Associations of visceral and abdominal subcutaneous adipose tissue with markers of cardiac and metabolic risk in obese adults.

OBJECTIVE: Visceral (VAT) and abdominal subcutaneous (SAT) adipose tissues contribute to obesity but may have different metabolic and atherosclerosis risk profiles. We sought to determine the associations of abdominal VAT and SAT mass with markers of cardiac and metabolic risk in a large, multiethnic, population-based cohort of obese adults. DESIGN AND METHODS: Among obese participants in the Dallas Heart Study, we examined the cross-sectional associations of abdominal VAT and SAT mass, assessed by magnetic resonance imaging (MRI) and indexed to body surface area (BSA), with circulating biomarkers of insulin resistance, dyslipidemia, and inflammation (n = 942); and with aortic plaque and liver fat by MRI and coronary calcium by computed tomography (n = 1200). Associations of VAT/BSA and SAT/BSA were examined after adjustment for age, sex, race, menopause, and body mass index. RESULTS: In multivariable models, VAT significantly associated with the homeostasis model assessment of insulin resistance (HOMA-IR), lower adiponectin, smaller LDL and HDL particle size, larger VLDL size, and increased LDL and VLDL particle number (p < 0.001 for each). VAT also associated with prevalent diabetes, metabolic syndrome, hepatic steatosis, and aortic plaque (p < 0.001 for each). VAT independently associated with C-reactive protein but not with any other inflammatory biomarkers tested. In contrast, SAT associated with leptin and inflammatory biomarkers, but not with dyslipidemia or atherosclerosis. Associations between SAT and HOMA-IR were significant in univariable analyses but attenuated after multivariable adjustment. CONCLUSION: VAT associated with an adverse metabolic, dyslipidemic, and atherogenic obesity phenotype. In contrast, SAT demonstrated a more benign phenotype, characterized by modest associations with inflammatory biomarkers and leptin, but no independent association with dyslipidemia, insulin resistance, or atherosclerosis in obese individuals. These findings suggest that abdominal fat distribution defines distinct obesity sub-phenotypes with heterogeneous metabolic and atherosclerosis risk.

Addition of highly sensitive troponin T and N-terminal pro-B-type natriuretic peptide to electrocardiography for detection of left ventricular hypertrophy: results from the Dallas Heart Study.

Left ventricular hypertrophy (LVH) is an independent, modifiable risk factor for cardiovascular disease. However, current screening strategies are limited. In 2478 participants without clinical disease from the Dallas Heart Study, we evaluated a multimarker screening strategy that complements electrocardiographic (ECG) criteria for LVH with 2 biomarkers, amino-terminal pro-B-type natriuretic peptide and highly sensitive cardiac troponin T. An integer LVH risk score from 0 to 3 was determined as the sum of the following: (1) LVH by Sokolow-Lyon ECG; (2) amino-terminal pro-B-type natriuretic peptide in the highest sex-specific quartile; and (3) detectable cardiac troponin T. Cardiac magnetic resonance imaging-determined LVH served as the primary outcome. The probability of LVH increased from 2% with an LVH risk score of 0 to 50% with a score of 3 (P<0.001). Sokolow-Lyon ECG afforded low sensitivity (26% [95% confidence interval {CI}, 17-32%]) and high specificity (96% [95% CI, 95-97%]), whereas a risk score ≥2 offered higher sensitivity (44% [95% CI, 34-51%]) with good specificity (90% [95% CI, 89-93%]) and a score threshold of 1 offered reasonable sensitivity (76% [95% CI, 67-83%]) with lower specificity (55% [95% CI, 53-61%]) and high negative predictive value (98% [95% CI, 97-98%]). Area under the receiver operator characteristic curve improved from 0.760 (95% CI, 0.716-0.804) for ECG alone to 0.798 (95% CI, 0.754-0.842) for the LVH risk score (P=0.0012), consistent with modest improvement in overall discrimination. Better screening for LVH may be achieved by combining simple tests, which collectively provide additional information compared with ECG alone. Further studies are needed to evaluate the impact and cost-effectiveness of a multimarker screening strategy.