Increased soft tissue deposits around the upper airway will reduce the size of the upper airway

There is a higher prevalence of OSA in males, which is partially due to physiological differences in gender, but also to progesterone levels. This gender difference neutralises when women reach menopause

Resulting in muscular and neurological loss of muscle tone of the upper airway

Temporary decrease in muscle tone caused by muscle relaxants, sedatives, anesthetics and opioid analgesics

Caused by traumatic brain injury, neuromuscular disorders, or other disorders

Structural features that reduce the size of the upper airway, including a receding jaw, large neck circumference, nasal congestion, brachycephaly. Characteristic features of genetic craniofacial syndromes may involve the nose, mouth, jaw and resting muscle tone. For example, in Down Syndrome there are some characteristic features of the syndrome that predispose to OSA, including an enlarged tongue, low muscle tone and a narrow nasopharynx

Certain irritants can cause inflammation of the upper airway, leading to narrowing. These include smoking and air pollution

Those with a family history of OSA are more likely to develop OSA

The upper airway have collections of lymphoid tissue, or tonsils, which act as a line of defence again inhaled and ingested pathogens. When these become enlarged (adenotonsillar hyperplasia) or inflamed (tonsillitis) this can occlude the upper airway

Certain conditions directly cause OSA, including acromegaly, androgen therapy, hypothyroidism and polycystic ovarian syndrome