Relation of increased leptin concentrations to history of myocardial infarction and stroke in the United States population.

Leptin, an adipose tissue-derived hormone, has been linked to cardiovascular outcomes; however, data are limited in the United States population, especially women. To assess the association between leptin concentrations and history of myocardial infarction (MI) and stroke independently of traditional cardiovascular risk factors, we analyzed data from 6,239 subjects (mean age 47 years; 3,336 women) with measurements of serum leptin and full assessment of cardiovascular risk factors from the National Health and Nutrition Examination Survey (NHANES) III. Logistic regression was used to estimate the cross-sectional association of leptin concentrations (highest quartile versus lowest quartile) and history of MI, stroke, and the composite end point of MI or stroke (MI/stroke). Gender-specific models of leptin were adjusted for age, race, dyslipidemia, hypertension, diabetes, smoking, and obesity status. There were 212 men with MI/stroke (5.4%), 154 with MI (4.1%), and 82 with stroke (1.7%). There were 135 women with MI/stroke (2.6%), 74 with MI (1.5%), and 78 with stroke (1.4%). In multivariate analysis, high leptin level was significantly and independently associated with MI/stroke in men (odds ratio [OR] 2.41, 95% confidence interval [CI] 1.20 to 4.93) and women (OR 4.26, 95% CI 1.75 to 10.73); with MI in men (OR 3.16, 95% CI 1.40 to 7.37) and women (OR 3.96, 95% CI 1.29 to 12.72), and with stroke in women (OR 3.20, 95% CI 1.04 to 10.54) but not in men (OR 1.37, 95% CI 0.38 to 3.88). In conclusion, in the United States population, increased leptin concentrations are significantly associated with MI/stroke in men and women independently of traditional cardiovascular risk factors and obesity status.

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.