- Full (HTML) - Full (PDF) - Supplemental Material - Related EHP Articles - PubMed:Related Articles - PubMed:Citation - Cited in PMC - Purchase This Issue

Denise Felber Dietrich,¹ Armin Gemperli,¹ Jean-Michel Gaspoz,² Christian Schindler,¹ L.-J. Sally Liu,^1,3 Diane R. Gold,⁴ Joel Schwartz,^4,5 Thierry Rochat,⁶ Jean-Claude Barthélémy,⁷ Marco Pons,⁸ Frédéric Roche,⁷ Nicole M. Probst Hensch,⁹ Pierre-Olivier Bridevaux,⁶ Margaret W. Gerbase,⁶ Urs Neu,¹⁰ Ursula Ackermann-Liebrich,¹ and the SAPALDIA Team*

¹Institute of Social and Preventive Medicine, University of Basel, Basel, Switzerland; ²Department of Community Medicine and Primary Care, University Hospitals, Geneva, Switzerland; ³Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; ⁴Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, USA; ⁵Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; ⁶Division of Pulmonary Medicine, University Hospitals, Geneva, Switzerland; ⁷Laboratoire de Physiologie Clinique et de l'Exercice, Université Jean Monnet, Saint-Etienne, France; ⁸Service of Pulmonology, Ospedale Regionale, Lugano, Switzerland; ⁹Molecular Epidemiology/Cancer Registry, University of Zürich, Zürich, Switzerland; ¹⁰ProClim, Swiss Academy of Sciences, Bern, Switzerland

Abstract
Background: Heart rate variability (HRV) , a measure of cardiac autonomic tone, has been associated with cardiovascular morbidity and mortality. Short-term studies have shown that subjects exposed to higher traffic-associated air pollutant levels have lower HRV.

Objective: Our objective was to investigate the effect of long-term exposure to nitrogen dioxide on HRV in the Swiss cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) .

Methods: We recorded 24-hr electrocardiograms in randomly selected SAPALDIA participants ≥ 50 years of age. Other examinations included an interview investigating health status and measurements of blood pressure, body height, and weight. Annual exposure to NO₂ at the address of residence was predicted by hybrid models (i.e., a combination of dispersion predictions, land-use, and meteorologic parameters) . We estimated the association between NO₂ and HRV in multivariable linear regression models. Complete data for analyses were available for 1,408 subjects.

Results: For women, but not for men, each 10-µg/m³ increment in 1-year averaged NO₂ level was associated with a decrement of 3% (95% CI, –4 to –1) for the standard deviation of all normal-to-normal RR intervals (SDNN) , –6% (95% CI, –11 to –1) for nighttime low frequency (LF) , and –5% (95% CI, –9 to 0) for nighttime LF/high-frequency (HF) ratio. We saw no significant effect for 24-hr total power (TP) , HF, LF, or LF/HF or for nighttime SDNN, TP, or HF. In subjects with self-reported cardiovascular problems, SDNN decreased by 4% (95% CI, –8 to –1) per 10-µg/m³ increase in NO₂.

Conclusions: There is some evidence that long-term exposure to NO₂ is associated with cardiac autonomic dysfunction in elderly women and in subjects with cardiovascular disease.

Key words: air pollution, autonomic nervous system, cardiovascular diseases, cohort study, heart rate variability, long-term exposure, nitrogen dioxide, sex. Environ Health Perspect 116:1357–1361 (2008) .  doi:10.1289/ehp.11377 available via http://dx.doi.org/ [Online 20 June 2008]

Address correspondence to D. Felber Dietrich, Institute of Social and Preventive Medicine, University of Basel, Steinengraben 49, 4051 Basel, Switzerland. Telephone: 41-61-267-60-66. Fax: 41-61-267-61-90. E-mail: denise.felber@unibas.ch

*SAPALDIA Team. Study directorate: T. Rochat, U. Ackermann-Liebrich, J.M. Gaspoz, P. Leuenberger, L.J.S. Liu, N.M. Probst Hensch, and C. Schindler. Scientific team: J.C. Barthélémy, W. Berger, R. Bettschart, A. Bircher, G. Bolognini, O. Brändli, M. Brutsche, L. Burdet, M. Frey, M.W. Gerbase, D. Gold, W. Karrer, R. Keller, B. Knöpfli, N. Künzli, U. Neu, L. Nicod, M. Pons, E. Russi, P. Schmid-Grendelmeyer, J. Schwartz, P. Straehl, J.M. Tschopp, A. von Eckardstein, J.P. Zellweger, and E. Zemp Stutz. Scientific team at coordinating centers: P.O. Bridevaux, I. Curjuric, J. Dratva, D. Felber Dietrich, A. Gemperli, D. Keidel, M. Imboden, and G.A. Thun.

Supplemental Material is available online at http://www.ehponline.org/members/2008/11377/suppl.pdf

This study was supported by the Swiss National Science Foundation ; the Federal Office for Forest, Environment and Landscape ; the Federal Office of Public Health ; the Federal Office of Roads and Transport ; the canton's government of Aargau, Basel-Stadt, Basel-Land, Geneva, Luzern, Ticino, and Zurich ; the Swiss Lung League ; the Lung Leagues of Basel-Stadt/Basel-Landschaft, Geneva, Ticino, and Zurich ; and the U.S. National Institute of Environmental Health Sciences (D.R.G. and J.S.) .

The authors declare they have no competing financial interests.

Received 15 February 2008 ; accepted 19 June 2008.