Summary
Platelet aggregation to collagen, and productions of 6-ketoprostagltandin-F1-alpha and tromboxane 82 during aggregation were measured after an overnight fast,
involving both food and cigarettros, in 19 clinically healthy habitual smokers (10
or more cigarettes/day) and 23 non-smokers receiving the same diet. The subjects (all
males; ages == 21-30 years) were residents of a school hostel. Mean platelet aggregation
was significantly lower in smokerr; than non-smokers (23.2 ohms vs 3L.5 ohmS, p <
0.005). Non-smokers had significantly higher mean concentration of 6-keto-prostaglandin-F1-alpha than smokers (109.8 pmol/1 vs 92.3 pmol/1, p < 0.05). The level of thromboxane
B2 did not differ significerntly between the two groups. These observations suggest
that the role of smokittg as a risk factor for ischaemic heart disease is unlikely
to be related to a direct enhancement of aggregation. On the contrary, the observations
seem to suggest that habitual smoking may directly reduce platelet aggregability.
