New research has uncovered a significant link between sleep apnea and early cognitive decline in middle-aged men, irrespective of their overall health or weight. The study, which focused on non-obese men without other health conditions, revealed notable impairments in various cognitive functions such as executive functioning, visuospatial memory, vigilance, sustained attention, impulse control, and social cognition.
Recent evidence suggests that sleep apnea, specifically obstructive sleep apnea (OSA), can lead to cognitive impairments in middle-aged men, regardless of the presence of other health conditions or obesity.
Obstructive sleep apnea is a potentially hazardous condition in which the throat muscles become relaxed during sleep, causing a disruption in the airflow to the lungs and leading to frequent episodes of breathing cessation. Symptoms of OSA include disturbed sleep, loud snoring, daytime fatigue, and recurring morning headaches, which can significantly impact the lives of both sufferers and their partners.
Currently, OSA is underdiagnosed, with estimates suggesting that it may affect around 15 to 30% of men and 10 to 15% of women globally, totaling approximately 1 billion adults. Astonishingly, about 80% of these individuals are likely unaware of their condition. Key risk factors for OSA include advancing age, obesity, tobacco use, chronic nasal congestion, high blood pressure, and being male.
A recent study conducted by researchers from the UK, Germany, and Australia has unveiled groundbreaking findings, indicating that OSA can lead to early cognitive decline in middle-aged men, even in the absence of comorbidities or obesity. The study’s outcomes were published in the journal Frontiers in Sleep.
Dr. Ivana Rosenzweig, the lead author of the study and a neuropsychiatrist heading the Sleep and Brain Plasticity Centre at King’s College London, stated, “We have observed poorer executive functioning and visuospatial memory, deficits in vigilance, sustained attention, psychomotor skills, and impulse control in men with OSA. Most of these deficits were previously attributed to other health conditions.” Dr. Rosenzweig also noted, “Furthermore, our research has demonstrated for the first time that OSA can significantly impair social cognition.”
The study focused on a unique cohort of 27 men, aged 35 to 70, who had recently been diagnosed with mild to severe OSA, but without any comorbidities. This group is relatively uncommon, as most individuals with OSA also have other health conditions like cardiovascular and metabolic diseases, stroke, diabetes, chronic inflammation, or depression.
The men in the study were not smokers or heavy drinkers and were not classified as obese, with a body mass index (BMI) below 30. For comparison, the researchers also included a group of seven men matched in terms of age, BMI, and education who did not have OSA. The diagnosis of OSA was confirmed through a WatchPAT test that assessed respiratory function during sleep at home, as well as video-polysomnography conducted at King’s College sleep center. The latter method involved measuring brain waves using electroencephalography (EEG) while monitoring blood oxygen levels, heart rate, breathing patterns, and eye and leg movements.
The researchers evaluated the cognitive function of the participants using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and found that patients with severe OSA performed worse than the control group in vigilance, executive functioning, short-term visual recognition memory, and social and emotional recognition. Patients with mild OSA performed better than those with severe OSA but worse than the control group in these domains.
The authors of the study concluded that OSA alone is sufficient to cause these cognitive deficits, which previous studies had associated with the common comorbidities of OSA, such as hypertension, cardiovascular and metabolic diseases, and type 2 diabetes.
The exact mechanism through which OSA leads to premature cognitive decline remains unclear. The authors speculated that intermittent low oxygen and high carbon dioxide levels in the blood, alterations in blood flow to the brain, sleep fragmentation, and neuroinflammation in OSA patients may contribute to the cognitive deficits observed. Dr. Rosenzweig explained, “This intricate interplay is still not fully understood, but it is likely that they result in widespread changes in the brain’s structure and function, leading to cognitive and emotional impairments.”
It is yet to be determined whether comorbidities have similar negative effects on cognition beyond those directly caused by OSA.
Dr. Rosenzweig emphasized, “Our study serves as a proof of concept. However, our findings suggest that comorbidities likely exacerbate and perpetuate the cognitive deficits directly caused by OSA itself.” Further research is needed to ascertain whether comorbidities have an additive or synergistic impact on these deficits and whether differences exist in the brain circuitry of OSA patients with or without comorbidities.
The study received funding from the Wellcome Trust.
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Frequently Asked Questions (FAQs) about Sleep apnea
What is obstructive sleep apnea (OSA)?
Obstructive sleep apnea (OSA) is a potentially dangerous health condition characterized by the relaxation of throat muscles during sleep, leading to the obstruction of airflow to the lungs and frequent pauses in breathing. It is often accompanied by symptoms such as disturbed sleep, loud snoring, daytime fatigue, and morning headaches.
Does sleep apnea only affect obese individuals?
No, sleep apnea can affect individuals regardless of their weight. While obesity is a known risk factor for sleep apnea, the recent research mentioned in the text highlights that middle-aged men without obesity can also experience cognitive decline associated with obstructive sleep apnea.
Are cognitive impairments solely attributed to other health conditions?
Previous studies attributed cognitive impairments observed in individuals with sleep apnea to co-existing health conditions like hypertension, cardiovascular diseases, and diabetes. However, the new research indicates that obstructive sleep apnea itself can directly cause cognitive deficits, even in the absence of these comorbidities.
Is obstructive sleep apnea commonly diagnosed?
Obstructive sleep apnea is underdiagnosed, with estimates suggesting that a significant percentage of the population may be affected by it. Approximately 15 to 30% of men and 10 to 15% of women globally are believed to have sleep apnea, and alarmingly, about 80% of these individuals may be unaware of their condition.
How does obstructive sleep apnea lead to cognitive decline?
The exact mechanism behind the relationship between obstructive sleep apnea and cognitive decline is not fully understood. However, it is hypothesized that intermittent low oxygen and high carbon dioxide levels, changes in blood flow to the brain, sleep disruption, and neuroinflammation in sleep apnea patients may contribute to the observed cognitive deficits.
What implications does this research have?
The research highlights the need for increased awareness and early intervention for sleep apnea, as it can have detrimental effects on cognitive function, even in otherwise healthy individuals. It underscores the importance of diagnosing and treating sleep apnea promptly to prevent or minimize cognitive decline.
More about Sleep apnea
- “Frontiers in Sleep” journal: Link
- Wellcome Trust: Link
- Cambridge Neuropsychological Test Automated Battery (CANTAB): Link
