Findings of a recently conducted study showed that irregular sleeping patterns can lead to cancer. Study researchers gave these findings after they conducted tests on mice. The reports presented in Current Biology raise concerns about the damaging impact of shift work on health.

The researchers stated that women with a family history of breast cancer should never work in shifts. The researchers used mice for the study and found that animals were 20% heavier despite eating the same amount of food.

Gijsbetus van der Horst, from the Erasmus University Medical Centre and one of the study researchers, in the Netherlands, said in a statement that if one had a situation where a family has had a breast cancer history, then in such case people are advised not to work as a flight attendant or to do shift work.

Experts said the link between irregular sleep and cancer is uncertain because the type of person who works shifts may also be more likely to develop cancer due to factors such as social class, activity levels or the amount of vitamin D they get.

As per researchers, normally the mice develop tumors after 50 weeks, but with regular sleep disruption, the tumors appeared eight weeks earlier.

According to the report, "This is the first study that unequivocally shows a link between chronic light-dark inversions and breast cancer development".

Dr Michael Hastings, from the UK's Medical Research Council, told the BBC, he wants the study to provide definitive experimental proof, in mouse models, that circadian disruption can accelerate the development of breast cancer.