Seasonality and predictors of childhood stunting and wasting in drought-prone areas in Ethiopia: A cohort study

ABSTRACT Background and objectives Over centuries, Ethiopia has experienced severe famines and periods of serious drought, and malnutrition remains a major public health problem. The aims of this study were to estimate seasonal variations in child stunting and wasting, and identify factors associated with both forms of child malnutrition in drought-prone areas. Methods This cohort study was conducted among a random sample of 909 children in rural southern Ethiopia. The same children were followed for one year (2017 - 2018) with quarterly repeated measurements of their outcomes: height-for-age and weight-for-height indices (Z-scores). Linear regression models were used to analyse the association between both outcomes and baseline factors (e.g., household participation in a social safety net program and water access) and some time-varying factors (e.g., household food insecurity). Results Child wasting rates (i.e., low weight-for-heigh Z-scores) varied with seasonal household food insecurity (□ 2 trend = 15.9, p = 0.001), but stunting rates (i.e., low height-for-age Z-scores) did not. Household participation in a social safety net program was associated with decreased stunting ( p = 0.001) and wasting ( p = 0.002). In addition to its association with decreased wasting ( p = 0.001), protected drinking water access enhanced the association between household participation in a social safety net program and decreased stunting ( p = 0.009). Absence of a household latrine ( p = 0.011), lower maternal education level ( p = 0.001), larger family size ( p = 0.004), and lack of non-farming income ( p = 0.002) were associated with increased child stunting. Conclusions Seasonal household food insecurity was associated with child undernutrition in rural Ethiopia. Strengthening community-based food security programs, such as the Ethiopian social safety net program, could help to reduce child undernutrition in drought-prone areas. Improving clean water access and sanitation could also decrease child undernutrition. Limitations and strengths of this study This study accounted for agro-ecological strata and random selection of households; however, we did not initially estimate separate samples for the different strata (e.g., by household participation social safety net program). Seasonality was accounted for in our repeated measurements using some time-varying exposure variables (e.g., household food insecurity and child diarrhoeal illness); however, we did not assess other illnesses, such as malaria, measles, tuberculosis, etc. We did not initially estimate separate samples for our repeated measurements, but our analytical sample (i.e., counts of observations compiled from the repeated measurements) showed adequate statistical power of estimation to meet the primary aims of the study. This study analysed height-for-age Z-score and weight-for-height Z-score indices as continuous measures using linear regression models; our estimates were adjusted for the observed clustering effects at the primary sampling stage (at the kebele level) and time series effects of our repeated measurements. As our data were analysed in a cohort design, a certain underestimated time element may exist in our repeated measurements beyond the scope of our time-varying exposures.