title: Breastfeeding duration and weight gain trajectory in infancy.
abstract: OBJECTIVE
  Short breastfeeding duration may exacerbate accelerated early growth, which is linked to higher obesity risk in later life. This study tested the hypothesis that infants at higher risk for obesity were more likely to be members of a rising weight-for-length (WFL) z score trajectory if breastfed for shorter durations.
  
  
  METHODS
  This prospective, observational study recruited women from an obstetric patient population in rural central New York. Medical records of children born to women in the cohort were audited for weight and length measurements (n = 595). We identified weight gain trajectories for infants' WFL z scores from 0 to 24 months by using maximum likelihood latent class models. Individual risk factors associated with weight gain trajectories (P ≤ .05) were included in an obesity risk index. Logistic regression analysis was performed to investigate whether the association between breastfeeding duration (<2 months, 2-4 months, >4 months) and weight gain trajectory varied across obesity risk groups.
  
  
  RESULTS
  Rising and stable weight gain trajectories emerged. The obesity risk index included maternal BMI, education, and smoking during pregnancy. High-risk infants breastfed for <2 months were more likely to belong to a rising rather than stable weight gain trajectory (odds ratio, 2.55; 95% confidence interval, 1.14-5.72; P = .02).
  
  
  CONCLUSIONS
  Infants at the highest risk for rising weight patterns appear to benefit the most from longer breastfeeding duration. Targeting mothers of high-risk infants for breastfeeding promotion and support may be protective against overweight and obesity during a critical window of development.
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, New York; and sjc268@cornell.edu.
authors.forename: Stacy J
authors.initials: SJ
authors.lastname: Carling
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, New York; and.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Demment
authors.affiliation: Mary Imogene Bassett Hospital and Research Institute, Cooperstown, New York.
authors.forename: Chris L
authors.initials: CL
authors.lastname: Kjolhede
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, New York; and.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Olson
mesh_terms: D000367:Age Factors; D001942:Breast Feeding / Q000706:statistics & numerical data*; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D015430:Weight Gain
keywords: breastfeeding; infants; obesity; weight-for-length z score trajectory