Editorial
Which Components of Fine Particulate Matter Have Adverse Vascular Health?
2023 年 30 巻 11 号 p. 1547-1548
詳細
2023 年 30 巻 11 号 p. 1547-1548
See article vol. 30: 1552-1567
Airborne particles with aerodynamic diameters ≤ 2.5 µm were called fine particulate matter (PM2.5). Because the standardized measurement method is defined as mass measurement with sample collection on filter1), we have examined the association between total mass concentrations of PM2.5 and health, mainly cardiorespiratory health, and set Ambient Air Quality Standards in terms of its total mass concentrations. However, PM2.5 consists of many different chemical components having different toxic effects2). There may be specific components of PM2.5 that are more sensitive to health effects than its total mass. Therefore, we are looking for new evidence of the health effects associated with PM2.5 components.
In this issue of the Journal of Atherosclerosis and Thrombosis, Lin et al cross-sectionally analyzed data of 124,387 participants with metabolic abnormalities in China, and observed the association between the 1-year average total mass concentration of PM2.5 and subclinical atherosclerotic parameters, including brachial–ankle pulse wave velocity (baPWV) and ankle–brachial index (ABI)3). The findings demonstrated a consistent pattern that total mass concentration of PM2.5 is likely to be a risk factor for atherosclerosis4). Intriguingly, some PM2.5 components, including black carbon (BC) and ammonium salts, were associated with increased baPWV as a marker of arterial stiffness and reduced ABI as a marker of peripheral atherosclerosis. There is a lack of sufficient epidemiological results of the vascular effects of PM2.5 components. One example was a cohort study (The Multi-Ethnic Study of Atherosclerosis and Air Pollution) in six U.S. metropolitan areas, and this study found that 1-year average concentrations of organic carbon (OC) and sulfur were associated with an increase in carotid intima-media thickness reflecting early arterial wall changes5). BC and OC are categorized as carbonaceous components of PM2.5, and are emitted by the combustion of fossil fuels6). Although experimental studies focused on the cardiovascular effects of BC were previously conducted7), the biological mechanism linking BC to subclinical atherosclerotic parameters and later cardiovascular health are still not understood8).
Lin’s study had some limitations in that it was a cross-sectional study; it only included participants who had metabolic abnormalities, such as elevated body mass index, elevated triglyceride, reduced high-density lipoprotein cholesterol, elevated blood pressure and elevated fasting blood glucose, and estimated exposure to PM2.5 based on the address of the health management center that the participants attended the health examinations. Additionally, the mean 1-year average total mass concentration of PM2.5 was 66.33 µg/m3, which was well above the Japanese Air Quality Standards (annual standard ≤ 15 µg/m3)1). However, their study provided the additional evidence for vascular health effects focusing on the individual PM2.5 components. We should fill major knowledge gaps about the cardiovascular disease pathway resulting in exposure to PM2.5 components.
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