New Delhi: There has been nearly 60% drop in global deaths due to diarrhoeal diseases, but children and the elderly remain vulnerable and accounted for the highest mortality rates, particularly in sub-Saharan Africa and South Asia, according to a study published in the Lancet Infectious Diseases on Wednesday.
“In 2021, diarrhoeal diseases caused 1.2 million deaths worldwide, which is a substantial drop from 2.9 million deaths recorded in 1990. The largest decrease was among children under 5 years with a 79% decline, but that age group still had the highest mortality rate among all ages, followed by those 70 years and older,” read the findings from the study.
According to the authors, it is by far the most comprehensive Global Burden of Disease (GBD) study conducted by the Institute for Health Metrics and Evaluation (IHME) and published in The Lancet Infectious Diseases journal.
Regional disparities in diarrhoeal disease deaths remain stark, the authors said. Regions with high-income countries see less than one death per 100,000 population in children under five. In sub-Saharan Africa, at least 150 deaths per 100,000 population were reported in children under five — the highest mortality rate for children in that age group when compared to all other global regions.
South Asia had the highest mortality rates among those aged 70 years and older with 476 deaths per 100,000 population. Diarrhoeal mortality rates declined substantially across age groups in most super-regions.
Researchers analysed the overall burden of diarrhoeal diseases by measuring disability-adjusted life years, or DALYs — the sum of the number of years of life lost and the number of years lived with disability. DALYs declined from 186 million in 1990 to 59 million in 2021, including the maximum 31 million in children younger than five years.
The study provides annualised rates of change in diarrhoeal disease mortality in 1990-2019 and 2019-2021. It shows that before the Covid-19 pandemic, from 1990 to 2019, the global all-age diarrhoeal disease mortality rate changed at a rate of 4·2% per year, with substantial variation across regions and countries, indicating an increase, decrease, or no change in diarrhoeal disease mortality rates.
From 2019 to 2021, the global all-age diarrhoeal disease mortality rate changed at a rate of –5% per year, showing similar variation across regions and countries, the researchers said.
Major risk factors for diarrhoeal DALYs include poor neonatal conditions such as low birthweight and preterm birth, child growth failure, unsafe water, and poor sanitation.
The decline in diarrhoeal mortality and morbidity suggests health interventions are working, said the authors. The interventions include oral rehydration therapy, enhanced water, sanitation, and hygiene infrastructure, and global immunisation efforts against rotavirus. Preventive measures against key risk factors and pathogens could further reduce the global burden. According to researchers’ estimates, if leading risk factors were eliminated around the world, DALYs could be reduced to less than 5 million in 2021.
“The new granular-level analysis by our study can further help decision-makers better target and prioritize the evidence-based strategies to fight diarrheal diseases,” said Dr Hmwe Hmwe Kyu, study author and associate professor at IHME, in a statement. “In spite of the encouraging progress made combating diarrhoeal mortality, a multipronged approach is required to simultaneously tackle live-saving solutions while also prioritising preventive interventions to alleviate burdens on health systems.”
WHO-recommended rotavirus vaccines, now administered in at least 100 countries, have led to substantial reductions in hospitalizations and deaths from diarrhoea. With more vaccines being added to WHO’s Expanded Programme on Immunization, combining them could reduce manufacturing costs and make scheduling easier.
“In addition to increasing immunisations globally, we need to expand vaccine development to target specific pathogens that cause diarrheal diseases and consider combining vaccines to create a broader protection. This approach would be efficient and cost-effective for regions that are hit hardest by this global health crisis,” said Dr Heidi Soeters, epidemiologist with WHO’s Department of Immunization, Vaccines and Biologicals, in a statement.
For the first time, this research incorporates pathogen-specific data from WHO’s Global Pediatric Diarrhea Surveillance network from many high-burden countries.
“The GBD is the most comprehensive assessment of health, which includes granular estimates of burden across all age groups, sexes, and locations, as well as risk factors for 204 countries and territories from 1990 to 2021,” said the study.
