Elevated white blood cell levels, their association with risk factors and prognostic value for the Russian Federation population aged 55 years and older mortality

Objective. To assess the prognostic value of elevated peripheral white blood cell count regarding the risk of death in men and women aged 55 years and older, as well as the association of this indicator with cardiovascular diseases and their risk factors, based on data from a population-based study. Materials and methods. This analysis included data of 1.876 participants (898 men and 978 women) aged 55 years and older from the prospective cohort study «Stress Aging and Health in Russia» carried out between 2007 and 2011. The sex-specific fifth quintile values (7.5·109/L for men and 6.9·109/L for women) were used to define an elevated white blood cell count. During the observation period (median, 16 years), 212 participants with an elevated white blood cell count died from all causes, including 107 deaths from cardiovascular diseases (CVDs) and 46 from malignant neoplasms (MNs). Associations of white blood cell levels with variables were assessed using logistic regression, and the risk of all-cause, cardiovascular, and cancer mortality was evaluated using Cox proportional hazards models. Results. High white blood cell counts in men were associated with smoking, elevated blood pressure, obesity, and a history of myocardial infarction, whereas in women, they correlated with increased heart rate. Elevated white blood cell counts served as an independent predictor of all-cause mortality in both men (HR=1.36; 95% CI 1.11—1.67) and women (HR=1.31; 95% CI 1.03—1.66) after adjustment for age, CVDs, and their risk factors. Among women, elevated white blood cell counts are also associated with a 73% increased risk of MN mortality. Conclusion. An elevated peripheral white blood cell count is an independent predictor of all-cause mortality in both men and women aged 55 years and older. In the female cohort, high values of this indicator were also associated with an increased risk of MN mortality. Thus, white blood cell count can be used to stratify the risk of adverse outcomes in individuals aged 55 years and older.