Shining the Light on Breast Cancer Statistics–Literally


night shift and breast cancer

Pakhnyushchyy / Dollar Photo Club

Most solid cancers have a long list of well-documented ways to prevent them. Treatment, however, remains shaky. Breast, prostate, colon and pancreatic cancers are all very preventable.

But the lifestyle choices known to prevent these deadly cancers are not always easy.  Luckily, many of them are easy to implement and live by.  More troubling, however, are the risk factors that you may not be aware of or that you can’t change.

Exposures in the womb are something that you can’t go back and change.  It is established that chemicals like diethylstilbestrol (DES) that was given to pregnant women in the 1960s increased the risk of breast cancer in the moms as well as the female children later in life.  Other estrogen-like environmental chemicals like BPA and phthalates have been linked to breast cancer and it is highly likely that exposure in the womb would increase breast cancer rates later in life as well.

Things that happened to you as a teenager can have a lifelong effect on breast cancer rates.  You age when you started menstruation, how much sun exposure you got and how much soy you ate as a teen are all influential factors.

But what about your own personal circadian rhythms?

“My what?”

I’m not talking about a blues band from Atlanta.  I’m talking about your body’s daily rhythm as it pertains to day and night.  We are NOT nocturnal creatures.  We’ll leave that to the bats.  We should be sleeping at night.

Despite this, sleeping disturbances are quite common in society.  Insomnia, sleep apnea, restless legs, late nights and problems falling asleep plague society.  Much of this is because we are so stressed that we can’t relax enough at night to settle into a restful night’s sleep.

Then there are the midnight-shift workers and airline personnel that are frequently changing time zones.  This group of people have problems with their circadian rhythms because of their work schedules.

There are documented health problems that midnight shift workers experience.  Weight gain and obesity are on the top of the list.  Higher rates of breast cancer have also been demonstrated.

Which brings us to this particular article.  In it, researchers take a much deeper look at the relationship between sleep disturbances, light exposure at night and breast cancer risk.  In this study, female mice at an increased risk of breast cancer (along the lines of a BRCA mutation) were evaluated to see what kind of effect swapping dark and light exposure had on tumor growth over a lifetime.  At the end of each week, the mice were exposed to a full 24-hour period of either light or dark.

The results were a little shocking:

  • Switching up light and dark led to a decrease in the body’s ability to stop tumor growth, leading to an increased numbers of tumors that developed faster.
  • In addition, there was an increase in body weight.
  • These mice also slept much more, increasing sleep times by 50% (which led to a reduction in overall physical activity)

Based on this study, it is clear that messing up the normal day-night rhythms that we are all designed for creates problems.  There are a number of ways in which this might occur, such as:

  1. Suppression of the brain-protective melatonin by light exposure at night
  2. Stress from sleep disruption
  3. Alterations in lifestyle due to sleep disturbances (smoking, unhealthy diet, altered timing of food)
  4. Decreased vitamin D levels due to lack of sunlight exposure

Whatever the reason, the links continue to be proven.  If you are one of these people that gets exposed to light at night, here are some tips:

If you have a job that requires the midnight shift or lots of travel to different timezones, there may not be a lot you can do in this regard.  However, there is still a long list of lifestyle choices that go a long way to combat your sleep / wake cycle disturbances.  These choices become that much more important.


James Bogash

For more than a decade, Dr. Bogash has stayed current with the medical literature as it relates to physiology, disease prevention and disease management. He uses his knowledge to educate patients, the community and cyberspace on the best way to avoid and / or manage chronic diseases using lifestyle and targeted supplementation.