title: Longitudinal study of thinness from birth to early childhood: the association with parental thinness.
abstract: OBJECTIVE
  Epidemiological research on thinness, particularly in early childhood, is limited. This study tracked thin children aged 5 years back to birth, compared them with normal-weight children and investigated the relationship with parental thinness.
  
  
  METHODS
  We enrolled 2678 children (50.5% boys) aged 5 years and attending kindergarten or nursery in the Nara Prefecture of Japan. The children's height and weight at birth, 1.5 years and 3.5 years, were obtained from mother-child health records. Child thinness was defined as having a body mass index (BMI) of less than the fifth percentile of the reference values for Japanese children, and parental thinness was defined as a BMI of <18.5.
  
  
  RESULTS
  The overall prevalence of thinness at 5 years of age was 4%, with no significant difference between genders. At every age, weight z-scores and BMI percentiles were significantly lower in thin children than normal-weight children. The increment in weight z-scores between birth and the age of 1.5 years was significantly lower in thin children. The only parental link was paternal thinness and thinness in boys.
  
  
  CONCLUSIONS
  Careful observation of body weight from birth is important to reduce thinness at 5 years of age. Paternal thinness may be a risk factor for thinness in boys.
authors.affiliation: Faculty of Human Life and Environment, Nara Women's University, Nara, Japan.
authors.forename: Rena
authors.initials: R
authors.lastname: Kato
authors.forename: Masaru
authors.initials: M
authors.lastname: Kubota
authors.forename: Yukie
authors.initials: Y
authors.lastname: Higashiyama
authors.forename: Ayako
authors.initials: A
authors.lastname: Nagai
mesh_terms: D000367:Age Factors; D015992:Body Mass Index; D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D010290:Parents; D015995:Prevalence; D012737:Sex Factors; D013851:Thinness / Q000453:epidemiology*
keywords: Body mass index; Early childhood; Longitudinal study; Parents; Thinness