What are the common risk factors of developing sleep apnea?

Risks for developing sleep apnea are largely dependent on the type of sleep apnea. While there are several subsets of sleep apnea, they generally fall into physical (obstructive) and neurological (central) classifications, although mixed sleep apnea combines problems of both classifications. Obstructive sleep apnea and central sleep apnea have different risk factors.

The risk to develop obstructive sleep apnea is related to the presence of one or more of the following factors:

• Being overweight or obese - Weight gain can happen in the throat as well as in other tissue, which can narrow the airways and make breathing especially difficult once the body relaxes during sleep.
• Ageing - The throat muscles can lose their elasticity and tend to sag as people age.
• Upper airway restrictions - Smaller upper airways can lead to the development of sleep apnea. This can be caused by nasal congestion from allergies, enlarged tonsils and adenoids, or just a tight throat and thick neck.
• Family history - Having a family history of sleep apnea is often an indicator an individual will develop sleep apnea symptoms.
• Gender - Men have a double risk of developing sleep apnea compared with women. However, menopausal women have a higher risk than younger women, although the exact reason behind this is unknown.
• Substances consumption - Alcohol and medication (i.e. sedatives) that relax the throat muscles, and smoking, which can triple risk, are all introduced substances that can increase the chance of a person developing sleep apnea.

There is some evidence that genetic factors especially related to race and ethnicity may also have a link with sleep apnea but there is no robust evidence available so far.

In addition, sleep apnea is associated with several conditions such as pregnancy, end-stage renal disease, hypertension, chronic lung disease, metabolic syndrome, insulin resistance, and diabetes.

Central sleep apnea is a neurological type of sleep apnea and while it has some common risk factors with the obstructive sleep apnea classification, such as ageing, gender, and sedating opiates, it also has other specific risk factors.

• Heart disorders including atrial fibrillation and congestive heart failure may increase the risk.
• Brain diseases including tumors and lesions, as well as stroke, which causes the brain to loose its capacity of breathing regulation.
• Living at a high altitude can cause a temporary central sleep apnea in some cases.
• Continuous positive airway pressure (CPAP) machines used to treat obstructive sleep apnea can sometimes cause a secondary central sleep apnea although the exact relationship of these events is not yet understood.