Uppsala, Sweden – New research shows that people who snore may be more likely to develop cancer, cardiovascular disease and dementia. Scientists in Sweden say that obstructive sleep apnea, in which snoring is the main symptom, cuts off the oxygen supply – fueling tumors, blood clots, and loss of brain cells.
Sleep apnea (OSA) affects about 30 million Americans — although only 6 million have been diagnosed, according to the American Medical Association. The condition causes the walls of the throat to relax and narrow, interrupting normal breathing several times at night. Individuals who are overweight are particularly susceptible to OSA. Preventive measures include losing weight or wearing a mask in bed that blows air into the back of the throat.
The findings, presented at the European Respiratory Society (ERS) meeting in Barcelona, could lead to screening programmes. They are based on three studies across Europe.
“It is already known that patients with obstructive sleep apnea have an increased risk of developing cancer, but it has not been clear whether this is due to the obstructive sleep apnea itself or risk factors associated with cancer, like obesitycardiovascular disease and lifestyle factors,” says Dr Andreas Palm, senior researcher and consultant at Uppsala University, in statement. “Our findings show that oxygen deprivation due to obstructive sleep apnea is independently associated with cancer.”
The study authors analyzed data from 62,811 Swedes five years before the start of treatment Sleep Apnea Using a CPAP (continuous positive airway pressure) mask. They combined it with information from the Swedish National Cancer Registry, taking into account body size, other health problems, and socioeconomic status. It enabled them to match 2,093 patients with OSA and Cancer diagnosis Up to five years prior to OSA diagnosis with a control group of 2093 patients with obstructive sleep apnea but without cancer.
Severity was measured using the sleep apnea index (AHI) – which counts breathing disorders during sleep – or the oxygen desaturation index (ODI), which measures the number of times per hour blood levels drop by at least three percent for ten seconds or more .
“We found patients with cancer to have slightly more severe obstructive sleep apnea, as measured by a mean hypoventilation index of 32 versus 30, and an oxygen desaturation index of 28 versus 26,” Palm says. In further analysis of the subgroups, ODI was higher in Lung cancer patients (38 vs. 27) prostate cancer (28 vs. 24) and malignant melanoma (32 vs. 25).
“The findings in this study highlight the need to consider untreated sleep apnea as a risk factor for cancer and for clinicians to be aware of the potential for cancer when treating patients with obstructive sleep apnea.” “However, extending cancer screening to all OSA patients is not justified or recommended in the results of our study.”
The researchers plan to increase the number of patients and follow up with patients over time to study the potential effects of PAP therapy on cancer incidence and survival.
The association between obstructive sleep apnea and cancer is less well established than it is heart disease blood vessels, insulin resistance, diabetes, and fatty liver disease,” Palm adds. “Therefore, more research is needed, and we hope that our study will encourage other researchers to investigate this important topic.”
The effect of obstructive sleep apnea on the brain
A second study identified a link between OSA and greater decrease in mental strength over five years. It was based on sleep tests conducted by 358 over-65s in Switzerland. Global perceptual and executive function, verbal memory, language, and visual perception of spatial relationships were also assessed.
“We found that obstructive sleep apnea, particularly lower oxygen levels during sleep due to obstructive sleep apnea, is associated with greater declines in global cognitive function, processing speed, executive function and verbal memory,” says Dr. Nicolas Marchi of the University of Lausanne. “We also found that people aged 74 or older and men were at increased risk of cognitive decline associated with sleep apnea on some specific cognitive tests.”
For example, the Stroop test, which measures processing speed and executive function, showed a sharper decline in people aged 74 or older compared to younger participants. Verbal fluency showed a sharp decline in men, but not in women.
This study demonstrates the severity of sleep apnea and nighttime oxygen deprivation Cognitive decline in old ageIt also shows that sleep apnea is associated with decreased specific cognitive functions, such as processing speed, executive function, and verbal memory, but not a decrease in all cognitive functions; for example, language and visuospatial function were not affected.
People with obstructive sleep apnea and their doctors should be aware that obstructive sleep apnea may play a role in cognitive decline. However, to date, treatment of obstructive sleep apnea with continuous positive airway pressure (CPAP) has not been clearly demonstrated to prevent cognitive decline. Our study indicates that it is likely that not all patients with OSA have the same risk of cognitive decline; There is likely to be a subset of patients, particularly those with more nocturnal hypoxia but also older patients and men, who may be at greater risk of cognitive decline associated with obstructive sleep apnea.”
The researchers plan to analyze data on the impact of obstructive sleep apnea after ten years to learn more about who is most at risk of cognitive decline. Dr. Marchi suggests that a randomized controlled trial with these patients in order to investigate the effect of CPAP on cognition should be the next step thereafter.
Increased risk of blood clots
A third study showed that patients with severe obstructive sleep apnea, as measured by AHI and markers of nocturnal oxygen deprivation, were more likely to have blood clots (venous thromboembolism) It can lead to heart attacks or stroke.
“This is the first study to investigate the relationship between obstructive sleep apnea and the occurrence of unexplained venous thromboembolism,” explains Wojciech Trzepizur, from Angers University Hospital in France. “We found that those who spent more than six percent of their time at night with oxygen levels in their blood below 90 percent of normal had a doubled risk of developing venous thromboembolism compared to patients without hypoxia. More studies are needed to find out. Whether appropriate treatment of obstructive sleep apnea, for example with CPAP therapy, may reduce the risk of venous thromboembolism in patients with marked nocturnal oxygen deprivation.”
The results were based on 7,355 patients followed for more than six years, 104 of whom developed VTEs.
Professor Winfried Randrath, of the Bethanian Hospital at the University of Cologne in Germany, is head of the ERS Group specializing in sleep-disorders of breathing and was not involved in the three studies. “These three studies show disturbing associations between obstructive sleep apnea and important diseases that affect survival and quality of life,” he says. Data support the importance of sleep apnea on cancer, venous thromboembolism and mental health. While they cannot prove that obstructive sleep apnea causes any of these health problems, people should be aware of these links and should try to make lifestyle changes in order to reduce their risk of obstructive sleep apnea, for example, by Maintain a healthy weight.
“However, if obstructive sleep apnea is suspected, specific diagnosis and treatment should be initiated,” he asserts. “We look forward to further research that may help clarify whether obstructive sleep apnea may be causing some of the health issues shown in these studies.”
Southwest News Service writer Mark Waghorn contributed to this report.