FNDC5 and type 2 diabetes mellitus: Within the older adult cohort, neither HTN (raw median difference 0.05 ng/mL, 20% higher, 95% CI: −56% to 53%, p = 0.49) nor T2D (raw median difference 0.10 ng/mL, 17% higher, 95% CI: −57% to 74%, p = 0.60) were significantly associated with baseline irisin levels (Figure 2).