Platelet Aggregation in Cigarette Smokers: A Meta-Analysis

The relationship between platelet aggregation and cigarette smoking was examined by analyzing 150 separate platelet aggregation results taken from 56 studies. Nonparametric statistical analysis and meta-analysis suggest that smoking has two effects on platelets: a significant acute potentiation of platelet activation occurring shortly after smoking a cigarette, and a chronic, longer term desensitization of the cell to activating agents occurring during the period between cigarettes. The acute potentiation and the chronic desensitization are hypothesized to result from the nicotine-induced release of epinephrine. The clinical relevance of the increase in platelet aggregability observed on an acute basis after cigarette smoke inhalation is not known. While smokers reportedly experience transient increases in platelet aggregability and adhesiveness with the consumption of an initial cigarette, the possibility exists that the first few cigarettes consumed each day give the greatest response.