California WIC: New Classification Criteria and WHO Growth References Alter Anthropometric Risk Estimates

Abstract

WIC California has recently switched (October 2012) from use of CDC Child Growth Curves to use of WHO Child Growth Curves in evaluating the growth of children under 2 years of age. Additionally, WIC California has changed the criteria for classification of anthropometric risks. The objective of this study is to examine changes in the prevalence of risk based on the new classifications and the use of WHO standards relative to the previous classifications and CDC references. Five categories of risk are defined, Underweight (UW), At‐risk‐of‐underweight (ARUW), High Weight‐for‐Length (HWL), Short Stature (SS), and At‐risk‐of‐short‐stature (ARSS). Using one month of child growth data collected at 11 WIC offices within San Diego County (n=8027), of children between 3 months and 21 months of age, the new and old classifications of risk were each calculated relative to WHO and relative to CDC. Comparisons were then made between incidence of the five risk types using Pre‐October criteria with CDC (OLD) and Post‐October criteria with WHO (NEW). For those classified as UW: OLD resulted in 1.27% (n=102) versus NEW 0.04% (n=3); ARUW: OLD 1.91% (n=153) vs. NEW 0.20% (n=16); HWL: CDC 7.75% (n=622)vs. WHO 6.98% (n=579); SS:OLD 9.63% (n=773) vs. NEW 2.84%(228); ARSS: CDC 2.69% (n=216) vs WHO 2.78 % (n=223). Changes in criteria as well as growth curves resulted in significant and meaningful shifts in risk classifications. Additionally, interesting patterns emerge by gender, ethnicity, and feeding choice. Funded by SDSURF/WIC.