Obstructive sleep apnea (OSA) occurs when throat muscles collapse during sleep, inhibiting airflow, and can be a very serious, potentially fatal, condition.
Thanks to considerable scientific research, the symptoms and effects of OSA are much better understood and treatment methods, such as CPAP, have been developed. However, there is one glaring deficiency in most of the research studies: they were conducted predominantly or exclusively on men.
You might be thinking “Well it’s primarily a man’s condition, right?”. It is true that OSA affects men more frequently than women, with a 2 to 3:1 ratio, but it nevertheless poses a potential health risk to the women who do suffer from it.
Furthermore, as seen with other medical concerns such as heart disease and depression, men and women don’t necessarily express the same symptoms or effects, which can lead to decreased recognition and thus lack of needed treatment.
It has been estimated that >90% of women with moderate to severe OSA are undiagnosed.
So, let’s focus the sleep apnea spotlight on women. What are the symptoms, risks, and treatments for women? And how do these factors differ from sleep apnea in men?
Symptoms of Sleep Apnea in Women
The most common complaints made by OSA suffers, regardless of gender, are of snoring, snorting, gasping, observed apneas (breathing pauses caused by airway obstruction), and excessive daytime sleepiness.
Morning headaches, depression, and insomnia are additional symptoms that occur in women that are not or rarely seen in men. Physicians may inadvertently focus on these non-standard symptoms, which could divert diagnosis away from sleep apnea. This may explain why OSA diagnosis is heavily reduced in women.
Even more, women are less likely to be aware of apneic events, and therefore not complain of them to their doctor. The reason for this lack of awareness is not clear. Perhaps women who are bed-partners to men with sleep apnea are more sensitive to their partner’s disruptive behaviour and inform him in the morning, whereas men who are bed-partners to women with sleep apnea either sleep through the disturbances or are not bothered by them and don’t inform their female partner.
Another, less apparent symptom of OSA is hypercapnia, abnormally elevated CO2 levels in the blood, though blood work is necessary to reveal this.
Causes of Sleep Apnea in Women
Overall, the direct cause of sleep apnea is the same regardless of gender, age, or race: muscles in the back of the throat collapse during sleep, blocking air passage. This produces pauses in breathing that can last from 30 to 120 seconds before asphyxia wakes the sleeper and airflow is restored. This cycle, characterized by loud snoring and then moments of silence, may be repeated 200 to 400 times a night depending on OSA severity.
The indirect causes and symptoms are where gender differences start to appear.
Excess weight, notably obesity, is the predominant factor causing sleep apnea in both men and women. Excess weight is often stored around the neck, which puts pressure on the wall of the throat (the pharynx walls), and can lead to OSA. One study even found a correlation between neck size and OSA severity.
By the time that women develop clinical symptoms however, they are comparatively much more overweight than men. This is due to different fat distribution; men are more prone to upper-body weight gain, leading to more fat accumulation around the neck and earlier negative effects on airflow.
Menopause is another factor that studies frequently list as influencing the development of sleep apnea. The prevalence of sleep apnea is relatively high in postmenopausal women (~5.5%) in comparison to pre-menopausal women (~0.6%). Although, there is a significant reduction in prevalence in postmenopausal women on hormone replacement therapy (~1.1%)12, underlining a link between hormone levels and sleep apnea.
In one study, hormone treatments with progestin (synthetic progesterone) and estrogen reduced the number of apneas and hypopneas in all patients (all women), suggesting that these hormones are involved in protecting premenopausal women from sleep apnea.
Moreover, increased levels of androgens, hormones that control the development and maintenance of masculine characteristics (e.g. testosterone), saw an increase in OSA in women.
The correlations between OSA and androgens, progesterone, and estrogen may explain the higher prevalence in men and postmenopausal women.
Polycystic Ovary Syndrome (PCOS)
Polycystic ovary syndrome (PCOS) is another common disorder in which a woman’s sex hormones (progesterone and estrogen) are out of balance, and can lead to ovarian cysts, irregular periods, infertility, obesity, heart disease, and OSA.
This connection between PCOS and OSA is logical since OSA is heavily influenced by sex hormones; a decrease in progesterone and/or estrogen caused by PCOS may increase the risk of OSA in pre-menopausal women. Moreover, PCOS-caused weight gain could exacerbate this problem.
Hypothyroidism has also been linked to OSA, but studies are inconclusive on whether it is a causing factor.
Health Risks for Women with Sleep Apnea
The health complications caused by sleep apnea in women include excessive daytime sleepiness, depression, insomnia, lack of energy, high blood pressure, stroke, arrhythmias, heart disease, and potential death.
The severity of OSA is a large factor determining the likelihood of these complications. In multiple clinical trials, mild to moderate OSA was not associated with increased mortality.
Sleep apnea is also common in women suffering from coronary artery disease (CAD), and may be particularly hazardous to these individuals.
Sleep Apnea Treatments for Women
Weight loss, quitting smoking, and alcohol restriction are important health measures that can see improvement in sleep apnea. Weight loss is particularly crucial since it is the major cause of OSA in women.
Sleeping in the lateral sleeping position (on your side) also helps reduce sleep apnea events since the pharynx is less collapsible in the lateral position than the supine position (on your back). However, not everyone can sleep comfortably on their side, or remain in that position all night, and this may not stop apnea events entirely.
Getting checked for PCOS is another important measure that should be taken, particularly for pre-menstrual women.
Oral appliances, or mandibular advancement devices, are devices inserted into the mouth to modify the position of the jaw, tongue, and other structures in the upper airway. They prevent airway collapse and allow free airflow throughout the night. This is a good option for women since they are more likely to have treatment success with oral appliances than men. However, this treatment is generally more effective for women with mild to medium OSA.
In one study, hormone treatments with progesterone and/or estrogen saw a decrease in apnea events and waking episodes in women. Women already on estrogen replacement treatments were also less likely to have OSA. Additionally, administration methods are numerous (pill, cream, ring, patch, etc.).
Continuous Positive Airway Pressure
CPAP, or continuous positive airway pressure, uses air pressure to open the airway tract and prevent blockage. It is a common and effective treatment for OSA for both genders. See our article on CPAP for more information.
Surgery, such as soft palate surgery (UPPP), has the same efficacy in treating primary snoring as the above mentioned methods, but it is much more expensive and requires a recovery period. It also has a highly variable success rate in treating sleep apnea, and there is very little research on its effectiveness for women.
OSA is a serious condition that can negatively influence the well-being of women who suffer from it. It is important to be aware of the symptoms, particularly the gender-specific symptoms that might lead to miss-diagnosis, and the treatment options available for women.