Smaller LDL particle size in women with polycystic ovary syndrome compared to controls

OBJECTIVE Women with polycystic ovary syndrome (PCOS) have an increased risk of cardiovascular disease, The contribution of lipid abnormalities to this higher risk, in particular atherogenic modifications of tory density lipoprotein (LDL) such as a shift towards smaller IDL, has not been properly explored. We aimed to examine LDL size variation in relation to androgens and other risk factors in women with PCOS. DESIGN Comparison of clinical and biochemical measurements in women with PCOS and women with normal ovarian function, of similar age and body mass index (BMI). PATIENTS Thirty-one women with PCOS and 27 controls were studied. Patients were recruited from the outpatient endocrine clinic. MEASUREMENTS Pasting total cholesterol, triglycerides (TG), high density lipoprotein (HDL), LDL, glucose, insulin, gonadotrophins, androgens, oestradiol: II OH progesterone and SHBG were measured, LDL particle diameter was calculated based on distance travelled in polyacrylamide native gels. Recumbent blood pressure was measured automatically. RESULTS LDL particle size appeared to be significantly smaller in hyperandrogenic PCOS as compared to regularly cycling women (P = 0006), independent of variations in lipid levels, SHBG was the only independent predictor of LDL size In this population, with a strong correlation, which persisted after adjustment for all confounding variables. CONCLUSIONS Our results suggest that androgen excess and mild insulin-resistance (both responsible for lower SHBG) may have an early modifying effect on low density lipoprotein size in polycystic ovary syndrome women. The denser pattern observed in polycystic ovary syndrome women could by itself constitute a higher cardiovascular risk, even in the absence of overt dyslipidaemia, and contribute to the excess risk of cardiovascular disease reported in this syndrome.