Background:In four European cohorts, we investigated the cross-sectional association
between long-term exposure to air pollution and intima-media thickness of
the common carotid artery (CIMT), a preclinical marker of
atherosclerosis.Methods:Individually assigned levels of nitrogen dioxide, nitrogen oxides,
particulate matter ≤ 2.5 μm (PM2.5), absorbance of
PM2.5 (PM2.5abs), PM10,
PMcoarse, and two indicators of residential proximity to
highly trafficked roads were obtained under a standard exposure protocol
(European Study of Cohorts for Air Pollution Effects—ESCAPE study) in
the Stockholm area (Sweden), the Ausburg and Ruhr area (Germany), and the
Girona area (Spain). We used linear regression and meta-analyses to examine
the association between long-term exposure to air pollution and CIMT.Results:The meta-analysis with 9,183 individuals resulted in an estimated increase in
CIMT (geometric mean) of 0.72% (95% CI: –0.65%, 2.10%) per
5-μg/m3 increase in PM2.5 and 0.42% (95%
CI: –0.46%, 1.30%) per 10–5/m increase in
PM2.5abs. Living in proximity to high traffic was also
positively but not significantly associated with CIMT. Meta-analytic
estimates for other pollutants were inconsistent. Results were similar
across different adjustment sets and sensitivity analyses. In an extended
meta-analysis for PM2.5 with three other previously published
studies, a 0.78% (95% CI: –0.18%, 1.75%) increase in CIMT was
estimated for a 5-μg/m3 contrast in PM2.5.Conclusions:Using a standardized exposure and analytical protocol in four European
cohorts, we found that cross-sectional associations between CIMT and the
eight ESCAPE markers of long-term residential air pollution exposure did not
reach statistical significance. The additional meta-analysis of CIMT and
PM2.5 across all published studies also was positive but not
significant.Citation:Perez L, Wolf K, Hennig F, Penell J, Basagaña X, Foraster M, Aguilera
I, Agis D, Beelen R, Brunekreef B, Cyrys J, Fuks KB, Adam M, Baldassarre D,
Cirach M, Elosua R, Dratva J, Hampel R, Koenig W, Marrugat J, de Faire U,
Pershagen G, Probst-Hensch NM, de Nazelle A, Nieuwenhuijsen MJ, Rathmann W,
Rivera M, Seissler J, Schindler C, Thiery J, Hoffmann B, Peters A,
Künzli N. 2015. Air pollution and atherosclerosis: a cross-sectional
analysis of four European cohort studies in the ESCAPE Study. Environ Health
Perspect 123:597–605; http://dx.doi.org/10.1289/ehp.1307711