Early signs of heart disease in young adult smokers may quickly dissipate soon after they kick the habit, a new study from Japan shows.

Smoking disrupts the normal function of the lining of arteries, known as the endothelium, which must contract and relax to regulate blood flow. This can promote the development of atherosclerosis or “hardening of the arteries” thereby increasing the risk of heart attack and stroke, according to the authors of the report in the Journal of Nuclear Medicine.

The researchers used positron emission tomography or “PET” imaging to examine the effects of smoking cessation on the blood flow in the coronary arteries of 15 men in their twenties and thirties who reported smoking an average of 20 cigarettes per day for more than 5 years and agreed to stop smoking for at least 6 months.

The men had no evidence of heart disease and, aside from smoking, no other risk factors for heart or blood vessel disease.

According to Dr. Nagara Tamaki of Hokkaido University in Sapporo and colleagues, after just one month without cigarettes, abnormal coronary artery function visible on PET scans had normalized. The improvement was preserved six months after the study subjects had quit smoking, the team reports.

The finding that young healthy smokers have impaired artery function but that it is reversible within a month after smoking cessation, supports the value of quitting smoking to ward off heart disease in young adults, the investigators say. They are eager to see if similar benefits can be obtained in middle-aged smokers.

SOURCE: The Journal of Nuclear Medicine, December 2006.