Sunday, April 10, 2005

Particle Studies in Community Settings - A Tree that Fell in the Occupational Health Forest, but Made No Noise

BrooklynDodger was conversating [a current expression in certain in certain inner city schools] with a colleague on particular workplace situation, when the fine particle question arose. Although the Dodger has blogged on this issue repeatedly, the Dodger felt that a series of posts on the evolution of this issue might prove helpful to reframing occupational health perceptions of a reference dose to particles with no other toxicity.

The big tree in this forest is the Harvard Six-Cities study.

The Dodger's extract from the abstract:

Survival analysis was conducted with data from a 14-to-16-year mortality follow-up of 8111 adults in six U.S. cities... After adjusting for smoking and other risk factors, we observed statistically significant and robust associations between air pollution and mortality. The adjusted mortality-rate ratio for the most polluted of the cities as compared with the least polluted was 1.26 ... Air pollution was positively associated with death from lung cancer and cardiopulmonary disease but not with death from other causes considered together... Mortality was most strongly associated with air pollution with fine particulates, including sulfates.

The full text of this seminal paper is available through medline for free, the Dodger invites readers to get it themselves. Obviously this was the bomb, combining Harvard and the New England Journal. It provoked political and scientific events to be described in later posts.

Important to note is the date of publication: more than a decade ago.

Also important to note, found only by reading the paper, is that these 6 cities were largely in compliance with the EPA then and now NAAQS for particulate. Exposure-response within this group of city provides clear evidence for hazard identification, and this is the only observation noted in the abstract. The exposure data in the study, however, provides an anchor for an exposure-response assessment for risk. BrooklynDodger opines that an acceptable exposure limit should be some factor below a no-effect level, which could be derived from these data.

If the Dodger were reviewing this paper, the Dodger would have asked the authors to include a sentence on the range of exposures in the abstract.


N Engl J Med. 1993 Dec 9;329(24):1753-9.

Comment in:
N Engl J Med. 1993 Dec 9;329(24):1807-8.
N Engl J Med. 1994 Apr 28;330(17):1237-8.
N Engl J Med. 2004 Jan 8;350(2):198-9.

An association between air pollution and mortality in six U.S. cities.

Dockery DW, Pope CA 3rd, Xu X, Spengler JD, Ware JH, Fay ME, Ferris BG Jr, Speizer FE.Environmental Epidemiology Program, Harvard School of Public Health, Boston, MA 02115.

1 comment:

James said...

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