCormack
mesh_terms: D050154:Adiposity / Q000208:ethnology; D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D063766:Pediatric Obesity / Q000175:diagnosis* / Q000208:ethnology*; D012307:Risk Factors; D015430:Weight Gain / Q000208:ethnology; D055815:Young Adult
references: J Clin Endocrinol Metab. 2012 Sep;97(9):E1579-639
references: 22730516
references: Am J Hum Biol. 2013 May-Jun;25(3):378-88
references: 23606227
references: Am J Clin Nutr. 2003 Jun;77(6):1374-8
references: 12791612
references: PLoS One. 2013;8(12):e80517
references: 24324605
references: Int J Obes (Lond). 2014 Jan;38(1):53-9
references: 24080793
references: Pediatrics. 2010 Apr;125(4):686-95
references: 20194284
references: Matern Child Health J. 2012 Jul;16(5):1015-20
references: 21643834
references: Am J Clin Nutr. 2013 Jul;98(1):49-56
references: 23697708
references: Autism Res. 2011 Dec;4(6):438-48
references: 21905245
references: JAMA Pediatr. 2014 Jul;168(7):681-2
references: 24797161
references: Pediatrics. 2002 Jan;109(1):45-60
references: 11773541
references: J Racial Ethn Health Disparities. 2014 Mar 1;1(1):12-20
references: 24921060
references: JAMA Pediatr. 2013 Aug 1;167(8):731-8
references: 23733179
references: BMC Med Res Methodol. 2012;12:38
references: 22458308
references: BMC Pregnancy Childbirth. 2012;12:121
references: 23116061
references: Science. 2013 Aug 23;341(6148):856-8
references: 23970691
references: Pediatr Diabetes. 2014 Nov;15(7):534-42
references: 24785566
references: Diabetes Res Clin Pract. 2014 Mar;103(3):e14-7
references: 24552682
references: JAMA. 2014 Feb 26;311(8):806-14
references: 24570244
references: J Natl Med Assoc. 1986 Dec;78(12):1157-60
references: 3806690
references: N Engl J Med. 2005 Oct 27;353(17):1802-9
references: 16251536
references: Int J Obes (Lond). 2009 Aug;33(8):929-37
references: 19564879
references: Int J Obes (Lond). 2014 Oct;38(10):1290-8
references: 25012772
references: Drug Alcohol Depend. 2013 Nov 1;133(1):212-21
references: 23726978
references: Public Health Nutr. 2012 Sep;15(9):1603-10
references: 22717390
references: Evol Med Public Health. 2014 Aug 05;2014(1):109-21
references: 25095791
references: JAMA. 2012 Feb 1;307(5):491-7
references: 22253363
references: Am J Public Health. 2012 Nov;102(11):2057-67
references: 22994179
references: Int J Obes Relat Metab Disord. 2000 Mar;24(3):325-9
references: 10757626