Comparison of Apolipoprotein-B/Apolipoprotein-AI in Subjects With Versus Without the Metabolic Syndrome

Recent studies have suggested that the apolipoprotein-B (apo-B)/apolipoprotein-AI (apo-AI) ratio predicts cardiovascular risk better than any of the cholesterol indexes. The aim of the present study was to assess if the apo-B/apo-AI ratio is related to the metabolic syndrome and its components. Data were analyzed from 2,964 subjects (mean age 48 years; 1,516 men, 1,448 women) from the National Health and Nutrition Examination Survey III with apolipoprotein data who were evaluated for the metabolic syndrome and its components. The metabolic syndrome was defined according to the criteria of the National Cholesterol Education Program Adult Treatment Panel III and the International Diabetes Federation. The mean values of the apo-B/apo-AI ratio in subjects with and without the metabolic syndrome were compared. Overall, the median distribution of the apo-B/apo-AI ratio was significantly greater (p <0.0001) in subjects with the Adult Treatment Panel III metabolic syndrome (0.90) than without (0.69). The apo-B/apo-AI ratio was associated significantly with each of the metabolic syndrome components, in descending order of magnitude: low high-density lipoprotein cholesterol (odds ratio [OR] 5.7), high triglycerides (OR 4.7), high waist circumference (OR 2.6), high fasting glucose (OR 1.9), and high blood pressure (OR 1.5). The apo-B/apo-AI ratio was also different between subjects with and without the metabolic syndrome. Mean values of apo-B/apo-AI increased significantly as the numbers of metabolic syndrome components increased in men (p <0.0001) and women (p <0.0001). After excluding high-density lipoprotein cholesterol and triglycerides as criteria for the metabolic syndrome, the association between means persisted (analysis of variance p <0.0001) in men and women. Apo-B/apo-AI was significantly associated with the presence of the metabolic syndrome (OR 5.1, p <0.0001). In conclusion, the apo-B/apo-AI ratio is strongly associated with the presence of individual metabolic syndrome components, with the metabolic syndrome itself, and with insulin resistance. An elevated apo-B/apo-AI ratio may constitute an important feature of the metabolic syndrome and may provide an additional mechanism to explain the increased cardiovascular risk in subjects with this syndrome.