Obstructive sleep apnea in women

Too often unrecognized, undiagnosed and untreated

Category: Sleep Health & Disorders , Screening & Diagnosis

Topic: Comorbidities & Other Conditions, Primary Care & Sleep Health, Personalized Sleep Medicine, Symptoms & Presentation

Heart attacks, stroke, multiple sclerosis, and stress. These are just a few of the conditions in which female symptoms may vary from those of their male counterparts. It’s time to add obstructive sleep apnea (OSA) to that list and give women a fair chance at good sleep and good health.

Fatigue and a lack of energy. Insomnia and frequent nightmares. Depression, anxiety and gastric reflux. They might not be the symptoms that immediately spring to mind when someone mentions obstructive sleep apnea (OSA), but sleep experts increasingly think that they should be—at least for women.

OSA in women: Not your standard OSA

There’s a stereotype that OSA affects overweight men who snore loudly at night and nap during the day. It’s this stereotype that often prompts concerned women to take their snoring husbands to the doctor to seek sleep testing and treatment. And it’s this same stereotype that can dissuade women from seeking help with their ‘unladylike’ snoring.¹ Even more concerning, this stereotype means that sleep apnea is often not even on the radar when women raise concerns with their care teams. It’s time to move past the stereotype though, because sleep—and sleep apnea—can and does look different in men and women.

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How women’s anatomy and hormones impact sleep and sleep apnea

Compared to men, women generally need more sleep, take longer to fall asleep, and have more slow-wave sleep. They experience less disturbance from outside stimuli but are faster to waken if their breathing is disturbed. They have smaller tongues, shorter airways and less soft tissue in the airways. Pre-menopause, they have stronger, more stable airways during sleep and they’re less likely to have fat around the throat, stomach, and waist.¹

These factors mean that women with sleep apnea are less likely to snore loudly, their airways are more likely to remain at least partially open, and they are more likely to waken and ‘reset’ their breathing relatively quickly if they experience an apneic event. The result is a female-specific, ‘non-classic’, presentation of sleep apnea. It doesn’t look like the stereotypical sleep apnea people recognise in men, but it does cause ongoing, nightly sleep disturbances and reduced oxygen flow which can have a significant impact in women’s health and quality of life.

Sex-based differences in the presentation and prevalence of OSA fade post menopause due to changes in hormones, muscle tone, and airway physiology.² As a result, OSA prevalence increases significantly post-menopause³ and more women report stereotypical sleep apnea symptoms. The existence of a large cohort of women with easily recognisable symptoms may make it even more difficult for women with ‘non-classic’ symptoms to receive an appropriate diagnosis.

The trouble with non-specific OSA symptoms

While some women with OSA report ‘classic’ symptoms like excessive daytime sleepiness, snoring and witnessed apneas, many others report symptoms like insomnia, restless legs, nightmares, depression, and night-time palpitations and hallucinations.⁴ Because these non-specific symptoms of OSA in women do not appear to relate to sleep apnea but could reasonably have a range of other causes, these women run the risk of being misdiagnosed with conditions like depression, insomnia or hypothyroidism.⁵

Complicating this picture—and the diagnostic challenge— is the fact that women with OSA are, in fact, likely to have other comorbidities such as high blood pressure, high cholesterol, gastric reflux, type 2 diabetes, depression or asthma.⁶ These conditions can have similar symptoms to OSA and can mask or exacerbate each other. Obesity, for example, is strongly correlated with OSA and independently causes sleepiness and fatigue. It’s also correlated with cardiovascular problems and type 2 diabetes, which themselves are more prevalent in women with OSA.

"Women with OSA are, in fact, likely to have other comorbidities such as high blood pressure, high cholesterol, gastric reflux, type 2 diabetes, depression or asthma."

The challenge of identifying poor sleep as a root cause of a patient’s symptoms is only the first hurdle women with OSA face. Even if a sleep test is ordered, they run the risk of being misdiagnosed.

The trouble with AHI

OSA is diagnosed with sleep tests, conducted at home or in a sleep lab or clinic. Disease severity is scored using the apnea-hypopnea Index (AHI), which measures the number of apnoeas and hypopnoeas experienced per hour of sleep. Crucially, like many treatment and testing protocols, the AHI was developed and validated with male subjects. It measures the classic presentation of OSA: the gasps of the apnea, the oxygen desaturation of the hypopnea.

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As we know, anatomy and hormones result in a different presentation of obstructive sleep apnea in women, particularly before menopause. Women are likely to experience ongoing flow limitation during the night but have fewer, shorter apneas. Their hypopneas tend to have lower oxygen desaturation, because they waken and reset their breathing pattern before significant desaturation occurs.

The consequence is that, in women, the AHI is likely to under-report disease severity: shorter apneas and hypopneas with lower oxygen desaturation might not be scored as events; poor sleep in a clinic environment might mean that some women do not enter the REM stage where their events are often clustered; ongoing flow limitation is not identified as an issue. As a result, women may be told that their AHI is normal or that they have ‘mild’ or ‘very mild’ OSA, but they will still be experiencing significant symptoms that are impairing quality of life, mood and daytime functioning.⁷

Increasing access to effective treatment

Mild, moderate, and severe OSA in women and men is associated with an increased risk of a number of serious conditions, including hypertension, cardiovascular disease, gastric reflux, depression and anxiety, and type 2 diabetes. Interestingly, women with mild OSA have significantly worse quality of life symptoms than men when presenting at the sleep clinic.⁸

Despite this, women are less likely to be diagnosed and treated than men, even when they present with the same symptoms. This is important, as PAP therapy provides immediate treatment of OSA and can quickly alleviate troublesome symptoms, even in patients with mild OSA severity.⁸ Unfortunately, even women who are properly diagnosed with OSA consistently experience longer times to PAP treatment initiation compared to men.⁹

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Screening, diagnosis and treatment

The challenge of providing effective care to women with OSA starts with increasing awareness of the possible signs and symptoms of this condition among women and their physicians. The high symptomatic burden of even mild OSA, and the potential to significantly alleviate that burden through treatment, means that sleep should always be considered as a possible explanation of non-specific symptoms, particularly when the patient has comorbidities that commonly accompany OSA.

Women deserve careful scoring and testing for sleep apnea to ensure that they do not fall foul of a protocol that was developed before female-specific characteristics of this disorder were widely recognized. Work on patient phenotypes for women with sleep apnea¹⁰,¹¹ should, in time, contribute to better diagnosis and the development of more targeted screening tools.

Finally, women who are diagnosed with sleep apnea, even if it is mild, may have the potential to alleviate their symptoms and improve quality of life by treating their OSA.¹²

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