The association between lipid levels and leukocyte count: A cross-sectional and longitudinal analysis of three large cohorts

Background: Relationships between dyslipidaemia and leukocyte counts have been investigated in several studies, demonstrating limited evidence of associations in humans. As such, studying a diverse range of cohorts will ensure evidence is robust. This study focused on investigating cross-sectional and longitudinal relationships in three large-scale cohorts.Methods: The cross-sectional analysis included a total of 27,566 participants with valid data on lipid measures and leukocyte counts from three study cohorts: National Health and Nutrition Survey (NHANES), Korean National Health and Nutrition Survey (KNHANES) and Treating to New Targets (TNT) trial. The longitudinal analysis included 9323 participants with valid data on lipid measures and leukocyte counts at baseline and one year with statin treatment. Associations between lipid levels and leukocyte counts were analysed by multivariable linear regression and adjusted for basic demographic and cardiovascular risk factors.Results: Cross-sectional data from NHANES demonstrated the association of lower high-density lipoprotein (HDL) cholesterol and higher triglycerides with higher leukocyte count (0.9% lower and 0.3% higher count per 10 mg/ dL increase in HDL cholesterol and triglycerides respectively, both p < 0.001). Similar trends were found in TNT trial (both p < 0.001), but not in KNHANES. In the TNT trial, 10 mg/dL increase in triglycerides over one year was also associated with a 0.09 x 10(3)/mu L increase in leukocyte count over the same period.Conclusions: The findings of this study are consistent with those of previous human studies, supporting weak yet noteworthy associations between dyslipidaemia and leukocytosis.