Global sex- and income-stratified disparities in mortality due to tobacco-associatedleukemia, 1990–2021

Abstract

Abstract Abstract Introduction: Leukemia, a heterogeneous group of hematologic malignancies, has established associations with modifiable risk factors such as tobacco use. Despite the widespread implementation of tobacco control measures over the past three decades, disparities persist in tobacco-attributable leukemia mortality across sex and socio- demographic strata. This study aimed to quantify and compare long-term global and regional trends in mortality due to tobacco-associated leukemia between 1990 and 2021, with a focus on sex-based and income-level disparities. Methods: We obtained age-standardized mortality rates (ASMRs) for leukemia attributable to tobacco use from the Global Burden of Disease (GBD) 2021 dataset for 204 countries and territories. ASMRs were analyzed for the years 1990 and 2021 and stratified by sex (male, female, both) and socio-demographic index (SDI) regions (high, high-middle, middle, low- middle, low). Temporal trends were assessed using Average Annual Percent Change (AAPC) with corresponding 95% confidence intervals (CI). Additionally, univariate linear regressions by location were conducted to quantify associations between time and mortality. Results: Globally, tobacco-related leukemia mortality decreased substantially between 1990 and 2021. The overall ASMR declined from 0.64 to 0.40 per 100,000 population (AAPC: –1.51%; 95% CI: –1.59 to –1.43). Sex-disaggregated data revealed a more favorable reduction in females (from 0.23 to 0.12; AAPC: –2.25%; 95% CI: –2.41 to –2.09) compared to males (from 1.20 to 0.77; AAPC: –1.45%; 95% CI: –1.51 to –1.39), suggesting persistent gender disparities in tobacco exposure and/or access to care. These trends were statistically significant (p < 0.001), and global univariate regression confirmed a significant negative slope (–0.0088; p = 0.021). Marked regional differences emerged by SDI status. High-SDI countries experienced the steepest declines in mortality. In these regions, ASMRs dropped from 1.16 to 0.69 among both sexes combined (AAPC: –1.70%; 95% CI: –1.80 to –1.61), with females improving from 0.56 to 0.31 (AAPC: –1.90%; 95% CI: –2.03 to –1.76) and males from 2.07 to 1.17 (AAPC: –1.88%; 95% CI: –1.96 to –1.80). The associated regression slope (–0.0183) was statistically significant (p = 0.0014), with an R² of 0.10, indicating a strong temporal association. High-middle SDI regions showed moderate progress: ASMRs declined from 0.62 to 0.45 among both sexes (AAPC: –0.99%; 95% CI: –1.10 to –0.88). Reductions were steeper in females (0.12 to 0.07; AAPC: –1.32%; 95% CI: –1.55 to –1.09) than in males (1.40 to 0.96; AAPC –1.19%; 95% CI: –1.29 to –1.09). However, regression slopes were not statistically significant (p = 0.18), suggesting heterogeneous trends within this group. Low-SDI regions, in stark contrast, exhibited minimal improvements. Between 1990 and 2021, ASMRs decreased marginally from 0.098 to 0.074 (AAPC: –1.01%; 95% CI: –1.10 to –0.91), with male mortality decreasing from 0.17 to 0.12 (AAPC: –1.22%; 95% CI: –1.32 to –1.13) and female rates from 0.037 to 0.027 (AAPC: –0.88%; 95% CI: –1.04 to –0.72). However, the regression slope (–0.00084) was not statistically significant (p = 0.17), and the effect size (R² = 0.02) suggested only a weak temporal association. Middle and low-middle SDI countries also demonstrated underwhelming progress. In low- middle SDI settings, the combined-sex ASMR dropped from 0.21 to 0.16 per 100,000, with a weak negative slope (–0.0012; p = 0.43), and an AAPC of –0.83% (95% CI: –0.95 to –0.71). These results highlight stagnation and growing inequities in health burden mitigation. Conclusion: From 1990 to 2021, global mortality due to tobacco-attributable leukemia significantly declined, with the greatest improvements seen in high-SDI countries and among females. However, regions with lower income levels lagged, showing minimal or no significant decline in mortality despite decades of global tobacco control efforts. The pronounced disparities by sex and socioeconomic status underscore the need for context- specific, equity-focused tobacco cessation initiatives and leukemia screening programs, especially in underserved populations. Without urgent intervention, the global burden of leukemia attributable to tobacco may continue to disproportionately affect those with the fewest resources and weakest health infrastructure.