Getting a Good Night’s Sleep Might Help Avoid Cancer

There are many things to worry about while lying awake in bed at night. A recent study has added something else to your list: avoiding cancer. Many people don’t sleep well at night due to an undiagnosed sleep disorder.

More than eighty different types of sleep disorders have been documented in the medical literature. You probably know someone with one of these disorders. Recent studies have documented that, unfortunately, most people are never correctly diagnosed with a sleep disorder. For this reason, the prevalence and comprehensive comorbidity of sleep disorders remain underestimated.

Several recent studies have uncovered a link between sleep disorders and impaired daytime cognitive function or mood disorders. But, a newly published study investigated whether having a sleep disorder is an independent risk factor for cancer.

The study initially enrolled 144,581 people who were diagnosed with a sleep disorder and 823,450 people who had not been diagnosed with a sleep disorder. Ultimately, researchers followed about two-thirds of these participants for 12 years.

Sleep disorders were categorized into sleep apneas and non-apneas. The latter group was divided into different types of insomnias. All the subjects were confirmed to have a preexisting sleep disorder at least two years before getting a cancer diagnosis. The final subject groups were also balanced for sex, age, years of diagnosis of their sleep disorder, income level, urbanization, general health status, Parkinson’s disease, asthma, hyperlipidemia, hypertension, liver cirrhosis, diabetes, COPD, smoking use, alcohol use, and obesity. This is the first study that investigated the effects of long-term preexisting sleep disorders on the risk of developing all cancers.

Researchers determined that the risk for all cancers, including breast and ovarian cancer, was significantly greater for subjects with a sleep disorder than those without a sleep disorder. Consistent with previous investigations, being male and older than 65 years were also significant risk factors for developing cancer.

What can explain the increased risk of cancers, particularly those of the breast and ovaries?

A few studies have suggested that reduced melatonin production may play a role in the carcinogenic effects of sleep disorders. The amount of melatonin released each night decreases linearly with aging. In addition, obesity, dysfunction of estrogen signaling pathways, and the disruption of circadian rhythms can lead to a loss of normal rhythmicity in the neuroendocrine and immune systems.

Soon after falling asleep, melatonin is released by the pineal gland. Melatonin has many roles, including controlling aspects of the circadian rhythm and sleep cycles. It is also thought that melatonin can reduce cancer progression via many different biological pathways, including stimulating the immune system and preventing cell proliferation.

Melatonin may have anti-estrogen actions via its ability to suppress estrogen production. Some authors have speculated that a lack of melatonin might explain why women with sleep disorders, particularly older women, are more vulnerable to breast and ovarian cancers. In addition, women with subjective sleep problems may have higher levels of inflammatory biomarkers than males with sleep disorders. Increased levels of pro-inflammatory proteins likely also contribute significantly to the risk of cancer.

If you think that you are not sleeping well, get evaluated soon. Your healthcare provider can help you get the treatment that might significantly reduce your cancer risk.