title: Association between distorted body image and changes in weight status among normal weight preadolescents in Japan: a population-based cohort study.
abstract: BACKGROUND
  Distorted body image may be important risk factors for being underweight and overweight. The objective of this study was to investigate the association between having a distorted body image and being overweight or underweight among normal weight preadolescents in a population-based cohort study in Japan for each sex.
  
  
  METHODS
  The study participants were 1431 normal weight fourth-grade students (age range: 9-10 years) in Ina town, Japan from 2002 to 2007. The height and weight of each student were measured while they were in the fourth grade (at baseline) and seventh grade (3 years later). Childhood underweight and overweight were defined using the body mass index cut-off points proposed by the International Obesity Task Force. Information regarding the self-perceived weight status of each student at baseline was collected using a self-administered questionnaire. Children who were normal weight but perceived themselves as heavy or thin were regarded as having a distorted body images. A logistic regression model was used to calculate the odds ratios (ORs) and 95 % confidence interval (95 % CI) for being overweight or underweight 3 years later among those having a distorted body image at baseline.
  
  
  RESULTS
  Both boys and girls who perceived themselves to be heavy at baseline were at a statistically significantly greater risk of being overweight 3 years later as compared to boys and girls, respectively, who identified as being at a normal weight at baseline (boys: adjusted OR: 4.66, 95 % CI: 1.01-21.48; girls: 3.88, 1.56-9.65). Both boys and girls who perceived oneself to be thin at baseline were at a statistically significantly greater risk of bring underweight 3 years later as compared to boys and girls, respectively, who identified as being at a normal weight at baseline (boys: 5.51, 2.20-13.80; girls: 2.93, 1.40-6.11).
  
  
  CONCLUSIONS
  The results of the present study suggest that having a distorted body image in preadolescence is associated with being overweight or underweight in adolescence, among boys and girls, separately. Therefore, education regarding self-perceived weight could be important to help prevent underweight and overweight/obesity among preadolescent boys and girls in Japan.
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Shirasawa
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ochiai
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Hinako
authors.initials: H
authors.lastname: Nanri
authors.affiliation: Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Rimei
authors.initials: R
authors.lastname: Nishimura
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Hoshino
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Akatsuki
authors.initials: A
authors.lastname: Kokaze
keywords: Distorted body image; Japanese; Overweight; Preadolescents; Underweight