Global and National Trends and Projections of Type 2 Diabetes Mellitus Burden Attributable to Tobacco Use, 1990–2021

Objective To assess the trends in T2DM burden attributable to tobacco exposure in China and globally from 1990 to 2021, and to project the future burden, providing evidence to support integrated strategies for tobacco control and diabetes prevention. Methods Data on T2DM deaths, disability-adjusted life years (DALYs), age-standardized death rates (ASDR), and age-standardized DALY rates attributable to tobacco, active smoking, and secondhand smoke from 1990 to 2021 were obtained from the Global Burden of Disease Study 2021 (GBD 2021). Joinpoint regression models were used to analyze temporal trends in standardized rates. The Das Gupta decomposition method was applied to quantify the contributions of population growth, population aging, and epidemiological changes to the overall burden. A Bayesian age-period-cohort (BAPC) model was used to forecast trends in attributable burden from 2022 to 2035. Results From 1990 to 2021, global T2DM deaths and DALYs attributable to tobacco exposure increased by 94.26% and 136.94%, respectively, while the increases in China were even greater at 128.79% and 165.03%. Over the same period, the global ASDR declined, whereas the DALY rate showed an overall upward trend, with a more pronounced increase observed in China. The burden related to active smoking was predominantly seen in males, while the burden from secondhand smoke was more prominent among females. Burden peaked among individuals aged 55–74 years, with a slight delay in peak age in China compared to global patterns. Trend analysis showed that although ASDR declined in certain periods, DALY rates continued to rise throughout most of the time span. Decomposition analysis identified population growth and aging were the main contributors to the increasing burden. BAPC projections indicated that both attributable deaths and DALYs will continue to rise globally and in China through 2035, with sharper increases projected for China. Conclusions From 1990 to 2021, the T2DM burden attributable to tobacco exposure increased substantially in both China and globally, with notable sex and age disparities. The burden is projected to continue growing in the coming years. These findings underscore the need for strengthened and integrated tobacco control and diabetes prevention strategies, particularly targeting smoking among middle-aged and older men and secondhand smoke exposure among women, to curb the rising T2DM burden.