Research Long-Term Urban Particulate Air Pollution, Traffic Noise, and Arterial Blood Pressure Kateryna Fuks,1 Susanne Moebus,2 Sabine Hertel,2 Anja Viehmann,2 Michael Nonnemacher,2 Nico Dragano,2 Stefan Möhlenkamp,3 Hermann Jakobs,4 Christoph Kessler,4 Raimund Erbel,3 and Barbara Hoffmann,1,5 on behalf of the Heinz Nixdorf Recall Study Investigative Group 1Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany; 2Institute for Medical Informatics, Biometry, and Epidemiology, and 3West German Heart Centre of Essen, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; 4Rhenish Institute for Environmental Research, University of Cologne, Cologne, Germany; 5Medical School, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany Background : Recent studies have shown an association of short-term exposure to fine particulate matter (PM) with transient increases in blood pressure (BP), but it is unclear whether long-term exposure has an effect on arterial BP and hypertension. o Bjectivs : We investigated the cross-sectional association of residential long-term PM exposure with arterial BP and hypertension, taking short-term variations of PM and long-term road traffic noise exposure into account. Methods : We used baseline data (2000–2003) on 4,291 participants, 45–75 years of age, from the Heinz Nixdorf Recall Study, a population-based prospective cohort in Germany. Urban background exposure to PM with aerodynamic diameter ≤ 2.5 mμ (PM2.5) and ≤ 10 mμ (PM 10) was assessed with a dispersion and chemistry transport model. We used generalized additive models, adjusting for short-term PM, meteorology, traffic proximity, and individual risk factors. r esult : An interquartile increase in PM2.5 (2.4 μg/m 3) was associated with estimated increases in mean systolic and diastolic BP of 1.4 mmHg [95% confidence interval (CI): 0.5, 2.3] and 0.9 mmHg (95% CI: 0.4, 1.4), respectively. hTe observed relationship was independent of long-term exposure to road traffic noise and robust to the inclusion of many potential confounders. Residential proximity to high traffic and traffic noise exposure showed a tendency toward higher BP and an elevated prevalence of hypertension. words c onclusi : We found an association of long-term exposure to PM with increased arterial BP in a population-based sample. hTis finding supports our hypothesis that long-term PM exposure may pro - mote atherosclerosis, with air-pollution–induced increases in BP being one possible biological pathway. k ey : atherosclerosis, environmental epidemiology, hypertension, particulate matter, traffic emissions. Environ Health Perspect 119:1706–1711 (2011). http://dx.doi.org/10.1289/ ehp.1103564 [Online 9 August 2011] one component among many that determine urban background concentration of PM and b) the dispersions of traffic-related PM and traffic noise follow different patterns. In our study, we investigated the cross- sectional association of long-term urban back- ground PM with arterial BP and hypertension in a population-based sample, taking long- term traffic noise and short-term variations of air pollution into account. We used data from a large, well-characterized population-based cohort, residing in a densely populated area in West Germany. The availability of different exposure indicators, including a state-of-the- art dispersion and chemistry transport model for the assessment of urban background PM exposure, in addition to small-scale indicators of traffic and traffic noise exposures, enabled us to account for the effects of road traffic noise when estimating the effects of PM. Materials and Methods P o p u l a t i o n . W e u s e d b a s e l i n e d a t a (2000–2003) from the Heinz Nixdorf Recall Study, a population-based, prospective cohort Address correspondence to K. Fuks, Leibniz Research Institute for Environmental Medicine, Epidemiology Unit, Auf’m Hennekamp 50, 40225 Düsseldorf, Germany. Telephone: 0049-211-3389-341. Fax: 0049-211-3389-283. E-mail: kateryna.fuks@ uni-duesseldorf.de Supplemental Material is available online (http:// dx.doi.org/10.1289/ehp.1103564). We thank all study participants and the dedi- cated personnel of the Heinz Nixdorf Recall Study, in particular, U. Roggenbuck, U. Slomiany, and I. Vanberg. We gratefully acknowledge the collabo- ration with K.-H. Jöckel, D. Grönemeyer, R. Seibel, K. Mann, L. Vollbracht, and K. Lauterbach. We thank the North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection for providing emission data, and the city councils of Bochum, Essen, and Mülheim. The study was supported by the Heinz Nixdorf Foundation [chairman: M. Nixdorf; former chair- man: G. Schmidt (deceased)], the German Ministry of Education and Science, the German Research Foundation (DFG; projects JO-170/8-1, SI 236/8-1, and SI236/9-1). Analyses combining environmental and social factors were additionally funded by the Volkswagen Foundation. The authors declare they have no actual or potential competing financial interests. Received 11 February 2011; accepted 9 August 2011. ovlume 119 | number 12 | December 2011 • Environmental Health Perspectives High blood pressure (BP) and hypertension have been identified as the leading risk factors for cardiovascular mortality and, together, as the third most important cause of disability in the developed world (Ezzati et al. 2002). Chronically elevated BP is an important deter- minant for the development and progression of atherosclerosis, the underlying pathology for most cardiovascular events. Recent studies suggest that long-term exposure to particulate matter (PM) contributes to atherogenesis and that the induction of a chronically elevated BP could be one biological pathway by which PM exerts its influence on atherosclerosis (Adar et al. 2010; Allen et al. 2009; Bauer et al. 2010; Diez Roux et al. 2008; Hoffmann et al. 2007; Künzli et al. 2010). Increasing evidence suggests that short-term increases in PM air pollution lead to acute but transient increases in arterial BP (Brook et al. 2011; Chuang et al. 2010; Delfino et al. 2010; Dvonch et al. 2009; Mordukhovich et al. 2009; Zanobetti et al. 2004). Less is known regarding whether long-term exposure to air pollution can chronically raise BP and induce hyperten- sion. Recent epidemiologic studies provide pre- liminary evidence showing positive associations 1706 between medium- and long-term residential exposures to fine PM and BP and left ventricu- lar mass (Auchincloss et al. 2008; Chuang et al. 2011; Van Hee et al. 2009). Although biological mechanisms for the effects of PM on BP have not yet been estab- lished, several pathways have been suggested, including local and systemic inflammation and oxidative stress, autonomic imbalance, and endothelial dysfunction (Brook 2007; Brook et al. 2009; Mills et al. 2009). The composition of urban PM air pollu- tion is determined by multiple sources, includ- ing regionally transported PM, local industrial sources, home heating, and traffic. Traffic is also an important source of long-term residen- tial noise exposure, which has been suggested to increase arterial BP and promote hyperten- sion (Babisch 2006). When studying the effects of long-term urban air pollution on BP, it is therefore necessary to account for the effects of road traffic noise when estimating the effects of air pollution. One possible solution is to meas- ure urban background PM concentration and small-scale indicators of traffic exposure and traffic noise separately. This separation can be achieved because a) traffic-related PM is only