title: Validity of self-reported weight and height among 13-14 year old schoolchildren in Israel.
abstract: BACKGROUND
  Data regarding the validity of self-reported weight and height in adolescents are conflicting.
  
  
  OBJECTIVE
  To evaluate the validity of self-reported weight and height among 13-14 year olslddren.
  
  
  METHODS
  We conducted a cross-sectional study of 517 schoolchildren aged 13-14 years and compared self-reported and measured weight and height by gender, population group, parental education and crowdedness.
  
  
  RESULTS
  Females under-reported their weight on average by 0.79 +/- 5.46 kg (P = 0.03), resulting in underestimation of the body mass index with borderline significance (mean difference 0.28 +/- 2.26 kg/m2, P = 0.06). Males over-reported their height on average by 0.75 +/- 5.81 cm (P = 0.03). Children from less crowded homes (< or = 1 person per room) overestimated their height more than children from more crowded homes, resulting in a significant underestimation of BMI (mean difference between reported BMI and measured values was 0.30 +/- 2.36 kg/m2, P = 0.04). Measured BMI was a significant predictor of the difference between self-reported and measured BMI, adjusted for gender, population group, parents' education, and crowdedness (beta = -0.3, P < 0.0001). As a result of this reporting bias, only 54.9% of children with overweight and obesity (BMI > or = 85th percentile) were classified correctly, while 6.3% of children were wrongly classified as overweight and obese. The largest difference in BMI was observed in obese females (4.40 +/- 4.34) followed by overweight females (218 +/- 1.95) and underweight females (-1.38 +/- 13.75). Similar findings were observed for males, where the largest difference was found among obese males (2.83 +/- 3.44).
  
  
  CONCLUSIONS
  Studies based on self-reported weight and height in adolescents may be biased. Attempts should be made to correct this bias, based on the available data for each population.
authors.affiliation: Tel Aviv District Health Office, Ministry of Health, Tel Aviv, Israel. yifat.linhart@telaviv.health.gov.il
authors.forename: Yifat
authors.initials: Y
authors.lastname: Linhart
authors.forename: Orly
authors.initials: O
authors.lastname: Romano-Zelekha
authors.forename: Tamy
authors.initials: T
authors.lastname: Shohat
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007557:Israel; D008297:Male; D015203:Reproducibility of Results; D012647:Self-Assessment; D012737:Sex Factors; D012959:Socioeconomic Factors