Sleep disorder doubles cancer risk

Sleep apnoea, linked with snoring and dangerous pauses in breathing, could almost double the risk of fatal cancer risk as those who sleep soundly, says a study.

The largest study of its kind found that sufferers with the highest oxygen deprivation in apnoea were at the highest risk. The sleep disorder is already linked to obesity, heart disease, diabetes, day-time fatigue and high blood pressure.

Sufferers are advised treatment because maintaining oxygen levels at night may reduce the risk of developing related illnesses. At least half a million Britons are affected, mostly middle-aged, overweight men, who may stop breathing hundreds of times a night.

The condition causes the muscles in the airway to collapse during sleep, cutting off breathing for 10 seconds or more before brain signals force the muscles to work again, the Daily Mail reported.

Spanish researchers studied more than 5,600 patients from seven sleep clinics, looking at the duration for which oxygen in a person’s blood dropped below 90 percent at night – a measure called the hypoxemia index. The patients, none of whom had a cancer diagnosis when the study began, were followed for seven years.

Researchers found that the greater the extent of hypoxemia, or oxygen depletion, the more likely a person would be to receive a cancer diagnosis during the study period.

Miguel Angel Martinez-Garcia, of La Fe University and Polytechnic Hospital in Valencia, Spain, said the cancer risk increased with the time spent without oxygen.

Severely affected sufferers who spent more than 14 percent of their sleep with levels of oxygen saturation below 90 percent had twice the risk of fatal cancer than those without sleep apnoea.

The findings were presented at the European Respiratory Society congress in Vienna, Austria.