People Who Snore May Be at Increased Risk of Cancer and a Decline in Mental Processing Powers

A significant study that was presented on September 5 at the European Respiratory Society (ERS) International Congress in Barcelona, Spain, found that people with obstructive sleep apnea (OSA) have a higher chance of developing cancer. [1] Loud snoring is a common sign of obstructive sleep apnea, while not everyone who snores has the disorder.

A second study discovered a connection between OSA and a loss in cognitive abilities in the elderly. Some cognitive tests revealed a greater deterioration in men and those 74 years of age or older. According to a third study, patients with more severe OSA were more likely to experience blood clots in their veins, a condition that could be fatal.

People with OSA frequently experience partial or total obstruction of their upper airway while they sleep, which results in frequent breathing pauses. This frequently leads to daytime lethargy, loud snoring, gasping, and choking. OSA is thought to affect between 7 and 13 percent of people. The disorder is particularly common in those who are overweight or obese, have diabetes, smoke, or drink a lot of alcohol.

The first study's presenter, Dr. Andreas Palm, is a senior consultant and researcher at Sweden's Uppsala University. It is previously known that people with obstructive sleep apnea have a higher risk of developing cancer, but it is unclear whether this is attributable to OSA itself or to other cancer-related risk factors such obesity, cardiometabolic disease, and lifestyle choices. Our findings demonstrate an independent link between cancer and oxygen deprivation brought on by OSA.

Five years before OSA treatment in Sweden began, data from 62,811 individuals were examined by Dr. Palm and colleagues. Continuous positive airway pressure (CPAP), which delivers a positive pressure of air through a mask to keep the airways open while you sleep, was used to treat patients between July 2010 and March 2018. The researchers combined these data with those from Statistics Sweden's socioeconomic database and the Swedish National Cancer Registry.

The investigators took into account elements that might have an impact on the findings, including socioeconomic status, body size, and other health issues. A control group of 2,093 patients with OSA but no cancer was matched with 2,093 patients with OSA and a cancer diagnosis that had occurred up to five years earlier. The apnea-hypopnea index (AHI), which counts the number of breathing interruptions while sleeping, or the oxygen desaturation index (ODI), which counts the number of times an hour the blood oxygen levels fall by at least 3% for ten seconds or longer, were used to assess the severity of OSA.

According to an average apnea-hypopnea index of 32 as opposed to 30, as well as an oxygen desaturation index of 28 as opposed to 26, he stated, "we observed that individuals with cancer had slightly more severe OSA." ODI was higher in patients with lung cancer (38 versus 27), prostate cancer (28 versus 24), and malignant melanoma, according to a further examination of subgroups (32 versus 25).

The results of this study show that untreated sleep apnea should be taken into account as a risk factor for cancer and that clinicians should be aware of this potential when treating OSA patients. Our study's findings, however, do not support or advise expanding cancer screening to all OSA patients.

The study could not prove that OSA causes cancer; rather, it could only demonstrate that it is related to cancer because it only examined data at a single point in time. The study did not capture several crucial lifestyle aspects on an individual basis, such as eating preferences and physical activity. The study's key advantages are its magnitude and the excellent data on cancer detection and OSA.

In order to investigate potential effects of CPAP therapy on cancer incidence and survival, Dr. Palm and his associates intend to expand the patient population and monitor them over time in the future. In comparison to the link with conditions of the heart and blood vessels, insulin resistance, diabetes, and fatty liver disease, he noted, the relationship between OSA and cancer is less well established. Therefore, more research is required. We hope that our work will inspire other academics to investigate this crucial subject.

In a subsequent presentation[2], Professor Raphael Heinzer, the director of the Centre for Investigation and Research on Sleep (CIRS) at Lausanne University in Switzerland, informed the congress that a study led by Dr. Nicola Marchi, a colleague, revealed a link between OSA and a greater decline in mental processing abilities over a five-year period.

