An ecological study of the association between childhood stunting, water, sanitation, and protein access, 2000–20

Adequate height attainment during early childhood foreshadows lifelong health. Stunting may be caused by environmental enteric dysfunction but has persisted after improvements in water and sanitation access. Recent studies suggest tryptophan and other amino acids improve height attainment. This study used ecological data from 94 countries over 21 years (2000–20) (n = 1836) to evaluate the association between the percentage of children with stunting and 4 normalized environmental variables: access to adequate water, sanitation, urban residence, and country-level supply of animal protein. We used mixed effects linear models controlling for year with varying intercepts by country after verifying residuals were uncorrelated and had uniform variance. Water and sanitation access, urban residence, and animal protein supply are all associated with lower stunting: 6 percentage-points for each standard deviation (s.d.) change in water, 3 percentage-points for each s.d. change in sanitation, 3 percentage-points for each s.d. change in urban residence, and 1.5 percentage-points for each s.d. change in animal protein, controlling for time. Improvements in water and sanitation infrastructure and animal protein access are both important interventions to reduce childhood stunting. These findings complement the 2023 FAO report conclusions regarding the importance of animal protein to childhood growth.