Size matters: HDL particle populations and the risk of infection

Low levels of high-density lipoprotein (HDL) cholesterol are a risk factor for infection and hospitalization for infectious disease. Recent research indicates that low levels of specific sizes of HDL particles are responsible for this risk. HDL is known to have a role in the immune system, regulating signal transduction by Toll-like receptors and responding to inflammation. Clinical studies have shown an association between HDL cholesterol levels and host defence mechanisms. A Mendelian randomization analysis found a causal association between low HDL cholesterol levels and an increased risk of hospitalization for infectious disease. The study also suggests HDL is the primary risk factor for the observed positive association with triglyceride levels.