Determinants of height-for-age Z-score (HAZ) among Ethiopian children aged 0-59 months: a multilevel mixed-effects analysis

Abstract

Background: Height-for-age z-score (HAZ), based on WHO Child Growth Standards, measures linear growth in children, with lower values indicating potential undernutrition. This study examines HAZ as a continuous measure to explore its proximal and distal determinants.

Methods: Data from 5,045 children aged 0-59 months from the 2019 Ethiopian Mini Demographic and Health Survey were used. The survey employed a stratified two-stage cluster design. A multilevel mixed-effects linear regression model was applied to estimate the associations between HAZ and various proximal (individual and household-level) and distal (community-level) factors. Proximal factors included child age, sex, early breastfeeding, maternal age, education, age at first birth, maternal literacy, delivery place, number of children under-five, household size, wealth index, media access, household head sex, cooking fuel, toilet type, and water source. Distal factors included urban/rural residence, altitude, and capital city residence. Effect sizes were reported as unstandardized beta coefficients (β) with 95% confidence intervals (CI).

Results: The mean HAZ was - 1.26 (SD = 1.47). The mean age of the children was 28.9 months, and 36.23% of mothers were literate. Child age was inversely associated with HAZ, with each additional month linked to a 0.02 unit reduction (β = -0.02; 95% CI: -0.024, -0.016; p < 0.001). Maternal age and education were positively associated with HAZ, with each additional year of maternal age linked to a 0.015 unit increase (β = 0.015; 95% CI: 0.003, 0.026; p = 0.012) and each additional year of education associated with a 0.036 unit increase (β = 0.036; 95% CI: 0.009, 0.062; p = 0.008). Higher altitude was associated with a 0.21 unit reduction in HAZ per 1000 m increase (β = -0.21; 95% CI: -0.34, -0.07; p = 0.003). Residence in the capital city was associated with a 0.388 unit increase in HAZ (β = 0.388; 95% CI: 0.093, 0.683; p = 0.01).

Conclusion: Key determinants of HAZ include child age, maternal age, education, altitude, and capital city residence. These findings highlight the need for multifaceted interventions to improve child linear growth. Enhancing maternal education is a crucial strategy to improve child HAZ scores in Ethiopia.

Keywords: Children under-5; Chronic malnutrition; Demographic and health survey; Ethiopia; Height-for-age z-score (HAZ); Linear growth.

Fig. 1

Height-for-age z-score (HAZ) in Ethiopian children aged 0–59 months by child age, maternal age, education and altitude, 2019 EMDHS. Shaded areas represent 95% confidence intervals from locally estimated scatterplot smoothing (LOESS)