The findings are based on three studies conducted across Europe.

Snorers may be more likely to get cancer, cardiovascular disease, and dementia, according to new research.

A recent study by Swedish experts has revealed that obstructive sleep apnea, the major symptom of which is snoring, cuts off oxygen supply, feeding tumours, blood clots, and brain cell death.

Obstructive sleep apnea (OSA) is a disorder that causes the throat walls to relax and narrow, interfering with proper breathing while asleep. Overweight people are especially vulnerable to OSA, with experts noting preventative measures include weight loss and sleeping with a mask that blows air into the back of the throat.

The findings, which were presented at the European Respiratory Society (ERS) meeting in Barcelona, could lead to screening programmes and are based on three studies conducted across Europe.

“It’s known already patients with obstructive sleep apnea have an increased risk of cancer, but it has not been clear whether or not this is due to the OSA itself or to related risk factors for cancer, such as obesity, cardiometabolic disease and lifestyle factors,” says Dr. Andreas Palm, a researcher and senior consultant at Uppsala University, in a statement. 

“Our findings show that oxygen deprivation due to OSA is independently associated with cancer.”

The researchers examined data from 62,811 Swedes five years before they began using a CPAP (continuous positive airway pressure) mask to treat obstructive sleep apnea.

They combined it with data from the Swedish National Cancer Registry, accounting for body size, other health issues, and socioeconomic status. It allowed them to compare 2,093 patients with OSA and a cancer diagnosis up to five years prior to OSA diagnosis to a control group of 2,093 patients with OSA but no cancer.

The apnea hypopnea index (AHI), which counts breathing disturbances during sleep, or the oxygen desaturation index (ODI), which counts how many times per hour blood levels fall by at least 3% for ten seconds or longer, were used to determine severity.

“We found patients with cancer had slightly more severe OSA, as measured by an apnea hypopnea index average of 32 versus 30, and an oxygen desaturation index of 28 versus 26,” says Palm. “In further analysis of subgroups, ODI was higher in patients with lung cancer (38 versus 27) prostate cancer (28 versus 24) and malignant melanoma (32 versus 25).”

“The findings in this study highlight the need to consider untreated sleep apnea as a risk factor for cancer and for doctors to be aware of the possibility of cancer when treating patients with OSA,” said Palm. “However, extending screening for cancer to all OSA patients is not justified or recommended by our study results.”

“The association between OSA and cancer is less well established than the link with diseases of the heart and blood vessels, insulin resistance, diabetes and fatty liver disease,” adds Palm. “Therefore, more research is needed, and we hope our study will encourage other researchers to research this important topic.”

A second study found a link between OSA and a greater decline in brainpower over a five-year period. It was based on sleep tests completed by 358 people over the age of 65 in Switzerland.

Global cognitive and executive function, verbal memory, language, and spatial perception were all evaluated.

It was found that OSA and, in particular, low oxygen levels during sleep due to OSA, was associated with a greater decline in global cognitive function, processing speed, executive function and verbal memory. They also found that people aged 74 and older and men were at higher risk of cognitive decline related to sleep apnea in some specific cognitive tests.

The Stroop test, which measures processing speed and executive function, for example, revealed a steeper decline in people aged 74 and older when compared to younger participants. Men’s verbal fluency declined more rapidly than women’s.

A third study found that patients with more severe obstructive sleep apnea, as measured by AHI and nocturnal oxygen deprivation, were more likely to develop blood clots (venous thromboembolism), which can lead to heart attacks or stroke.

The findings were based on 7,355 patients who were followed for more than six years, 104 of whom developed blood clots.