Evidence on vulnerability and susceptibility to health risks associated with short-term exposure to particulate matter: a systematic review and meta-analysis

Abstract

Although there is strong evidence that short-term exposure to particulate matter is associated with health risks, less is known about whether some subpopulations face higher risks. We identified 108 papers published after 1995 and summarized the scientific evidence regarding effect modification of associations between short-term exposure to particulate matter and the risk of death or hospitalization. We performed a meta-analysis of estimated mortality associations by age and sex. We found strong, consistent evidence that the elderly experience higher risk of particular matter--associated hospitalization and death, weak evidence that women have higher risks of hospitalization and death, and suggestive evidence that those with lower education, income, or employment status have higher risk of death. Meta-analysis showed a statistically higher risk of death of 0.64% (95% confidence interval (CI): 0.50, 0.78) for older populations compared with 0.34% (95% CI: 0.25, 0.42) for younger populations per 10 μg/m3 increase of particulate matter with aerodynamic diameter ≤10 μm. Women had a slightly higher risk of death of 0.55% (95% CI: 0.41, 0.70) compared with 0.50% (95% CI: 0.34, 0.54) for men, but these 2 risks were not statistically different. Our synthesis on modifiers for risks associated with particulate matter can aid the design of air quality policies and suggest directions for future research. Studies of biological mechanisms could be informed by evidence of differential risks by population, such as by sex and preexisting conditions.

Keywords: PM10; PM2.5; age; effect modifiers; hospital admissions; mortality; particulate matter; socioeconomic status.

Figure 1.

Meta-analysis of the association of sex with increased risk of death by exposure to particulate matter with aerodynamic diameter ≤10 µm (PM₁₀). Solid points represent results for women; open points represent results for men. Points reflect central estimates; horizontal lines represent 95% confidence intervals. Boxes represent individual study results; diamonds represent results from the meta-analysis.

Figure 2.

Meta-analysis of the association of age with increased risk of death by exposure to particulate matter with aerodynamic diameter ≤10 µm (PM₁₀). Solid points represent results for younger populations; open points represent results for older populations. Points reflect central estimates; horizontal lines represent 95% confidence intervals. Boxes represent individual study results; diamonds represent results from the meta-analysis.