White blood cell count, sex and age are major determinants of heterogeneity of platelet indices in an adult general population: results from the MOLI-SANI project

The understanding of non-genetic regulation of platelet indices--platelet count, plateletcrit, mean platelet volume, and platelet distribution width--is limited. The association of these platelet indices with a number of biochemical, environmental and clinical variables was studied in a large cohort of the general population. Men and women (n=18,097, 52% women, 56±12 years) were randomly recruited from various villages in Molise (Italy) in the framework of the population-based cohort study "Moli-sani". Hemochromocytometric analyses were performed using an automatic analyzer (Beckman Coulter, IL, Milan, Italy). Associations of platelet indices with dependent variables were investigated by multivariable linear regression analysis. Full models including age, sex, body mass index, blood pressure, smoking, menopause, white and red blood cell counts, mean corpuscular volume, D-dimers, C-reactive protein, high-density lipoproteins, low-density lipoproteins, triglycerides, glucose, and drug use explained 16%, 21%, 1.9% and 4.7% of platelet count, plateletcrit, mean platelet volume and platelet distribution width variability, respectively; variables that appeared to be most strongly associated were white blood cell count, age, and sex. Platelet count, mean platelet volume and plateletcrit were positively associated with white blood cell count, while platelet distribution width was negatively associated with white blood cell count. Platelet count and plateletcrit were also positively associated with C-reactive protein and D-dimers (P