The International Agency for Research on Cancer, the World Health Organization's back-up for cancer, will categorize shift work as a "probable" carcinogen by December.
The act will also put shift work in the same classification as cancer-causing agents like anabolic steroids, ultraviolet radiation, and diesel engine exhaust.
This would indicate a possible danger to millions of people worldwide, if the shift work theory provides evidences on its accuracy.
A cancer epidemiologist and professor at the University of Connecticut Health Centre, Richard Stevens, stated that it is an unexpected twist for an idea that scientists initially expressed as nutty or "wacky".
Steven's proposal in his 1987 published paper was attempting to assess why breast cancer incidence abruptly increase starting in the 1930s in developed societies, where graveyard shift job was considered a feature of growth.
However as years passed by, numerous explorations have proven that women working at night for a number of years have definite threats to cancer, and that animals who have their light-dark schedules switched grow more cancerous tumors and have higher risk of dying.
Some studies have also shown that men who work during night have a higher rate of prostate cancer.
These studies have been done mostly in nurses and airline staffs, which suggest more research in various populations for more considerable results.
Meanwhile, scientist are currently seeking for possible solutions to trim down shift worker's risk of getting cancer, one of which is taking melatonin as a supplement, but is not a long-term recommendation by the experts since the substance could damage the ability of the body to produce it in a natural way.
Stevens suggested: "The balance between light and dark is very important for your body," which entails that a darkened room for sleep should be the basic solution for these night-time workers.
