MSTN and chronic obstructive pulmonary disease: For instance, heart failure (Furihata et al., 2016) and chronic obstructive pulmonary disease (Ju & Chen, 2012) have been associated with higher, while cirrhosis has been associated with lower (Ruiz‐Margáin et al., 2023), serum myostatin levels than controls, and metformin has been reported to induce the expression of myostatin in muscle (Kang et al., 2022).