P1565Abdominal tissue echogenicity in postmenopausal women. A novel marker of morbid obesity?

Abstract

Obesity, defined as the excessive adipose tissue accumulation, is one of the most recognized risk factors associated with cardiovascular disease (CVD). Different adipose tissue depots, such as subcutaneous adipose tissue (SAT) or visceral adipose tissue (VAT) could have a more significant effect on CVD risk, compared to other depots. Menopause-related changes in sexual hormone status significantly affect adipose tissue accumulation in postmenopausal women, increasing the prevalence of overweight and obesity and thus CVD risk. Purpose(s): We sought to assess whether echogenicity of SAT and pre-peritoneal adipose tissue (pPAT), acquired by ultrasonography, correlate with metabolic characteristics, traditional risk factors and vascular markers of subclinical atherosclerosis in postmenopausal women without overt CVD. Method(s): Two hundred and forty-four non-diabetic white Caucasian post-menopausal women (mean age 56+/-6.53) were consecutively recruited. Biochemical indices and peripheral and aortic blood pressures were assessed. Intimamedia thickness (IMT) and the presence and number of atherosclerotic plaques in both carotid arteries were measured by high resolution ultrasonography. The average IMT was calculated from three paired segments, of both right and left common carotid artery, carotid bifurcation and internal carotid artery. Measurements of adipose tissue thickness and echogenicity were performed by simple ultrasonography below the level of xiphoid process. Result(s): The mean gray scale median (GSM) values of SAT echogenicity [median 41.2 (20.5-68.7)] were significantly higher than those of pPAT echogenicity [(median 25.5 (14.4-42.4)]. SAT echogenicity was positively correlated with SAT layer (p=0.002). A marginal correlation of SAT echogenicity with adiponectin was also observed (p=0.098). By multivariable linear regression analysis, mean SAT GSM was associated with common carotid IMT (p=0.003) and combined IMT (p=0.016), independently of age, prevalence of hypertension, dyslipidemia, smoking, HOMA, BMI, waist circumference and fat layer thickness. By multivariable logistic regression analysis, mean SAT GSM was an independent determinant of the presence of carotid and/or femoral plaques (adjusted OR=2.44 per 1-SD increase in mean SAT GSM, 95% CIs 1.55-3.93, p<0.001). ROC analysis revealed that a cut-off value equal to 47.8 for SAT GSM predicted with 62% sensitivity and 63% specificity the presence of arterial plaque (AUC=0.63, 95 CIs 0.546-0.714, p=0.002). Ordinal logistic analysis indicated that SAT GSM increased the odds for higher number of carotid, femoral or both arterial plaques (adjusted OR=2.32 per 1-SD increase in mean SAT GSM, 95% CIs 1.55-3.45, p<0.001). Conclusion(s): Ultrasound is an easily available method, accessible in daily clinical routine, and SAT echogenicity may serve as a simple marker to identify postmenopausal women that may be at an increased CVD risk irrespectively of traditional adiposity markers.