title: Developmental trajectories of body mass index among Japanese children and impact of maternal factors during pregnancy.
abstract: BACKGROUND
  The aims of this study were to 1) determine the distinct patterns of body mass index (BMI) trajectories in Japanese children, and 2) elucidate the maternal factors during pregnancy, which contribute to the determination of those patterns.
  
  
  RESULTS
  All of the children (1,644 individuals) born in Koshu City, Japan, between 1991 and 1998 were followed in a longitudinal study exploring the subjects' BMI. The BMI was calculated 11 times for each child between birth and 12 years of age. Exploratory latent class growth analyses were conducted to identify trajectory patterns of the BMI z-scores. The distribution of BMI trajectories were best characterized by a five-group model for boys and a six-group model for girls. The groups were named "stable thin," "stable average," "stable high average," "progressive overweight," and "progressive obesity" in both sexes; girls were allocated to an additional group called "progressive average." Multinomial logistic regression found that maternal weight, smoking, and skipping breakfast during pregnancy were associated with children included in the progressive obesity pattern rather than the stable average pattern. These associations were stronger for boys than for girls.
  
  
  CONCLUSIONS
  Multiple developmental patterns in Japanese boys and girls were identified, some of which have not been identified in Western countries. Maternal BMI and some unfavorable behaviors during early pregnancy may impact a child's pattern of body mass development. Further studies to explain the gender and regional differences that were identified are warranted, as these may be important for early life prevention of weight-associated health problems.
authors.affiliation: Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan. chiyorih@yamanashi.ac.jp
authors.forename: Chiyori
authors.initials: C
authors.lastname: Haga
authors.forename: Naoki
authors.initials: N
authors.lastname: Kondo
authors.forename: Kohta
authors.initials: K
authors.lastname: Suzuki
authors.forename: Miri
authors.initials: M
authors.lastname: Sato
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ando
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokomichi
authors.forename: Taichiro
authors.initials: T
authors.lastname: Tanaka
authors.forename: Zentaro
authors.initials: Z
authors.lastname: Yamagata
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000209:etiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D055815:Young Adult