INCREASED PLATELET ACTIVATION AND FIBRINOGEN IN ASIAN INDIANS - POTENTIAL IMPLICATIONS FOR CORONARY RISK

Aims To determine whether Asian Indians (Indians), a group known to ha ve high rates of coronary heart disease, have increased platelet activ ation and fibrinogen levels relative to white Americans of European or igin (whites). Methods and Results Forty healthy, non-smoking Indians, aged 25-45; were matched with 40 healthy whites for age (within 3 yea rs) and gender. Platelet activation was tested in blood exiting a blee ding time wound at 1 and 2 min post-incision (wound-induced activation ), as well as in venous blood stimulated in vitro with collagen, using whole blood flow cytometry. Other risk factors, including fibrinogen levels, family history of diabetes or coronary heart disease, fasting insulin and lipid levels, and Lp(a) were also assessed. Fibrinogen lev els were higher among Indians than whites, even after adjustment for g ender or family history of coronary heart disease (P<0.05). Indians ha d higher levels of wound-induced glycoprotein IIb/IIIa binding and pla telet secretion (P-selectin expression) than whites, with the greatest differences found when comparing the upper quintile of activation for each group (Ps<0.05). Indians with a family history of coronary heart disease (n=15) had higher levels of platelet secretion (wound-induced and in vitro) than Indians without a family history (Ps<0.05), while the relationship was reversed among whites. Platelet activation measur es were not consistently related to other coronary risk factors, while fibrinogen was related to triglyceride and insulin levels among India ns. Conclusion Indians have elevated fibrinogen and platelet activatio n levels relative to whites. These factors may contribute to the incre ased coronary risk observed in Indians.