title: Development and validation of correction formulas for self-reported height and weight to estimate BMI in adolescents. Results from the KiGGS study.
abstract: OBJECTIVE
  The use of reported instead of measured height and weight induces a bias in prevalence rates for overweight and obesity. Therefore, correction formulas are necessary.
  
  
  METHODS
  Self-reported and measured height and weight were available from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) baseline study (2003-2006) from 3,468 adolescents aged 11-17 years. With regression analyses, correction formulas for height and weight were developed. Cross-validation was conducted in order to validate and compare the formulas. Corrected BMI was calculated, and corrected prevalence rates were estimated. Sensitivity, specificity, and predictive values for overweight and obesity were calculated.
  
  
  RESULTS
  Through the correction procedure, the mean differences between reported and measured height and weight become remarkably smaller and thus the estimated prevalence rates more accurate. The corrected proportions for overweight and obesity are less under-reported, while the corrected proportions for underweight are less over-reported. Sensitivity for overweight and obesity increased after correction. Specificity remained high.
  
  
  CONCLUSIONS
  The validation process showed that the correction formulas are an appropriate tool to correct self-reports on an individual level in order to estimate corrected prevalence rates of overweight and obesity in adolescents for studies which have collected self-reports only.
authors.affiliation: Department of Epidemiology and Health Monitoring, Robert Koch Institute, Berlin, Germany.
authors.forename: Anna-Kristin
authors.initials: AK
authors.lastname: Brettschneider
authors.forename: Angelika
authors.initials: A
authors.lastname: Schaffrath Rosario
authors.forename: Susanna
authors.initials: S
authors.lastname: Wiegand
authors.forename: Maximilian
authors.initials: M
authors.lastname: Kollock
authors.forename: Ute
authors.initials: U
authors.lastname: Ellert
mesh_terms: D000293:Adolescent; D015982:Bias; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D004812:Epidemiologic Methods; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D015203:Reproducibility of Results; D057566:Self Report