Supplementary Material for: Association between dietary microplastic intake with all-cause and cardiovascular diseases burden: a global analysis based on GBD 2021

Introduction
Microplastic (MP) has been proposed as a potential risk factor for cardiovascular disease (CVD), but the available epidemiological evidence remains limited and inconclusive. This study aimed to evaluate the association between dietary MP exposure and the global burden of CVD and all-cause outcomes.
Methods
We conducted a global analysis using data from 109 countries and regions between 2018 and 2021 to assess the association between dietary MP intake and global CVD burden. Outcomes included age-standardized mortality rate (ASMR), age-standardized disability-adjusted life years rate (ASDR), and age-standardized incidence rate (ASR) for both all causes and CVD. Multivariable linear mixed models were used to estimate associations, supported by nonlinear exposure–response analysis and stratified subgroup evaluations by demographic indicators, sociodemographic index (SDI), and geographic location.
Results
Dietary MP intake varied widely across regions, with the highest levels observed in low and low-middle SDI countries, particularly in coastal areas of Asia and Africa. Between 2018 and 2021, all-cause ASMR and ASDR increased globally, while CVD-related ASMR and ASDR showed a slight decline. After full adjustment, each 1 mg per capita per day increase in dietary MP intake was associated with an increase of 0.347 per 100,000 in CVD ASMR(P < 0.001) and 7.165 per 100,000 in CVD ASDR(P < 0.001). For all-cause outcomes, dietary MP intake was significantly associated with increased ASR. Subgroup analyses indicated stronger associations among older adults, populations in low SDI countries, and European regions.
Conclusions
Dietary MP exposure is significantly associated with increased global CVD burden, especially in socioeconomically disadvantaged populations. These findings highlight the growing health risks of MP pollution and support the necessity for global efforts to reduce exposure and guide public environmental health strategies.