Night Shifts Linked to Cancer

A new cancer study may add new meaning to the term "graveyard shift." The finding suggest that night-time work can increase a person's risk of getting cancer.

Next month, an arm of the World Health Organization will classify shift work as a "probable" carcinogen.

That will put shift work in the same category as cancer-causing agents like anabolic steroids, ultraviolet radiation and diesel engine exhaust.

The American Cancer Society says it would likely add shift work to its list of "known and probable carcinogens" when the WHO makes its change.