PC27. AN UPDATE OF CEPHALIC INDEX NORMS IN A LARGE AND DIVERSE POPULATION OF WELL CHILDREN

Abstract

PURPOSE: The incidence of brachycephaly has increased since the implementation of Back-to-Sleep Campaign. Current cephalic index (CI) norms, established by a small sample of Caucasian children in the 1980’s, need to be updated. This study aims to redefine the CI norm and to examine risk factors related to increased CI. METHODS: Children aged 0-6 months, 7-12 months, 2-3 years, and 12-14 years are enrolled. Those with plagiocephaly or other craniofacial disorders are excluded. Biparietal and anteroposterior diameters are obtained using a manual caliper. A survey containing the subjects’ birth, past medical and sleeping history is administered. RESULTS: 1,156 subjects are included. 41% are Caucasian, 31% are Hispanic, 18% are African American and 9% are Asian. Mean CI for 0-6 months are 83.2±6.55 for males and 83.2±5.93 for females, which is significantly greater than the established norms of 74.4±5.2 and 74.3±6.1, respectively (p<0.0001). Asian race and back sleep are risk factors for increased CI (p<0.0005). Scatterplot of CI and age shows positive trend from 0-6 months (R2=0.051, p<0.0001) and negative trend from 7-48 months (R2=0.021, p=0.0009). CONCLUSION: Mean CI has increased for 0-6 months infants compared to the old norms. Asian race and back sleep are associated with increased CI. CI increases before 6 months, and naturally decreases afterwards without intervention. The current criteria for orthotic treatment should be re-examined due to this shift in CI norms.