For nonsmokers, exposure to low levels of secondhand smoke for just 30 minutes can cause significant damage to the lining of their blood vessels, the results of a new study indicate.

The findings could have major public health implications because this type of damage has been associated with atherosclerosis (hardening of the arteries), which can lead to heart attack or stroke.

"Breathing in very low levels of secondhand smoke -- the same amount many people and children would encounter out and about in the community -- appears to impair one's vascular function after just 30 minutes of exposure," the study's lead investigator, Dr. Paul Frey, of the division of cardiology at San Francisco General Hospital, said in a news release from the American College of Cardiology. ...