Clinical relevance of dual-energy X-ray absorptiometry (DXA) as a simultaneous evaluation of fatty liver disease and atherosclerosis in patients with type 2 diabetes

Background: Whole body dual-energy X-ray absorptiometry (DXA) can simultaneously measure both regional fat and non-fat mass. Android-to-gynoid (A/G) ratio measured by DXA has been reported to be associated with cardiovascular risks and visceral adiposity; however, little is known regarding its relationship with fatty liver disease and atherosclerosis among patients with diabetes. This study was designed to investigate the association of android and gynoid fat mass measured by DXA with fatty liver disease and atherosclerosis in patients with type 2 diabetes. Methods: This is a cross-sectional study of 259 patients with type 2 diabetes (mean age 64 +/- 13 years; 40.2 % female). Android and gynoid fat mass (kg) were measured by DXA. Skeletal muscle index (SMI) was calculated as appendicular non-fat mass (kg) divided by height (m(2)). Visceral fat area (VFA, cm(2)), subcutaneous fat area (SFA, cm(2)), and liver attenuation index (LAI) were assessed by abdominal computed tomography. Intima media thickness (IMT, mm) in common carotid arteries was determined by carotid ultrasonography. Results: A/G ratio was significantly correlated with VFA (r = 0.72, p < 0.001), SFA (r = 0.32, p < 0.001) and LAI (r = -0.26, p < 0.001). A/G ratio (standardized beta -0.223, p = 0.002) as well as VFA (standardized beta -0.226, p = 0.001) were significantly associated with LAI in the univariate model. A/G ratio remained to be significantly associated with LAI (standardized beta -0.224, p = 0.005) after adjusting for covariates including body mass index and transaminases. Among patients with low SMI (SMI < 7.0 in male and < 5.4 in female), A/G ratio was significantly associated with carotid IMT in the multivariate model (standardized beta 0.408, p = 0.014). Conclusions: DXA can be used to simultaneously estimate the risks for both fatty liver disease and atherosclerosis in patients with type 2 diabetes.