The relative effects of socioeconomic inequalities and nutritional factors in explaining child linear growth in Bangladesh

Background: While nutrition is essential, an individual’s socioeconomic position (SEP) within hierarchical societies can be influential in determining adequate child growth. This study assessed the relative effects of SEP inequalities and nutritional factors (NF) on linear growth, i.e., height-for-age-Z-score (HAZ), using data from Bangladesh. Methods: Data from mother-child dyads were analysed using: 1) the nationally representative ‘Food Security Nutrition Surveillance Project (FSNSP)’ (2011–2014), n=37,929 (children <5 years); and 2) an evaluation of a multisectoral nutrition programme, Suchana, targeting the most vulnerable households in northeast Bangladesh (2016 and 2019), n=13,062 (children <2 years). Applying polychoric principal component analysis, a composite SEP scale was constructed combining parental education, occupation, land ownership, assets, and other household characteristics. Difference in HAZ between SEP groups [FSNSP: “richest” (5th quintile) vs. “poorest” (1st quintile); Suchana: “poor” (SEP values median and above) vs. “poorest” (below median)] reflected SEP inequalities. The NF included child’s minimum dietary diversity (MDD) and morbidity status. Multiple linear regression model for the HAZ outcome included SEP groups and NF as main variables of interests, adjusted for covariates (child age, sex, birth order, wasting, maternal short stature, BMI, household size). Standardised beta coefficients were utilised to compare relative effects of SEP and NF. Results: In both contexts, SEP group inequalities was significantly associated with a larger difference in HAZ (FSNSP: 0.22 SD units, 95% CI: 0.19,0.25; Suchana: 0.13 SD units, 95% CI: 0.09,0.17). Achieving MDD was significantly associated with better HAZ (0.06, 95% CI: 0.03,0.09) for FSNSP, but not for Suchana. However, morbidity and HAZ had no significant association in either model. Conclusions: This research suggest socioeconomic inequalities have stronger effects on HAZ than NF, raising questions about international development priorities. Efforts to achieve optimal linear growth for children would require an integrated approach: prioritising this to address the wider issue of social inequalities rather than just nutrition.