An overall increase in life expectancy worldwide by 6.2 years was observed by a new study published in The Lancet from 1990 to 2021. This progress is owing to a reduction in deaths from enteric infections, lower respiratory infections, ischemic heart disease, and strokes across the globe. COVID-19, however, was a dampener in many countries.
Enteric illnesses are food and waterborne illnesses, that are bacterial, parasitical, and viral diseases, contributed to the highest reduction in deaths. The category of diseases includes typhoid and diarrhea. A reduction in deaths from these diseases increased life expectancy by 1-1 years during 1990-2021, with the increase more striking in the decade between 1990 and 2000 compared with subsequent decades.
Reduced mortality from enteric infectious diseases, contributed to a substantial gain of 3.1 years in life expectancy in South Asia.
“We already know how to save children from dying from enteric infections including diarrheal diseases, and progress in fighting this disease has been tremendous,” Mohsen Naghavi, the Director of Subnational Burden of Disease Estimation at the Institute for Health Metrics and Evaluation (IHME), said in his statement.
“Now, we need to focus on preventing and treating these diseases, strengthening and expanding immunization programs, and developing brand-new vaccines against E. coli, norovirus, and Shigella,” Naghavi, the study’s lead author, added.
The researchers found that the second-largest contributing factor towards increasing life expectancy was the reduction in deaths from lower respiratory infections, leading to 0.9 years of gained life expectancy from 1990 to 2021.
Similarly, the researchers noted that a drop in chronic respiratory diseases contributed to an increase of 0.5 years in life expectancy. East Asia had a significant role in this, with improvements in mortality in China.
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Life expectancy was highly variable between regions. Southeast Asia, east Asia, and Oceania gained 8.3 years of life expectancy overall, the highest worldwide. This is while simultaneously having the smallest reduction in life expectancy due to COVID-19 at 0.4 years.
“The global community must ensure that the lifesaving tools that have cut deaths from ischemic heart disease, stroke, and other non-communicable diseases in most high-income countries are available to people in all countries, even where resources are limited,” said Eve Wool, a senior research manager at IHME in a statement.
“Our study also found that some vaccine-preventable diseases, such as measles, have shown widespread reductions in mortality rates and were geographically concentrated. Under-5 deaths from measles were concentrated within western and eastern sub-Saharan Africa,” the researchers said.
The study, however, pointed out that digestive diseases and cirrhosis posed significant threats, with a lack of improvement from 2010 to 2019. Further, diabetes and kidney diseases result in a global loss of 0.1 years in life expectancy.
COVID-19 spanner
Across all causes, COVID-19, resulted in a decline of 1.6 years between 2019 and 2021, causing the largest dent on global life expectancy estimates.
“The effect of COVID-19 on life expectancy showed varying degrees of severity, ranging from a large loss of 4.9 years in Andean Latin America to almost no change in East Asia,” the paper said.
While life expectancy in sub-Saharan Africa was impacted during the pandemic, the reduction was compounded by high mortality rates from HIV/AIDS.
Regions with advanced medical facilities were able to contain the number of COVID-19 cases, in contrast to the locations with poor healthcare infrastructure. The researchers, however, said that, “strong health-care systems did not singularly influence the outcome of the pandemic.”
Read India’s life expectancy falls to 67.2 in 2021, decade-long improvement undone
There was no change in the leading causes of death in 1990 and 2019, but the COVID-19 pandemic shifted the rankings of these causes. In 2019, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections were the leading causes of age-standardised deaths globally.
However, in 2021, COVID-19 emerged as the second leading cause of age-standardised deaths in 2021. It replaced stroke with 94 deaths per 100,000 population. Chronic obstructive pulmonary disease was shifted to the fourth-leading position.
“The effect of COVID-19 on age-standardized mortality was similar to that of chronic obstructive pulmonary disease in 2020 but increased by 60.2 percent in 2021, becoming similar to that of stroke and ischaemic heart disease,” the paper said.
The researchers added to the Global Burden of Diseases 2021 report and identified 12 additional causes of death.
These are COVID-19 and other pandemic-related mortality diseases, pulmonary arterial hypertension, and nine cancer types such as, “hepatoblastoma, Burkitt lymphoma, another non-Hodgkin lymphoma, eye cancer, retinoblastoma, other eye cancers, soft tissue and other extraosseous sarcomas, malignant neoplasm of bone and articular cartilage, and neuroblastoma and other peripheral nervous-cell tumors.”
The study estimated excess mortality during the pandemic in 2020 and 2021 in lower respiratory infections due to the complications of the disease. For measles, malaria, and pertussis, excess deaths were reported due to deferred care-seeking.
Successes and effective disease mitigation programmes can guide future policy in burdened countries, the researchers added. They said they plan to simplify their approach to estimating COVID-19-related deaths, removing the category of the residual ‘other pandemic-related mortality (OPRM)’ added by them to the GBD 2021.
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