Snoring can raise Cancer risk five-fold • Daily Telegraph 20 May 2012
I’ve never been an alarmist but when I saw this headline by the Medical Correspondent of the Daily Telegraph, and then saw it once more, as a lead page on NHS Choices, who used the line:
Snorers ‘have higher cancer risk’ • NHS Choices 21 May 2012
I was concerned enough to investigate these claims more thoroughly and find their origin. The results were frankly, astonishing to read. Because it’s so important I want to include a lot of the detail as I think you’d like to read it.
What did the research involve?
Researchers looked at data collected from a Sleep study that featured 1,522 adults. Their sleep was thoroughly monitored in a sleep laboratory, and then followed up for 22 years. The researchers looked at whether those with sleep-disordered breathing (SDB), or in simple everyday language, Snoring, were more likely to die from cancer than those without.
The researchers categorised people as having normal sleep breathing, mild SDB, moderate SDB or severe SDB based on their score on a standard scale called the “apnoea-hypopnea index” (AHI). This score is calculated based on the average number of times per hour of sleep that a person’s nasal and oral airflow stopped for 10 seconds or more (apnoea), or how many times they have a detectable reduction in breathing and blood oxygen levels (hypopnea). Participants who reported using a device to treat apnoea (a “continuous positive airway pressure” (CPAP) machine) were considered to have severe SDB. This machine blows air into a sleeper’s airways through a special mask, preserving the flow of air into the lungs.
The researchers also asked people about severe daytime sleepiness, their alcohol consumption, smoking habits, general health, physical activity and recorded whether they had been diagnosed by a GP as having diabetes or sleep apnoea.
Each participant’s body mass index (BMI) was calculated at the start of the study.
Any deaths were identified from national and regional records. The researchers then analysed whether deaths from cancer were more common among those with SDB than those without the condition and they took into account factors such as age, gender, BMI and smoking, all of which could affect cancer risk.
I have kept the records of the results and they are available to you if required.
How did the researchers interpret the results?
They concluded that their findings suggested that Snoring or “sleep-disordered breathing” is associated with higher levels of cancer death and said that as this is the first study to report such an association, more studies are needed to confirm it. This is a worrying story evolving over 22 years. So how long do we have to wait for absolute proof? Is there time for you or I to wait for this further study? I think not.
Conclusion • Quoted from the Report
This study has suggested that there may be an association between severe sleep-disordered breathing and cancer mortality. However, there are the following limitations to consider:
- The number of people with severe sleep-disordered breathing in this study was small, as was the number of deaths from cancer. These small numbers mean that the results of the study may not be very reliable, as they are more susceptible to being influenced by chance. Larger studies will therefore be needed to confirm these findings.
- Sleep was only monitored once, at the start of the study, and may not be representative of a person’s long-term sleep breathing.
- The researchers took into account various factors that could be linked to both sleep-disordered breathing and cancer, such as obesity. However, even with adjustments these and other factors may still have affected the results. For example, the average BMI among the 39 people with severe sleep-disordered breathing was high, at 38.6 kg/m2 (a BMI of 30kg/m2 or above is considered obese, and a BMI of over 40kg/m2 morbidly obese).
- The study did not look at the risk of getting cancer; it only looked at risk of death from cancer.
Obviously these findings are of serious interest and even concern to all of us and also to Doctors, Clinics and Hospitals. Major Studies like this are not published on NHS Choices without them being important. However more evidence will definitely need to be gathered before a definite conclusion emerges. In the meantime we simply ask: Is there a possible link between Snoring and death from Cancer.
What was most significant to me however was that the link between Snoring and Cancer held true even after all their lifestyle adjustments for things such as smoking, alcohol, diet and weight.
And alarmingly, the link was stronger for those of a healthy weight than the obese. Snoring can be a simple thing to resolve with something as simple as a SleepPro mouthpiece so I ask myself “Why take this risk?”
By John Redfern