Sleep Apnea Linked with Increased Risk of Cancer Death, Growing Links to Cancers
Several new studies find links between this chronic breathing problem during sleep and cancer – sleep apnea risk highest in
Sept. 4, 2012 – Three new studies indicate a link between sleep apnea, a common disorder in which you have one or more
pauses in breathing or shallow breaths while you sleep, and cancer. The risk of this condition increases with age. A key study that finds an
association between sleep apnea and increased cancer deaths will be presented today.
Two further studies presented at the European Respiratory Society’s (ERS) Annual Congress in Vienna, Austria, also show
evidence suggesting an increase in cancer incidence among sleep apnea patients and an association between the spread of cancer and sleep
apnea. This research adds to evidence presented earlier this year highlighting a link between severe sleep apnea and cancer.
The risk of sleep apnea increases with age, according to the National Heart Lung and Blood Institute. About half of those
with this condition are overweight and it is more common in men than women. A family history of sleep apnea also increases the risk.
Sleep apnea usually is a chronic (ongoing) condition that disrupts your sleep.
The NHLBI also notes that about half with the problem have high blood pressure. It is also linked to smoking, metabolic
syndrome and diabetes. There is also a link to risk factors for stroke and heart failure.
First Study: Focused on cancer mortality
In the first study, over 5,600 patients from 7 different sleep clinics in Spain were analyzed to investigate the link
between sleep apnea and cancer mortality.
The severity of sleep apnea was then measured, using a hypoxemia index. This index measures the amount of time during the
night that a person suffers from low levels of oxygen in the blood (less than 90% oxygen saturation).
The results showed that people with sleep apnea who spent more than 14% of their sleep with levels of oxygen saturation
below 90% (usually severe sleep apnea patients) had approximately double the relative risk of death due to cancer (odds ratio 1.94), than
people without sleep apnea. The results showed that this association was even higher in men and younger people.
People with sleep apnea can be treated using continuous positive airway pressure (CPAP) therapy, which generates a stream
of air to keep the upper airways open during sleep. In the first study, patients who were not using this device consistently had an increased
relative risk (odds ratio 2.56) of death from cancer.
Lead author, Dr Miguel Angel Martinez-Garcia from La Fe University Hospital in Valencia, Spain, said: “We found a
significant increase in the relative risk of dying from cancer in people with sleep apnea. This adds to evidence presented earlier this year
that found for the first time a link between cancer and sleep apnea mortality.”
He emphasized, “Our research has only found an association between these disorders but this does not mean that sleep
apnea causes cancer.”
Second Study: All-type cancer incidence
Similar results were also found in the second study which showed an increase in all-type cancer incidence in people with
severe sleep apnea. The link was present even when factors such as age, sex, weight and other comorbidities of participants, were controlled
“Further studies are necessary to corroborate our results and analyse the role of CPAP treatment on this association,”
said lead author, Dr Francisco Campos-Rodriguez from Valme University Hospital in Seville, Spain.
‘We hope the findings of our studies will encourage people to get their sleep apnea diagnosed and treated early to help
maintain a good quality of life.”
Third Study: Spread of melanoma
In a third study, researchers used a mouse model of skin cancer (melanoma) to investigate tumor spread (metastasis) and
whether this was associated with sleep apnea.
The results showed that the spread of cancer was more abundant in mice that had been subjected to intermittent hypoxic
air, with low levels of oxygen as in sleep apnea, than those who breathed normal air during the experiment.
“The data from this study in animals strongly suggests a link between the spread of cancer and sleep apnea. This
provides strong evidence to encourage further study in this area to understand in more detail the links between sleep apnea and cancer,” says
lead author, Professor Ramon Farre from University of Barcelona, Spain.
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