What Is Sleep Apnea Caused By? Risk Factors Explained

Sleep apnea is a common sleep disorder affecting millions of people worldwide. It is more common in middle-aged men than females or patients of other ages. If left untreated, it can be potentially serious and is characterized by repeated interruptions in breathing during sleep. 

There are two types of sleep apnea: obstructive (OSA) and central (CSA). OSA is the most common of the two types. It occurs when the tissue in the throat blocks or narrows the airway, resulting in reduced airflow to the lungs. 

CSA is less common and is often associated with other medical conditions, such as heart failure. CSA occurs when the brain fails to signal to the muscles to breathe whilst sleeping. The symptoms can vary in the two types of sleep apnea but both result in poor quality sleep and if left untreated, can have longer-term implications. 

Sleep apnea is caused by a combination of factors rather than by a single risk factor.  Common risk factors include obesity, certain medical conditions such as hypothyroidism and enlarged tonsils, and specific medications that can cause sleep apnea, for example, opioids and benzodiazepines. 

Certain anatomical features, such as overbite or underbite, can also cause sleep apnea. Recognizing these risk factors can help manage the condition more effectively.

Understanding the Causes of Sleep Apnea

Obstructive Sleep Apnea (OSA)

Obstructive Sleep Apnea (OSA) is the most common type of sleep apnea. It is estimated that approximately 1.5 million adults in the UK are affected by OSA, although many are undiagnosed and untreated. It occurs when the walls of the throat relax and narrow or collapse during sleep. This interrupts normal breathing, causing poor quality sleep, broken sleep, and hypoxia. Over time, this increases the risk of developing more serious health complications because it causes added strain to the heart. 

It can impact your quality of life by causing drowsiness and fatigue during the day as well as other symptoms related to lack of sleep, for example, headaches, loss of concentration, and impaired cognitive function. It can also impact mental health and well-being. 

The risk of developing OSA increases with age, and it is more common in middle-aged patients. Men are more likely to be affected than women. Obesity is often linked to OSA, and studies show that patients with a higher BMI have a greater risk of developing the disorder. Excess fat around the neck can increase the likelihood of the airway collapsing. Other anatomical features, such as a large tongue or a shorter lower jaw, can also increase the risk of OSA.

Studies also show that smokers have a higher risk of suffering from OSA compared to those who have quit or never smoked. Alcohol and certain medications can also be associated with an increased risk of OSA. 

Hormone abnormalities such as an underactive thyroid or increased production of growth hormone can increase the risk of OSA. Patients with certain medical conditions such as cardiovascular disease or respiratory disease, are also at greater risk. 

Central Sleep Apnea (CSA)

Central Sleep Apnea (CSA) is a less common form of sleep apnea caused by the brain's inability to send proper signals to the muscles responsible for breathing. This results in interrupted breathing during sleep. 

CSA not only causes poor quality sleep, but patients also experience shortness of breath, tightening in the chest, and overall discomfort throughout the night. CSA is usually associated with health conditions such as chronic heart failure, Parkinson's disease, stroke, and kidney failure. It is more common in patients over the age of 65, and it is more common in men than women.

Medications that affect the central nervous system, including opioids, benzodiazepines, and some antidepressants, can also cause CSA. Furthermore, being at high altitudes, where oxygen levels are lower, can impact the brain's ability to regulate breathing and contribute to CSA.

Complex Sleep Apnea Syndrome

Complex Sleep Apnea Syndrome, or treatment-emergent central sleep apnea (TESCA), is a combination of OSA and CSA. This means there is a narrowing or collapse of the airway and impaired signaling from the brain to the respiratory muscles simultaneously. This can be seen in patients undergoing continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) therapy. Even though the airway remains open due to treatment, central apneas may still occur, causing pauses in breathing.

There are many factors that can cause complex sleep apnea. This includes rapid or high adjustments of CPAP settings or mask air leaks. Patients with severe OSA, central nervous system dysfunction and heart failure often develop complex sleep apnea, as do those on opioid medications. 

Who Is at Highest Risk for Sleep Apnea?

Demographic and Lifestyle Factors

The likelihood of developing sleep apnea increases with age. OSA is more common in middle-aged patients, whereas CSA is more common in patients over the age of 65. 

