Tobacco use and urinary excretion of thromboxane A2 and prostacyclin metabolites in women stratified by age.

BACKGROUND: Activated platelets have been implicated in both acute thrombus formation and atherogenesis. Because smoking is a risk factor for cardiovascular disease in men and women and male smokers have biochemical evidence of increased platelet activation, we found it of interest to study whether smoking augments platelet activity in women as well. METHODS AND
RESULTS: Data on smoking habits and a urinary sample were obtained from 125 healthy female nonsmokers and an equal number of smokers, stratified by age in five groups from 18 to 59 years old. Urinary samples were analyzed with gas chromatography/mass spectrometry for the 2,3-dinormetabolites of thromboxane A2 (Tx-M), reflecting platelet activity, and prostacyclin (PGI-M), representing platelet/vessel wall interaction. Urinary Tx-M in smokers was higher than in nonsmokers (p < 0.001), increasing with the number of cigarettes smoked per day and with age. In nonsmokers, there was no difference in Tx-M between the age groups. Urinary PGI-M in smokers was higher than that in nonsmokers (p < 0.001) and decreased with age in nonsmokers but not in smokers. There was no difference in Tx-M between previous smokers and lifelong nonsmokers.
CONCLUSIONS: The elevated Tx-M in women who smoke cigarettes indicates an increased platelet activity that is dependent on smoking intensity. In parallel, PGI-M is augmented, suggesting that platelet/vessel wall interaction is stimulated. Quitting smoking is an effective means to restore platelet function. We propose that the observed increase in platelet activity in women who smoke cigarettes may be related to subsequent development of cardiovascular disease and that quitting smoking should be considered a high-priority medical target also in this sex.