The exact prevalence of<unk>  is unknown, and it is thought that many people with symptoms of<unk>  have not been diagnosed. About a third of all people with morbid<unk>  (a body mass index exceeding 40 kg/m2) have elevated carbon dioxide levels in the blood. When examining groups of people with obstructive sleep apnea, researchers have found that 10–20% of them meet the criteria for<unk>  as well. The risk of<unk>  is much higher in those with more severe<unk> , i.e. a body mass index (BMI) of 40 kg/m2 or higher. It is twice as common in men compared to women. The average age at diagnosis is 52. American Black people are more likely to be obese than American whites, and are therefore more likely to develop<unk> , but obese Asians are more likely than people of other ethnicities to have<unk>  at a lower BMI as a result of physical characteristics. It is anticipated that rates of<unk>  will rise as the prevalence of<unk>  rises. This may also explain why<unk>  is more commonly reported in the United States, where<unk>  is more common than in other countries.
Obesity hypoventilation syndrome
Central hypoventilation syndrome
Hyperventilation syndrome
Upper airway resistance syndrome
Reactive airway disease
Sleep apnea
Cardiac asthma
Central sleep apnea