The association of plasma lipids with white blood cell counts: Results from the Multi-Ethnic Study of Atherosclerosis

Abstract

Previous studies have demonstrated that elevated cholesterol results in increased white blood cell counts in mouse models. However, there is insufficient evidence to support this in humans. The objective of the study was to investigate the relationship of plasma lipids with white blood cell counts (basophils, eosinophils, monocytes, neutrophils and lymphocytes) in the Multi-Ethnic Study of Atherosclerosis. The analysis included 2873 Multi-Ethnic Study of Atherosclerosis participants witha complete white blood count and differential analysis. The cross-sectional association of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels with different white blood cell counts was analyzed by multivariable linear regression. After adjusting for sociodemographic and confounding factors including red blood cell counts, platelet counts, use of lipid-lowering medication, cardiovascular disease risk factors and other lipid measures, and multiple testing correction, a one-standard deviation increment in total cholesterol and low-density lipoprotein cholesterol was associated with 2.8% and 2.3% lower total white blood cell counts, 3.7% and 3.0% lower monocyte counts, and 3.4% and 2.7% lower neutrophil counts (all P<.01). The same increment in logarithm-transformed triglyceride levels was associated with 2.3% higher total white blood cell counts and 4.5% higher lymphocyte counts (both P<.001). Similar results were obtained after excluding participants taking lipid-lowering medication. A one-standard deviation increase in high-density lipoprotein cholesterol was associated with a 1.5% lower white blood cell count (P=.018) but was not significantly associated with changes in any individual cell type. While significant associations were observed between plasma lipid levels and white blood cell populations, the heterogeneous and modest nature of these relationships makes it hard to support the hypothesis that lipids are in the causal pathway for leukogenesis in humans.