Artikel
Influence of short-term exposure to ultra-fine particles on systemic inflammatory markers
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Autoren
Veröffentlicht: | 2. September 2009 |
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Gliederung
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Background: Fine particulate matter has been linked with systemic inflammatory responses. It is hypothesized that smaller particles confer higher toxicity. The aim is to analyze lag structure and shape of the association between short-term exposure to ultrafine and fine particles and systemic inflammation.
Material and Methods: We use baseline data (2000–2003) of the Heinz-Nixdorf-Recall Study, a population-based cohort study of 4814 participants in the Ruhr Area. A chemistry transport model was applied to model daily surface concentrations of particulate air pollutants on a grid of 1 km2. Exposure included particle number (PN) and particulate matter mass concentration with an aerodynamic diameter ≤1.0µm (PM1.0), ≤2.5µm (PM2.5) and ≤10µm (PM10). Generalized additive models were used to explore the relation between air pollutants with single day lags and averaging times of up to 28 days before examination, and high-sensitivity C-reactive protein (hs-CRP). We adjusted for meteorology, season, time trend, time-invariant and -variant personal characteristics. Effects are compared per increase in interquartile range (IQR) of the exposure metric. Participants with acute inflammatory diseases(hs-CRP>100mg/L), no exposure assessment or personal characteristics are excluded.
Results: Median hs-CRP level in the 4042 included participants was 1.5 mg/L. Median daily concentration of PN was 84,946/ml (IQR 46,685/ml), of PM1.0 9.9µg/m³ (IQR 8.3µg/m³), of PM2.5 14.5µg/m³ (IQR 11.4µg/m³) and of PM10 16.8µg/m³ (IQR 13.2µg/m³). A linear association between PN and hs-CRP could be observed for single day lags and for averaged PN concentrations with higher estimates for longer averaging times. The highest hs-CRP-increase of 6.9%(95%-CI:1.7%,12.4%) per 33,441/ml increase in PN was found for the 28-day average. Other particle metrics showed a linear, but less clear and consistent association.
Discussion: Stronger effects for longer averaging times imply that particle exposure has a cumulative effect on systemic inflammation. Traffic exposure, a major source of urban PN, might be responsible for this effect.