In a 2019 retrospective chart analysis of 80 patients who underwent OSA surgery, 40 patients categorised as surgical responders (defined as decrease in the AHI of >50% from the pre-operative level and an AHI of less than 20/h in a follow-up sleep study at least 3 months post-operatively) demonstrated significantly improved metabolic profiles 3 months post-operatively, including reductions in LDL-C, triglycerides and leptin, without significant changes in BMI [97]. Here, LEP is linked to obstructive sleep apnea syndrome.