Secondhand Smoke Hurts Heart Like Smoking

May 23, 2005 -- The heart just doesn't like smoking, no matter who's doing it.

That's the take-home message of a review of research about secondhand smoke's cardiac toll. The report -- published in Circulation -- documents a long list of heart hazards from secondhand smoke.

Wisp for wisp, secondhand smoke's heart damage often rivals that of active smoking, and even a little exposure may have an impact, says the review by Joaquin Barnoya, MD, MPH, and colleagues.

Secondhand smoke's heart effects are "rapid and large," like those of air pollution, say Barnoya and colleagues. How large? On average, the heart effects of even brief secondhand smoke exposure are about 80% to 90% as large as that from chronic active smoking, they say.

An 'Exquisitely Sensitive' Heart

Smokers' hearts bear the biggest burden. They are exposed to more toxins from smoking than people who only get secondhand smoke. But that doesn't appear to make much difference to the heart, says the review.

Passive smoke has a much larger effect on the heart than would be expected from a comparison of the dose of toxins, they write.

Despite the fact that the dose of smoke delivered to active smokers is 100 times or more than that delivered to a passive smoker, the risk of heart disease for smokers is more than two-thirds higher compared with a third higher for passive smokers, says the review.

The cardiovascular system may be "exquisitely sensitive to the toxins in secondhand smoke," write the researchers.

Growing Evidence of the Dangers of Secondhand Smoke

The researchers say that the effects of passive smoke are numerous and interact with each other, increasing the risk of heart disease. Here are some of the heart hazards that the review linked to secondhand smoke.

• Increased blood clotting ability
• Increased blood vessel wall abnormalities
• Higher risk of atherosclerosis (hardening of the arteries)
• Lower levels of HDL "good" cholesterol (even in children)
• More buildup of LDL "bad" cholesterol in artery walls
• Higher blood levels of markers of inflammation that are inked to heart disease and blood vessel wall plaque buildup
• Increased source of cell-damaging free radicals
• Lower levels of antioxidants, which fight free radicals

Evidence about secondhand smoke's heart dangers has been growing since the mid-1980s, say the researchers.

"Secondhand smoke increases the risk of heart disease by [about] 30%, accounting for at least 35,000 deaths annually in the United States," they write.