Passive Smoking's Aggressive Side

Secondhand smoke exposure leads to continuing heart risks, a new study finds.


March 14, 2007 — -- There's nothing passive about passive smoking.

Also known as secondhand smoke or environmental tobacco smoke, passive smoking has been known for quite some time to be associated with a laundry list of serious health effects.

This includes heart disease, lung cancer, emphysema, asthma, upper respiratory infections, sudden infant death syndrome, worsening of diabetes and a number of other conditions.

Now, a new study has just uncovered one more risk: a second heart attack or serious heart event within a month after hospitalization for acute coronary syndrome.

Acute coronary syndrome is the newest term for current, unstable heart disease. It encompasses the spectrum ranging from severe and prolonged episodes of chest pain all the way up to a heart attack.

The new study, published in the March issue of the medical journal Heart, was carried out by Dr. Demosthenes Panagiotakos and colleagues at Harokopio University in Athens, Greece.

These researchers followed 2,172 consecutive patients admitted with acute coronary syndrome at six major hospitals in Greece. Their main goal was to see if secondhand smoke exposure influenced developing another episode of acute coronary syndrome during the month after their hospital discharge.

After adjusting for factors that can influence heart disease, such as age and cholesterol, the researchers found that secondhand smoke exposure increased the risk of a second episode of acute coronary syndrome overall by 61 percent.

Surprisingly, nonsmokers exposed to secondhand smoke did worse than the group as a whole -- their risk for a second heart event increased by 71 percent.

As could be predicted, diabetics exposed to secondhand smoke had the worst outcomes of all -- their risk increased by 150 percent, confirming the known dangerous heart effects of diabetes combined with tobacco exposure.

Almost one half of all serious heart disease events 30 days after these patients' discharge could be attributable to secondhand smoke.

The worst place to have been exposed to secondhand smoke? The workplace. The authors hypothesize that these patients had a second heart episode more often because of greater duration and intensity of exposure to environmental tobacco smoke at work.

Overall, nearly half of all patients reported some exposure to secondhand smoke -- either at home, at work, or other places.

Previous research suggests that, volume for volume, secondhand smoke may be more poisonous than "mainstream" smoke (e.g., smoking a cigarette). This is because the tar and other toxins in "sidestream" smoke do not pass through a filter, but directly expose people nearby.

Even though people exposed to secondhand smoke breathe in less tobacco smoke than a smoker does, over time the cumulative effects can be devastating.

Secondhand smoke damages the lining of the blood vessels, making them more susceptible to dangerous blockages. It also revs up the body's clot-making blood cells, called platelets, making them more likely to start a clot on a damaged blood vessel.

Add to this the worsened cholesterol that secondhand smoke produces, and you have an extremely hazardous condition; in these patients, acute coronary syndrome was virtually waiting to recur.

Research such as this study underscores the urgency many health advocates feel about reducing secondhand smoke exposure in public places.

According to the Centers for Disease Control and Prevention, exposure to secondhand smoke results in approximately 3,000 lung cancer deaths and 35,000 heart disease deaths in the United States each year.

Fortunately, policies establishing smoke-free public places are a very effective method for reducing exposure to secondhand smoke. For example, restricting smoking in public places decreases per capita cigarette consumption and increases smoking cessation rates.

It also increases the health of the public. One famous example occurred in Helena, Mont. This town prohibited smoking in all workplaces and public places in 2002.

Six months after this ordinance, the number of hospital admissions for heart attacks declined 40 percent, but then rebounded when the ordinance was suspended.

Though strict local laws are the most effective in reducing smoking in public places, an increasing number of states, possibly influenced by tobacco companies, have enacted "pre-emptive" smoking laws that forbid local laws from being more stringent than the lax statewide no-smoking laws.

Panagiotakos and colleagues acknowledge that their study was limited by the reliance on patients' recollection of exposure to secondhand smoke, as well as by the fact that the researchers did not chemically verify if the patients had actually been exposed.

Nonetheless, the authors conclude: "Our findings add to the current scientific knowledge by showing that the exposure to secondhand smoke substantially increases the risk of short-term recurrent events in hospitalized patients for acute coronary syndrome."

Dr. John Spangler is director of tobacco intervention programs and professor of family medicine at Wake Forest University School of Medicine.

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