John Britton is Professor of Epidemiology at Nottingham University and staunch anti smoker; the following is an email exchange between him and Robert Feal-Martinez, campaign leader here at Freedom To Choose.
Dear Professor Britton,
I have been vigorously scouring research for the last 4 years in an attempt to find proof that passive smoking causes serious ill health. It is true to say that I have found many pieces of research where the 'headline' report or press release makes such a claim, however when one reads the detail the results appear to conclude the opposite. I would ask, as a Professor of Epidemiology for you to confirm my understanding that the relative risk necessary to show causation is in fact 3, and the baseline neutral risk is 1.
Am I also right in believing that a RR of 1.25, represented as 25% by some studies is in fact scientifically insignificant. The only study I have found which seems to be emphatic in it's view actually states that Environmental Tobacco Smoke poses no serious health risk at all, I also note in the 1998 WHO study your collegue Professor Bofetta concludes ETS can in fact be beneficial for young children, in guarding against later environmental effects. Whilst I appeaciate the Scientific and Medical Community seem to consistently claim ETS/Passive Smoking to be harmful, the evidence I have seen does not confirm this, which leaves one slightly confused.
This confusion was compounded even more when an advisory document issued by the Health and Safety Executive in August 2006, quite clearly stated at paragraph 9, that they (HSE) could find no epidemeological evidence to show an elevated risk to workers exposed to passive smoke, it is also true to say that the US Federal Agency the OHSA, also responsible for worker health reached this same conclusion. So I am sure you can see my confusion, in an effort to seek out the truth I find that the very agencies responsible for workers, patently disagree with the need for smoking bans to protect worker health, both having stated policies showing safe levels of ETS, something again the WHO says does not exist.
More confusion then, given that if there is no safe level of ETS, this poses two dilemma's 1. Why do world Governments not ban tobacco products outright? 2. The laws of Particle Science clearly need to be re-written, as it is my understanding that there is not a substance or particle known to man that cannot be removed from the air, by some method or other.
Thank you taken the time to read this email, and I would seek your indulgence in replying, addressing my concerns.
Robert Feal-Martinez (Life Long Never Smoker)
The evidence is summarised at and downloadable from
there isn’t any level of relative risk that distinguishes causal from non-causal associations.
Dear Professor Britton,
thank for for your prompt response. I have to say I am now even more confused. Are you saying that you personally reject the HILL model for relative risk which is internationally recognised as the 'holy graille' of epidimiologists or that the Scientific community as a whole does not accept the model. If the latter why then would such renowned publication as the new England Journal say this;
'Marcia Angell of the New England Journal of Medicine has stated "As a general rule of thumb we are looking for a relative risk of three or more [before accepting a paper for publication], particularly if it is biologically implausible or if it's a brand-new finding."
Having glanced at your papers conclusion at page 197, I have to say the more I research the more unclear things become. In 2004 Professor Jamrozik, a visiting professor at Imperial College and one of the worlds leading epidiologists stated that 3600 deaths a year are cause by Passive Smoking in the UK, and indeed HMG/DoH frequently quote Jamorozik's work. He also puts the number in public to be 700, of which one a week are in hospitality. Your report states 11 to 12 thousand deaths with 500 in publc places. Put simply with such a wide variance on both fronts what is the truth. So I have 2 questions.
1. Who is right over RR and causation.?
2. Which mortality figures are correct.?
The hill criteria do not specify a level of risk above which an association can be deemed causal, and nor is it appropriate to do so Publication in the new England journal is not a determinant of causality
The figures in the rcp report were calculated by professor Jamrozik.
Dear Professor Britton,
With respect it is not just the New England Journal,
" In epidemiologic research,increases in risk of less than 100 percent] are considered small and are usually difficult to interpret. Such increases may be due to chance, statistical bias, or the effects of confounding factors that are sometimes not evident." [Source: National Cancer Institute, Press Release, October 26, 1994.]
"As a general rule of thumb, we are looking for a relative risk of 3 or more before accepting a paper for publication." - Marcia Angell, editor of the New England Journal of Medicine"
"My basic rule is if the relative risk isn't at least 3 or 4, forget it." - Robert Temple, director of drug evaluation at the Food and Drug Administration.
"An association is generally considered weak if the odds ratio [relative risk] is under 3.0 and particularly when it is under 2.0, as is the case in the relationship of ETS and lung cancer." - Dr. Kabat, IAQC epidemiologist.
Accepting what you say Professor re the RCP report, how can, realistically, Professor Jamrozik understate the deaths, by eight thousand in 2004 and less than 18 months later 'correct' them. Put simply should any organisation let alone HMG accept at face value the 300% change in mortality. It seems odd to me that Patricia Hewitt and Caroline Flint made claims that 95% of all deaths a illness from ETS occurs in the home, during debates and press releases in late 2005/6 and yet the original figures from Professor Jamorozik, make those statements impossible, ie 3600, and 700. The 700 hundred is 20% of the total, meaning 80% in the home. However the RCP figures redress that imbalance, 500 being 4.55% of 11000. One would be forgiven for thinking that the figures were altered to 'back up' the mistakes made by the two Ministers. I would certainly be interested to know what evidence base Jamrozik found so compelling as to dramatically change his whole staistical analysis by such a wide margin.
Ive done my best to answer your questions.