Comparing Growth Assessments Using CDC and WHO Reference Data in Native Hawaiian Pacific Islander Children: Baseline Data from the Children's Healthy Living (CHL) Program in Hawaiʻi

Abstract

In the diverse US Affiliated Pacific Centers for Disease Control (CDC) 2000 and 2006 World Health Organization (WHO) reference data are available to assess child growth. WHO reference data includes children who met recommended breastfeeding guidelines from six countries, while CDC data describes growth of US children where few were breastfed. Baseline data from the CHL program in Hawai'i (n=941) was used to calculate BMI z‐scores and percentiles to compare growth relative to the two reference data sets and identify the role of breastfeeding history, age, sex, and ethnicity on growth assessment. Mean BMI z‐scores calculated with CDC reference data were lower than WHO (z‐score difference=‐0.31, p<0.001). A general linear model on BMI z differences against child age, sex, ethnicity and breastfeeding history showed the difference by CDC reference was greater in boys than girls (z score difference = 0.20, p<0.001). No difference was found by breastfeeding history, age or ethnicity. Kappa statistics showed strong agreement between the two references on CDC defined BMI categories (weighted Kappa=0.50, p<0.001), with percentage of agreement highest for healthy weight (92%), followed by obese (85%), then overweight (76%). CDC and WHO growth reference data samples differ by breastfeeding history and ethnicity; differences between BMI z‐scores calculated from the two reference data sets were not related to either factor. Researchers and practitioners can choose either reference data to analyze BMI and child growth in NHPI children but should be cautious that CDC growth references may underestimate childhood overweight and obesity, and delay early intervention.