title: Timing of solid food introduction and risk of obesity in preschool-aged children.
abstract: OBJECTIVE
  To examine the association between timing of introduction of solid foods during infancy and obesity at 3 years of age.
  
  
  METHODS
  We studied 847 children in Project Viva, a prospective pre-birth cohort study. The primary outcome was obesity at 3 years of age (BMI for age and gender ≥ 95th percentile). The primary exposure was the timing of introduction of solid foods, categorized as <4, 4 to 5, and ≥ 6 months. We ran separate logistic regression models for infants who were breastfed for at least 4 months ("breastfed") and infants who were never breastfed or stopped breastfeeding before the age of four months ("formula-fed"), adjusting for child and maternal characteristics, which included change in weight-for-age z score from 0 to 4 months-a marker of early infant growth.
  
  
  RESULTS
  In the first 4 months of life, 568 infants (67%) were breastfed and 279 (32%) were formula-fed. At age 3 years, 75 children (9%) were obese. Among breastfed infants, the timing of solid food introduction was not associated with odds of obesity (odds ratio: 1.1 [95% confidence interval: 0.3-4.4]). Among formula-fed infants, introduction of solid foods before 4 months was associated with a sixfold increase in odds of obesity at age 3 years; the association was not explained by rapid early growth (odds ratio after adjustment: 6.3 [95% confidence interval: 2.3-6.9]).
  
  
  CONCLUSIONS
  Among formula-fed infants or infants weaned before the age of 4 months, introduction of solid foods before the age of 4 months was associated with increased odds of obesity at age 3 years.
authors.affiliation: Division of Gastroenterology and Nutrition, Children's Hospital Boston, 300 Longwood Ave, Boston, MA 02115, USA. susanna.huh@childrens.harvard.edu
authors.forename: Susanna Y
authors.initials: SY
authors.lastname: Huh
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Rifas-Shiman
authors.forename: Elsie M
authors.initials: EM
authors.lastname: Taveras
authors.forename: Emily
authors.initials: E
authors.lastname: Oken
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Gillman
mesh_terms: D000328:Adult; D002657:Child Development; D002675:Child, Preschool; D005248:Feeding Methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007225:Infant Food / Q000592:standards*; D008297:Male; D009765:Obesity / Q000453:epidemiology* / Q000517:prevention & control; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014886:Weaning