FNDC5 and type 2 diabetes mellitus: Unlike irisin, betatrophin levels were 0.55‐fold lower in older adults with HTN or T2D compared to older adults without either condition (HTN: raw median difference −1.11 ng/mL, 55% lower, 95% CI: −67% to −8%, p = 0.02; T2D: raw median difference −1.37 ng/mL, 55% lower, 95% CI: −68% to −1%, p = 0.047) (Figure 2).