This study found that the capsaicin cough sensitivity was increased in MetS patients independent of the presence OSAHS, manifesting as a decreased cough threshold accompanied by an increased percentage of neutrophils in induced sputum and an increased concentration of IL-8, SP, CGRP and pepsin in the supernatant; additionally, the GerdQ scores for MetS patients was significantly higher than those for the control group. Here, TFF2 is linked to obstructive sleep apnea syndrome.