The rising disabling share of health loss among adults aged 80 years and older: A 34-year GBD 2023 analysis across 10 selected countries, 1990-2023.

BACKGROUND: Increasing life expectancy has created an epidemiological paradox of declining mortality alongside sustained disability, particularly among the oldest-old. We quantified changes in the fatal and non-fatal composition of health loss among adults aged ≥80 years in 10 selected countries. METHODS: We analyzed Global Burden of Disease (GBD) Study 2023 estimates of years of life lost (YLLs) and years lived with disability (YLDs) from 1990 to 2023. Restricted age-standardized rates (ASRs) were calculated using published GBD 2023 world-standard weights renormalized within ages ≥80 years. We examined the YLD share of disability-adjusted life-years (DALYs), termed the disabling burden ratio (DBR), Level-2 cause composition, Joinpoint trends, descriptive Socio-demographic Index-matched benchmarks, and exploratory time-series projections. RESULTS: The combined population aged ≥80 years increased from 31.8 million in 1990 to 103.8 million in 2023 (3.26-fold). YLL ASRs declined in all 10 countries (median change, -31.3%), whereas YLD ASRs increased in six (median change, +1.9%). Median DBR increased from 19.0% to 25.9%, although no country reached a YLD-over-YLL crossover. Mean cardiovascular-disease share decreased from 42.3% to 28.6%, while neoplasm and neurological shares increased from 11.7% to 15.7% and from 9.4% to 13.3%, respectively. CONCLUSIONS: Across this purposively selected country sample, health loss at ages ≥80 years shifted toward a larger disabling share while fatal burden remained dominant. The findings support greater emphasis on function-preserving geriatric care and long-term care, but do not by themselves establish individual-level expansion or compression of morbidity.