Evidence before this study

This manuscript builds on previous GBD publications with updated data and methods. Diarrhoeal diseases are a leading cause of morbidity and mortality, especially in children younger than 5 years, and the global burden has been estimated by several groups, including the Maternal and Child Health Epidemiology Estimation group and the Global Burden of Disease Study (GBD) 2013. Diarrhoea mortality has declined substantially since 1990, but morbidity has not declined as rapidly. Diarrhoeal mortality attributable to aetiologies has mainly been based on categorical attribution from non-molecular diagnostic methods with low overall attribution.

Added value of this study

This study provides a comprehensive assessment of diarrhoea burden based on the findings of GBD 2015, including new and more robust evidence on the mortality, morbidity, and risk factors associated with diarrhoea and 13 aetiologies and is the first cause-specific description of diarrhoea from the GBD group. Moreover, it introduces molecular diagnostic case definitions for diarrhoeal aetiologies. In addition to descriptions of trends in morbidity and mortality, this analysis uses a Socio-demographic Index to relate changes in diarrhoea burden to demographic transitions and assesses the effect of changing population characteristics and risk factor exposure to decompose trends in diarrhoea mortality.

Implications of all the available evidence

This study provides a detailed picture of the decreasing diarrhoeal burden over time and 13 aetiologies across all geographies while relating these trends to changes in risk factor exposure. This work allows for an in-depth understanding of national health challenges and areas for intervention. The findings will have great implications for strategies and programmes to address the burden of diarrhoea at the global, country, and local level.