Blood tests improve within two weeks of quitting smoking

Long-term smokers who quit may benefit from almost immediate improvements in blood platelet function, which could potentially reduce their risk of heart attacks or strokes caused by blood clots, according to a new study in the Feb. 15, 2005 issue of the Journal of the American College of Cardiology.

“To the best of our knowledge, we provided the first demonstration that smoking cessation rapidly improved two key measures of platelet function, platelet aggregability and intraplatelet redox imbalance,” said Hisao Ikeda, M.D., Ph.D., at the Kurume University School of Medicine in Kurume, Japan. “Thus, smoking cessation at any time is beneficial, even in chronic smokers; and it is anticipated that the effects will last as long as they don’t smoke.”

The researchers, including lead author Hirohiko Morita, M.D., studied platelet function in 27 men who were long-term smokers. Thirteen of the men resumed smoking after two weeks, while the remaining 14 men abstained from cigarettes for four weeks. In both groups, laboratory tests of platelets, which form the basis of blood clots, showed improved function within two weeks. The improvements disappeared soon after the men resumed smoking.

“Our findings may not only contribute to the understanding of pathophysiological links between smoking cessation and beneficial cardiovascular effects in acute coronary syndromes, but also strengthen the motivation for smokers, especially patients with atherothrombosis, to quit smoking,” Dr. Ikeda said.

Atherothrombosis is clotting in a blood vessel that is narrowed by the build-up of fatty plaque.

Dr. Ikeda noted that this study was done with only a small number of apparently healthy men.

“In the present study, because we studied young healthy subjects, caution is warranted when extrapolating present findings to patients with atherosclerosis or to those with multiple cardiovascular risk factors,” he said.

Stavros Konstantinides, M.D., at the University of Göttingen in Germany, who was not connected with this study, noted that the observation of a significant change in a small group of participants indicates that the effect of quitting smoking is strong.

“It was a smoking cessation period that was very short. It was just two weeks. Despite this short duration, they saw very beneficial effects on platelet function,” Dr. Konstantinides said. “If this effect was obvious and significant in 27 people, then, of course, one would expect that on a population basis, among many thousands of people, the effects could be dramatic with regard to the reduction of heart attack or stroke, for example.”

Dr. Konstantinides agreed with the study authors that evidence of rapid benefits may help motivate smokers to quit. However, he also noted that the study results should be confirmed by studies with a larger number of participants, especially those with cardiac disease, diabetes, hypertension and other ailments. He pointed out that the observation of a rapid effect on blood platelet function offers clues to how smoking damages blood vessels and the lungs.

“So there are, I think, very interesting issues and areas of research here,” Dr. Konstantinides said.

Wolfgang Muntean, M.D., at the Medical University of Graz in Austria, said this article contains a new message for the general public and especially smokers who thought that the benefits of quitting came only very slowly.

“While the detrimental effects of long time smoking on the cardiovascular system are well established and widely recognized, this paper for the first time demonstrates the effects of cessation of smoking in the short run. This might be very important for patients who already had experienced a cardiovascular event since cessation of smoking might help to prevent further events. Of course, at this time, the paper is only a laboratory investigation, but it might serve as a basis for appropriate clinical studies,” Dr. Muntean said.