title: Short Sleep Duration in the First Years of Life and Obesity/Overweight at Age 4 Years: A Birth Cohort Study.
abstract: OBJECTIVE
  To investigate whether short sleep duration from the first year of life influenced weight at an early age.
  
  
  METHODS
  During 2004, children born in Pelotas, Brazil, were enrolled in a cohort study. Sleeping habits during the previous 2 weeks were assessed, and the children were weighed and measured at 1-, 2-, and 4-year follow-ups. Overweight and obesity at 4 years were defined according to World Health Organization z-scores for body mass index for age. Short sleep duration was defined as fewer than 10 hours of sleep per night at any follow-up.
  
  
  RESULTS
  Out of the 4263 live births, 4231 were recruited. The prevalence of short sleep duration at any follow-up from 1-4 years of age was 10.1%. At 4 years of age, 201 children were obese (5.3%), and 302 (8%) were overweight. Among short sleepers, the prevalence ratio for overweight/obesity after adjusting for maternal and children's characteristics was 1.32 (1.03; 1.70).
  
  
  CONCLUSIONS
  Children who slept for fewer than 10 hours per night at any follow-up from 1-4 years of age were more likely to be overweight or obese at 4 years of age, despite their sociodemographic and sleep characteristics.
authors.affiliation: PhD Program of Medicine and Health Sciences, Pontificia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Conceição Hospital Group, Porto Alegre, Brazil. Electronic address: camilahalal@hotmail.com.
authors.forename: Camila S E
authors.initials: CSE
authors.lastname: Halal
authors.affiliation: Department of Preventive Medicine, School of Medicine, University of São Paulo, São Paulo, Brazil; Postgraduate Epidemiology Program, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Alicia
authors.initials: A
authors.lastname: Matijasevich
authors.affiliation: Medical Research Council Integrative Epidemiology Unit at the University of Bristol, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors.forename: Laura D
authors.initials: LD
authors.lastname: Howe
authors.affiliation: Postgraduate Epidemiology Program, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Iná S
authors.initials: IS
authors.lastname: Santos
authors.affiliation: Postgraduate Epidemiology Program, Federal University of Pelotas, Pelotas, Brazil; Postgraduate Program of Health and Behavior, Catholic University of Pelotas, Pelotas, Brazil.
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Barros
authors.affiliation: Division of Neurology, Pontificia Universidade Católica do Rio Grande do Sul School of Medicine and Brain Institute (INSCER), Porto Alegre, Brazil.
authors.forename: Magda L
authors.initials: ML
authors.lastname: Nunes
mesh_terms: D015992:Body Mass Index; D001938:Brazil; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000209:etiology*; D050177:Overweight / Q000453:epidemiology / Q000209:etiology*; D015995:Prevalence; D012307:Risk Factors; D012890:Sleep; D012892:Sleep Deprivation / Q000150:complications*; D013997:Time Factors