LEP and Central hypoventilation: There is growing evidence to support a role for leptin resistance in inducing or driving OHS.[42–46] In a recent paper by Campo et al., a total of 245 obese subjects underwent detailed testing, and it was found that hyperleptinemia was associated with a reduction in respiratory drive and hypercapnic response, irrespective of the amount of body fat, which suggests the extension of leptin resistance to the respiratory center.[47] Various forms of SDB have been implicated in the pathogenesis of OHS, including OSA, central hypoventilation and upper airway resistance syndrome.