Global, regional, and national disability-adjusted life-years (DALYs) for 359 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.
Level 3 - non-randomized controlled study
Level assigned by design analogy: comprehensive longitudinal epidemiological modeling and comparative multi-country disease burden analysis.
PubMed 30415748 · doi:10.1016/S0140-6736(18)32335-3
What was done
Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, researchers calculated healthy life expectancy (HALE) and disability-adjusted life-years (DALYs) across 195 countries and territories from 1990 to 2017. Metrics were derived from age-specific mortality rates, years of life lost (YLLs) to premature death, and years lived with disability (YLDs) across 359 diseases and injuries. The authors evaluated differences across Socio-demographic Index (SDI) strata and decomposed life-years gained into years in good health versus poor health, as well as sex disparities.
What was found
Globally between 1990 and 2017, life expectancy at birth rose by 7.4 years (95% uncertainty interval [UI] 7.1–7.8; from 65.6 to 73.0 years), while HALE at birth rose by 6.3 years (95% UI 5.9–6.7; from 57.0 to 63.3 years). Gains varied widely: life expectancy rose 5.1 years in high-SDI countries compared to 12.0 years in low-SDI countries. In most countries, HALE gains lagged behind total life expectancy gains, meaning a greater share of additional years are lived in poor health (e.g., 26.3% of gained years spent in poor health in high-SDI countries vs 11.7% in low-middle SDI). By 2017, Singapore had the highest HALE (females 75.8 years, males 72.6 years) and Central African Republic the lowest (females 47.0 years, males 42.8 years). The leading 2017 DALY causes were neonatal disorders, ischaemic heart disease, stroke, lower respiratory infections, and chronic obstructive pulmonary disease. While age-standardised DALY rates fell for communicable diseases (-41.3%) and neonatal disorders (-49.8%), total DALYs from non-communicable diseases rose by 40.1%.
Why it matters
This study documents that while global longevity has expanded, healthspan has not kept pace, substantially increasing the global volume of disability and shifting health system burdens heavily toward non-communicable chronic conditions.
Limits
The abstract does not report individual country primary data coverage or gaps; results rely heavily on statistical modeling and estimation where vital statistics or disability registries are sparse or absent. Standardized disability weights may not capture subjective or culture-specific variations in functional impairment.
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- context On average, humans spend the last 20% of their lives in poor health or living with disease.