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Can a night work schedule increase the risk of cancer? How are sleep disturbances related to oncogenic factors? Sleep medicine specialist and clinical psychologist Michael Breus shares important and disturbing insights from recent research findings.
Restless, “fragmented” and irregular sleep is definitely associated with an increased risk of getting cancer – doctors have recently come to such a disappointing conclusion. While research to date does not answer all questions, the link between cancer risk and sleep problems is clear; it has been studied in breast, prostate, and thyroid cancers.
Dr. Michael Breus, clinical psychologist and sleep medicine specialist, believes that we should all stick to a routine that matches our body’s natural circadian rhythms. But sometimes this is hardly feasible due to the rhythm of life and work schedule.
Stress and overload, the abundance of monitors and artificial lighting at night are just some of the problems that we face on a daily basis. They interfere with the natural rhythm of alternating healthy sleep and wakefulness.
Due to their profession, many people are forced to adhere to a schedule that does not allow them to sleep at night. Accordingly, working in the evening, at night and in the morning, a person has to find time and opportunities for sleeping during the day – that is, when nature and society dictate to be active and awake. And for the body, this, as a rule, is not at all harmless.
Night work schedule as a possible risk factor
Scientists often invite such people as test subjects. The findings suggest that this social group is at greater risk of developing several types of cancer. In particular, breast cancer has been suggested to be associated with night work as well as exposure to artificial lighting during this time of day.
According to a 2018 study, women who worked long night shifts had a 19% higher overall risk of getting cancer compared to others. For certain types of diseases, including breast, gastrointestinal, and skin cancers, the risk was even higher. It increased with the increase in work experience in this mode.
The researchers found that every additional five years of night shift work resulted in a 3,3% increase in the likelihood of developing breast cancer. Because of this data, the International Agency for Research on Cancer and the World Health Organization now define night shift work as a probable carcinogen or carcinogen.
What is it with circadian rhythms?
Dr. Breus emphasizes that the risk of developing cancer can be increased if our sleep schedule does not match our natural circadian rhythms. They govern the sleep-wake cycles as well as many key bodily processes, including digestion, immune function, and hormone production. Disturbance of circadian rhythms is one of the main factors of restless, poor-quality sleep and its disorders.
Research has identified circadian disruptions associated with an increased risk of developing several types of cancer. In addition, they lead to chronic health problems and the development of depression and other mood disorders, as well as diabetes and obesity.
So is there a link between sleep disorders and cancer?
Sleep disorders: insomnia, restless legs syndrome and sleep apnea – affect both the amount of sleep and its quality. They can also be both a symptom and a contributing factor to disruption of circadian rhythms.
One study found a link between several common sleep disorders and an increased risk of cancer. It turned out that people with insomnia, obstructive sleep apnea and parasomnias have an increased risk of developing several types of cancer, including breast, oral and prostate cancer. Parasomnia includes a wide range of destructive manifestations, including tooth grinding, nighttime cramps, movement disorders, and nightmares.
“The associations between obstructive sleep apnea and cancer risk seem particularly strong,” says Dr. Breus. We know that sleep apnea is unhealthy for a number of reasons. It is dangerous for the brain and cognition, increases the risk of cardiovascular disease, obesity and diabetes, as well as accidental injury and death.”
Scientists still have a lot of work to do to better understand the link between sleep disturbances and the likelihood of getting cancer, and to determine exactly how sleep regulation can help reduce the risk of cancer.
About the Expert: Michael Breus is a clinical psychologist and spokesperson for the American Board of Sleep Medicine.