| Cardiovascular Effects of Nickel in Ambient Air Morton Lippmann,1* Kazuhiko Ito,1 Jing-Shiang Hwang,2 Polina Maciejczyk,1 and Lung-Chi Chen1* 1New York University School of Medicine, Nelson Institute of Environmental Medicine, Tuxedo, New York, USA; 2Institute of Statistical Science, Academia Sinica, Taipei, Taiwan Abstract
Background: Fine particulate matter (FPM) in ambient air causes premature mortality due to cardiac disease in susceptible populations. Objective: Our objective in this study was to determine the most influential FPM components. Methods: A mouse model of atherosclerosis (ApoE–/–) was exposed to either filtered air or concentrated FPM (CAPs) in Tuxedo, New York (85 µg/m3 average, 6 hr/day, 5 days/week, for 6 months) , and the FPM elemental composition was determined for each day. We also examined associations between PM components and mortality for two population studies: National Mortality and Morbidity Air Pollution Study (NMMAPS) and Hong Kong. Results: For the CAPs-exposed mice, the average of nickel was 43 ng/m3, but on 14 days, there were Ni peaks at ~ 175 ng/m3 and unusually low FPM and vanadium. For those days, back-trajectory analyses identified a remote Ni point source. Electrocardiographic measurements on CAPs-exposed and sham-exposed mice showed Ni to be significantly associated with acute changes in heart rate and its variability. In NMMAPS, daily mortality rates in the 60 cities with recent speciation data were significantly associated with average Ni and V, but not with other measured species. Also, the Hong Kong sulfur intervention produced sharp drops in sulfur dioxide, Ni, and V, but not other components, corresponding to the intervention-related reduction in cardiovascular and pulmonary mortality. Conclusions: Known biological mechanisms cannot account for the significant associations between Ni with the acute cardiac function changes in the mice or with cardiovascular mortality in people at low ambient air concentrations ; therefore, further research is needed. Key words: atherosclerosis, cardiac function, cardiovascular mortality, concentrated airborne particles (CAPs) , fine particulate matter, heart rate, heart rate variability, nickel, susceptible populations, vanadium. Environ Health Perspect 114:1662–1669 (2006) doi:10.1289/ehp.9150 available via http://dx.doi.org/ [Online 20 July 2006]
Address correspondence to M. Lippmann, New York University School of Medicine, Nelson Institute of Environmental Medicine, 57 Old Forge Rd., Tuxedo, NY 10987 USA. Telephone: (845) 731-3558. Fax: (845) 351-5472. E-mail: lippmann@env.med.nyu.edu *Authors contributed equally to this manuscript. The work of M.L., K.I., P.M., and L.C.C. was supported by U.S. Environmental Protection Agency Center Grant R827351 and National Institute of Environmental Health Sciences Center Grant ES00260 ; J.S.H.'s work was supported by the Academia Sinica. The authors declare they have no competing financial interests. Received 7 March 2006 ; accepted 20 July 2006. An erratum was published in Environ HealthPerspect 115:A294 (2007) .
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