Sunday, April 27, 2008

Second Hand Smoke

– Peggy Spencer, MD

UNM is considering becoming a completely smoke-free campus, indoors and out. Smoking is already prohibited inside the buildings and within 20 feet of the entrances. I’m a physician, not a politician, but, as a physician, I feel moved to offer information about the health effects of second-hand smoke and smoke-free workplaces.

In case you think this doesn’t apply to you, you should know that 15% of UNM students smoke cigarettes, according to a 2006 survey. Twenty percent of New Mexico adults smoke. FYI, that puts us roughly in the middle. Utah is the lowest, with just under 10% of adults smoking, and Kentucky is the highest at almost 30%. So even if you are a nonsmoker, chances are very good that you will be exposed to second hand smoke.

Second hand smoke (SHS) is made of sidestream smoke, from the burning end of the cigarette or cigar, plus exhaled mainstream smoke, from the smoker’s mouth and lungs. Everyone knows that cigarette smoke is harmful to the health of the smoker. Now we know that second hand smoke is harmful to the nonsmoker as well. In fact, SHS has higher concentrations of some toxins, due to cooler temperatures and other factors.

There are more than 250 toxic chemicals in SHS, including at least 50 that are known to cause cancer (carcinogens). SHS has been classified as a “known human carcinogen” by the Environmental Protection Agency. An example of a carcinogen in SHS is formaldehyde. Formaldehyde is used to preserve biology tissue specimens and to embalm dead bodies.

Besides carcinogens, SHS contains many toxic gases, like carbon monoxide, the deadly gas in car exhaust. Also chemicals, like hydrogen cyanide, which is used in chemical weapons, and heavy metals, like arsenic, which is an ingredient in pesticides.

The health effects of SHS on nonsmokers have been studied quite extensively, using household members and coworkers of smokers who smoke indoors. The degree of SHS exposure can actually be measured. There is a chemical named cotinine (an anagram of “nicotine”), C10H12N2O, that is a unique metabolite of nicotine. In other words, it doesn’t exist anywhere except in the blood, urine and saliva of people exposed to nicotine, including second hand smokers. More about this below.

Outdoor studies are difficult to do, as outdoor SHS is difficult to quantify, but I have no doubt the evidence is forthcoming. Meanwhile, a degree of extrapolation to outdoor environments is reasonable.

SHS is a respiratory irritant. An irritated respiratory system is more susceptible to colds, bronchitis, allergies and asthma. It is also, as I mentioned above, a carcinogen, estimated to cause 3,000 lung cancer deaths per year in nonsmokers.

Smoking increases heart disease, as you probably know. So does SHS. There are immediate and long term effects. The moment you inhale SHS, the platelets in your blood become “stickier,” and the lining of your blood vessels is damaged right away also. This increases the risk of a clot forming inside your blood vessels, which could translate into a heart attack or stroke, especially if you already have vessel disease.

Long term, SHS causes heart disease just like first hand smoke. In fact, a conservative estimate is that SHS causes 35,000 heart disease deaths a year in nonsmokers. That’s equivalent to the whole UNM student body.

Babies and children are especially susceptible to SHS. Low birth weight, Sudden Infant Death Syndrome (SIDS), and respiratory infections are some of the problems that can be caused by SHS in babies.

Another group that can be adversely affected by SHS is ex-smokers. For some, even a whiff of smoke in the air really triggers their craving and makes it tough to stay quit.

If you can smell smoke, you’re second hand smoking. Will one puff kill you? Doubtful. But if you already have asthma or heart disease, it could trigger an asthma attack or a heart attack. Far more likely than instant death is temporary irritation, of mood and respiratory system, and long term gradual buildup effects discussed above.

How much is too much? The surgeon general has issued a conclusion that there is NO SAFE LEVEL of second hand smoke. The only way to really protect nonsmokers from smoke is to have separate, indoor, isolated buildings for smokers. Called “smoking pavilions” or “butt huts,” these do exist in some places.

Naturally, I would be happy if nobody ever smoked again, for the sake of their health and everyone else’s. But smoking is a legal activity, and we can’t stop people from making legal behavior choices. Since smoking affects others, however, it becomes a public health issue. Over the years, measures to protect the public from SHS have broadened in scope, from smoke-free sections of rooms to whole.

Our neighbor Arizona was the first state to institute bans on smoking in public buildings. Most other states have followed suit. Federal measures have led to smoking bans on airplanes, federal buildings and facilities that provide federally funded services to children. New Zealand and Norway have laws that all workplaces must be smoke-free. In this country, some businesses such as Nike and Scott Paper now have 100% smoke-free campuses. Over 100 colleges and universities in the US are completely smoke-free as well.

Public health policy is only as good as the health outcome. It turns out, smoking bans actually help people quit, and that is good for their health. Their coworkers and household members benefit as well. Body fluid levels of cotinine, that nicotine metabolite, have fallen 70% overall in the last 15 years. However, there are still measurable levels of cotinine in 43% of nonsmokers in the US.

The healthiest way to deal with cigarette smoke is to avoid it. Don’t start smoking in the first place. If you smoke, quit. This is far easier said than done. Tobacco addiction is extremely tenacious. Most smokers who quit take a long time and several tries to get there. But it is possible. The good news for UNM students is that there is free help available to help you quit.

My sources for this article are the US Dept of Health and Human Services, the National Cancer Institute, the Centers for Disease Control, and the National Institutes of Health.

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