Global burden of Alzheimer’s disease and other dementias attributable to smoking in 204 countries and territories, 1990–2021

Abstract

Background Alzheimer’s disease and other dementias (ADD) are significant global public health challenges. Smoking is a clearly established modifiable risk factor for dementia. Objective This study aims to systematically elucidate the burden of ADD attributable to smoking from 1990 to 2021. Methods We obtained data on Disability Adjusted Life Years (DALYs) and age-standardized DALYs rate (ASDRs) associated with ADD attributable to smoking from the Global Burden of Disease (GBD) database for the years 1990–2021. These data were disaggregated by gender, age, sociodemographic index (SDI), and region. Temporal trends in the burden of smoking-induced ADD were examined by calculating the average annual percentage changes. Results From 1990−2021, global ASDR of smoking-attributed ADD declined 21.3% (EAPC=−0.88%) while DALYs increased 93% to 1.53 million. Females showed faster ASDR decline (EAPC=−1.50% vs male −0.73%). DALYs peaked at 65−85 years with accelerated crude rates post-75. Regionally, East Asia (611760.52, 262060.15–1401979.1), Western Europe (184593.67, 78898.94–420812.86), High-income North America (164283.74, 72809.79–373190.34) had highest 2021 DALYs; East Asia (29.95, 12.67–68.10), High income North America (23.32, 10.39–52.46), Tropical Latin America (20.81, 9.05–48.62) had highest ASDR. Nationally, China, United States of America and Lebanon led burdens. Steepest declines occurred in Mexico (EAPC=−3.14%), South Africa (−3.14%), and Sri Lanka (−2.84%). ASDR correlated with SDI (r=0.44, p<0.001) showing bimodal peaks at SDI=0.5 and 0.8. Frontier analysis revealed peak heterogeneity in Alzheimer’s disease ASDR around SDI 0.75, with the largest effectiveness disparities observed primarily in Middle-High SDI countries, indicating urgent needs for targeted health interventions despite declining trends in high-SDI nations. Conclusion Despite declining dementia ASDR, global DALYs rose absolutely. The burden disproportionately impacted older populations, males, and high-middle-income nations. Mitigation requires context-adapted interventions including enhanced tobacco control, equitable healthcare access, and targeted health education.