Global, regional, and national burden of smoking-attributable digestive cancers in adults aged ≥60 years, 1990–2021, with projections to 2036: A secondary dataset analysis of Global Burden of Disease (GBD) 2021

INTRODUCTION Smoking is a key driver of esophageal, stomach, liver, pancreatic, and colorectal cancers, and its impact is stronger in adults aged ≥60 years due to cumulative exposure and population aging. A comprehensive analysis of temporal trends and sociodemographic drivers for major digestive cancers in this population is lacking. This study quantified smoking-attributable deaths and disability-adjusted life years (DALYs) from digestive cancers in adults aged ≥60 years globally from 1990 to 2021. It also projected future burdens to 2036 to inform age-focused tobacco control and cancer prevention.

METHODS This study is a secondary dataset analysis of data from GBD 2021. We analyzed smoking-attributable deaths and DALYs for esophageal, stomach, liver, pancreatic, and colorectal cancers among adults aged ≥60 years across 204 countries and territories (1990-2021). We decomposed temporal changes into contributions from population growth, aging, and changes in age-specific rates. Associations with the sociodemographic index (SDI) were assessed, and future burdens (2022-2036) were projected using a Bayesian age-period-cohort model.

RESULTS From 1990 to 2021, global smoking-attributable deaths increased by 27.5% (398426 to 508147) and DALYs by 14.6% (8.9 to 10.2 million). Decomposition attributed the increase primarily to population growth (41-43%), partially offset by declining age-specific rates (-30% to -35%). Regional disparities were stark: high-SDI regions stabilized burdens through epidemiological improvements, while low-SDI regions saw population-driven escalations. SDI was positively correlated with burden at the country level (ρ=0.20-0.48; p<0.001), peaking at mid-high SDI.

CONCLUSIONS Despite falling age-specific rates, the absolute burden of smoking-attributable digestive cancers in older adults is rising in parallel with demographic growth. Projections to 2036 suggest that, if current demographic trends continue, absolute deaths and DALYs are expected to continue increasing as populations age and grow.