Differential impact of serum glucose, triglycerides, and high-density lipoprotein cholesterol on cardiovascular risk factor burden in nondiabetic, obese African American women: implications for the prevalence of metabolic syndrome

Metabolic syndrome (MetS) as defined by the Adult Treatment Panel (ATP) III criteria includes 3 metabolic parameters: serum glucose, triglycerides, and high-density lipoprotein cholesterol (HDL-C) measurements. However, the impact of each of the 3 metabolic parameters on cardiovascular disease (CVD) risk in African American women (AAW) is unknown. Therefore, we investigated CVD risk clusters associated with each of the 3 metabolic components of MetS in adult nondiabetic, overweight/obese AAW. We studied the clinical and metabolic CVD risk factors of 258 AAW (mean age, 42.4 +/- 8.4 years; mean body mass index, 33.4 +/- 8.0 (kg/m(2)). Fasting serum insulin, glucose, and C-peptide levels were obtained in each subject. Waist circumference and systolic and diastolic blood pressure were measured. Insulin sensitivity (Bergman minimal model method) and insulin resistance (homeostasis model assessment) were calculated. We examined the prevalence of MetS and its components associated with each of the 3 metabolic components (ie, serum glucose, HDL-C, and triglycerides) of the MetS as defined by ATP III. Worsening of any of the 3 metabolic parameters was associated with increasing waist circumference but not with age and body mass index nor with insulin, C-peptide, homeostasis model assessment of insulin resistance, and insulin sensitivity. As a group, the prevalence of MetS was 35.5% in our AAW. The prevalence of MetS increased 3-fold from first to third tertiles of serum glucose (14.1% and 42.3%, respectively). Worsening of serum HDL-C from tertiles 3 to 1 was associated with significant increases in the prevalence of MetS (1.2% vs 42.3%, respectively). Comparing first with third tertile of triglycerides, there was no significant increase in MetS in our AAW (7% vs 17%). Contrasting the 3 metabolic components, the prevalence of MetS was higher in the third tertile of glucose (43.2%) and first tertile of HDL-C (42.3%) and least with the third tertile of triglycerides (17%). In summary, each of the metabolic components of MetS was associated with different degrees of the clustering of CVD risk factors in AAW. We found that alterations in serum glucose and HDL-C were more predictive of MetS, each yielding approximately 40% of the prevalence of MetS in our nondiabetic, obese AAW. We found that triglycerides had the least impact on MetS in our AAW. We propose (1) that the 3 metabolic parameters for MetS defined by ATP III should be weighted differently with respect to their potential for CVD risks and perhaps outcomes and (2) that nondiabetic AAW in our third tertile of serum glucose (>100 mg/dL) and/or first tertile of HDL-C (<40 mg/dL) should be targeted for screening for MetS. (C) 2010 Elsevier Inc. All rights reserved.