Secondhand Smoke: Damage in Mere Minutes

April 28, 2008 -- Just 30 minutes in a smoky room can cause profound blood vessel injury in healthy young adults, greatly increasing the risk of cardiovascular disease, according to a new study published in the May 6 issue of the Journal of the American College of Cardiology.

The findings add to the growing body of evidence that suggests that there is no risk-free level of secondhand smoke. Secondhand smoke, also called environmental tobacco smoke, contains an array of harmful chemicals, including nicotine, which have been shown to increase one’s risk for cardiovascular disease. Exposure to such smoke causes upwards of 50,000 heart disease deaths in adult nonsmokers every year in the United States, making it a major public health concern.  

Study author Christian Heiss, MD, currently affiliated with the University RWTH Aachen in Germany, and colleagues in California evaluated blood vessel function in healthy, young, nonsmoking adults after they were exposed to a half hour of secondhand smoke at levels commonly found in public smoking areas. The study participants also underwent similar evaluations after exposure to smoke-free air on a different day.

The researchers learned that in healthy nonsmokers, even brief exposure to secondhand smoke resulted in blood vessel dysfunction and interfered with the activity of endothelial progenitor cells (EPCs), which are believed to play a key role in repairing blood vessels. The damage to the EPCs appeared to last as long as a day.

"Taken together, these findings provide further evidence that even a very short period of passive smoke exposure has strong, persistent vascular consequences," the scientists write in the journal article.

Heiss' team is the first to describe the effect of secondhand smoke on EPCs in humans.

A decrease in the number and function of EPCs has been linked to cardiovascular risk factors, including chronic smoking, high blood pressure, and high cholesterol.

"These findings have significant public health implications and should raise further awareness of the negative side effects of even brief exposures to secondhand smoke," Heiss tells WebMD.  "Our results help explain why there is a big immediate drop in heart attacks when smoke-free laws are passed."

In a related editorial, David S. Celermajer, MD, a cardiologist with the Royal Prince Alfred Hospital in Sydney, Australia, writes that Heiss' current findings regarding the adverse effect of secondhand smoke on EPC activity, and not just their number, are worthy of much further investigation, adding that the team has shown that "where's there's smoke, there is indeed fire."