Maternal socioeconomic status and early childhood growth and nutrition in the PERSIAN Birth Cohort with insights into the double burden of malnutrition

Abstract

In low- and middle-income countries, undernutrition often coexists with rising obesity, creating a double burden of malnutrition (DBM). Our study employs a mathematical approach to examine how maternal socioeconomic status (SES) impacts child growth in Iranian children from infancy to age two, offering new insights into strategies for tackling both undernutrition and obesity. We used data from the PERSIAN Birth Cohort. SES was divided into quintiles using multiple correspondence analysis (MCA), and child growth was assessed with eight indicators. Missing data were handled via multiple imputation (MI). SES impacts on growth were analyzed using Generalized Estimating Equations (GEE), and BMI-Z was predicted from WAZ and HAZ through linear regression by SES and age. We explored obesity risk by comparing HAZ-to-WAZ ratios from GEE models with WAZ-to-HAZ beta ratios from regressions. Sensitivity analyses compared MI with complete-case analyses (CCA). 7169 neonates were assessed at 2, 4, 6, 12, and 24 months. SES increasingly improved WAZ with age, preventing underweight in higher SES groups. SES consistently improved HAZ, significantly enhancing stunting prevention in higher SES groups. The impact on BMI-Z increased with age, peaking in Very High SES, which shows a significant rise in obesity risk by 24 months. Comparing ratios from GEE and regression models, we found that GEE ratios were lower where BMI-Z increased. Sensitivity analysis confirmed MI and CCA consistency. Addressing DBM requires understanding how imbalanced increases in HAZ and WAZ heighten obesity risk. Future research should focus on targeted interventions to manage DBM effectively.