Peripheral leukocyte counts vary with lipid levels, age and sex in subjects from the healthy population

Background and aims: Disorders in blood lipid metabolism and leukocyte-mediated inflammation are considered the main mechanisms of the pathogenesis of atherosclerosis. This study aims to show whether and how peripheral leukocyte counts are associated with serum lipid levels. Methods: This is a cross-sectional study of 175,079 subjects from the healthy population. Results: Age and sex are two key factors dictating the relationship between peripheral leukocyte counts and serum lipid levels. The log-transformed level of triglycerides (LnTG) was positively associated with all leukocyte counts in males except monocyte count in younger subjects. LnTG was positively associated with total leukocyte count in females regardless of age, and it was positively associated with lymphocyte and monocyte counts and neutrophil count only in elderly and young women, respectively. Total cholesterol levels were positively associated with total leukocyte, neutrophil and lymphocyte counts only in young males and with lymphocyte counts only in elderly women. LDL-C was negatively associated with monocyte count in males regardless of age; by contrast, it was positively associated with total leukocyte and lymphocyte counts in females regardless of age range and neutrophil and LnEosinophil counts only in young women. HDL-C was negatively associated with total leukocyte, lymphocyte and monocyte counts in both young men and young women; was negatively associated with monocyte count in elderly men and women; and was negatively associated with LnEosinophil count only in older men. Conclusions: Peripheral leukocyte counts are extensively associated with serum lipid levels, with patterns differing by sex, age, lipid and leukocyte subset.