Platelet counts and platelet activation markers in obese subjects.

OBJECTIVE: In this work we studied the correlation between platelet count, platelet activation, and systemic inflammation in overweight, obese, and morbidly obese individuals. METHODS AND SUBJECTS: A total of 6319 individuals participated in the study. Complete blood counts, high sensitivity C-reactive protein (hs-CRP) serum levels, and body mass index (BMI) were measured during routine checkups. Platelet activation markers were studied among 30 obese (BMI = 41 +/- 8 kg/m(2)) and 35 nonobese (BMI = 24 +/- 3 kg/m(2)) individuals. Platelet activation status was evaluated by flow cytometry using specific antibodies against the activated platelet membrane glycoprotein IIb/IIIa, p-selectin (CD-62 p), and binding of Annexin-V to platelet anionic phospholipids. RESULTS: Overweight, obese, and morbidly obese females had significantly elevated platelet counts ( P < .0001) compared with normal-weight females. No significant elevation of platelet counts was observed in the male subgroups. A significant age adjusted correlation between BMI and platelet counts ( P < .0001) was found among females. This correlation was attenuated (P = .001) after adjustment for hs-CRP concentrations. The flow cytometry analysis of platelets showed no significant differences in activation marker expression between nonobese and obese individuals. DISCUSSION: Obesity may be associated with elevated platelet counts in females with chronic inflammation. Obesity is not associated with increased platelet activation.