Objective: We aimed to quantify the relationship between national income and infant and under-five mortality in developing countries.
Design: We conducted a systematic literature search of studies that examined the relationship between income and child mortality (infant and/or under-five mortality) and meta-analysed their results.
Setting: Developing countries.
Main outcome measures: Child mortality (infant and /or under-five mortality).
Results: The systematic literature search identified 24 studies, which produced 38 estimates that examined the impact of income on the mortality rates. Using meta-analysis, we produced pooled estimates of the relationship between income and mortality. The pooled estimate of the relationship between income and infant mortality before adjusting for covariates is -0.95 (95% CI -1.34 to -0.57) and that for under-five mortality is -0.45 (95% CI -0.79 to -0.11). After adjusting for covariates, pooled estimate of the relationship between income and infant mortality is -0.33 (-0.39 to -0.26) while the estimate for under-five mortality is -0.28 (-0.37 to -0.19). If a country has an infant mortality of 50 per 1000 live births and the gross domestic product per capita purchasing power parity increases by 10%, the infant mortality will decrease to 45 per 1000 live births.
Conclusion: Income is an important determinant of child survival and this work provides a pooled estimate for the relationship.
Keywords: Sub Saharan Africa; child mortality; income mortality elasticity; meta-analysis; systematic review.