Mixed Effects Analysis of Height Growth in Ethiopian Children Aged 1-12 Years: A Cohort Study

Abstract

Modelling physical growth is a key component to examine and identify defining characteristics in the growth process. The goal of this study was to model and capture known features of height growth in Ethiopian children aged 1–12 years. Height measurements of 1760 children followed from 1 to 12 years at Young Lives Ethiopia, a younger cohort, used in the study. The mixed effects method was used to estimate the rate of change within and between subjects over time and to identify defining covariates. Adult height and rate of change over time were individual-specific resulting individual-level growth differences. There was a negative relationship between individual-specific adult height and rate of change over time. The decelerated rate of change was observed from childhood to the onset of puberty in both sexes. Boys were taller than girls between the ages of 3 and 7 years. Mother’s educational status, access to quality drinking water, age, and sex had a significant effect on height growth.  Children who had a decelerated rate of growth change during the childhood period become taller later in life. Adult height could be determined by an individual-specific rate of change over time.