Particulate matter-induced health effects: who is susceptible?
BACKGROUND
Epidemiological, controlled human exposure, and toxicological studies have demonstrated a variety of health effects in response to particulate matter (PM) exposure with some of these studies indicating that populations with certain characteristics may be disproportionately affected.


OBJECTIVE
To identify populations potentially at greatest risk for PM-related health effects, we evaluated epidemiological studies that examined various characteristics that may influence susceptibility, while using results from controlled human exposure and toxicological studies as supporting evidence. Additionally, we formulated a definition of susceptibility, building from the varied and inconsistent definitions of susceptibility and vulnerability used throughout the literature.


RESULTS
We evaluated recent epidemiological studies to identify characteristics of populations potentially susceptible to PM-related health effects. Additionally, we evaluated controlled human exposure and toxicological studies to provide supporting evidence. We conducted a comprehensive review of epidemiological studies that presented stratified results (e.g., < 65 vs. ≥ 65 years of age), controlled human exposure studies that examined individuals with underlying disease, and toxicological studies that used animal models of disease. We evaluated results for consistency across studies, coherence across disciplines, and biological plausibility to assess the potential for increased susceptibility to PM-related health effects in a specific population or life stage.


CONCLUSIONS
We identified a diverse group of characteristics that can lead to increased risk of PM-related health effects, including life stage (i.e., children and older adults), preexisting cardiovascular or respiratory diseases, genetic polymorphisms, and low-socioeconomic status. In addition, we crafted a comprehensive definition of susceptibility that can be used to encompass all populations potentially at increased risk of adverse health effects as a consequence of exposure to an air pollutant.
National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA. sacks.jason@epamail.epa.gov
Jason D
JD
Sacks
Lindsay Wichers
LW
Stanek
Thomas J
TJ
Luben
Douglas O
DO
Johns
Barbara J
BJ
Buckley
James S
JS
Brown
Mary
M
Ross
D000368:Aged; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D000397:Air Pollution / Q000706:statistics & numerical data*; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003710:Demography; D004198:Disease Susceptibility / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis* / Q000633:toxicity; D012140:Respiratory Tract Diseases / Q000453:epidemiology; D018570:Risk Assessment; D012959:Socioeconomic Factors
D000393:Air Pollutants; D052638:Particulate Matter