FABP4 and diabetes mellitus: Moreover, circulating FABP4 was obviously increased in Ab+FDR subjects (median 10.7 [IQR 5.8–14.0] vs. 5.0 [3.7–6.8] ng/mL; P < 0.001), and moderately elevated in Ab–FDR individuals (median 6.3 [IQR 4.8–10.6] vs. 5.3 [3.7–7.2] ng/mL; P < 0.01), suggesting that augmented FABP4 production occurs well before overt diabetes (Figure 1A).