Q&A: Declining rates of death from diarrheal diseases

Dr. Hmwe Kyu shares findings from the Global Burden of Disease showing that diarrheal diseases are causing fewer deaths than in 1990, but remain a significant burden on children under 5 and elderly populations. 

This transcript has been lightly edited for clarity

What makes this research different from previous studies and why is it important?

This study differs from previous global diarrheal diseases studies in two different ways. First, it conducted a detailed analysis of the diarrheal disease burden across all age groups.

Second, it introduces risk-deleted burden estimates, which are estimates in an ideal scenario where all the risk factors were removed. These results can be used to inform targeted health interventions aimed at further reducing the diarrheal disease burden.

What were the key findings of your research?

We found a substantial decrease in diarrheal disease deaths across all age groups globally since 1990, with a 60% decrease overall and a notable 79% decrease in children younger than 5 years.  

In this graph, we can see dramatic declines in years of life lost across granular age groups among children younger than 5 years.

However, there were still 1.2 million diarrheal disease deaths in 2021, with the highest mortality rates in young children and elderly people. As this graph shows, we saw similar decreases in years of life lost across all age groups between 1990 and 2021.

The key risk factors include poor neonatal conditions such as low birth weight and short gestation, child growth failure, and unsafe water and sanitation. Our results showed that if all evaluated risk factors were removed, disability-adjusted life years due to diarrheal diseases could be reduced from 59 million to less than 5 million in 2021.

What initiatives have contributed to the decline in the burden of diarrheal disease?

The decrease in diarrheal disease burden can be attributed to several key interventions, including oral rehydration therapy; improvements in water, sanitation, and hygiene, or WASH, infrastructure; and rotavirus vaccination.

To further reduce the burden, a comprehensive approach that combines lifesaving interventions and preventive measures against key risk factors and pathogens will be crucial.

What variations did you find between regions and income groups?

Despite the decline in diarrheal disease deaths, striking disparities across regions persist. For instance, in high-income regions, there was less than 1 death per 100,000 population, versus more than 150 deaths per 100,000 population in sub-Saharan Africa among children younger than 5 years.

This variation highlights the need for improvements in health care access, WASH infrastructure, and nutrition, particularly in low- and middle-income settings.

What pathogens were primarily responsible for diarrheal diseases?

In 2021, rotavirus was the leading pathogen across all age groups globally. Symptoms of rotavirus infection in may include vomiting and watery diarrhea. Among children younger than 5 years, Shigella was the second-leading pathogen, following rotavirus. Symptoms of Shigella infection may include bloody diarrhea, fever, and stomach pain. Other significant contributors include adenovirus, cryptosporidium, and enterotoxigenic E. coli producing heat-stable toxin.

Efforts to enhance rotavirus vaccination coverage, as well as the development of new vaccines against other key diarrheal pathogens, could further help reduce the diarrheal disease burden.