Acute effects of fine particulate matter constituents on mortality: A systematic review and meta-regression analysis

Abstract

Background The link between PM2.5 exposure and adverse health outcomes is well documented from studies across the world. However, the reported effect estimates vary across studies, locations and constituents. We aimed to conduct a meta-analysis on associations between short-term exposure to PM2.5 constituents and mortality using city-specific estimates, and explore factors that may explain some of the observed heterogeneity. Methods We systematically reviewed epidemiological studies on particle constituents and mortality using PubMed and Web of Science databases up to July 2015. We included studies that examined the association between short-term exposure to PM2.5 constituents and all-cause, cardiovascular, and respiratory mortality, in the general adult population. Each study was summarized based on pre-specified study key parameters (e.g., location, time period, population, diagnostic classification standard), and we evaluated the risk of bias using the Office of Health Assessment and Translation (OHAT) Method for each included study. We extracted city-specific mortality risk estimates for each constituent and cause of mortality. For multi-city studies, we requested the city-specific risk estimates from the authors unless reported in the article. We performed random effects meta-analyses using city-specific estimates, and examined whether the effects vary across regions and city characteristics (PM2.5 concentration levels, air temperature, elevation, vegetation, size of elderly population, population density, and baseline mortality) can explain the observed heterogeneity. Results We found a 0.89% (95% CI: 0.68, 1.10%) increase in all-cause, a 0.80% (95% CI: 0.41, 1.20%) increase in cardiovascular, and a 1.10% (95% CI: 0.59, 1.62%) increase in respiratory mortality per 10 µg/m3 increase in PM2.5. Accounting for the downward bias induced by studies of single days, the all-cause mortality estimate increased to 1.01% (95% CI: 0.81, 1.20%). We found significant associations between mortality and several PM2.5 constituents. The most consistent and stronger associations were observed for elemental carbon (EC) and potassium (K). For most of the constituents, we observed high variability of effect estimates across cities. Conclusions Our meta-analysis suggests that (a) combustion elements such as EC and K have a stronger association with mortality, (b) single lag studies underestimate effects, and (c) estimates of PM2.5 and constituents differ across regions. Accounting for PM mass in constituent’s health models may lead to more stable and comparable effect estimates across different studies. Systematic review registration PROSPERO: CRD42017055765

Outdoor Air Pollution and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

“…The role of environmental pollutants was evident from the consistent report of the role of persistent organic phosphate pollutants in the development of IR (51)(52)(53)(54)(55). In addition, exposure to AAP has been reported to be associated with endothelial dysfunction elevated levels of inflammatory mediators including tumor necrosis factor (TNF) α, prostaglandin (PG) E2, C-reactive protein, interleukin-1β, and endothelin-1 (56)(57)(58). The increased level of inflammation mediator has been shown to interrupt and inhibit insulin signaling and transaction (59)(60)(61).…”

Random forest models for PM2.5 speciation concentrations using MISR fractional AODs

“…Numerous studies have reported the associations between adverse health effects and exposure to ambient fine particulate matter (particles with a diameter less than 2.5 μm, PM 2.5 ) [1][2][3]. It is also increasingly recognized that various chemical components of PM 2.5 might have differential toxicities to human health [4][5][6]. For example, combustion-related species such as elemental carbon (EC) and Potassium (K) were found to have a stronger association with mortality than other species [4].…”

“…It is also increasingly recognized that various chemical components of PM 2.5 might have differential toxicities to human health [4][5][6]. For example, combustion-related species such as elemental carbon (EC) and Potassium (K) were found to have a stronger association with mortality than other species [4]. However, information regarding the health effects of PM 2.5 components is limited, mainly hindered by the sparse or non-existent coverage of ground PM 2.5 speciation monitors.…”

Probabilistic predictive principal component analysis for spatially misaligned and high‐dimensional air pollution data with missing observations

“…Examples of environmental studies utilizing PM 2.5 data include studies on the associations between various health outcomes and long‐term (Chan et al, ; Kaufman et al, ; Künzli et al, ; Miller et al, ; Pope III et al, ) or short‐term (Achilleos et al, ; Gold et al, ; Hsu et al, ; Pascal et al, ; Tian et al, ; Tolbert, Klein, Peel, Sarnat, & Sarnat ) exposures to PM 2.5 . For instance, Chan et al () found significant associations between long‐term exposure to PM 2.5 and higher systolic blood pressure, pulse pressure, and mean arterial pressure in the Sister Study.…”

“…Kaufman et al () showed evidence of strong association between ambient concentration of PM 2.5 and accelerated atherosclerosis in the Multi‐Ethnic Study of Atherosclerosis and Air Pollution (MESA Air). In a recent systematic review of epidemiological studies, Achilleos et al () found substantial increases in all‐cause, cardiovascular, and respiratory mortalities due to acute exposure of PM 2.5 . Many studies have suggested that the associations between PM 2.5 total mass and various health outcomes can be modified by some specific constituents or the overall chemical composition (Bell, Ebisu, Peng, Samet, & Dominici, ; Dai, Zanobetti, Koutrakis, & Schwartz, ; Franklin, Koutrakis, and Schwartz, ; Keller et al, ; Kioumourtzoglou et al, ; Krall, Anderson, Dominici, Bell, & Peng, ; Wang et al, ; Zanobetti, Austin, Coull, Schwartz, & Koutrakis, ).…”