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