Wednesday, March 21, 2007

American Cancer Society Still Misrepresenting Scientific Evidence; Is it in a Position to Be Attacking Others for Scientific Misconduct?

Earlier today, I commented on the American Cancer Society's (ACS) attack upon UCLA professor and epidemiologist Dr. James Enstrom, in which the ACS accused him of scientific misconduct, prompting an internal investigation by the University. The ACS has also alleged that Dr. Enstrom communicated invalid conclusions regarding the health effects of secondhand smoke and misrepresented scientific evidence on the health effects of secondhand smoke.

The Rest of the Story

Let's take a look at what the American Cancer Society is telling the public about the health effects of secondhand smoke.

Exhibit 1

"Immediate effects of secondhand smoke include cardiovascular problems such as damage to cell walls in the circulatory system, thickening of the blood and arteries, and arteriosclerosis (hardening of the arteries) or heart disease, increasing the chance of heart attack or stroke."

What the ACS is telling the public is that one of the immediate effects of secondhand smoke exposure is hardening of the arteries and heart disease, and as a result, an increased risk of heart attack or stroke.

However, the fact is that it takes many years for hardening of the arteries (atherosclerosis) to develop. It is simply not accurate to claim that this is an immediate effect.

What makes this claim particularly troublesome are the following two factors:

1) It is not just an isolated statement by the ACS. It comes in the context of a strategy guide which is making specific recommendations about exactly what statements anti-smoking groups throughout the world should make about the health effects of secondhand smoke. So the ACS is not just claiming that secondhand smoke exposure immediately causes hardening of the arteries and heart disease, they are instructing anti-smoking groups worldwide to make this statement to the public.

2) It comes in the context of instructing anti-smoking groups how to sensationalize their messages about the health effects of secondhand smoke. According to the strategy guide, an effective message:

• conveys the fact that even short periods of exposure are harmful.
• evokes an emotional reaction from the use of scientific terms.
• utilizes startling and memorable imagery.
• clearly states the risk of grave health conditions such as heart attacks and strokes.

Apparently, the fact that secondhand smoke does not immediately cause the grave health conditions of heart attacks and strokes is no deterrent to the ACS to publicly make such a statement and to encourage all anti-smoking groups to do the same.

Might I suggest that the ACS is in no position to be attacking others for misrepresenting scientific evidence on the health effects of secondhand smoke and for attacking others for alleged scientific misconduct? Might I suggest that the ACS first needs to examine its own misrepresentations and fallacious claims that it is making to the public?

As if this weren't enough, I offer the following additional exhibits:

Exhibit 2

"Short-term exposure to tobacco smoke has a measurable effect on the heart in nonsmokers. Just 30 minutes of exposure is enough to reduce blood flow to the heart."

The truth is that the very study which the ACS cites to support this statement actually showed that 30 minutes of exposure to secondhand smoke had no effect on basal coronary blood flow. In other words, it did not reduce blood flow to the heart. What brief secondhand smoke exposure reduces is coronary flow velocity reserve, which is a measure of blood flow under experimental (artificial) conditions. What it indicates clinically is that endothelial function has been affected, not that a person is suffering from a clinically meaningful reduction in blood flow to his or her coronary arteries.

Exhibit 3

"Nonsmokers who are exposed to secondhand smoke in the home have a 25 percent increased risk of heart disease. As is the case with active smoking, much of the cardiovascular effect is due to acute poisoning."

This one is a shame, because it started out on a roll. There is scientific evidence that nonsmokers who are chronically exposed to secondhands smoke in the home do have about a 25% increased risk of heart disease. But to state that this effect is due to acute poisoning is very misleading.

Acute poisoning implies that a brief exposure to secondhand smoke acutely causes clinically meaingful injury, harm, disease, or death. However, this is not the case. A person exposed briefly to secondhand smoke faces no clinically meaningful, adverse cardiovascular consequences that would be accurately described as having been poisoned.

Being in a closed garage for several minutes with a car engine on exposes a person to carbon monoxide which causes measurable decrements in oxygen-carrying capacity of the blood. But we wouldn't say that such a person has been acutely poisoned?

Eating tater tots day in and day out for years could cause heart disease, but we wouldn't say that eating tater tots on one occasion represents acute poisoining.

The statement is ridiculous, and is a gross misrepresentation of the science.

The rest of the story is that the American Cancer Society is hardly in a position to be leveling attacks against others for misrepresenting the scientific evidence regarding the health effects of secondhand smoke.

No comments: