- Inflammation in COPD (IL-1, IL-6, TNF-α) impairs thyroid hormone regulation [217].- Smoking in COPD reduces thyroid hormone bioavailability [218].- Hypothyroidism decreases muscular strength, worsening COPD severity [218].- Hyperthyroidism induces hyperventilation, exacerbating COPD symptoms [218,220].- Hypercatabolic activity in hyperthyroidism weakens respiratory muscles, worsening COPD [218]. Here, IL6 is linked to hyperthyroidism.