How does sleep apnea increase heart disease risk?
How does sleep apnea increase heart disease risk?
Study Reveals the Link Between Sleep Apnea and Cardiovascular Risk
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A new study has shed light on the connection between obstructive sleep apnea and an increased risk of cardiovascular disease. The researchers propose that reduced blood oxygen levels during sleep, primarily caused by severe obstruction of the airways, may explain this link.
Understanding Obstructive Sleep Apnea
Obstructive sleep apnea occurs when the upper airway becomes blocked during sleep, leading to a reduction or complete cessation of airflow. Several factors can increase an individual’s risk of developing this condition, including obesity, large tonsils, and hormonal changes.
According to a 2020 study, approximately one-seventh of the global adult population is likely to have sleep apnea, making it the most common type of sleep-disordered breathing. Previous research has already established a connection between obstructive sleep apnea and increased cardiovascular risk, leading to significant morbidity and mortality.
Dr. Marishka Brown, director of the National Center on Sleep Disorder Research (NCSDR), highlights the impact of sleep problems, including sleep apnea, on cardiovascular health. She explains that “Sleep problems contribute significantly to cardiovascular morbidity, as well as all-cause mortality.”
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Unveiling the Mechanism: Reduced Blood Oxygen Levels
The new study, published in the American Journal of Respiratory and Critical Care Medicine, explores the mechanism behind the association between obstructive sleep apnea and cardiovascular risk. Researchers have found that reduced blood oxygen levels during sleep may be a key factor.
To measure the severity of obstructive sleep apnea, the Apnea Hypopnea Index (AHI) is commonly used. It calculates the number of apneas (breathing stoppages) and hypopneas (reduced breathing) per hour of sleep. However, the researchers argue that additional measures, besides the AHI, are necessary to fully understand and predict the impact of sleep apnea on individuals.
Dr. Brown, while not directly involved in the study, supports this perspective. She explains that “trying to identify the mechanisms underlying obstructive sleep apnea for an individual is really quite imperative to helping in the space of personalized therapy.”
The study highlights three physiological features of obstructive sleep apnea that contribute to the development of cardiovascular disease and mortality: hypoxic burden (reduction in blood oxygen levels), ventilatory burden (interruptions in breathing due to airway obstruction), and nighttime arousals (sudden wakefulness due to interrupted breathing).
Dr. Yu-Ming Ni, a cardiologist and lipidologist, comments that the three burdens have different effects on cardiovascular health. Disruptions to sleep, in these various forms, can impact an individual’s well-being.
Study Participants and Findings
The researchers analyzed data from two large studies, the Osteoporotic Fractures in Men Study (MrOS) and the Multi-Ethnic Study of Atherosclerosis (MESA), totaling over 4,500 middle-aged and older adults.
The findings revealed that a reduction in blood oxygen levels was associated with an increased risk of experiencing a cardiovascular event or dying from cardiovascular disease in both cohorts. The researchers emphasize that hypoxic burden acts as a strong and consistent predictor of cardiovascular disease and mortality.
It is worth noting that the high hypoxic burden observed in participants was primarily due to severe airway obstruction and not solely linked to factors such as obesity or reduced lung function.
Among participants in the MESA study, airway obstruction accounted for a 38% increase in the associated risk of a primary cardiovascular event. Similarly, among MrOS participants, airway obstruction contributed to a 12% increased risk.
Interestingly, sudden awakenings during sleep, a measure of nighttime arousals, showed different associations with cardiovascular outcomes between the two cohorts. While not associated with cardiovascular events in the MESA group, sudden awakenings were linked to cardiovascular-related deaths in the MrOS group.
However, of the three measures (hypoxic burden, ventilatory burden, and arousal burden), arousal burden was found to be the weakest predictor of cardiovascular disease and mortality.
Implications for Future Research and Treatment
The study’s findings have the potential to influence the assessment and treatment of sleep apnea. Researchers advocate for larger studies with longer follow-ups to gain a more comprehensive understanding of sleep apnea’s impact on individuals. The inclusion of younger individuals and those diagnosed with multiple illnesses would provide further insight.
Dr. Brown believes that the study’s results may lead to a shift in how sleep apnea is evaluated and how clinical trials are conducted. Considering the diverse mechanisms underlying sleep apnea in different individuals, personalized therapy becomes essential.
In conclusion, good quality sleep is crucial for overall health and well-being. Excessive daytime sleepiness or snoring should not be ignored, and individuals should consult their doctors if they experience these symptoms.
Dr. Ni stresses the importance of addressing sleep quality with patients, as sleep not only impacts physical health but also mental health. By initiating conversations about sleep, healthcare providers can improve their patients’ overall well-being.
Please note that the information provided here is based on the study mentioned and expert opinions. Consult a healthcare professional for personalized advice and treatment.
