In chronic smokers who stop smoking, there is a rapid increase in the number of circulating cells that aid in the repair of the lining of blood vessels, researchers have found.

Therefore, “even short-term cessation of smoking may be an effective means to reduce cardiovascular risk,” they write in the medical journal Arteriosclerosis, Thrombosis, and Vascular Biology.

Researchers at the Nagoya University Graduate School of Medicine in Japan counted the number of circulating “endothelial progenitor” cells - stem cells that can become new cells lining arteries and veins - in 14 healthy nonsmokers and in 15 otherwise healthy age-matched smokers. The smokers were recruited from among people who wanted to quit smoking.

According to Dr. Takahisa Kondo and colleagues, the levels of progenitor cells were reduced in the chronic smokers compared with nonsmokers, and the more people smoked the fewer cells they had.

All of the smokers did quit, eight with nicotine patches and seven without. When they stopped smoking, levels of the circulating endothelial progenitor cells rose rapidly, the team found.

In lighter smokers - those who smoked less than 20 cigarettes per day - the magnitude of the recovery was greater than in smokers who smoked 20 or more cigarettes per day.

However, after a month, all the smokers had “unexpectedly” relapsed, and progenitor cells dropped nearly to their original low numbers.

“Because the decreased number of endothelial progenitor cells in peripheral circulation is a strong predictor for cardiovascular risk, our findings provide further evidence for the consensus that smoking cessation is to be highly recommended for the prevention of cardiovascular disease,” the researchers conclude.

SOURCE: Arteriosclerosis, Thrombosis, and Vascular Biology, August 2004.