Abstract 2093: Effect of Metabolic Syndrome on Lipoprotein Subclass Particle Size and Concentration in Postmenopausal Women
Metabolic syndrome is associated with dyslipidemia and increased cardiovascular risk. The extent to which metabolic syndrome is associated with alterations in lipoprotein subclasses in postmenopausal women has not been rigorously studied. Therefore, the aim of this study was to evaluate differences in lipoprotein subclasses in women with metabolic syndrome (MS) and those without MS among 216 healthy postmenopausal women (104 African-American and 112 White) who were participating in a randomized controlled trial of dietary soy. Data on the components of MS, lipoproteins, and lipoprotein subclasses were collected at baseline using standardized approaches. Lipoprotein subclasses were determined by nuclear magnetic resonance spectroscopy. MS was defined according to the criteria of the NCEP-ATP III clinical guidelines. Women were on average 57 years of age and 10 years postmenopausal. MS was present in 19% of the women (22% of AA women and 15 % of W women; p=0.19). As expected, compared to women without MS, women with MS had lower levels of high-density lipoprotein cholesterol (HDL) (62 ± 13 vs. 47 ± 7 mg/dL; p< 0.001) and higher levels triglycerides (102 ± 39 vs. 157 ± 65 mg/dL; p< 0.001) without significant differences in total cholesterol (224 ± 26 vs. 217 ± 24 mg/dL; p=0.09) or low-density lipoprotein (LDL) cholesterol (141 ± 23 vs. 138 ± 18 mg/dL; p=0.28). However, there were significant differences in major lipoprotein subclass measures. Compared to women without MS, women with MS had smaller mean LDL size (21.31 ± 0.54 vs. 20.60 ± 0.67 nm; p< 0.0001), higher LDL particle concentration (1352 ± 243 vs. 1569 ± 343 nmol/L; p=0.0004), and smaller mean HDL size (9.21 ± 0.39 vs. 8.83 ± 0.24 nm; p<0.0001), factors associated with higher risk for CVD. These significant differences persisted in multiple regression analyses adjusting for age, BMI, and race. Conventional lipid panels using only LDL cholesterol to assess the need for LDL-lowering therapy may not provide critical information needed for comprehensive assessment of the changes in LDL particle size and number in postmenopausal women with MS. Future research should explore whether lipoprotein subclass parameters can be used to manage risk more effectively in postmenopausal women with MS.