Evaluation of bias in estimates of early childhood obesity from parent-reported heights and weights.
OBJECTIVE
We evaluated bias in estimated obesity prevalence owing to error in parental reporting. We also evaluated bias mitigation through application of Centers for Disease Control and Prevention's biologically implausible value (BIV) cutoffs.


METHODS
We simulated obesity prevalence of children aged 2 to 5 years in 2 panel surveys after counterfactually substituting parameters estimated from 1999-2008 National Health and Nutrition Examination Survey data for prevalence of extreme height and weight and for proportions obese in extreme height or weight categories.


RESULTS
Heights reported below the first and fifth height-for-age percentiles explained between one half and two thirds, respectively, of total bias in obesity prevalence. Bias was reduced by one tenth when excluding cases with height-for-age and weight-for-age BIVs and by one fifth when excluding cases with body mass-index-for-age BIVs. Applying BIVs, however, resulted in incorrect exclusion of nonnegligible proportions of obese children.


CONCLUSIONS
Correcting the reporting of children's heights in the first percentile alone may reduce overestimation of early childhood obesity prevalence in surveys with parental reporting by one half to two thirds. Excluding BIVs has limited effectiveness in mitigating this bias.
Michael S. Rendall is with the Department of Sociology, University of Maryland, College Park. Margaret M. Weden, Christopher Lau, and Peter Brownell are with RAND, Santa Monica, CA. Zafar Nazarov is with the Department of Economics, Purdue University, Fort Wayne, IN. Meenakshi Fernandes is with the World Food Programme, Rome, Italy.
Michael S
MS
Rendall
Margaret M
MM
Weden
Christopher
C
Lau
Peter
P
Brownell
Zafar
Z
Nazarov
Meenakshi
M
Fernandes
D015982:Bias; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002675:Child, Preschool; D003625:Data Collection; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D010290:Parents; D063766:Pediatric Obesity / Q000453:epidemiology*; D015995:Prevalence; D057566:Self Report