An inadequate amount of sleep or irregular sleeping patterns have been known to lead to various health problems. Now, in a study by a team of researchers from the Netherlands, experts say that poor sleep patterns may also be linked to breast cancer, the BBC reported.

For about a year, researchers conducted tests on genetically-engineered mice and manipulated their body clock by delaying sleep for 12 hours weekly. One group was exposed to cycle inversions, while another group remained in a "stable light/dark environment."

In a typical cancer experiment, the mice subjects would have developed cancer tumors at 50 weeks. But the researchers discovered that when their sleeping patterns were affected, the mice developed cancer cells eight weeks earlier. In fact, at least 80 percent of the test subjects developed cancer, according to Medical Daily.

The researchers also noted that the mice with poor sleeping patterns gained weight by 20 percent.

Their findings is raising a crucial issue among shift workers, like flight attendants, who have to manage their work and sleep time schedules. Additionally, women who have a history of breast cancer in the family may increase their chances of developing the disease due to their sleep patterns.

"If you had a situation where a family is at risk for breast cancer, I would certainly advise those people not to work as a flight attendant or to do shift work," said Gijsbetus van der Horst, the researcher from the Erasmus University Medical Centre, according to BBC.

"The general public health message coming out of my area of work is shift work, particularly rotational shift work is a stress and therefore it has consequences. There are things people should be looking out for - pay more attention to your body weight, pay more attention to inspecting breasts, and employers should offer more in-work health checks," he recommended.

The assumption, however, poses some limitations as links to breast cancer in women may also be caused by other factors such as lifestyle and diet. Further studies will still be needed to draw out a concrete conclusion in relation to sleep patterns.

The study was published in the journal Current Biology.