Marrow adiposity as an indicator for insulin resistance in postmenopausal women with newly diagnosed type 2 diabetes – an investigation by chemical shift-encoded water-fat MRI

Abstract

BackgroundMarrow fat accumulates in diabetic conditions but remains elusive. The published works on the relationships between marrow fat phenotypes and glucose homeostasis are controversial. PurposeTo detect the association of insulin resistance with marrow adiposity in postmenopausal women with newly diagnosed type 2 diabetes (T2D) using chemical shift-encoded water–fat MRI. MethodsWe measured vertebral proton density fat fraction (PDFF) by 3T-MRI in 75 newly diagnosed T2D and 20 nondiabetic postmenopausal women. Bone mineral density (BMD), whole body fat mass and lean mass were determined by dual-energy X-ray absorptiometry. Insulin sensitivity was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). ResultsLumbar spine PDFF was higher in women with T2D (65.9 ± 6.8%) than those without diabetes (59.5 ± 6.1%, P = 0.009). There was a consistent inverse association between the vertebral PDFF and BMD. PDFF had a positive association with glycated hemoglobin and HOMA-IR but not with fasting plasma glucose and insulin. PDFF was significantly increased, and BMD was decreased in a linear trend from the lowest (<1.90) to highest (≥2.77) HOMA-IR quartile. Multivariate linear regression analyses revealed a positive association between log-transformed HOMA-IR and PDFF after adjustment for multiple covariates (ß = 0.382, P < 0.001). The positive association of HOMA-IR with PDFF remained robust when total body lean mass and fat mass, BMD was entered into the multivariate regression model, respectively (ß = 0.293 and ß = 0.251, respectively; all P <0.05). ConclusionsElevated HOMA-IR was linked to higher marrow fat fraction in postmenopausal women with newly diagnosed T2D independently of body compositions.