Obesity and Sleep Apnea: Understanding the Connection

As you undoubtedly know, quality sleep is crucial to many areas of health. Obstructive sleep apnea (OSA) is one of the most common sleep disorders.

The condition affects 39 million U.S. adults, according to the National Council on Aging.

It shares a complex relationship with obesity; its only truly reversible risk factor. This means that the treatment of obesity holds promise for helping the many people living with OSA.

What is Sleep Apnea?

OSA is a potentially life-threatening sleep disorder in which breathing significantly decreases or stops during sleep, usually due to a collapse of the airway.

OSA is medically defined as having at least 5 or more events called apnea-hypopnea index or AHI) . AHI represents the average number of apneic episodes (breathing stops completely or reduced to 10% of normal levels for at least 10 seconds) and hypopneic episodes (are when airways partially collapse by more than 30% for at least 10 seconds) over an hour. The most common clinical presentation is a person complaining of daytime sleepiness.

The prevalence of OSA increases as body mass index (BMI) increases. Neck circumference and waist-to-hip ratio also aid in diagnosis. In a study of almost 700 adults, a 10% increase in weight was associated with a six-fold increase in OSA risk.

In another study of more than 1,000 adults, moderate to severe OSA was found in 11% of men and 3% of women of normal weight, 21% of men and 9% of women who were overweight, and 63% of men and 22% of women who were obese.

OSA also occurs in nearly 60% of children with obesity. Each condition can exacerbate the other, so it is useful to consider them together.

The Connection Between Excess Weight and Sleep Apnea

Excess body weight contributes to sleep apnea by causing increased pressure on the upper airways from fatty deposits.

The pressure leads to collapse, decreased neuromuscular control, and decreased lung volume, making it more difficult to breathe. This is why factors like BMI and neck circumference are used as diagnostic criteria.

To be clear, individuals without obesity can have sleep apnea. Other risk factors include hypothyroidism, allergies, and deviated septum. However, the relationship between obesity and OSA can work in both directions.

Can Sleep Apnea Cause Weight Gain?

Just as weight gain may increase the risk for sleep apnea, untreated sleep apnea may indirectly cause weight gain.

Sleep disruption of any kind affects the circadian system.

An altered circadian system is associated with changes in eating patterns, which, in turn, may affect weight. It can also lead to hyperglycemia, high blood pressure, dyslipidemia, and an increased risk of heart attack and stroke. You can read more about this relationship in our Obesity Algorithm.

OSA, specifically, is associated with glucose intolerance and insulin resistance. Lipid abnormalities associated with OSA include high triglycerides and low HDL. Hormones related to obesity are also altered by OSA. Ghrelin, an appetite stimulant, is higher in patients with OSA.

Sleep deprivation tends to lower leptin production, a possible reason that poor sleep may contribute to obesity. Leptin, a hormone produced by adipose tissue, functions in the hypothalamus to signal satiety to the brain.

Adiponectin is another adipokine that improves glucose control and lipid metabolism and may reduce inflammation and atherosclerosis. Levels of adiponectin are reduced in both obesity and obstructive sleep apnea.

Another, perhaps shockingly, straightforward way in which OSA affects weight is that it can make someone too tired to exercise. Physical activity, one of the four pillars of obesity treatment, is important for maintaining a healthy weight.

Impact of Untreated Sleep Apnea

OSA is a chronic condition that requires a long-term treatment strategy. Treating OSA can improve energy levels, concentration, and mood. A Continuous Positive Airway Pressure machine (CPAP) is most commonly the first step in treating OSA.

Left untreated, OSA can have far-reaching health implications. A 2015 study published in the World Journal of Otorhinolaryngology-Head and Neck Surgery concluded:

“Undiagnosed and untreated obstructive sleep apnea syndrome can lead to abnormal physiology that can have serious implications, including increased cardiovascular disease, stroke, metabolic disease, excessive daytime sleepiness, workplace errors, traffic accidents, and death. These consequences result in significant economic burden.”

Some of the conditions that are already a concern for patients with obesity are also those linked with OSA.

For example, multiple studies have shown an association between sleep apnea and problems like type 2 diabetes, stroke, and heart attacks. The compounding effects of many of these conditions can even worsen obesity.

Can Weight Loss Cure Sleep Apnea?

Weight loss has been found to reduce the severity of sleep apnea as well as the development of the disorder.

Overweight and obesity remain the most important modifiable causes of sleep apnea. By maintaining a healthy weight, one can potentially avoid sleep apnea and other obesity-related disorders.

Reduction in weight by as little as 5-10% can potentially reduce the severity of sleep apnea that is already present and, in some cases, prevent its development.

Considerations When Treating People with OSA and Obesity

A patient may come to a doctor's visit already suspecting sleep apnea. They may be suffering from fatigue, have a partner who reports that they snore, or even have gathered information using a fitness tracker or smartwatch.

These devices can measure heart rate and, in some models, oxygen saturation. They also detect movement during sleep, which can point to a diagnosis of sleep apnea.

Often, however, a patient will simply complain of tiredness. You can then weigh multiple factors, as well as rule out other conditions, to determine if OSA is the right diagnosis.

Diagnosing Obstructive Sleep Apnea

Several physical factors may provide clues to a diagnosis of OSA. One is neck circumference. A neck circumference greater than 16 inches for a woman or 17 inches for a man is considered an indicator, as well as certain head and nasal abnormalities.

Other high risk medical issues include stroke, heart failure, hypertension, coronary artery disease, and dysrhythmias.

There are several validated questionnaires clinicians can use, such as the Berlin Sleep Questionnaire, the Epworth Sleepiness Scale, or the STOP-BANG Questionnaire.

Supporting a Patient with Obesity and OSA

It’s important to help a patient with both obesity and OSA understand that these conditions are related. They cannot expect to treat either in isolation. This may require getting them used to the idea of obesity as a disease and dispelling social stigma.

You can then assure them that there are multiple treatment options to try, including but not limited to weight loss. If the patient is struggling with insomnia, particularly if it may be related to a mental health issue, you might encourage them to seek a mental health practitioner to get help.

Treating Obstructive Sleep Apnea

A continuous positive airway pressure (CPAP) machine is most commonly the first step in the treatment of sleep apnea.

The CPAP machine has a pump that provides a positive flow of air into the nasal passages to keep the airway open. The pump is connected by a hose to a nasal or face mask.

Most people who use a CPAP machine feel immediate relief of symptoms and experience increased energy, improved mood and relief from morning headaches. In addition, a highly effective, long-term treatment for sleep apnea is weight loss. Even a 10% weight loss can result in a 20% improvement in the severity of sleep apnea.

Other, more conservative measures may help, such as oral appliances or behavior modification to improve the quality of sleep. The person may also benefit from stopping smoking or avoiding alcohol and other sedatives. Surgical treatments also exist.

Understanding Sleep Apnea and Obesity Together

Like obesity, sleep apnea is a multifaceted disorder with a range of interconnected causes and risk factors, and every patient will experience both a bit differently.

When you combine two different conditions of this nature, it takes a personalized and sensitive approach to find the right course of treatment.

To learn more about how best to support your patients with obesity, including those who may have OSA, consider purchasing a copy of the Obesity Algorithm or becoming an OMA member.