Atherogenic lipoprotein phenotype and low-density lipoproteins size and subclasses in women with polycystic ovary syndrome

Context: An altered lipid profile is common in polycystic ovary syndrome ( PCOS) and is usually characterized by increased triglycerides and low high-density lipoprotein (HDL)-cholesterol levels. In the general population, these alterations are often associated with the increase of small low-density lipoproteins ( LDLs) in the so-called "atherogenic lipoprotein phenotype" ( ALP) that determines a further increase of cardiovascular risk. In this study, we evaluated the presence of ALP in the plasma of women with PCOS. Setting: Measurements and analysis of LDL size were performed at the Clinic of Endocrinology, Diabetes, and Clinical Nutrition, University Hospital, Zurich. PCOS patients were recruited at the Department of Clinical Medicine, University of Palermo, and the Department of Obstetrics and Gynecology, University of Pisa. Patients: Thirty patients with PCOS ( hyperandrogenism and chronic anovulation) and 24 matched controls were studied. Anthropometric data, blood glucose, serum insulin lipid profile, and LDL size and subclasses were evaluated. Results: Compared with controls, patients with PCOS had higher plasma concentrations of insulin and triglycerides and lower HDL-cholesterol concentrations but no differences in LDL-cholesterol and total cholesterol. Patients with PCOS had smaller LDL size due to a reduction in LDL subclass I, with a concomitant increase in LDL subclasses III and IV. Fourteen PCOS patients had an increase of smaller LDL particles, and it represented the second most common lipid alteration after decrease in HDL- cholesterol. However, because in this PCOS population hypertriglyceridemia was only present in two patients, complete ALP was relatively uncommon. Conclusions: Increase of type III or type IV LDL subclasses is a common finding in PCOS and represents the second most common lipid alteration after HDL- cholesterol decrease. However, in our PCOS patients, because of relatively low triglyceride levels, complete ALP is uncommon.