Global, regional, and national trends in the morbidity gap and contributing diseases, injuries, and risk factors, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023.

Abstract

As survival improves globally, the central public health challenge increasingly shifts from extending life to extending healthy lifespan. The compression of morbidity hypothesis proposes that effective prevention and care will delay disability more than death, reducing the morbidity gap-ie, the duration or proportion of life spent in poor health. We aimed to comprehensively estimate changes in the morbidity gap globally, regionally, and nationally from 1990 to 2023, by sociodemographic development levels and sex, and analysed leading diseases and injuries and their underlying risk factors contributing to years lived in poor health. Using Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 estimates of life expectancy and healthy life expectancy (HALE) at birth for 204 countries and territories from 1990 to 2023, we calculated the morbidity gap as life expectancy minus HALE, and the proportional morbidity gap as this difference divided by life expectancy. Results are presented globally, by GBD super-region and country, Socio-demographic Index (SDI) quintile, and sex. We decomposed the morbidity gap into cause-specific and risk-specific contributions, assigning to each cause group its proportional share of years lived with disability (YLD), adjusted for comorbidity to avoid double counting disability for co-occurring conditions. We report mean estimates and 95% uncertainty intervals (UIs) derived from 250 or more draws from posterior distributions. From 1990 to 2023, the global morbidity gap increased from 8·8 years (95% UI 6·7-11·2) to 10·7 (8·2-13·7), an increase of 1·9 years (1·3-2·6), or 21·9% (16·0-27·9), with point estimates suggesting widening morbidity gaps in 203 of 204 countries and territories. Globally in 2023, an average of 14·5% of life was spent in poor health, compared to 13·6% in 1990. From 1990 to 2023, across locations, age-specific morbidity gaps widened across the adult life course, rather than concentrating in the final years of life. In 2023, morbidity gaps were largest in the high SDI quintile and smallest in the low SDI quintile. Countries with longer life expectancies had larger morbidity gaps and both had a positive relationship with SDI; however, the relationship between life expectancy and the proportional morbidity gap was less clear. A small number of chronic, largely non-fatal causes were the primary contributors to the morbidity gap, with musculoskeletal disorders (especially low back pain), mental disorders (depressive and anxiety disorders), sense organ diseases (age-related hearing loss), unintentional injuries (falls), and other non-communicable diseases together accounting for 57·4% of unhealthy years in 2023, globally. High fasting plasma glucose, high body-mass index, and child and maternal malnutrition were the leading risk factors contributing to the global morbidity gap. The expansion of the morbidity gap across nearly all locations indicates that improvements in survival have consistently outpaced reductions in non-fatal health loss across geographies, SDI levels, and sexes, with most populations now spending a decade or more of life in poor health across the lifespan. Progress towards healthy ageing should therefore be assessed not only by reduced mortality, but also by declines in years lived in poor health, with emphasis placed on extending healthspan. The Gates Foundation.