Obstructive sleep apnoea (OSA) may raise the risk of cancer in women – but not men, according to research.
Greek scientists analysed data from 19,000 people to examine if there was a link between OSA and cancer.
They found cancer was more prevalent in women with sleep apnoea than those without. The trend did not exist in men, however.
The findings remained true when other cancer-causing factors, such as a high BMI, smoking status and alcohol consumption, were taken into account.
Millions of people around the world have OSA, which can cause snoring.
Snoring, feeling fatigued or having morning headaches could be linked to cancer, researchers in Germany have warned after conducting a study on more than 19,000 people
Experts said the findings should not alarm people who snore, and warned it is not the first time the link to cancer has been made.
Lifestyle changes can combat the condition, often caused by being overweight, smoking, or drinking too much alcohol.
Obstructive sleep apnoea, where the airways narrow during sleep and interrupts normal breathing, can have a big impact on quality of life.
HOW DOES SLEEP APNOEA AFFECT LIFE AND IS IT LINKED TO CANCER?
People with obstructive sleep apnoea (OSA) may not be aware they have the condition, as the symptoms are normally spotted by a family member or partner first when they hear the person snoring.
During an episode in the night, the lack of oxygen triggers your brain to pull you out of deep sleep – either to a lighter sleep or to wakefulness – so your airway reopens and you can breathe normally.
These repeated sleep interruptions can make the person feel very tired during the day, causing problems with performance at their job or at school.
Poorly controlled OSA may also increase the risk of developing high blood pressure (hypertension), having a stroke or heart attack, developing an irregular heartbeat – such as atrial fibrillation, developing type 2 diabetes – although it’s unclear if this is the result of an underlying cause, such as obesity.
Research has shown someone who has been deprived of sleep because of OSA may be up to 12 times more likely to be involved in a car accident.
One study by researchers at the University of Sydney Nursing School found that people with moderate to severe obstructive sleep apnoea could be 250 per cent more likely to develop cancer and more than three times more likely to die of the disease.
Another study, of about 1,500 government workers in Wisconsin, showed that those with the most breathing abnormalities at night had five times the rate of dying from cancer as people without the sleep disorder, the New York Times reports.
It affects between four and ten per cent of people in the UK, and in the region of 22million in the US, according to estimates.
The NHS states OSA could lead to high blood pressure, a stroke, heart attack, or developing type 2 diabetes.
Researchers from Aristotle University of Thessaloniki led the study, using data of 5,789 women and 13,767 men.
The study looked at how many times the volunteers experienced partial or complete airways closure per hour of sleep.
The experts also looked at how many times during the night the blood oxygen levels of participants dropped below 90 per cent.
The data showed that 388 people – two per cent – of the participants had been diagnosed with a serious cancer.
This included 160 women, 2.8 per cent of the total women, and 228 men, which is 1.7 per cent of all men in the group.
Scientists suggested a lower level of oxygen in the blood, caused by restricted breathing, could play a role in the development of cancer.
Dr Athanasia Pataka, co-author of the study, published in the European Respiratory Journal, said: ‘This area of research is very new.
‘And the effects of gender on the link between OSA and cancer have not been studied in detail before.
‘Our study of more than 19,000 people shows that severity of OSA is linked to a cancer diagnosis.
‘This link was especially strong in the women that we analysed, and less so in the men.’ She called for more trials to confirm the results.
The researchers also cautioned that the results not prove that OSA causes an increased risk of cancer.
Professor Anita Simonds, consultant in respiratory and sleep medicine at Royal Brompton and Harefield NHS Foundation Trust, was sceptical of the study.
She said: ‘In this study the overall cancer prevalence was low at just two per cent, therefore OSA patients should not be alarmed by this research.’
Men with OSA are more likely to be sleepy, snore, or stop breathing in the middle of the night.
Whereas women are more likely to feel fatigued, have insomnia, depression and morning headaches.
WHAT IS OBSTRUCTIVE SLEEP APNOEA?
Obstructive sleep apnoea (OSA) occurs when the walls of a person’s throat relax and narrow during sleep, blocking their airways.
This interrupts normal breathing, with symptoms including loud snoring, noisy and laboured breathing, and repeated episodes when breathing is interrupted by gasping and snorting.
OSA affects between four and 10 per cent of people in the UK. In the US, around 22 million are affected.
During an episode, the lack of oxygen triggers a sufferer’s brain to pull them out of deep sleep so their airways reopen.
These repeated sleep interruptions can make the person very tired, with them often being unaware of what the problem is.
Risks for OSA include:
- Being overweight – excess body fat increases the bulk of soft tissues in the neck
- Being male
- Being 40 or over
- Having a large neck
- Drinking excessive amounts of alcohol
- Being in the menopause – hormonal changes cause the throat muscles to relax
Treatment includes lifestyle changes, such as loosing weight, if necessary, and avoiding alcohol.
In addition, continuous positive airway pressure (CPAP) devices prevent the airway closing by delivering a continuous supply of compressed air through a mask.
A mandibular advancement device (MAD) can also be used, which is like a gum-shield that holds the jaw and tongue forward to increase the space at the back of the throat.
Untreated, OSA increases a person’s risk of high blood pressure, stroke, heart attacks and type 2 diabetes.