Night Shift Work May Increase Risk of Breast Cancer

Working late night hours can be particularly taxing on your health, and according to a new study, working night shifts over a 30-year-period can actually double a woman's risk for developing breast cancer.

Canadian researchers with the Queen's Cancer Institute, the British Columbia Cancer Agency and other medical facilities, looked at 1,134 Canadian women who had developed breast cancer and compared them to 1,179 without the disease.

A link between about a third of the women who had developed breast cancer showed that they had a history of night shift work. And those who had a history of working nights for more than 30 years were twice as likely to develop breast cancer, according to study results.

"An association between more than 30 years of night shift work in diverse occupations and breast cancer is supported here, consistent with other studies among nurses," the authors note, according to the study.

Though researchers of the study and other previous works are still investigating these links, many health organizations, including the International Agency for Research on Cancer, have declared working night shifts carcinogenic to humans as it disrupts the circadian rhythm, also known as the body's biological clock.

Some also believe that a lack of melatonin could pose a risk, that can also disrupt sleep and cause a lack of vitamin D.

Aside from missing vitamins, late night work has also been linked to inactivity and poor diet that can lead to other help problems. 

More information regarding the study can be found in the journal Occupational and Environmental Medicine.