LEP and obstructive sleep apnea syndrome: These data suggest that CIH and the resulting increased plasma leptin levels may not only contribute to long-term deleterious effects observed in overweight and obese patients (Phillips and Cistulli, 2006; Gileles-Hillel et al., 2016; Figure 8), but may also impact non-overweight patients with OSA as these patients also display increased circulating levels of leptin and associated cardio-metabolic disorders over time (Pamidi et al., 2012).