Citation
Gray, Christine L. & Robinson, Whitney R. (2014). Throwing out the Baby with the Bathwater? Comparing 2 Approaches to Implausible Values of Change in Body Size. Epidemiology, 25(4), 591-594. PMCID: PMC4417741Abstract
BACKGROUND: In childhood obesity research, the appearance of height loss, or "shrinkage," indicates measurement error. It is unclear whether a common response-excluding "shrinkers" from analysis-reduces bias.METHODS: Using data from the National Longitudinal Study of Adolescent Health, we sampled 816 female adolescents (≥17 years) who had attained adult height by 1996 and for whom adult height was consistently measured in 2001 and 2008 ("gold-standard" height). We estimated adolescent obesity prevalence and the association of maternal education with adolescent obesity under 3 conditions: excluding shrinkers (for whom gold-standard height was less than recorded height in 1996), retaining shrinkers, and retaining shrinkers but substituting their gold-standard height.
RESULTS: When we estimated obesity prevalence, excluding shrinkers decreased precision without improving validity. When we regressed obesity on maternal education, excluding shrinkers produced less valid and less precise estimates.
CONCLUSION: In some circumstances, ignoring shrinkage is a better strategy than excluding shrinkers.
URL
http://dx.doi.org/10.1097/EDE.0000000000000111Reference Type
Journal ArticleYear Published
2014Journal Title
EpidemiologyAuthor(s)
Gray, Christine L.Robinson, Whitney R.