Despite advances in air quality, global heart disease deaths tied to particulate pollution have soared, especially for seniors and in developing nations, with women facing the sharpest future rise.
Study: Global cardiovascular disease burden attributable to particulate matter pollution, 1990–2021: an analysis of the global burden of disease study 2021 and forecast to 2045 - Image credit: NadyGinzburg/Shutterstock.com
A new study analyzing data from the Global Burden of Disease (GBD) 2021 study, and scheduled for publication in BMC Cardiovascular Disorders in May 2025, revealed a significant increase in the cardiovascular disease burden attributable to particulate matter pollution from 1990 to 2021.
Background
The Global Burden of Disease (GBD) 2021 study identifies cardiovascular disease as a major cause of death and disability-adjusted life-years (DALYs) worldwide, with ischemic heart disease and ischemic stroke contributing the most. DALY is a measure of disease burden, combining the impact of premature death and years lived with disability.
The burden of cardiovascular disease is significantly higher in countries with lower social, educational, and healthcare development (socio-demographic status), as compared to countries with higher socio-demographic development.
Specific risk factors, including air pollution, lack of physical activity, smoking, hypertension, and high cholesterol, can accelerate the progression of cardiovascular disease. Exposure to ambient particulate matter (PM) is a potent risk factor for cardiovascular disease.
Among the three main PM categories, fine PM 2.5 (diameter less than 2.5 μm) is particularly concerning because it can enter the bloodstream through the respiratory system and trigger systemic inflammation, oxidative stress, and endothelial dysfunction. All these processes can significantly contribute to the development and progression of cardiovascular disease.
This study utilized the GBD 2021 data to analyze cardiovascular disease attributed to PM2.5 exposure across global regions over the past three decades.
Study design
The study analyzed data from the GBD 2021 study, a collaborative project involving over 11,000 contributors from more than 160 countries and regions. All available data were reviewed, and modeling techniques were applied to generate estimates. The project estimates 371 diseases and injuries in 204 countries and regions worldwide from 1990 to 2021.
In the current study, researchers utilized the GBD 2021 data to evaluate age-standardized mortality rates and DALYs for cardiovascular disease attributable to PM 2.5 from 1990 to 2021. They also used mathematical models, including age-period-cohort models to assess temporal trends and the Bayesian age-period-cohort (BAPC) model for its robustness in handling long-term epidemiological trends, to predict the future burden of cardiovascular disease up to 2045.
Study findings
The study reported that the global number of deaths and DALYs associated with PM 2.5-attributable cardiovascular disease increased by 91.68% and 78.89%, respectively, between 1990 and 2021. Despite these increases, age-standardized mortality rates (adjusting for the impact of age on mortality) and age-standardized DALYs decreased by 80.39% and 75.84%, respectively, over the same period. The reduction was more pronounced among females.
These changes in the age group distribution of global cardiovascular disease burden may be attributed to the population's rapid aging and the global population's growth.
A disproportionate distribution of the global PM-attributable cardiovascular disease burden was observed across age groups. A significantly greater burden was observed in elderly populations.
From 1990 to 2021, while the age-standardized mortality rate and DALYs declined, the absolute burden in older populations increased due to population aging. This trend is particularly significant in older adults (80 years and above).
The proportion of deaths and DALYs due to ischemic stroke was significantly higher than that of ischemic heart disease in the elderly population. This may be due to the brain's higher sensitivity to ischemia compared to the heart. In the brain, ischemia can cause irreversible damage within minutes, whereas ischemic heart disease can be improved through medication, stents, or surgery.
Furthermore, ischemic stroke often leads to severe long-term disabilities, increasing DALYs more in seniors.
The study observed national-level disparities in cardiovascular disease burden. Countries with high and low socio-demographic status exhibited lower age-standardized mortality rates and DALYs. In contrast, countries with moderate socio-demographic status exhibited higher age-standardized mortality rates and DALYs.
The researchers provided several explanations for a careful interpretation of these observations. In countries with high socio-demographic status, lower PM-attributable cardiovascular disease burden may be associated with better medical resources and stricter environmental management policies, such as using clean energy sources (electricity, natural gas, and hydrogen) rather than solid fuels (coal).
In countries with a moderate socio-demographic status, rapid industrialization and urbanization may lead to a significant increase in pollutant emissions without corresponding improvements in healthcare systems, resulting in a higher disease burden.
The study found differences in mortality and DALY rates between genders during the 1990-2021 period, with females experiencing lower age-standardized disease burdens and a more significant decline in these rates than males. This may be due to the protective effect of estrogen, a female reproductive hormone, on the cardiovascular system, which can have lasting benefits even after menopause due to early-life protective effects and metabolic memory. Furthermore, historically, females may have been less likely to be employed in construction, agriculture, or other outdoor occupations, resulting in lower exposure to ambient PM 2.5. Behavioral factors, such as higher mask usage in some female populations, could also contribute to observed differences.
The study predicted a threefold increase in the number of deaths and an almost 2.5-fold increase in DALYs from cardiovascular disease attributable to PM 2.5 exposure by 2045, with females experiencing a larger increase in these absolute numbers. This projected increase refers to absolute numbers, not age-standardized rates.
This increase may be associated with several factors, including a global rise in the elderly population and higher exposure to PM pollution due to industrialization and urbanization.
Study significance
The study reports a global rise in the absolute cardiovascular disease burden attributable to PM 2.5 exposure, despite improvements in age-standardized rates.
The study observed age-, gender-, and socio-demographic status-related disparities in disease burden, highlighting the need for prioritizing strict air pollution controls, early screening, and healthcare resource allocation in high-risk regions and among vulnerable populations. It is also important to acknowledge that, as with any modeling study, these projections have uncertainties.
The original paper notes limitations such as primary data quality in some regions, the focus on PM2.5, excluding other pollutants, and the specific CVD outcomes examined, which could influence estimates and future projections.
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