LEP and obstructive sleep apnea syndrome: As would be anticipated, leptin levels were higher in obese than in non-obese OSA patients (4.49 [3.59–5.26] vs. 3.36 [2.38–4.68] ng mL−1, p = 0.001), whereas active TGF-β1 levels did not differ between subgroups of OSA patients (Table S1).