['Increasing plasma glucose levels are associated with increasing risk of vascular disease. We tested the hypothesis that there is a glycaemia-mediated impairment of reverse cholesterol transport (RCT). We studied the influence of plasma glucose on expression and function of a key mediator in RCT, the ATP binding cassette transporter-A1 (ABCA1) and expression of its regulators, liver X receptor-α (LXRα) and peroxisome proliferator-activated receptor-γ (PPARγ).', 'Leukocyte ABCA1, LXRα and PPARγ expression was measured by polymerase chain reaction in 63 men with varying degrees of glucose homeostasis. ABCA1 protein concentrations were measured in leukocytes. In a sub-group of 25 men, ABCA1 function was quantified as apolipoprotein-A1-mediated cholesterol efflux from 2-3 week cultured skin fibroblasts. Leukocyte ABCA1 expression correlated negatively with circulating HbA1c and glucose (rho\u200a=\u200a-0.41, p<0.001; rho\u200a=\u200a-0.34, p\u200a=\u200a0.006 respectively) and was reduced in Type 2 diabetes (T2DM) (p\u200a=\u200a0.03). Leukocyte ABCA1 protein was lower in T2DM (p\u200a=\u200a0.03) and positively associated with plasma HDL cholesterol (HDL-C) (rho\u200a=\u200a0.34, p\u200a=\u200a0.02). Apolipoprotein-A1-mediated cholesterol efflux correlated negatively with fasting glucose (rho\u200a=\u200a-0.50, p\u200a=\u200a0.01) and positively with HDL-C (rho\u200a=\u200a0.41, p\u200a=\u200a0.02). It was reduced in T2DM compared with controls (p\u200a=\u200a0.04). These relationships were independent of LXRα and PPARγ expression.'] Is type 2 diabetes associated with reduced ATP-binding cassette transporter A1 gene expression , protein and function?