People 65 and older from the Lausanne general population who were enrolled in the CoLaus/PsyCoLaus and HypnoLaus studies between 2003 and 2008 and who were followed up every five years were the subject of a study conducted by Professor Heinzer, Dr. Nicola Marchi of the Lausanne University Hospital, and colleagues. When they signed up for the trials, a total of 358 participants had a sleep test to determine whether they had OSA and how severe it was. Their ability to process information was also examined during the initial follow-up between 2009 and 2013, and a new cognitive assessment was performed during the second follow-up five years later.

The cognitive tests evaluated verbal memory, language, language processing speed, processing speed (time taken to understand and react to information), executive function (ability to organize thoughts and activities, prioritize tasks, and make decisions), global cognitive function (knowledge and reasoning skills), executive function, and spatial relationships between objects perception in the visual field (visuospatial function).

"We discovered that OSA and, in particular, reduced oxygen levels during sleep due to OSA, was related with a higher loss in general cognitive function, processing speed, executive function, and verbal memory," Dr. Marchi stated in a speech to the congress. In several specific cognitive tests, we also discovered that men and those 74 years of age and older had a higher risk of cognitive loss associated to sleep apnea.

For instance, the verbal fluency test revealed a steeper decline in men only, but not in women, while the Stroop test, which assesses processing speed and executive function, revealed a steeper decline in participants aged 74 and older compared to younger participants.

This study shows that nighttime oxygen deprivation and the severity of sleep apnea both lead to cognitive deterioration in old age. Additionally, it demonstrates that sleep apnea is not associated with a loss in all cognitive processes; for example, language and visuospatial function were not impacted, according to Dr. Marchi. These cognitive skills include verbal memory, executive function, and processing speed.

"Doctors and patients with OSA should be informed that OSA may contribute to cognitive deterioration. Continuous positive airway pressure (CPAP) therapy for OSA has not, as of yet, been conclusively shown to stop cognitive impairment. Our findings reveals that not all OSA patients have the same risk of cognitive decline; there is likely a subgroup of patients who could be at greater risk of OSA-related cognitive decline, including older patients and men as well as those who experience greater nocturnal oxygen deprivation, he added.

In order to learn more about who is more at risk of cognitive deterioration associated to OSA, the researchers want to study data on the effects of OSA after ten years. The next step, in Dr. Marchi's opinion, should be to conduct a randomized controlled trial with these individuals to look into how CPAP affects cognition.

The study's strengths include the fact that participants were monitored over a five-year period, OSA was diagnosed using the "gold standard" polysomnography test, and a variety of tests were employed to examine a range of cognitive activities. The fact that the participants were generally in good health and free of dementia or significant cognitive impairment is a limitation, as is the fact that OSA was only evaluated at the start of the trial.

Professor Wojciech Trzepizur of the Angers University Hospital in France presented a third study,[3]. It shown that individuals were more likely to experience venous thromboembolism (VTE), also known as blood clots, when their OSA was more severe, as determined by the AHI and other indicators of nocturnal oxygen deprivation. 104 VTEs were formed in 7,355 patients who were observed for more than six years.

This study is the first to look into the relationship between spontaneous venous thromboembolism incidence and obstructive sleep apnea. We discovered that individuals with blood oxygen levels below 90% of normal for more than 6% of the night had a nearly two-fold increased chance of developing VTEs compared to those who did not experience oxygen deprivation, stated Professor Trzepizur. "More research is needed to determine whether proper OSA treatment, such as CPAP therapy, can lower the incidence of VTEs in patients with significant nocturnal oxygen deprivation." [4]

Head of the ERS specialized group on sleep-disordered breathing and Professor Winfried Randerath of the Bethanien Hospital at the University of Cologne in Germany, he was not engaged in any of the three investigations. These three research reveal unsettling connections between obstructive sleep apnea and significant illnesses that have an impact on survival and quality of life, he said. According to the findings, sleep apnea has a connection to cancer, venous thromboembolism, and mental health. People should be made aware of these connections and strive to make lifestyle adjustments to lower their risk of OSA, such as by keeping a healthy weight, even though it is impossible to definitively show that OSA causes any of these health issues. However, a formal diagnosis and course of treatment should be started if OSA is suspected. We anticipate more investigation that could help to determine whether OSA is responsible for some of the health issues identified in these studies.

By EUROPEAN LUNG FOUNDATION