Lower platelet count in healthy centenarians correlates with dispersion of the QT interval

Centenarians display a lower incidence of vascular ischemic events. A high platelet count and increased QT dispersion (QTd) represents a risk factor for cardiovascular events. The aim of this study was to evaluate platelet count and QTd in healthy centenarians and to establish correlations between these two indices. 16 healthy centenarians (4 males, 12 females, range 100-105 years) living in a municipality of Eastern Sicily, and 40 healthy control subjects, divided into two groups: group A (N=20), age range 45-65 years, 7 males, 13 females; and group B (N=20), range 65-85 years, 6 males, 14 females, were examined. Platelets were counted using a blood analyzer and QTd was measured in standard 12-lead electrocardiograms. Differences in platelet count were assessed by one-way analysis of variance (ANOVA) and the Bonferroni test. Correlation coefficients between platelet count and QTd were calculated with the Spearman rank test. Centenarians showed a lower platelet count compared with controls, which was significant with respect to older controls, group B (p