In addition, the serum MMP-9 and MMP-2 levels did not differ according to the Snoring, Tiredness, Observed apnea, high blood Pressure-Body mass index, Age, Neck circumference, and Gender (STOP-Bang) questionnaire scores (< 5 vs. ≥5; Supplementary Figure S3A and S3C) or ESS scores (< 10 vs. ≥10; Supplementary Figure S3B and S3D) in patients with OSA. This evidence concerns the gene MMP9 and obstructive sleep apnea syndrome.