Gender is another important factor. Men are twice as likely to have sleep apnea compared to women. However, women's risk increases after menopause, particularly within the first five years post-menopause.

Lifestyle choices also contribute to sleep apnea risk. Alcohol works as a relaxant and causes relaxation of the throat muscles, resulting in airway obstruction during sleep. Patients with sleep apnea should try to avoid alcohol completely, and everyone should try to avoid alcohol a few hours before bedtime to avoid such symptoms. Patients who smoke are also more likely to develop sleep apnea as a result of inflammation of the airway. With smoking cessation, this can be reduced. 

Physical and Genetic Factors

Physical characteristics are critical risk factors for sleep apnea. A larger neck circumference can pressure the airway, increasing the likelihood of collapse during sleep. Also, those with a naturally narrow throat or enlarged tonsils and adenoids are more likely to experience breathing difficulties during sleep.

Genetic predisposition also plays a role. A family history of sleep apnea or snoring significantly increases the risk, with studies suggesting a genetic link to the condition.

Certain medical conditions, including hypothyroidism (low thyroid hormone levels) and acromegaly (high growth hormone levels) can contribute to OSA. Craniofacial and upper airway abnormalities, such as a small lower jaw, also increase the likelihood of developing sleep apnea.

Compounding Effects of Sleep Apnea

Physical Health Impact

Sleep apnea must be diagnosed and managed effectively to prevent serious health complications. Not only does sleep apnea affect your daily life, but it can also result in irreversible damage to your physical health, particularly the cardiovascular system. Sleep apnea puts added strain on the heart whilst you sleep, and this can cause high blood pressure, heart disease, and even heart attack. 

Pauses in breathing trigger the release of stress hormones, which can cause atrial fibrillation and heart failure. This is because the repetitive cycle of breathing interruptions causes oxygen levels to drop and blood vessels to narrow, resulting in increased blood pressure. This causes increased strain on the cardiovascular system, resulting in heart disease and stroke.

Sleep apnea also affects metabolic health as it reduces the body’s response to insulin, causing metabolic syndrome and increasing the likelihood of weight gain, hypercholesterolemia, and type 2 diabetes.

Sleep apnea can worsen respiratory conditions like chronic obstructive pulmonary disease (COPD) and asthma. Repeated episodes of low oxygen levels can exacerbate symptoms, leading to increased shortness of breath and difficulty breathing.

Mental Health Consequences

Sleep apnea can have a significant negative impact on your mental health and well-being. Poor quality sleep or interrupted sleep can affect your daily life. It can affect your mood as well as your behavior. It may cause difficulty in concentration and impair your cognitive function. It can also cause psychological issues ,including anxiety, depression, and psychological distress. 

This is because poor-quality sleep reduces serotonin levels, a neurotransmitter crucial for regulating mood, sleep, appetite, and digestion. Reduced serotonin levels can reduce the release of melatonin, the hormone that regulates the sleep-wake cycle, causing further sleep disturbance. 

Research indicates that individuals with untreated sleep apnea are at a higher risk of developing these mental health disorders, with anxiety risk increasing by 3.68 times and depression risk increasing by 3.11 times.

Chronic sleep deprivation can also lead to more severe psychological symptoms such as hallucinations, paranoia, and even suicidal thoughts if left untreated.

Do You Have Signs of Sleep Apnea?

Sleep apnea is a common sleep condition affecting millions of patients worldwide. There are two types of sleep apnea: OSA and CSA. OSA is more common than CSA, and CSA is often associated with underlying medical conditions.

Both can have a significant negative impact on overall health and well-being. A range of factors can cause them. They are more common in middle-aged patients or older patients and affect men more than women. Obesity is a significant risk factor as well as confident lifestyle choices such as smoking and drinking. Particular medications can increase the likelihood of developing sleep apnea as can certain health conditions and physiological abnormalities.

If left untreated, sleep apnea can hurt your cardiovascular health, and it can result in irreversible complications such as heart attack and stroke. It can also have a huge negative impact on mental health and well-being.

To avoid these complications and enjoy good health and well-being, you must consult your doctor or health care professional immediately if you suspect that you may be affected by sleep apnea.