title: Breastfeeding and overweight in childhood: evidence from the Pelotas 1993 birth cohort study.
abstract: OBJECTIVE
  The effect of breastfeeding duration on the prevalence of overweight and on mean weight for height z-score (WHZ) was evaluated in Brazilian children.
  
  
  METHODS
  Prospective population-based birth cohort study.
  
  
  METHODS
  In total, 1,273 children aged 4 years, corresponding to a follow-up rate of 87.2%.
  
  
  METHODS
  Three explanatory variables were studied: duration of any breastfeeding, duration of exclusive or predominant breastfeeding, and ever breastfeeding. Weight and height were measured using a digital electronic scale and a portable stadiometer. Overweight was defined as WHZ >2 using the National Center for Health Statistics reference curve.
  
  
  RESULTS
  Overweight prevalence at the age of 4 years was 10.2% (95% CI 8.4; 11.8). The lowest prevalence (6.5%) was observed among children breastfed for >11 months. Among those breastfed for less than 3 months, the prevalence of overweight was approximately 9.5%. Mean WHZ ranged from 0.38 among children breastfed for less than 1 month to 0.62 among those breastfed for 9-11.9 months. No linear trends were detected in the association between breastfeeding and anthropometric indicators. None of the three breastfeeding variables was significantly associated with the prevalence of overweight or mean WHZ in multivariable analyses. No interactions were detected between breastfeeding and the variables sex, birth weight, socioeconomic status, skin color and pregestational in body mass index.
  
  
  CONCLUSIONS
  Our results do not support the hypothesis that breastfeeding promotion would reduce overweight or obesity in this population. Existing evidence on many other benefits of breastfeeding for the mother and the child supports its continued promotion, protection and support.
authors.affiliation: Post-graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: C L
authors.initials: CL
authors.lastname: Araújo
authors.forename: C G
authors.initials: CG
authors.lastname: Victora
authors.forename: P C
authors.initials: PC
authors.lastname: Hallal
authors.forename: D P
authors.initials: DP
authors.lastname: Gigante
mesh_terms: D000328:Adult; D000886:Anthropometry; D001724:Birth Weight / Q000502:physiology; D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D001938:Brazil / Q000453:epidemiology; D001942:Breast Feeding; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000517:prevention & control; D050177:Overweight / Q000502:physiology*; D012923:Social Class; D013997:Time Factors