Childhood stunting and subsequent educational outcomes: a marginal structural model analysis from a South African longitudinal study

OBJECTIVE: To examine the association between childhood stunting and grade completion (as educational outcome) in South Africa. DESIGN: Longitudinal study. Data were obtained using the National Income Dynamics Study over five waves (2008 to 2017). Children were tracked at wave 1 in 2008 until wave 5 in 2017 to determine their total years of schooling. We controlled for time-variant and time-varying confounding with a marginal structural model to estimate the associations between childhood stunting and subsequent grade completion. SETTING: Nationally representative study of South African households. PARTICIPANTS: A total of 2629 children aged 2 and 3 years in 2008. RESULTS: We observed a substantial decrease in the prevalence of stunting between wave 1 (28·2 %) and wave 4 (8·6 %). Our marginal structural model results suggest that childhood stunting was significantly associated with decreased odds (22 % less likely) of grade completion (OR = 0·78; 95 % CI: 0·40, 0·86; P = 0·015), while those who were only stunted during early childhood had a 29 % reduction in the odds of grade completion (OR = 0·71; 95 % CI: 0·51, 0·82; P = 0·020). CONCLUSION: These findings underscore the fact that stunting is a significant predictor of academic achievement, whose effects might be long-lasting.