Graveyard Shift Work Linked To Cancer

Like UV rays and diesel exhaust fumes, working the graveyard shift will soon be listed as a "probable" cause of cancer. It is a surprising step validating a concept once considered wacky. And it is based on research that finds higher rates of breast and prostate cancer among women and men whose work day starts after dark.

Scientists suspect that overnight work is dangerous because it disrupts the circadian rhythm, the body's biological clock. The hormone melatonin, which can suppress tumor development, is normally produced at night.

Having lower melatonin levels can raise the risk of developing cancer. Light shuts down melatonin production, so people working in artificial light at night may have lower melatonin levels.

Sleep deprivation may be another factor in cancer risk. People who work at night are not usually able to completely reverse their day and night cycles. Not getting enough sleep makes your immune system vulnerable to attack, and less able to fight off potentially cancerous cells.

Confusing your body's natural rhythm can also lead to a breakdown of other essential tasks. Certain processes like cell division and DNA repair happen at regular times.