From Stanton Glantz
You accuse scientists of “mangling the facts” about the immediate effects of second-hand smoke on the cardiovascular system (10 November, p 8). You quote Mike Siegel of Boston University saying: “It is certainly not correct to claim that a single 30-minute exposure to second-hand smoke causes hardening of the arteries, heart attacks or strokes.” You go on to imply that I agreed with the position that “there is no proof 30 minutes of passive smoking raises the risk of a heart attack for a non-smoker.” Both these statements oversimplify what we know about second-hand smoke’s cardiovascular effects, including potentially serious short-term effects.
There is strong and convincing evidence, from a wide variety of studies, that even brief exposure to second-hand smoke leads to blood and blood vessels behaving similarly to what is observed in chronic smokers. While 30 minutes of SHS exposure does not precipitate a heart attack in every non-smoker, it does, among other things, activate platelets and depress function of the vascular endothelium (the lining of arteries) in a way that is known to trigger heart attacks in people at risk. These are precisely the immediate effects that anti-platelet drugs like aspirin are designed to prevent.
While it would be unethical to do the obvious experiment – expose people at risk to 30 minutes of second-hand smoke to test whether it triggers a heart attack – there is direct evidence that eliminating second-hand smoke has an immediate and substantial effect on the risk of a heart attack. Seven independent studies – in Helena, Montana; Pueblo, Colorado; Bowling Green, Ohio; New York state; Piedmont, Italy; Ireland, and Scotland) have consistently shown about a 25 per cent drop in hospital admissions for heart attacks after smoke-free laws went into effect. This is exactly what one would expect based on the rapid biological effects.
The continuing attacks on the science and organisations that are working to help the public understand the important, substantial and immediate effects of second-hand smoke on the heart are following well-worn approaches that the tobacco industry pioneered: put words in other people’s mouths, set up straw men and knock them down. And, do it over and over and over again, hoping that the media will repeat them.
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The public statements from public-health and medical authorities and individual scientists who are actually conducting research in this area have been measured, carefully presented, and based on the evidence.
From Jonathan Bagley
The letter from ASH (UK) (1 December, p 24) is laughable. In an ASH briefing on second-hand smoke you can read: “A small study in 2001 concluded that even half an hour of exposure to SHS can reduce coronary blood flow”.
This would be interpreted by most people as “can cause a heart attack”.
Further down we have: “During the six months the (smoking ban) law was enforced the number of heart attack admissions fell from 40 admissions during the year prior to the law to 24 after the law was enacted. The ordinance was subsequently overturned and the number of heart attack admissions returned to previous levels, around 40 per year.”
This suggests that passive smoking can cause almost instant heart attacks. Furthermore, the Scottish study it quotes has been thoroughly challenged, for example by Michael Blastland on the BBC website.
Todmorden, Lancashire, UK
San Francisco, US
