James E. Enstrom in his own words

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This article is part of the Tobacco portal on Sourcewatch funded from 2006 - 2009 by the American Legacy Foundation. Help expose the truth about the tobacco industry.

James E. Enstrom originally added comments written in the third person to the main article page on October 31, 2006. These comments were transfered to this page and were changed to the first person with only minor editing and formatting changes. Additional comments were added on April 13, 2007.


"The impression given on SourceWatch's James E. Enstrom page is that my research has been inappropriately influenced by the organizations that have provided me with funding is entirely without merit. Ever since receiving my Ph.D. in 1970 I have followed a scientific philosophy based on the pursuit of truth [1]. This philosophy has been applied to all of my research, including the studies discussed above.

Epidemiology is the major scientific tool used to relate the occurrence of disease to various lifestyle and environmental factors. Epidemiology relies on the observational study of humans rather than on controlled experiments. Unfortunately, many excesses have occurred in recent years in the interpretation of epidemiologic associations.

For example, numerous weak and inconsistent associations involving passive smoking have been declared to be causal relationships by select committees, such as, the committee that prepared the June 27, 2006 Surgeon General’s Report on passive smoking [2]. To provide substantial new epidemiologic evidence on passive smoking, I conducted a large, long-term epidemiologic study in California using a cohort assembled by the American Cancer Society (ACS) in 1959. The ACS followed this cohort for 13 years and has used it for decades to make important findings on the relationship between active smoking and mortality.

I examined mortality risks associated with both active and passive smoking over a 39-year follow-up period. I published a paper with these findings in the May 17, 2003 British Medical Journal [3] (Pdf). This is the largest, most detailed, and most transparent epidemiologic paper on passive smoking and mortality ever published in a major medical journal. I found no relationship with passive smoking, but found a strong, long-term relationship with active smoking. In the years since its publication, no errors have been identified in the study, not even by the ACS, which possesses the underlying data. The BMJ editor has strongly defended my paper [4]. Although there is nothing wrong with my BMJ paper, since May 2003 I have been subjected to a massive and continuous campaign of ad hominem attack and character assassination, as typified by the "Enstrom & Tobacco" comments on the SourceWatch article about me.

Various elements of this attack include:

  • violation of the strict BMJ press embargo in order to poison the press coverage of the paper and "silence" its findings;
  • unsubstantiated and erroneous claims by the ACS that my paper is "fatally flawed" and meaningless;
  • attempts to discredit me and the paper by misstating my dealings with the tobacco industry;
  • a "peer-reviewed" journal article that contains nine pages of malicious libel about me and my co-author, Dr. Geoffrey C. Kabat;
  • inappropriate inclusion of this legitimate research in the August 17, 2006 District Court decision by Judge Gladys Kessler that the tobacco industry engaged in racketeering; and
  • gross mischaracterization of my research in an attempt to get the University of California to refuse tobacco industry funding.

The exaggeration of the health effects of passive smoking, particularly within in the US, is being driven by powerful US epidemiologists and organizations. In particular, the ACS possesses two massive Cancer Prevention Study cohort data bases, CPS I and CPS II, that contain most of the available US epidemiologic evidence on passive smoking. I used the California portion of the CPS I data base to conduct my research. However, the ACS overstates the strength of its own limited findings on passive smoking, refuses to fully and fairly analyze all the data that it possesses, and puts out false statements about me and my BMJ research. In addition, the Surgeon General's Report overstated the strength of the relationship of passive smoking to mortality within the US because it omitted the BMJ results without comment. This incessant exaggeration of the dangers of passive smoking has taken the focus off the large and real dangers of active smoking.

James E. Enstrom October 31, 2006


In recent months the campaign against me has escalated because of the actions of activists who dislike my research and want me silenced. First, the Regents of the University of California are now considering a University-wide ban on tobacco industry funding, as summarized in a January 26, 2007 Science news article [5]. Hopefully, this ban will never be implemented because it would have a chilling effect on academic freedom and would make virtually impossible the type of research that I published in my BMJ paper. Second, the University had to conduct an investigation of “scientific misconduct” allegations against me contained in October 12, 2006 and January 24, 2007 letters from the ACS. Fortunately, a March 22, 2007 letter from the University about this investigation completely exonerated me and concluded that the ACS allegations “provide no evidence of scientific misconduct.” This investigation was discussed in a March 30, 2007 commentary entitled “Enstrom Cleared of Scientific Misconduct Charges; American Cancer Society Owes Him An Apology” [6].

This campaign is not going to silence me and is not going to stop me from doing honest, high quality epidemiologic research. On the contrary, this campaign is going to help me get out the message that my BMJ results are entirely consistent with other US epidemiologic evidence relating ETS to mortality. One major piece of this evidence is the 199-page 1995 Emory University dissertation, “Environmental Tobacco Smoke and Lung Cancer Mortality in the American Cancer Society’s Cancer Prevention Study II” [7]. This dissertation was approved by Michael Thun, the top ACS epidemiologist. The dissertation abstract concluded: “This study found no evidence of an association between self-reported ETS and lung cancer risk among nonsmokers. However, using spousal smoking habits to assess exposure, we found ETS is only weakly, and not statistically significantly, related to lung cancer risk among nonsmoking women in seven years of follow-up of the CPS II cohort.” A second major piece of evidence is the new Western New York State study, published in the October 9, 2006 Archives of Internal Medicine [8]. This study found “After adjustment for covariates, exposure to secondhand smoke was not significantly associated with an increased risk of myocardial infarction.” Indeed, if all peer-reviewed epidemiologic evidence is fairly and fully evaluated, the relationship between ETS and lung cancer and coronary heart disease mortality in the US is very weak and is consistent with my findings [9].

New developments on this subject will continue to be posted on my Scientific Integrity Instititute website [10] and on this SourceWatch page.

James E. Enstrom April 13, 2007

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