What causes obstructive sleep apnea?

OSA is caused by a temporarily constricted airway, which interrupts breathing. During sleep, muscles become more relaxed, including those in the throat that help to keep the airway open. Although more relaxed, muscles in the throat are normally able to keep the airway open during sleep. In people with OSA, the airway is more constricted and becomes temporarily blocked, preventing breathing.^[1] The blockage can be caused by several factors, including individual physiology — some people have naturally narrow airways due to a large tongue, or large tonsils and adenoids. Having a large neck circumference also increases the risk for OSA^[2], as does obesity.^[3] Chronic inflammation may also play a causal role in developing OSA, but the mechanisms are not well-understood. One observational study found that increased inflammation during childhood may be a possible link between visceral body fat levels and developing OSA in adolescents.^[4]