Dataset Information

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

ABSTRACT:

Background

Several epidemiological studies have reported that long-term exposure to fine particulate matter (PM2.5) is associated with higher mortality. Evidence regarding contributions of PM2.5 constituents is inconclusive.

Objectives

We assembled a data set of 12.5 million Medicare enrollees (? 65 years of age) to determine which PM2.5 constituents are a) associated with mortality controlling for previous-year PM2.5 total mass (main effect); and b) elevated in locations exhibiting stronger associations between previous-year PM2.5 and mortality (effect modification).

Methods

For 518 PM2.5 monitoring locations (eastern United States, 2000-2006), we calculated monthly mortality rates, monthly long-term (previous 1-year average) PM2.5, and 7-year averages (2000-2006) of major PM2.5 constituents [elemental carbon (EC), organic carbon matter (OCM), sulfate (SO42-), silicon (Si), nitrate (NO3-), and sodium (Na)] and community-level variables. We applied a Bayesian hierarchical model to estimate location-specific mortality rates associated with previous-year PM2.5 (model level 1) and identify constituents that contributed to the spatial variability of mortality, and constituents that modified associations between previous-year PM2.5 and mortality (model level 2), controlling for community-level confounders.

Results

One-standard deviation (SD) increases in 7-year average EC, Si, and NO3- concentrations were associated with 1.3% [95% posterior interval (PI): 0.3, 2.2], 1.4% (95% PI: 0.6, 2.4), and 1.2% (95% PI: 0.4, 2.1) increases in monthly mortality, controlling for previous-year PM2.5. Associations between previous-year PM2.5 and mortality were stronger in combination with 1-SD increases in SO42- and Na.

Conclusions

Long-term exposures to PM2.5 and several constituents were associated with mortality in the elderly population of the eastern United States. Moreover, some constituents increased the association between long-term exposure to PM2.5 and mortality. These results provide new evidence that chemical composition can partly explain the differential toxicity of PM2.5.

SUBMITTER: Chung Y

PROVIDER: S-EPMC4421760 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

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Publications

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

Chung Yeonseung Y Dominici Francesca F Wang Yun Y Coull Brent A BA Bell Michelle L ML

Environmental health perspectives 20150106 5

<h4>Background</h4>Several epidemiological studies have reported that long-term exposure to fine particulate matter (PM2.5) is associated with higher mortality. Evidence regarding contributions of PM2.5 constituents is inconclusive.<h4>Objectives</h4>We assembled a data set of 12.5 million Medicare enrollees (≥ 65 years of age) to determine which PM2.5 constituents are a) associated with mortality controlling for previous-year PM2.5 total mass (main effect); and b) elevated in locations exhibiti ...[more]

PMID: 25565179

Similar Datasets

Project description:BackgroundNumerous studies have linked fine particles [? 2.5 µm in aerodynamic diameter (PM(2.5))] and health. Most studies focused on the total mass of the particles, although the chemical composition of the particles varies substantially. Which chemical components of fine particles that are the most harmful is not well understood, and research on the chemical composition of PM(2.5) and the components that are the most harmful is particularly limited in Asia.ObjectivesWe characterized PM(2.5) chemical composition and estimated the effects of cause-specific mortality of PM(2.5) mass and constituents in Seoul, Korea. We compared the chemical composition of particles to those of the eastern and western United States.MethodsWe examined temporal variability of PM(2.5) mass and its composition using hourly data. We applied an overdispersed Poisson generalized linear model, adjusting for time, day of week, temperature, and relative humidity to investigate the association between risk of mortality and PM(2.5) mass and its constituents in Seoul, Korea, for August 2008 through October 2009.ResultsPM(2.5) and chemical components exhibited temporal patterns by time of day and season. The chemical characteristics of Seoul's PM(2.5) were more similar to PM(2.5) found in the western United States than in the eastern United States. Seoul's PM(2.5) had lower sulfate (SO(4)) contributions and higher nitrate (NO(3)) contributions than that of the eastern United States, although overall PM(2.5) levels in Seoul were higher than in the United States. An interquartile range (IQR) increase in magnesium (Mg) (0.05 ?g/m³) was associated with a 1.4% increase (95% confidence interval: 0.2%, 2.6%) in total mortality on the following day. Several components that were among the largest contributors to PM(2.5) total mass--NO(3), SO(4), and ammonium (NH(4))--were moderately associated with same-day cardiovascular mortality at the p < 0.10 level. Other components with smaller mass contributions [Mg and chlorine (Cl)] exhibited moderate associations with respiratory mortality on the following day (p < 0.10).ConclusionsOur findings link PM(2.5) constituents with mortality and have implications for policy making on sources of PM(2.5) and on the relevance of PM(2.5) health studies from other areas to this region.

Dataset Information

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

Background

Objectives

Methods

Results

Conclusions

Publications

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

Similar Datasets

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