Orexin: A potential role in the process of obstructive sleep apnea

► There is a close relationship between orexin and obesity, sex, age, smoking. ► The numbers of orexin neurons decrease with age, but the prevalence of sleep apnea increases with age. ► Obesity in OSA patient may be induced by decreased orexin neurons activity or orexin levels. ► Nicotine in cigarettes may have a positive effect on OSA because of the promotion on orexin neurons.