Fifteen Conditions Account for More Than 80% of the Global Life Expectancy Gap Between the World's Healthiest and Least Healthy Populations

This cross-sectional study examined life expectancy disparities in 7 global regions and 165 countries from 2000 to 2021. Western Europe and Canada, referred to as the North Atlantic, in 2019 were used as a benchmark for life expectancy achievable with advanced health care and living standards. Life expectancy gaps in locations with life expectancy lower than the benchmark were decomposed by cause of death using the Pollard decomposition on the Global Health Estimates from the World Health Organization. Two sets of priority conditions were examined: the I-8, comprising 8 infectious and maternal and child health conditions including HIV/AIDS, tuberculosis, malaria, lower respiratory infections, diarrheal diseases, neonatal conditions, maternal conditions, and childhood-cluster diseases; and the NCD-7, comprising 7 non-communicable diseases and injuries including atherosclerotic cardiovascular disease, hemorrhagic stroke, diabetes, road injury, suicide, and NCDs related to tobacco and infection.

In the median country in 2019, the I-8 and NCD-7 together accounted for 80% (IQR, 71%–88%) of the life expectancy gap compared with the North Atlantic. The relative contributions of the two groups varied substantially by region. The decline in death rates from the I-8, particularly in sub-Saharan Africa, contrasts with the rising importance of the NCD-7, highlighting the evolving nature of global health challenges. Outside sub-Saharan Africa, the NCD-7 accounted for the largest share of the gap — in some regions exceeding the total life expectancy gap itself, meaning that if the NCD-7 burden were eliminated, life expectancy would actually surpass the North Atlantic benchmark.

• —The study relies on WHO Global Health Estimates, which themselves involve modeling and estimation in data-sparse settings. Cause-of-death attribution in low and middle income countries carries meaningful uncertainty that propagates into the decomposition results.
• —The North Atlantic benchmark represents an aspirational target, but it is also a moving target — life expectancy in Western Europe and Canada continues to improve, meaning the gap is measured against a standard that shifts over time.
• —The analysis captures mortality but not morbidity. Conditions that cause significant disability without early death — such as mental health disorders — are not fully reflected in life expectancy-based measures and may be underweighted in the priority conditions framework.
• —The cross-sectional design captures associations at points in time but cannot establish causal pathways between specific conditions and life expectancy gaps.

The global life expectancy gap is large but not inexplicable. Fifteen well-defined conditions account for most of it, and nearly all of them have known, scalable interventions. The gap between what we know how to do and what we are actually doing is where global health policy needs to focus.