National Univariate and Bivariate Reference Growth Charts for Preschool Children in Egypt Using Quantile Regression Methods

Childhood malnutrition is a serious health issue facing Egypt, owing to its negative impacts on children’s physical growth. Growth charts are important tools for evaluating children’s health, growth, and nutritional status and hence providing public health authorities with accurate and timely information for appropriate intervention. As physical growth can be influenced by genetic, socio-cultural, environmental, and economic factors, using international growth standards can be misleading. This study aims at developing reliable local reference growth curves for Egyptian pre-school children using parametric and nonparametric methods and comparing them against the WHO standards. The results of the different methods were consistent, yet the nonparametric methods provided slightly better estimates when distributional assumptions are not valid for some measurements at some ages. In contrast, the study results highlighted discrepancies between the WHO and newly estimated Egyptian growth curves. This emphasizes the importance of using national growth charts and standards for monitoring children growth for the accurate diagnosis of children growth problems in Egypt. Bivariate national height-weight quantile regression contours are also estimated for the first time in Egypt and compared to the univariate nationally estimated ones. The bivariate growth contours provided a more comprehensive tool for monitoring growth in height and weight simultaneously.