The Link Between Two Respiratory Disorders Is Strengthening
According to the results of a long-term observational study, individuals with asthma have a higher likelihood of developing obstructive sleep apnea (OSA) compared to those without asthma. In addition, the risk of developing sleep apnea accompanied by excessive daytime sleepiness is approximately three times higher among people with asthma. The study findings were published on January 13 in the Journal of the American Medical Association (JAMA), further reinforcing the connection between the two respiratory disorders.
Previous research had suggested an association between asthma and sleep apnea; however, most earlier studies were based primarily on self-reported data. The new study relies on objective laboratory-based measurements, providing more reliable evidence in this field. Nevertheless, it remains unclear whether asthma directly causes the development of sleep apnea.
What Is Obstructive Sleep Apnea?
Obstructive sleep apnea is characterized by temporary narrowing or blockage of the upper airways during sleep, leading to brief pauses in breathing. This condition reduces oxygen supply to the brain and disrupts normal sleep patterns.
According to the Centers for Disease Control and Prevention, approximately 39.5 million people in the United States have been diagnosed with asthma. The National Sleep Foundation estimates that around 18 million Americans suffer from sleep apnea.
Study Methodology
The research was based on data from the Wisconsin Sleep Cohort Study. In this long-term cohort study, participants have undergone laboratory-monitored sleep studies (polysomnography) every four years since 1988.
The study compared:
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81 participants with existing asthma,
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466 participants without asthma who had been followed for at least four years.
The analysis adjusted for the following variables:
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Age and sex
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Body mass index (BMI)
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Smoking status
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Alcohol consumption
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Chronic nasal congestion
Key Findings
After statistical adjustments:
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During the first four-year period, the risk of developing obstructive sleep apnea was 39% higher in the asthma group.
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The risk of apnea accompanied by daytime sleepiness was 2.7 times higher.
Approximately two-thirds of participants were followed for more than eight years. Long-term analysis revealed that:
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49% of individuals with asthma developed obstructive sleep apnea,
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Compared with 28% among those without asthma.
Possible Mechanisms
Researchers suggest that several shared pathophysiological mechanisms may explain the association, including:
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Chronic airway inflammation
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Structural weakness of the upper airways
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Nasal congestion
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Obesity
Inflammatory processes are believed to play a particularly important role in both asthma and sleep apnea. However, the level of airway inflammation was not directly measured in this study.
Clinical Significance
These findings suggest that screening for sleep apnea may be appropriate in patients diagnosed with asthma. Likewise, in patients with sleep apnea, it is important to evaluate for uncontrolled asthma symptoms.
A deeper understanding of the interaction between asthma and sleep apnea may contribute to:
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The development of more effective treatment strategies,
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Earlier detection of comorbid conditions
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Improved quality of life for patients.