title: Retrospective tracking of young obese children back to birth in Japan: special attention to the relationship with parental obesity.
abstract: OBJECTIVE
  Childhood obesity is tracked to adulthood at a high rate. However, longitudinal studies of obesity in early childhood remain limited. This study aimed at tracking young obese children back to birth in comparison with normal-weight children, and investigating the relationship with parental obesity.
  
  
  METHODS
  A total of 2,678 (1,353 boys) young children attending kindergarten or nursery school in Nara Prefecture, Japan, were enrolled. The present heights and weights of children and parents were obtained by a questionnaire, and children's heights and weights at birth, 1.5, and 3.5 years were obtained from mother-child health notebooks. Using body mass index (BMI), child and parental obesity were defined as >=90th percentile based on the reference values for Japanese children and >=25 (kg/m²), respectively.
  
  
  RESULTS
  The overall prevalence of obesity at birth was 10.2%, and decreased to 5.6% at 5 years. In the retrospective tracking, obese children at 5 years exhibited significantly higher weight Z-scores and BMI percentiles consistently from birth than in normal-weight children. The increased velocity of weight gain as judged by their Z-score during three periods; birth-1.5, 1.5-3.5, and 3.5-5 years were significantly associated with an increased risk for the obesity at 5 years of age. Only maternal obesity was found to be associated with daughters' obesity in the analysis of association of parents-children obesity.
  
  
  CONCLUSIONS
  It is important to manage body weight from early infancy for reducing the occurrence of obesity at 5 years. Where there is maternal obesity, greater attention may be required, especially for daughters.
authors.affiliation: Department of Human Life and Environment, Nara Women's University, Kitauoya- Nishi-Machi, Nara, 630-8506, Japan. mkubota@cc.nara-wu.ac.jp.
authors.forename: Rena
authors.initials: R
authors.lastname: Kato
authors.forename: Masaru
authors.initials: M
authors.lastname: Kubota
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yasui
authors.forename: Yumi
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Yukie
authors.initials: Y
authors.lastname: Higashiyama
authors.forename: Ayako
authors.initials: A
authors.lastname: Nagai
mesh_terms: D000367:Age Factors; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D010290:Parents; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires