Friday, December 01, 2006

Anti-Smoking Group Claims that Secondhand Smoke Causes Reduced Oxygen Flow in Children Comparable to Cyanotic Heart Disease

An anti-smoking group - Physicians for a Smoke-Free Canada - is claiming that exposure to secondhand smoke can cause children to turn blue.

I'm not kidding. The group states that secondhand smoke exposure among children can cause them to suffer reduced oxygen delivery to their body, similar as to what might occur with cyanotic heart disease.

For those who are not familiar with it, cyanotic heart disease is a condition, usually caused by a congenital abnormality of the heart in which oxygenated and non-oxygenated blood mix in the heart, causing the oxygen level of the blood to be very low, and these children literally can turn blue. Physicians for a Smoke-Free Canada is claiming that secondhand smoke exposure causes the same thing.

According to its fact sheet on the health impacts of secondhand smoke on children's health: "ETS is causally linked with a number of adverse health effects in children (under 18), including ... reduced oxygen flow to tissues, comparable to children with anemia, cyanotic heart disease or chronic lung disease."

The Rest of the Story

I've seen it happen all the time. Children are playing in their homes; their parents are smoking in the other room and then all of the sudden, the kids turn blue. This cyanosis - which is typically seen in severe congenital abnormalities such as cyanotic heart disease - is apparently causally linked to secondhand smoke exposure, according to Physicians for a Smoke-Free Canada.

While it may sound absurd, it is apparently not so absurd to stop a prominent anti-smoking group from publicly making the claim on its web site.

Unfortunately (actually, quite fortunately), this is a completely fallacious claim. There is no evidence that secondhand smoke exposure reduces oxygen flow to tissues comparable to the cyanosis seen in children with cyanotic heart disease.

To be honest with you, if it were shown to be true that secondhand smoke could cause cyanosis in children, I would be the first to immediately demand a prohibition of all smoking. Such extreme health effects, in which kids become blue from tobacco smoke, could simply not be tolerated.

If the effects of secondhand smoke on children were actually as severe as the effects of cyanotic heart disease, I don't think there would be any justification for Physicians for a Smoke-Free Canada not to call for the immediate prohibition of the sale of tobacco products in Canada (instead, this group has called for the government to take over the sale of these products, so that the government, rather than the tobacco companies, profit from killing people).

Readers should be rest assured that secondhand smoke exposure does not cause kids to become blue. Physicians for a Smoke-Free Canada appears to be pulling this one out of the woodwork. Frankly, I have no idea where they came up with this one.

The group does provide a scientific citation to support its statement: a review article by Dr. Jon Samet on the health effects of secondhand smoke among children. However, nowhere in the article does it mention that secondhand smoke has been found to be a cause of cyanosis among children.

It is true that secondhand smoke may have some effects on oxygen transport. This is particularly true in the fetus when the mother smokes. But among children, these effects are not known to even cause hypoxemia (reduced oxygen levels), much less cyanosis (turning blue). The effect is essentially a sub-clinical one.

To state that any reduced oxygen transport caused by secondhand smoke exposure is comparable to the reduced oxygen levels (caused by mixing oxygenated and non-oxygenated blood) in cyanotic heart disease is more than just an exaggeration; it's a blatant inaccuracy.

Now I should mention that secondhand smoke can cause asthma and pneumonia, both of which, if severe enough, could result in cyanosis. But this is not what the fact sheet is talking about. Separately, it mentions both pneumonia and asthma as health effects of secondhand smoke exposure. The fact sheet is clearly implying that secondhand smoke is a direct cause of reduced oxygen delivery and cyanosis.

I can think of no reason why this group would make such a claim other than to try to scare people and increase the emotional appeal of the message. But the shame of this all is that it isn't even necessary. The group already points out that secondhand smoke exposure can cause upper respiratory tract infections, lower respiratory tract infections (such as pneumonia), middle ear infections, asthma, and asthma exacerbation. Why do they need to distort and misrepresent the science and mislead people into thinking that it also causes cyanosis? Aren't these other health effects bad enough?

As I'm rapidly learning, no - they are not bad enough. We apparently need to sensationalize the science - the truth is no longer enough. It's not enough to state that chronic exposure to secondhand smoke can cause lung cancer and heart disease. Now we have to state that 30 minutes of exposure can cause these outcomes. And I guess it's not enough to state that secondhand smoke exposure can cause upper respiratory tract infections, otitis media, pneumonia, and asthma. Now we have to state that it can cause a child to turn blue.

It will be interesting to see whether the group corrects this claim. It will also be interesting to see whether any other anti-smoking groups will acknowledge that the claim is fallacious.

Just when I thought we had reached the lowest level of scientific quality - claiming that 30 seconds of secondhand smoke exposure causes coronary artery dysfunction equal to that seen in active smokers - I was shown to be wrong. Secondhand smoke exposure causes children to turn blue. That one is going to be hard to beat.

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