good point re: other factors. Stress is certainly connected to overall health, and working the swing shift can cause all sorts of stress...not the least, that caused by not being able to get sufficient sleep, as well as arranging day-care, accomplishing family chores, etc..

The connection seemingly sought here is the hormonal activity affected by natural light exposure and sleep patterns, and how that contributes to one's likelihood of cancer. It's interesting that it is breast, rectal and colon cancer specifically...all of these are actually related to fat consumption, too; do the night nurses eat from the vending machines more than the day shift? Most hospital cafeterias have round the clock access but I am sure some do not, and maybe salad bars and healthier options are not as readily available to the nightshift...or maybe since we are used to eating our "three squares" in daylight hours, night shift workers get by with sodas and candy and chips...

Most people exercise during the day; do night shift workers forgo exercise because it is too inconvenient or too dangerous etc. to do it at night? This would certainly be connected to cancer likelihood, especially the colo-rectal cancers, which are less common in those who exercise regularly.

Holistic healing traditions accept that the body has different systems which are at peak function, low function, or in a stage of renewal at certain hours of the day. For example, the liver renews itself (cells, resting after peak function, etc.) between 1 and 3 am, and working the night shift is bad for this because the liver achieves optimal renewal when the body is warm and at rest...the kidneys are at peak performance in the late afternoon, early evening, (3-7 pm) which is a good time to drink lots of water to flush them out...working the swing shift may disrupt this time-table...

I think that is an important distinction to be made here; are they night shift workers who always work nights? Or swing shift workers who must readjust their body clock every few days? I would think the latter is far more detrimental to one's health routine...

I had already sent this to a friend who works some night shifts as a respiratory therapist. Her response: "I'm eating my broccoli!"