A new scientific study of forecasts and alternative scenarios for life expectancy and major causes of death in 2040 shows all countries are likely to experience at least a slight increase in lifespans. In contrast, one scenario finds nearly half of all nations could face lower life expectancies.
The rankings of nations’ life expectancies offer new insights into their health status.
For example, Nigeria, with an average life expectancy of 65.0 years in 2016, ranked 156th among 195 nations. However, if recent health trends continue it could rise to a rank of 123rd in 2040 with an average life expectancy of 74.8 years, an increase of 9.8 years.
Nigeria’s life expectancy could increase by as much as 14.2 years in a better health scenario or as little as 5.1 years in a worse health scenario.
In contrast, the United States in 2016 ranked 43rd with an average lifespan of 78.7 years. In 2040, life expectancy is forecast to increase only 1.1 years to 79.8, but dropping in rank to 64th. China, on the other hand, had a lifespan of 76.3 years in 2016 and is expected to increase to 81.9, raising its rank from 68th to 39th in 2040.
In addition, the study, published today in the international medical journal The Lancet, projects a significant increase in deaths from non-communicable diseases (NCDs), including diabetes, chronic obstructive pulmonary disease (COPD), chronic kidney disease, and lung cancer, as well as worsening health outcomes linked to obesity.
In 2016, the top 10 causes of premature death in Nigeria were malaria, diarrheal diseases, HIV/AIDS, neonatal encephalopathy due to birth asphyxia and trauma, lower respiratory infections, neonatal preterm birth complications, congenital birth defects, neonatal sepsis, meningitis, and protein-energy malnutrition.
In 2040, however, the leading causes are expected to be malaria, lower respiratory infections, HIV/AIDS, diarrheal diseases, neonatal encephalopathy due to birth asphyxia and trauma, neonatal preterm birth complications, neonatal sepsis, congenital birth defects, meningitis, and ischemic heart disease.
However, there is “great potential to alter the downward trajectory of health” by addressing key risk factors, levels of education, and per capita income, authors say.
“The future of the world’s health is not pre-ordained, and there is a wide range of plausible trajectories,” said Dr. Kyle Foreman, Director of Data Science at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, and lead author on the study. “But whether we see significant progress or stagnation depends on how well or poorly health systems address key health drivers.”
The top five health drivers that explain most of the future trajectory for premature mortality are high blood pressure, high body mass index, high blood sugar, tobacco use, and alcohol use, Foreman said. Air pollution ranked sixth.