PPARD and type 2 diabetes mellitus: Peroxisome proliferator-activated receptors (PPAR) δ/β (hereafter PPARδ) (Ehrenborg and Krook, 2009; Phua et al., 2018) which is reduced in T2DM (Mensink et al., 2007; Shen et al., 2008), regulates skeletal muscle substrate utilization at the transcriptional level.